Mechanical Behavior of Polymers123
多尺度力学行为 英语
多尺度力学行为英语英文回答：Multiscale mechanics is a field of study that investigates the mechanical behavior of materials at multiple length scales. This field has become increasingly important in recent years due to the development of new materials and technologies that have made it possible to engineer materials with specific properties at different length scales.Multiscale mechanics can be used to study a wide range of materials, including metals, ceramics, polymers, and composites. At the smallest length scale, multiscale mechanics can be used to study the atomistic structure of materials. At larger length scales, multiscale mechanics can be used to study the microstructure of materials, including the grain size, grain boundaries, and defects. At the macroscopic length scale, multiscale mechanics can be used to study the overall mechanical behavior of materials,including their strength, stiffness, and toughness.Multiscale mechanics is a complex field of study, but it is becoming increasingly important as we develop new materials and technologies. By understanding the mechanical behavior of materials at multiple length scales, we can design materials with specific properties for a wide range of applications.中文回答：多尺度力学是一个研究材料在多个长度尺度上的力学行为的领域。
9 Mechanical Behavior of Polymers
9.2.3 Shear band and Craze
剪切带和银纹
Craze 银纹
裂缝
银纹是聚合物在应力作用下，于材料的某些 银纹 薄弱环节出现应力集中而产生局部的塑性形 变和取向，以至于在材料表面或内部垂直于 应力方向上出现的微细的空化条纹状形变区 银纹的长约100µm、宽约10µm、厚约1µm，外形与裂缝 （Crack）相似，但裂缝内部是空的，而银纹内部有许多高 度取向的聚合物微纤，这些微纤把银纹体的两个面连接起来 并沿外力方向取向，微纤之间为空隙隔开。银纹体中聚合物 的体积分数约为40~60%。银纹进一步发展，以至于微纤断 裂时，就成为裂缝 银纹形变导致的体积增加，而截面积基本不变 银纹的产生与发展吸收了大量能量
Energy
断裂的分子理论
U0’ A’ A U0 B
Distance
Potential barrier of a chemical bond
Blue: without stress Red: with stress
Activation energy of fracture 断裂活化能
在拉伸应力作用下，材料寿命与应力的关系为
9.3 Fracture Theory of Polymers
高分子的断裂理论
9.3.1 Griffith Fracture Theory
Griffith断裂理论 该理论由Griffith于60年前为解释玻璃纤维的 断裂强度而提出，目前广泛应用于金属和非 金属材料的断裂现象 Griffith认为，实际的脆性固体在受到外力作 用时，由于局部不均匀性，会在垂直于主应 力方向上产生裂缝，在裂缝的两端产生应力 集中。当局部应力超过材料的内聚力时，就 会导致裂缝增长并进而时材料断裂
高分子专业英语
What are polymers?For one thing,they are complex and giant molecules and are different from low molecular weight compounds like,say,common salt. To contrast the difference,the molecular weight of common salt is only 58.5,while that of a polymer can be as high as several hundred thousands,even more than thousand thousands. These big molecules or macro-molecules are made up of much smaller molecules. The small molecules, which combine to form a big molecule,can be of one or more chemical compounds. To illustrate, imagine that a set of rings has the same size and is made up of the same material. When these rings are interlinked,the chain formed can be considered as representing a polymer from molecules of the same compound. Alternatively,individual rings could be of different sizes and materials, and interlinked to represent a polymer from molecules of different compounds.This interlinking of many units has given the polymer its name, poly meaning many and mer meaning part(in greek). As an example,a gaseous compound called butadiene, with a molecular weight of54,combines nearly 4000 times and gives a polymer known as polybutadiene(a synthetic rubber) with about 200 000 molecular weight. The low molecular weight compounds from which the polymers form are known as monomers. The picture is simply as follows:Butadiene+butadiene+.....+butadiene___polybutadien e(4000 times)One can thus see how a substance (monomer) with as small a molecular weight as 54 grows to become a giant molecule (polymer) of 200000 molecular weight. It is essentially the giantness of the size of the polymer molecule that makes its behavior different from that of a commonly know chemical compound such as benzene. Solid benzene, for instance,melts to become liquid bezene at 5.5C and,on further heating,boils into gaseous benzene. As against this well-defined behavior of a simple chemical compound,a polymer like polyethylene does not melt sharply at one particular temperature into clean liquid. Instead , it becomes increasingly softer and,ultimately,turns into a veryviscous , tacky molten mass. Further heating of this hot, viscous,molten polymer does convert it into various gases but it is no longer polyethlene.Another striking difference with respect to the behavior of a polymer and that of a low molecular weight compound concerns the dissolution process. Let us take, for example, sodium chloride and add it slowly to a fixed quantity of water. The salt, which represents a low molecular weight compound,dissolves in water up to a point (called saturation point) but,thereafter, any further quantity added does not go into solution but settles at the buttom and just remains there as solid. The viscosity of the saturated salt solution is not very much different from that of water. But if we take a polymer instead, say, polyvinyl alcohol, and add it to a fixed quantity of water, the polymer does not go into solution immediately. The globules of polyvinyl alcohol first absorb water , swell and get distorted in shape and after a long time go into solution. Also, we can add a very large quantity of the polymer to the same quantity of water without the saturation point ever being reached. As more and more quantity of polymer isadded to water, the time taken for the dissolution of the polymer obviously increases and the mix ultimately assume a soft, dough-like consistency. Another peculiarity is that, in water, polyvinyl alcohol never retains its original powdery nature as the excess sodium chloride does in a saturated salt solution. In conclusion, We can say that (1) the long time taken by polyvinyl alcohol for dissolution , (2) the absence of a saturation point, and (3)the increase in the viscosity are all characteristics of a typical polymer being dissolved in a solvent and these characteristics are attributed mainly to the large molecular size of the polymer. The behavior of a low molecular weight compound and that of a polymer on dissolution are illustrated in Fig.1.2.Structure . data . equation . pressure . liquid Laboratory . solid . molecule . temperature Measurement . compound . electrical .科学science. ology技术technique化学chemistry物理physics气体gas原子atom性质character试验experimentation增加increase . add. gain减少reduce . decrease混合物mixture compoundStructure of polymer chainsin many cases polymer chains are linear. In evaluating both the degree of polymerization and the extended chain length, we assume that the chain has only two ends. While linear polymers are important, they are not The only type of molecules possible. Branched and cross-linked molecules are also important. When we speak of a branched polymer, we refer to the presence of additional polymeric chains issuing from the backbone of a linear molecule. Substituent groups such as methyl or phenyl groups on the repeat units are not considered branches. Branching is generally introduced into a molecule by intentionally adding some monomer with the capability of serving as a branch. Let us consider the formation of a polyester. The presence of difunctional acids and difunctional alcohols allows the polymer chain to grow. These difunctional molecules are incorporated into the chain with ester linkages at both ends of each. Trifunctional acids or alcohols, on the other hand, produce a linear molecule by reacting two of their functional groups. If the third reacts and the resulting chain continues to grow, a branch has beenintroduced into the original chain. Adventitious branching sometimes occurs as a result of an atom being abstracted from the original linear molecule, with chain growth occurring from the resulting active site. Molecules with this kind of accidental branching are generally still called linear, although the presence notably the tendency to undergo crystallization.The amount of branching introduced onto a polymer is an additional variable that must be specified for the molecule to be fully characterized. When only a slight degree of branching is present, the concentration of junction points is sufficiently low that these may be simply related to the number of chain ends. For example, two separate linear molecules have a total of four ends. If the end of one of these linear molecules attaches itself to the middle of the other to form a “T”, the resulting molecule has three ends. It is easy to generalize this result. If a moleculer has v branches, it has v+2 chain ends if the branching is relatively low. Branched molecules are sometimes described as either combs or stars. In the former, branch chains emanate from along the length of a common backbone; in thelatter, all branches radiate from a central junction.If the concentration of junction points is high enough, even branches will contain branches. Eventually a point is reached at which the amount of branching is so extensive that the polymer molecule becomes a giant three dimensional network. When this condition is achieved, the molecule is said to be cross-linked. In this case, an entire macroscopic object may be considered to consist of essentially one molecule. The forces which give cohesiveness to such a body are covalent bonds, not intermolecular forces. Accordingly, the mechanical behavior of cross-linked bodies is much different from those without cross-linking.Just as it is not necessary for polymer chains to be linear, it is also not necessary for all repeat units to be the same. We have already mentioned molecules like proteins where a wide variety of different repeat units are present. Among synthetic polymers, those in which a single kind of repeat unit are involved are called homopolymers, and those containing more than one kind of repeat unit are copolymers. Note that thesedefinitions are based on the repeat unit, not the monomer. An ordinary polyester is not a copolymer, even though two different monomers, acids and alcohols, are its monomers. By contrast, copolymers result when different monomers bond together in the same way to produce a chain in which each kind of monomer retains its respective substituents in the polymer molecule. The unmodified term copolymer is generally used to designate the case where two different repeat units are involved. Where three kinds of repeat units are present, the system is called a terpolymer; where there are more than three, the system is called a multicomponent copolymer.The moment we admit the possibility of having more than one kind of repeat unit, we require additional variables to describe the polymer. First, we must know how many kinds of repeat units are present and what they are. This is analogous to knowing what components are present in a solution, although the similarity ends there, since the repeat units in a polymer are bonded together and not merely mixed. To describe the copolymer quantitatively, the relativeamounts of the different kinds of repeat units must be specified. Thus the empirical formula of a copolymer may be written AxBy, where A and B signigfy the individual repeat units and x and y indicate the relative number of each. From a knowledge of the molecular weight of the polymer, the molecular weights of A and B, and the values of x and y, it is possible to calculate the number of each kind of monomer unit in the copolymer. The sum of these values gives the degree of polymerization of the copolymer. Note that we generally do not call nA and nB the degree of polymerization of the individual units. The inadvisability of the latter will become evident presently.。
材料科学与工程专业英语课文翻译(1,2,3,10).
United 1 材料科学与工程材料在我们的文化中比我们认识到的还要根深蒂固。
如交通、房子、衣物,通讯、娱乐和食物的生产,实际上,我们日常生活中的每一部分都或多或少地受到材料的影响。
历史上社会的发展、先进与那些能满足社会需要的材料的生产及操作能力密切相关。
实际上,早期的文明就以材料的发展程度来命名,如石器时代,铜器时代。
早期人们能得到的只有一些很有限的天然材料,如石头、木材、粘土等。
渐渐地,他们通过技术来生产优于自然材料的新材料,这些新材料包括陶器和金属。
进一步地,人们发现材料的性质可以通过加热或加入其他物质来改变。
在这点上,材料的应用完全是一个选择的过程。
也就是说,在一系列非常有限的材料中,根据材料的优点选择一种最适合某种应用的材料。
直到最近,科学家才终于了解材料的结构要素与其特性之间的关系。
这个大约是过去的60 年中获得的认识使得材料的性质研究成为时髦。
因此,成千上万的材料通过其特殊的性质得以发展来满足我们现代及复杂的社会需要。
很多使我们生活舒适的技术的发展与适宜材料的获得密切相关。
一种材料的先进程度通常是一种技术进步的先兆。
比如,没有便宜的钢制品或其他替代品就没有汽车。
在现代,复杂的电子器件取决于所谓的半导体零件.材料科学与工程有时把材料科学与工程细分成材料科学和材料工程学科是有用的。
严格地说,材料科学涉及材料到研究材料的结构和性质的关系。
相反,材料工程是根据材料的结构和性质的关系来设计或操纵材料的结构以求制造出一系列可预定的性质。
从功能方面来说,材料科学家的作用是发展或合成新的材料,而材料工程师是利用已有的材料创造新的产品或体系,和/或发展材料加工新技术。
多数材料专业的本科毕业生被同时训练成材料科学家和材料工程师。
“structure”一词是个模糊的术语值得解释。
简单地说,材料的结构通常与其内在成分的排列有关。
原子内的结构包括介于单个原子间的电子和原子核的相互作用。
在原子水平上,结构包括原子或分子与其他相关的原子或分子的组织。
分子量分布系数英文
分子量分布系数英文Molecular Weight Distribution CoefficientOne of the fundamental characteristics of polymeric materials is their molecular weight distribution (MWD), which is a critical parameter that significantly impacts the physical and mechanical properties of the final product. The molecular weight distribution coefficient, also known as the polydispersity index (PDI), is a measure of the breadth or heterogeneity of the molecular weight distribution.The molecular weight distribution of a polymer is typically represented by a Gaussian or normal distribution curve, where the x-axis represents the molecular weight and the y-axis represents the relative abundance or frequency of the various molecular weight species. The shape of this curve can provide valuable insights into the synthesis and processing of the polymer.The polydispersity index is a dimensionless quantity that is calculated by dividing the weight-average molecular weight (Mw) by the number-average molecular weight (Mn) of the polymer. This ratio provides a measure of the distribution of molecular weights within the polymer sample. A PDI value of 1 indicates a perfectlymonodisperse system, where all polymer chains have the same molecular weight. In contrast, a higher PDI value (greater than 1) suggests a broader distribution of molecular weights, with a greater range of chain lengths present in the sample.The polydispersity index can have a significant impact on the properties of a polymer. Polymers with a narrow molecular weight distribution (low PDI) tend to exhibit better mechanical properties, such as higher tensile strength and impact resistance, as well as improved processability. This is because the polymer chains are more uniform in length, allowing for more efficient packing and better stress transfer within the material.On the other hand, polymers with a broader molecular weight distribution (high PDI) can exhibit enhanced melt flow properties, which can be advantageous in certain processing techniques, such as injection molding or extrusion. The presence of shorter chains can improve the flow characteristics of the polymer melt, allowing for better filling of molds or die cavities.The polydispersity index is a crucial parameter in the characterization and optimization of polymer synthesis processes. It can be influenced by various factors, such as the polymerization mechanism, the presence of chain transfer agents, and the reaction conditions. For example, step-growth polymerizations, such as polycondensation,typically result in broader molecular weight distributions and higher PDI values compared to chain-growth polymerizations, such as free radical or anionic polymerization.In addition to the impact on physical and mechanical properties, the molecular weight distribution can also affect the rheological behavior of polymers, which is particularly important in processing operations. Polymers with a broader MWD tend to exhibit shear-thinning behavior, where the viscosity decreases with increasing shear rate. This can be advantageous in certain processing techniques, such as extrusion or injection molding, where the polymer needs to flow easily through the die or mold.To determine the polydispersity index of a polymer, various analytical techniques can be employed, such as size-exclusion chromatography (SEC) or gel permeation chromatography (GPC). These techniques separate the polymer chains based on their size or hydrodynamic volume, allowing for the determination of the number-average and weight-average molecular weights, and subsequently, the calculation of the PDI.In conclusion, the molecular weight distribution coefficient, or polydispersity index, is a critical parameter in the characterization and understanding of polymeric materials. It provides valuable insights into the synthesis, processing, and ultimate performance ofpolymers, making it an essential tool in the development and optimization of various polymer-based products.。
《材料科学专业英语》课程大纲
《材料科学专业英语》课程大纲一、课程概述课程名称（中文）：材料科学专业英语（英文）：Professional English for Materials课程编号：14351024课程学分：3学分课程总学时：48学时课程性质：专业课二、课程内容简介（300字以内）随着本科毕业生就业渠道的日益拓宽，对专业英语知识的需求也同样增加。
在了解基本的专业词汇的基础上，更需要对更为专业的表达方式和理论知识的英语表达具有一定的了解。
因此，本课程是大学英语教学的基础上，结合相关专业基础课程(如：高分子化学与物理、高分子材料、材料力学、生物质资源材料学等)和专业选修课程（如:纳米技术、生物质能源利用、功能性纤维等）开设的旨在提高学生使用英文对专业基础知识和技术资料进行阅读，并掌握英文论文的书写格写及英文论文摘要的写作技巧。
三、教学目标与要求通过学习有关专业科技英语的语法知识，了解和掌握英译汉的基本方法和翻译技巧，提高阅读和翻译速度。
培养学生顺利阅读科技及专业英文文献，并达到较高的翻译质量标准。
在此基础上，可以利用英语对本专业的简单问题进行口语交流。
四、教学内容与学时安排Introduction（4学时）1、教学目的要求了解学习专业英语的重要性；掌握本专业名称和主要课程的英文翻译；熟悉普通英语口语交流2、教学要点和难点第一节Why we need to lean professional English? （1学时）一、What is professional English?二、What can we learn from professional English?三、Is it any contribution of professional English to our future career?第二节What can we do in the professional English Class? （1学时）一、Learn how to read二、Learn how to write三、Learn how to use language freely第三节Do you know about in your major? （1学时）一、English name of our causes二、Main concerns of materials science三、Pioneer work in materials science第四节Can you introduce yourself to us? （1学时）一、Several essential points in your self introduction二、Oral English also important in language study三、Are you ready to enjoy losing your face?Chapter One Polymer Chemistry & polymer chains（12学时）1、教学目的要求掌握聚合物的定义和相关专业词汇，熟悉用英语表达常见高分子合成反应；了解分子量及其分布的英文表达方式2、教学要点和难点第一节What are Polymer ? （2学时）一、Definition of polymer and polymer science二、Development of polymer and polymer science三、Polymer and daily life第二节Polymerization method（2学时）一、Characterization of polymerization二、Catalogue of chemical polymerization method三、Chain reaction polymerization四、Step reaction polymerization五、Emulsion polymerization第三节Structure of Polymer chains（3学时）一、Polymer chains二、Conformation of polymer chains三、Molecular chains motion四、Movement of polymer chains五、Glass transition第四节Properties Polymer solution（3学时）一、Dissolution of polymer二、Definition of polymer solution三、Experimental investigation of polymer solution四、Application of polymer solution第五节Molecular Weight and its Distributions of Polymers（2学时）一、Polymer size and shape二、Molecular weight average三、Determination method of molecular weight四、Determination method of molecular weight distributionChapter two Polymer Physics and properties（10学时）1、教学目的要求掌握用英语表达高分子的结构，熟悉用英语表达高分子力学性能；了解用英语表达高分子热学、电学和光学性能。
高分子材料与工程专业英语课文
UNIT 22 Mechanical Properties of Polymers聚合物的力学性能The mechanical properties of polymers are of interest in all applications where polymers are used as structural materials. Mechanical behavior involves the deformation of a material under the influence of applied forces.聚合物的力学性能感兴趣的所有应用中聚合物被用作结构材料。
机械行为涉及材料形变的影响下，施加的力。
The most important and most characteristic mechanical properties are called moduli. A modulus is the ratio between the applied stress and the corresponding deformation. The re-ciprocals of the moduli are called compliances. The nature of the modulus depends on the na-ture of the deformation. The three most important elementary modes of deformation and the moduli (and compliances) derived from them are given in Table 22.1, where the definitions of the elastic parameters are also given. ® Other very important, but more complicated, de-formations are bending and torsion. From the bending or flexural deformation the tensile modulus can be derived. The torsion is determined by the rigidity.最重要和最具特色的机械特性被称为模。
高分子材料纳米二氧化硅外文文献翻译
纳米二氧化硅对成核、结晶和热塑性能的影响外文文献翻译(含：英文原文及中文译文)文献出处：Laoutid F, Estrada E, Michell R M, et al. The influence of nanosilica on the nucleation, crystallization andtensile properties of PP–PC and PP–PA blends[J]. Polymer, 2013, 54(15):3982-3993.英文原文The influence of nanosilica on the nucleation, crystallization andtensileproperties of PP–PC and PP–PA blendsLaoutid F, Estrada E, Michell R M, et alAbstractImmiscible blends of 80 wt% polypropylene (PP) with 20 wt% polyamide (PA) or polycarbonate (PC) were prepared by melt mixing with or without the addition of 5% nanosilica. The nanosilica produced a strong reduction of the disperse phase droplet size, because of its preferential placement at the interface, as demonstrated by TEM. Polarized Light Optical microscopy (PLOM) showed that adding PA, PC or combinations of PA-SiO2 or PC-SiO2 affected the nucleation density of PP. PA droplets can nucleate PP under isothermal conditions producing a higher nucleation density than the addition of PC or PC-SiO2. PLOM was found to be more sensitive to determine differences in nucleation than non-isothermal DSC. PP developed spherulites, whose growth was unaffected by blending, while its overall isothermal crystallizationkinetics was strongly influenced by nucleation effects caused by blending. Addition of nanosilica resulted in an enhancement of the strain at break of PP-PC blends whereas it was observed to weaken PP-PA blends. Keywords：Nanosilica，Nucleation，PP blends1 OverviewImmiscible polymer blends have attracted attention for decades because of their potential application as a simple route to tailor polymer properties. The tension is in two immiscible polymerization stages. This effect usually produces a transfer phase between the pressures that may allow the size of the dispersed phase to be allowed, leading to improved mixing performance.Block copolymers and graft copolymers, as well as some functional polymers. For example, maleic anhydride grafted polyolefins act as compatibilizers in both chemical affinities. They can reduce the droplet volume at the interface by preventing the two polymers from coalescing. In recent years, various studies have emphasized that nanofillers, such as clay carbon nanotubes and silica, can be used as a substitute for organic solubilizers for incompatible polymer morphology-stabilized blends. In addition, in some cases, nanoparticles in combination with other solubilizers promote nanoparticle interface position.The use of solid particle-stabilized emulsions was first discovered in 1907 by Pickering in the case of oil/emulsion containing colloidalparticles. In the production of so-called "Pickling emulsions", solid nanoparticles can be trapped in the interfacial tension between the two immiscible liquids.Some studies have attempted to infer the results of blending with colloidal emulsion polymer blends. Wellman et al. showed that nanosilica particles can be used to inhibit coalescence in poly(dimethylsiloxane)/polyisobutylene polymers. mix. Elias et al. reported that high-temperature silicon nanoparticles can migrate under certain conditions. The polypropylene/polystyrene and PP/polyvinyl acetate blend interfaces form a mechanical barrier to prevent coalescence and reduce the size of the disperse phase.In contrast to the above copolymers and functionalized polymers, the nanoparticles are stable at the interface due to their dual chemical nature. For example, silica can affect nanoparticle-polymer affinities locally, minimizing the total free energy that develops toward the system.The nanofiller is preferentially placed in equilibrium and the wetting parameters can be predicted and calculated. The difference in the interfacial tension between the polymer and the nanoparticles depends on the situation. The free-diffusion of the nanoparticle, which induces the nanoparticles and the dispersed polymer, occurs during the high shear process and shows that the limitation of the viscosity of the polymer hardly affects the Brownian motion.As a result, nanoparticles will exhibit strong affinity at the local interface due to viscosity and diffusion issues. Block copolymers need to chemically target a particular polymer to the nanoparticle may provide a "more generic" way to stabilize the two-phase system.Incorporation of nanosilica may also affect the performance of other blends. To improve the distribution and dispersion of the second stage, mixing can produce rheological and material mechanical properties. Silica particles can also act as nucleating agents to influence the crystallization behavior. One studies the effect of crystalline silica on crystalline polystyrene filled with polybutylene terephthalate (polybutylene terephthalate) fibers. They found a stable fibril crystallization rate by increasing the content of polybutylene terephthalate and silica. On the other hand, no significant change in the melt crystallization temperature of the PA was found in the PA/ABS/SiO2 nanocomposites.The blending of PP with engineering plastics, such as polyesters, polyamides, and polycarbonates, may be a useful way to improve PP properties. That is, improving thermal stability, increasing stiffness, improving processability, surface finish, and dyeability. The surface-integrated nano-silica heat-generating morphologies require hybrid compatibilization for the 80/20 weight ratio of the thermal and tensile properties of the blended polyamide and polypropylene (increasedperformance). Before this work, some studies [22] that is, PA is the main component). This indicates that the interfacially constrained hydrophobic silica nanoparticles obstruct the dispersed phase; from the polymer and allowing a refinement of morphology, reducing the mixing scale can improve the tensile properties of the mixture.The main objective of the present study was to investigate the effect of nanosilica alone on the morphological, crystalline, and tensile properties of mixtures of nanosilica alone (for mixed phases with polypropylene as a matrix and ester as a filler. In particular, PA/PC or PA/nano The effect of SiO 2 and PC/nanosilica on the nucleation and crystallization effects of PP as the main component.We were able to study the determination of the nucleation kinetics of PP and the growth kinetics of the particles by means of polarization optical microscopy. DSC measures the overall crystallization kinetics.Therefore, a more detailed assessment of the nucleation and spherulite growth of PP was performed, however, the effect of nanosilica added in the second stage was not determined. The result was Akemi and Hoffman. And Huffman's crystal theory is reasonable.2 test phase2.1 Raw materialsThe polymer used in this study was a commercial product: isotactic polypropylene came from a homopolymer of polypropylene. The Frenchformula (B10FB melt flow index 2.16Kg = 15.6g / 10min at 240 °C) nylon 6 from DSM engineering plastics, Netherlands (Agulon Fahrenheit temperature 136 °C, melt flow index 240 °C 2.16kg = 5.75g / 10min ) Polycarbonate used the production waste of automotive headlamps, its melt flow index = 5g / 10min at 240 °C and 2.16kg.The silica powder TS530 is from Cabot, Belgium (about 225 m/g average particle (bone grain) about 200-300 nm in length, later called silica is a hydrophobic silica synthesis of hexamethyldisilane by gas phase synthesis. Reacts with silanols on the surface of the particles.2.2 ProcessingPP_PA and PP-PC blends and nanocomposites were hot melt mixed in a rotating twin screw extruder. Extrusion temperatures range from 180 to 240 °C. The surfaces of PP, PA, and PC were vacuumized at 80°C and the polymer powder was mixed into the silica particles. The formed particles were injected into a standard tensile specimen forming machine at 240C (3 mm thickness of D638 in the American Society for Testing Materials). Prior to injection molding, all the spherulites were in a dehumidified vacuum furnace (at a temperature of 80°C overnight). The molding temperature was 30°C. The mold was cooled by water circulation. The mixture of this combination is shown in the table.2.3 Feature Description2.31 Temperature Performance TestA PerkineElmer DSC diamond volume thermal analysis of nanocomposites. The weight of the sample is approximately 5 mg and the scanning speed is 20 °C/min during cooling and heating. The heating history was eliminated, keeping the sample at high temperature (20°C above the melting point) for three minutes. Study the sample's ultra-high purity nitrogen and calibrate the instrument with indium and tin standards.For high temperature crystallization experiments, the sample cooling rate is 60°C/min from the melt directly to the crystal reaching the temperature. The sample is still three times longer than the half-crystallization time of Tc. The procedure was deduced by Lorenzo et al. [24] afterwards.2.3.2 Structural CharacterizationScanning electron microscopy (SEM) was performed at 10 kV using a JEOL JSM 6100 device. Samples were prepared by gold plating after fracture at low temperature. Transmission electron microscopy (TEM) micrographs with a Philips cm100 device using 100 kV accelerating voltage. Ultra-low cut resection of the sample was prepared for cutting (Leica Orma).Wide-Angle X-Ray Diffraction Analysis The single-line, Fourier-type, line-type, refinement analysis data were collected using a BRUKER D8 diffractometer with copper Kα radiation (λ = 1.5405A).Scatter angles range from 10o to 25°. With a rotary step sweep 0.01° 2θ and the step time is 0.07s. Measurements are performed on the injection molded disc.This superstructure morphology and observation of spherulite growth was observed using a Leica DM2500P polarized light optical microscope (PLOM) equipped with a Linkam, TP91 thermal stage sample melted in order to eliminate thermal history after; temperature reduction of TC allowed isothermal crystallization to occur from the melt. The form is recorded with a Leica DFC280 digital camera. A sensitive red plate can also be used to enhance contrast and determine the birefringence of the symbol.2.3.3 Mechanical AnalysisTensile tests were carried out to measure the stretch rate at 10 mm/min through a Lloyd LR 10 K stretch bench press. All specimens were subjected to mechanical tests for 20 ± 2 °C and 50 ± 3% relative humidity for at least 48 hours before use. Measurements are averaged over six times.3 results3.1 Characterization by Electron MicroscopyIt is expected that PP will not be mixed with PC, PA because of their different chemical properties (polar PP and polar PC, PA) blends with 80 wt% of PP, and the droplets and matrix of PA and PC are expectedmorphologies [ 1-4] The mixture actually observed through the SEM (see Figures 1 a and b).In fact, because the two components have different polar mixtures that result in the formation of an unstable morphology, it tends to macroscopic phase separation, which allows the system to reduce its total free energy. During shearing during melting, PA or PP is slightly mixed, deformed and elongated to produce unstable slender structures that decompose into smaller spherical nodules and coalesce to form larger droplets (droplets are neat in total The size of the blend is 1 ~ 4mm.) Scanning electron microscopy pictures and PP-PC hybrid PP-PA neat and clean display left through the particle removal at cryogenic temperatures showing typical lack of interfacial adhesion of the immiscible polymer blend.The addition of 5% by weight of hydrophobic silica to the LED is a powerful blend of reduced size of the disperse phase, as can be observed in Figures 1c and D. It is worth noting that most of the dispersed phase droplets are within the submicron range of internal size. The addition of nano-SiO 2 to PA or PC produces finer dispersion in the PP matrix.From the positional morphology results, we can see this dramatic change and the preferential accumulation at the interface of silica nanoparticles, which can be clearly seen in FIG. 2 . PP, PA part of the silicon is also dispersed in the PP matrix. It can be speculated that thisformation of interphase nanoparticles accumulates around the barrier of the secondary phase of the LED, thus mainly forming smaller particles [13, 14, 19, 22]. According to fenouillot et al. [19] Nanoparticles are mixed in a polymer like an emulsifier; in the end they will stably mix. In addition, the preferential location in the interval is due to two dynamic and thermodynamic factors. Nanoparticles are transferred to the preferential phase, and then they will accumulate in the interphase and the final migration process will be completed. Another option is that there isn't a single phase of optimization and the nanoparticles will be set permanently in phase. In the current situation, according to Figure 2, the page is a preferential phase and is expected to have polar properties in it.3.2 Wide-angle x-ray diffractionThe polymer and silica incorporate a small amount of nanoparticles to modify some of the macroscopic properties of the material and the triggered crystal structure of PP. The WAXD experiment was performed to evaluate the effect of the incorporation of silica on the crystalline structure of the mixed PP.Isotactic polypropylene (PP) has three crystalline forms: monoclinic, hexagonal, and orthorhombic [25], and the nature of the mechanical polymer depends on the presence of these crystalline forms. The metastable B form is attractive because of its unusual performance characteristics, including improved impact strength and elongation atbreak.The figure shows a common form of injection molding of the original PP crystal, reflecting the appearance at 2θ = 14.0, 16.6, 18.3, 21.0 and 21.7 corresponding to (110), (040), (130), (111) and (131) The face is an α-ipp.20% of the PA incorporation into PP affects the recrystallization of the crystal structure appearing at 2θ = 15.9 °. The corresponding (300) surface of the β-iPP crystal appears a certain number of β-phases that can be triggered by the nucleation activity of the PA phase in PP (see evidence The following nucleation) is the first in the crystalline blend of PA6 due to its higher crystallization temperature. In fact, Garbarczyk et al. [26] The proposed surface solidification caused by local shear melts the surface of PA6 and PP and forms during the injection process, promoting the formation of β_iPP. According to quantitative parameters, KX (Equation (1)), which is commonly used to evaluate the amount of B-crystallites in PP including one and B, the crystal structure of β-PP has 20% PP_PA (110), H(040) and Blends of H (130) heights (110), (040) and (130). The height at H (300) (300) for type A peaks.However, the B characteristic of 5 wt% silica nanoparticles incorporated into the same hybrid LED eliminates reflection and reflection a-ipp retention characteristics. As will be seen below, the combination of PA and nanosilica induces the most effective nucleatingeffect of PP, and according to towaxd, this crystal formation corresponds to one PP structure completely.The strong reductive fracture strain observations when incorporated into polypropylene and silica nanoparticles (see below) cannot be correlated to the PP crystal structure. In fact, the two original PP and PP_PA_SiO2 hybrids contain α_PP but the original PP has a very high form of failure when the strain value.On the other hand, PP-PC and PP-PC-Sio 2 blends, through their WAXD model, can be proven to contain only one -PP form, which is a ductile material.3.3 Polarized Optical Microscopy (PLOM)To further investigate the effect of the addition of two PAs, the crystallization behavior of PC and silica nanoparticles on PP, the X-ray diffraction analysis of its crystalline structure of PP supplements the study of quantitative blends by using isothermal kinetic conditions under a polarizing microscope. The effect of the composition on the nucleation activity of PP spherulite growth._Polypropylene nucleation activityThe nucleation activity of a polymer sample depends on the heterogeneity in the number and nature of the samples. The second stage is usually a factor in the increase in nucleation density.Figure 4 shows two isothermal crystallization temperatures for thePP nucleation kinetics data. This assumes that each PP spherulite nucleates in a central heterogeneity. Therefore, the number of nascent spherulites is equal to the number of active isomerous nuclear pages, only the nucleus, PP-generated spherulites can be counted, and PP spherulites are easily detected. To, while the PA or PC phases are easily identifiable because they are secondary phases that are dispersed into droplets.At higher temperatures (Fig. 4a), only the PP blend inside is crystallized, although the crystals are still neat PP amorphous at the observed time. This fact indicates that the second stage of the increase has been able to produce PP 144 °C. It is impossible to repeat the porous experiment in the time of some non-homogeneous nucleation events and neat PP exploration.The mixed PP-PC and PP-PC-SiO 2 exhibited relatively low core densities at 144 °C, (3 105 and 3 106 nuc/cm 3) suggesting that either PC nanosilica can also be considered as good shape Nuclear agent is used here for PP.On the other hand, PA, himself, has produced a sporadic increase in the number of nucleating events in PP compared to pure PP, especially in the longer crystallization time (>1000 seconds). In the case of the PP-PA _Sio 2 blend, the heterogeneous nucleation of PP is by far the largest of all sample inspections. All the two stages of the nucleating agent combined with PA and silica are best employed in this work.In order to observe the nucleation of pure PP, a lower crystallization temperature was used. In this case, observations at higher temperatures found a trend that was roughly similar. The neat PP and PP-PC blends have small nucleation densities in the PP-PC-SiO 2 nanocomposite and the increase also adds further PP-PA blends. The very large number of PP isoforms was rapidly activated at 135°C in the PP-PA nanoparticle nanometer SiO 2 composites to make any quantification of their numbers impossible, so this mixed data does not exist from Figure 4b.The nucleation activity of the PC phase of PP is small. The nucleation of any PC in PP can be attributed to impurities that affect the more complex nature of the PA from the PC phase. It is able to crystallize at higher temperatures than PP, fractional crystallization may occur and the T temperature is shifted to much lower values (see References [29-39]. However, as DSC experiments show that in the current case The phase of the PA is capable of crystallizing (fashion before fractionation) the PP matrix, and the nucleation of PP may have epitaxy origin.The material shown in the figure represents a PLOAM micrograph. Pure PP has typical α-phase negative spherulites (Fig. 5A) in the case of PP-PA blends (Fig. 5B), and the PA phase is dispersed with droplets of size greater than one micron (see SEM micrograph, Fig. 1) . We could not observe the spherulites of the B-phase type in PP-PA blends. Even according to WAXD, 20% of them can be formed in injection moldedspecimens. It must be borne in mind that the samples taken using the PLOAM test were cut off from the injection molded specimens but their thermal history (direction) was removed by melting prior to melting for isothermal crystallization nucleation experiments.The PA droplets are markedly enhanced by the nucleation of polypropylene and the number of spherulites is greatly increased (see Figures 4 and 5). Simultaneously with the PP-PA blend of silica nanoparticles, the sharp increase in nucleation density and Fig. 5C indicate that the size of the spherulites is very small and difficult to identify.The PP-PC blends showed signs of sample formation during the PC phase, which was judged by large, irregularly shaped graphs. Significant effects: (a) No coalesced PC phase, now occurring finely dispersed small droplets and (B) increased nucleation density. As shown in the figure above, nano-SiO 2 tends to accumulate at the interface between the two components and prevent coalescence while promoting small disperse phase sizes.From the nucleation point of view, it is interesting to note that it is combined with nanosilica and as a better nucleating agent for PP. Combining PCs with nanosilica does not produce the same increase in nucleation density.Independent experiments (not shown here) PP _ SiO 2 samplesindicate that the number of active cores at 135 °C is almost the same as that of PP-PC-SiO2 intermixing. Therefore, silica cannot be regarded as a PP nucleating agent. Therefore, the most likely explanation for the results obtained is that PA is the most important reason for all the materials used between polypropylene nucleating agents. The increase in nucleation activity to a large extent may be due to the fact that these nanoparticles reduce the size of the PA droplets and improve its dispersion in the PP matrix, improving the PP and PA in the interfacial blend system. Between the regions. DSC results show that nano-SiO 2 is added here without a nuclear PA phase.4 Conclusion5% weight of polypropylene/hydrophobic nanosilica blended polyamide and polypropylene/polycarbonate (80E20 wt/wt) blends form a powerful LED to reduce the size of dispersed droplets. This small fraction of reduced droplet size is due to the preferential migration of silica nanoparticles between the phases PP and PA and PC, resulting in an anti-aggregation and blocking the formation of droplets of the dispersed phase.The use of optical microscopy shows that the addition of PA, the influence of PC's PA-Sio 2 or PC-Sio 2 combination on nucleation, the nucleation density of PP polypropylene under isothermal conditions is in the following approximate order: PP <PP-PC <PP -PC-SiO 2<<PP-PA<<< PP-PA-SiO 2. PA Drip Nucleation PP Production of nucleation densities at isothermal temperatures is higher than with PC or PC Sio 2D. When nanosilica is also added to the PP-PA blend, the dispersion-enhanced mixing of the enhanced nanocomposites yields an intrinsic factor PP-PA-Sio2 blend that represents a PA that is identified as having a high nucleation rate, due to nanoseconds Silicon oxide did not produce any significant nucleation PP. PLOAM was found to be a more sensitive tool than traditional cooling DSC scans to determine differences in nucleation behavior. The isothermal DSC crystallization kinetics measurements also revealed how the differences in nucleation kinetics were compared to the growth kinetic measurements.Blends (and nanocomposites of immiscible blends) and matrix PP spherulite assemblies can grow and their growth kinetics are independent. The presence of a secondary phase of density causes differences in the (PA or PC) and nanosilica nuclei. On the other hand, the overall isothermal crystallization kinetics, including nucleation and growth, strongly influence the nucleation kinetics by PLOAM. Both the spherulite growth kinetics and the overall crystallization kinetics were successfully modeled by Laurie and Huffman theory.Although various similarities in the morphological structure of these two filled and unfilled blends were observed, their mechanical properties are different, and the reason for this effect is currently being investigated.The addition of 5% by weight of hydrophobic nano-SiO 2 resulted in breaking the strain-enhancement of the PP-PC blend and further weakening the PP-PA blend.中文译文纳米二氧化硅对PP-PC和PP-PA共混物的成核，结晶和热塑性能的影响Laoutid F, Estrada E, Michell R M, et al摘要80(wt%)聚丙烯与20(wt %)聚酰胺和聚碳酸酯有或没有添加5%纳米二氧化硅通过熔融混合制备不混溶的共聚物。
Mechanical Behavior of Materials
Mechanical Behavior of Materials The mechanical behavior of materials is a crucial aspect of engineering and manufacturing. It involves studying how materials respond to external forces and how they deform or break under stress. The mechanical properties of materials determine their suitability for different applications and help engineers design safe and efficient structures and machines. In this essay, we will explore the importance of understanding the mechanical behavior of materials and the challenges involved in this field. One of the primary reasons for studying the mechanical behavior of materials is to ensure their safety and reliability. Engineers need to know how much stress a material can withstand before it deforms or fractures, and how it behaves under different loading conditions. For example, in the aerospace industry, the structural materials used in aircraft must be able to withstand high stresses and fatigue cycles without failing. Similarly, in the automotive industry, the crashworthiness of a vehicle depends on the mechanical properties of the materials used in its construction. By understanding the mechanical behavior of materials, engineers can design structures and machinesthat are safe and reliable. Another reason for studying the mechanical behavior of materials is to improve their performance. By changing the composition or microstructure of a material, engineers can alter its mechanical properties tosuit specific applications. For example, by adding alloying elements to steel, its strength and toughness can be increased, making it suitable for use in high-stress applications such as bridges and buildings. Similarly, by changing the processing conditions of polymers, their stiffness and strength can be improved, making them suitable for use in automotive parts and medical devices. Understanding the mechanical behavior of materials is essential for optimizing their performance and developing new materials with improved properties. However, studying the mechanical behavior of materials is not without its challenges. One of the main challenges is the complex nature of the behavior of materials under stress. Materials can exhibit different types of deformation, such as elastic, plastic, and creep, depending on the stress level and loading conditions. Moreover, the behavior of materials can be affected by various factors such as temperature, humidity, and the presence of impurities. Understanding the mechanical behavior ofmaterials requires sophisticated testing methods and analytical techniques, which can be time-consuming and expensive. Another challenge in studying the mechanical behavior of materials is the need to balance conflicting requirements. For example, a material that is strong and tough may be brittle and prone to fracture under certain conditions. Similarly, a material that is lightweight and durable may be expensive and difficult to manufacture. Engineers need to consider various factors such as cost, performance, and safety when selecting materials for specific applications. Moreover, they need to balance the trade-offs between different properties and choose materials that meet the requirements of the application. In conclusion, the mechanical behavior of materials is a critical aspect of engineering and manufacturing. By understanding how materials respond to external forces, engineers can design safe and reliable structures and machines, and optimize the performance of materials for specific applications. However, studying the mechanical behavior of materials is not without its challenges. Engineers need to balance conflicting requirements and consider various factors such as cost, performance, and safety when selecting materials for specific applications.Despite these challenges, the study of the mechanical behavior of materials is essential for advancing technology and improving our quality of life.。
Unit 2 Polymer and Composites
Unit 2 Polymer and Composites2单元的聚合物和复合材Polymers and polymer composites are used in many different forms, ranging from synthetics through to structural composites in the construction industry and to the high technology composites of the aerospace and space satellite industries①.聚合物和聚合物复合材料的使用在许多不同的形式，从合成通过在建筑行业的结构复合材料到高科技的航空航天复合材料和太空卫星产业。
Plastics are generally considered to be a relatively recent development. In fact, they are members of the much larger family of polymers.塑料通常被认为是一个相对较新的发展。
事实上，他们是聚合物的大家庭成员。
Polymers are the products of combining a large number of small molecular units called monomers by the chemical process known as polymerization ( which is the process by which molecules or groups of atoms are joined together) to form iong-chain molecules. Natural materials such as bitumen，rubber and cellulose have this type of structure. There are two main types of polymerization. In the first type, a substance consisting of a series of long-chain polymerized molecules, called thermoplastics, is produced. All the chains of the molecules are separate and can slide over one another. In the second type, the chains become cross-linked so that a solid material is produced which cannot be softened and whicli will not flow. Such solids are called thermosetting polymers. These two groups classify polymer materials.聚合物是结合大量的小分子单元的化学过程称为聚合的单体产品（这是分子或原子团的过程结合在一起，形成长链分子）。
聚合物低温失效机理
聚合物低温失效机理1. 引言聚合物是一类具有高分子量的化合物，由重复的单体单元组成。
它们在许多领域中具有广泛的应用，如塑料制品、纤维材料、涂料和粘合剂等。
然而，在低温环境下，聚合物材料可能会出现失效现象，这会严重影响其性能和可靠性。
本文将探讨聚合物低温失效的机理，深入了解其原因，并提出相应的解决方案。
2. 低温失效机制2.1 冷冻-解冻循环低温环境下，聚合物材料容易遭受冷冻-解冻循环的影响。
当材料经历周期性的冷却和加热过程时，内部应力会不断积累并逐渐导致破坏。
这是由于聚合物分子在冷却过程中会收缩，而在加热过程中会膨胀。
循环往复的变形导致分子链断裂和晶体结构破坏。
2.2 玻璃化转变聚合物材料在低温下会发生玻璃化转变，即由高分子链的可流动状态转变为非晶态固体。
在玻璃化转变温度以下，聚合物的力学性能和物理性质会发生显著变化。
在这种状态下，材料的韧性和延展性降低，易于发生断裂和开裂。
2.3 晶体结构破坏聚合物材料通常具有晶体结构，其中分子链有序排列。
在低温下，晶体结构容易受到损害。
冷却过程中，分子链容易形成局部结晶区域，在解冻时这些区域会发生剥离和断裂。
这导致材料整体强度下降，并可能引起裂纹扩展。
3. 影响因素3.1 温度低温失效的主要因素之一是温度。
较低的温度会加剧聚合物材料的脆性和脆弱性。
当温度接近或低于玻璃化转变温度时，失效风险显著增加。
3.2 应力应力是导致聚合物材料低温失效的另一个重要因素。
较高的应力会加速聚合物分子链的断裂和晶体结构的破坏。
因此，在设计和使用聚合物制品时，应尽量避免或减少外部应力的作用。
3.3 材料特性不同类型的聚合物材料具有不同的特性，对低温失效也会产生影响。
例如，一些聚合物具有较高的玻璃化转变温度，因此在低温环境下更加稳定。
而另一些聚合物则容易发生冷冻-解冻循环引起的破坏。
4. 解决方案为了解决聚合物材料低温失效问题，可以采取以下措施：4.1 添加添加剂通过添加适当的添加剂，可以改善聚合物材料在低温下的性能。
大学本科高分子物理第五章《聚合物的转变与松弛》课件
E: Liquid flow region 粘流态：大分子链受
外力作用时发生位移，且无法回复。行为与小分 子液体类似。
三态两区
18
线形无定形高聚物随T增大，会出现三种不同的 力学状态。
玻璃态与高弹态之间的转变叫玻璃化转变（玻 璃—橡胶转变），其区域如曲线B区，对应的温 度叫玻璃化温度，以Tg表示，是链段运动的最低 温度； 高弹态与粘流态之间 的转变叫橡胶流动转变，该 区曲线上的D区，在其对应的温度叫粘流温度， 以Tf表示，是整个大分子链开始运动的最低温度。
13
The relationship between modulus and temperature
14
Mechanical Method
Strain-temperature
Modulus-temperature
非晶高聚物（非交联）的力学状态
15
Mechanical properties and transition of polymers
Glass region
Viscosity flow transition
Liquid flow region
Glass transition Rubber-elastic plateau region
Tg – glass transition temperature 玻璃化转变温度 Tf – viscosity flow temperature 粘流温度
19
Applications of the three states
Tb~Tg
Tg~Tf
Tf~Td 20
Thermal and Mechanical Properties of Polymers
Thermal and Mechanical Properties ofPolymers热力学和机械性能是聚合物材料的两大重要性能指标，它们直接影响着聚合物材料的使用范围以及应用效果。
本文将着重介绍聚合物材料的热力学和机械性能，并探讨其产生的原因和应用方向。
一、热力学性能热力学性能指的是聚合物材料在不同温度下的热膨胀系数、热传导率、热稳定性等指标。
其中热膨胀系数是指聚合物材料在温度变化下的尺寸变化率，该指标对于聚合物材料的加工工艺、尺寸控制以及热稳定性等具有重要作用。
热传导率是指聚合物材料的热传递能力，该指标主要与聚合物材料的结晶度、分子结构以及填料含量等因素相关。
热稳定性是指聚合物材料在高温、氧化或紫外辐射等条件下的稳定性，该指标对于聚合物材料的长期应用以及高温环境下的使用具有重要作用。
热力学性能的差异主要来源于聚合物材料的分子结构、结晶度、分子量、共聚物组成等因素的差异，不同的聚合物材料之间可能存在很大差异。
例如，聚丙烯具有较小的热膨胀系数、较高的热稳定性和较低的热传导率，而聚苯乙烯则具有较大的热膨胀系数和较低的热稳定性。
这些性能差异对于聚合物材料的应用具有重要的影响。
例如，在高温环境下，需要选择具有较高热稳定性的聚合物材料，以确保其稳定性和寿命。
而在冷却过程中，需要选择具有较小热膨胀系数的聚合物材料，以避免尺寸变化过大而导致制品失效。
二、机械性能机械性能指的是聚合物材料的组织、形态和取向对于其在载荷作用下的应变与应力关系的影响程度。
机械性能是材料的本质属性，对于聚合物材料的应用领域和产品表现具有重要影响。
常见的机械性能指标包括弹性模量、抗拉强度、断裂伸长率、冲击强度等。
聚合物材料的机械性能与分子结构、晶体结构、成分、加工工艺、温度、湿度等因素密切相关。
例如，在聚合物材料的成分方面，聚乙烯和聚丙烯等具有相对较高的韧性和可加工性，而聚碳酸酯和聚酰亚胺等则具有相对较高的强度和硬度。
不同的聚合物材料之间存在较大的差异，因此需要在选择材料时根据具体的使用场景和应用需求来进行选择。
高分子物理课件;第一章 高分子链的结构
20
Isomers
Examples:
1，4加成
nH2C CH CH CH2
1，2加成
顺式 CH2 CH CH CH n
26
支链形高分子
由于加聚过程中有自由基的链转移发生，常易产生 支化高分子。
支化分子对高分子材料的使用性能有一定的影响 例如：LDPE(Low Density PE)（自由基聚合） 支链多，密度小，较柔软。用于制食品袋、奶瓶等等
HDPE（配位聚合，Zigler催化剂）:几乎无 支链的线型PE，密度大，硬，规整性好，结晶度 高，强度、刚性、熔点均高。可用作工程塑料部件， 绳缆等等
31
Copolymers
Random copolymers 两种高分子无规则地平行联结
ABAABABBAAABABBAAA
由于两种高分子平行无规则地排列改变了结构单元 的相互作用，也改变了分子间的相互作用，因此在 溶液性质、结晶性质、力学性质方面和均聚物有明 显不同。 例1： PE，PP是塑料，但乙烯与丙烯无规共聚的 产物为橡胶。 例2： PTFE（聚四氟乙烯）是塑料，不能熔融加 工，但四氟乙烯与六氟丙烯共聚物是热塑性的塑料。
space. Molecular weight and MW distribution.
7
构型（Configuration）
Definition: 分子中由化学键所固定的原子在空间的排列 The term configuration refers to the organization of the atoms along the chain.
橡胶拉伸行为的分子动力学模拟
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第6期
何 燕等．橡胶拉伸行为的分子动力学模拟
ᔴॳӧ᭣᪃ፆҸᑞ kJgmol1
4 170 0
4 170 8 340 12510 16 680 20 850 25 020 29 190 33 360
0
20 40 60 80 100 120 140 160 180 ःԪ%
1 橡胶分子模型建立 NR 的 主 要 成 分 是 顺 式 -1，4- 聚 异 戊 二 烯，是
一 种 碳 氢 化 合 物，其 化 学 结 构 由 异 戊 二 烯 以 连 续 链的形式构建而成[2]。NR分子链中异戊二烯单元
基金项目：国家自然科学基金资助项目（51676103，51576102） 作 者 简 介：何 燕（1973—），女，山 东 青 州 人，青 岛 科 技 大 学 教 授，博士，主要从事强化传热与传质方面的研究。 *通信联系人（tangyuanzheng@163. com）
方回转半径变化最大，NR分子模型次之，TPI分子 模型最小，即3种分子链柔顺性由好到劣的顺序为 BR，NR，TPI。
高分子材料专业英语配翻译
As against this well-defined behavior of a simple chemical compound, a polymer like polyethylene does not melt sharply at one particular temperature into clean liquid. 与这类简单化合物明确的行为相比，像聚乙烯这样的聚合物不能在某一特定的温度快速地熔融成纯净的液体。
Also, we can add a very large quantity of the polymer to the same quantity of water without the saturation point ever being reached. 同样地，我们可以将大量的聚合物加入到同样量的水中，不存在饱和点。
While linear polymers are important, they are not the only type of molecules possible. 线状聚合物是很重要的,他们不是唯一可能类型的分子。
Substituent groups such as methyl or phenyl groups on the repeat units are not considered branches. Branching is generally introduced into a molecule by intentionally adding some monomer with the capability of serving as a branch. Let us consider the formation of a polyester. The presence of difunctional acids and difunctional alcohols allows the polymer chain to grow. These difunctional molecules are incorporated into the chain with ester linkages at both ends of each. Trifunctional acids or alcohols, on the other hand, produce a linear molecule by reacting two of their functional groups. If the third reacts and the resulting chain continues to grow, a branch has been introduced into the original chain. Adventitious branching sometimes occurs as a result of an atom being abstracted from the original linear molecule, with chain growth occurring from the resulting active site. Molecules with this kind of accidental branching are generally still called linear, although the presence of significant branching has profound effects on some properties of the polymer, most notably the tendency to undergo crystallization.The polymerization is a chain reaction in two ways: because of the reaction kinetic and because as a reaction product one obtains a chain molecule. 聚合反应是链式反应的原因有两种：因为反应动力学和因为作为反应产物它是一种链式分子。
分子链间 分子链内 英文
分子链间分子链内英文Molecular Chain Interactions and Intramolecular Chain Dynamics.The study of polymers and macromolecules involves a deep understanding of the interactions and dynamics within and between molecular chains. These chains, composed of repeating units, exhibit unique behaviors that depend on the nature of the chemical bonds, the flexibility of the chain, and the presence of external factors such as temperature and pressure.Molecular Chain Interactions.Molecular chain interactions refer to the forces that exist between different polymer chains. These interactions are primarily of two types: covalent and non-covalent. Covalent interactions, such as cross-linking, are permanent and result in a chemical bond formation between chains. Non-covalent interactions, on the other hand, are weakerand include forces like Van der Waals forces, hydrophobic interactions, and electrostatic interactions.Van der Waals forces, which are the weakest type of intermolecular force, arise due to temporary dipole-dipole interactions or the attraction between induced dipoles. Hydrophobic interactions occur when water-hating (hydrophobic) parts of different chains seek to avoid contact with water by associating with each other. Electrostatic interactions result from the attraction or repulsion between oppositely charged regions of different chains.The strength of these interactions determines the physical properties of the polymer, such as its viscosity, elasticity, and tendency to form aggregates. For example, polymers with strong intermolecular interactions tend to be more viscous and less elastic, while those with weak interactions may exhibit the opposite behavior.Molecular Chain Dynamics.Molecular chain dynamics refer to the movements and conformational changes that occur within a single polymer chain. These dynamics are governed by the thermal energy of the system and the flexibility of the chain.At high temperatures, thermal energy promotes more frequent and larger-scale conformational changes within the chain, leading to increased chain mobility. Conversely, at low temperatures, the chain becomes more rigid, and conformational changes occur less frequently.The flexibility of the chain, determined by the length of the bonds, the angle between bonds, and the presence of any steric hindrance, also plays a crucial role. Chains with shorter bonds and wider angles between them are generally more flexible and exhibit greater conformational freedom.Interactions and Dynamics in Polymer Processing.In polymer processing, such as extrusion, molding, and spinning, the understanding of chain interactions anddynamics is crucial. During processing, external forces are applied to the polymer, causing changes in its conformation and structure. The interactions between chains affect how the polymer flows, its viscoelastic behavior, and its final mechanical properties.For example, in extrusion, the polymer is forced through a die under high pressure and temperature. The strength of the intermolecular interactions determines the ease with which the polymer can be extruded. Strong interactions lead to higher viscosity and require higher processing temperatures and pressures.Similarly, in molding, the polymer is heated and pressed into a mold cavity. The chain dynamics determine how the polymer fills the cavity, its ability to form intricate shapes, and its final surface finish.Conclusion.The interactions and dynamics within and between molecular chains play a pivotal role in determining thephysical and mechanical properties of polymers. A fundamental understanding of these phenomena is essential for effective polymer processing, optimization of product properties, and the development of novel polymer materials. As polymer science continues to evolve, so does our understanding of the intricate dance performed by these molecular chains.。
聚乙二醇单油酸酯 分子结构
聚乙二醇单油酸酯分子结构聚乙二醇单油酸酯（Polyethylene Glycol Monooleate，以下简称PEGMO），是一种广泛应用的化学合成物。
它的分子结构简单，但具有许多重要的性质和应用领域。
在本文中，我们将深入探讨PEGMO 的结构、性质和应用，并对其进行全面评估。
1. PEGMO的分子结构PEGMO的分子结构可以通过两部分来描述：聚乙二醇（Polyethylene Glycol，简称PEG）和单油酸酯（Monooleate）。
PEGMONO的分子式为C32H62O6，由两个主要部分组成：聚乙二醇和油酸。
聚乙二醇是一种聚合物，具有一系列连续的乙二醇单元，而油酸则是一种长链不饱和脂肪酸。
两者通过酯键连接在一起，形成了PEGMO的分子结构。
2. PEGMO的性质PEGMO具有许多重要的性质，使其在各个行业中得到广泛的应用。
PEGMO是一种表面活性剂。
它在水和油之间起到界面活性的作用，可以降低液体之间的表面张力，使它们更容易混合和分散。
这一性质使PEGMO成为制备乳液、乳化剂和稳定剂的重要成分。
PEGMO具有良好的润滑性和润湿性。
由于其分子结构中带有聚乙二醇和油酸，PEGMO能够在固体和液体之间形成一层薄膜，起到减少摩擦和增加润滑的作用。
PEGMO常被用作润滑剂、润滑油和防腐剂。
PEGMO还具有良好的溶解性。
它可以在水和有机溶剂中均能溶解，并且可以与许多化合物形成复合物。
这一特性使得PEGMO在制备纳米材料、聚合物复合材料和药物传递系统等方面具有潜在的应用价值。
3. PEGMO的应用领域PEGMO在众多领域中得到广泛应用，以下是几个主要应用领域的简要介绍。
PEGMO在化妆品和个人护理产品中被广泛使用。
由于其良好的润滑性和润湿性，PEGMO可以作为护肤霜、唇膏、洗发水等产品中的成分，增加其舒适度和触感。
PEGMO在医药领域中具有重要的应用。
由于其良好的溶解性和可调控的药物释放性能，PEGMO被广泛用作药物传递系统中的载体。
材料科学与工程专业英语课文翻译(1,2,3,10).
United 1 材料科学与工程材料在我们的文化中比我们认识到的还要根深蒂固。
如交通、房子、衣物,通讯、娱乐和食物的生产,实际上,我们日常生活中的每一部分都或多或少地受到材料的影响。
历史上社会的发展、先进与那些能满足社会需要的材料的生产及操作能力密切相关。
实际上,早期的文明就以材料的发展程度来命名,如石器时代,铜器时代。
早期人们能得到的只有一些很有限的天然材料,如石头、木材、粘土等。
渐渐地,他们通过技术来生产优于自然材料的新材料,这些新材料包括陶器和金属。
进一步地,人们发现材料的性质可以通过加热或加入其他物质来改变。
在这点上,材料的应用完全是一个选择的过程。
也就是说,在一系列非常有限的材料中,根据材料的优点选择一种最适合某种应用的材料。
直到最近,科学家才终于了解材料的结构要素与其特性之间的关系。
这个大约是过去的60 年中获得的认识使得材料的性质研究成为时髦。
因此,成千上万的材料通过其特殊的性质得以发展来满足我们现代及复杂的社会需要。
很多使我们生活舒适的技术的发展与适宜材料的获得密切相关。
一种材料的先进程度通常是一种技术进步的先兆。
比如,没有便宜的钢制品或其他替代品就没有汽车。
在现代,复杂的电子器件取决于所谓的半导体零件.材料科学与工程有时把材料科学与工程细分成材料科学和材料工程学科是有用的。
严格地说,材料科学涉及材料到研究材料的结构和性质的关系。
相反,材料工程是根据材料的结构和性质的关系来设计或操纵材料的结构以求制造出一系列可预定的性质。
从功能方面来说,材料科学家的作用是发展或合成新的材料,而材料工程师是利用已有的材料创造新的产品或体系,和/或发展材料加工新技术。
多数材料专业的本科毕业生被同时训练成材料科学家和材料工程师。
“structure”一词是个模糊的术语值得解释。
简单地说,材料的结构通常与其内在成分的排列有关。
原子内的结构包括介于单个原子间的电子和原子核的相互作用。
在原子水平上,结构包括原子或分子与其他相关的原子或分子的组织。
Polymer Science and Engineering
Polymer Science and Engineering Polymer science and engineering play a crucial role in shaping our modern world, impacting various industries such as automotive, aerospace, electronics,and healthcare. The field focuses on the study of polymers, which are large molecules composed of repeating subunits. These materials exhibit uniqueproperties that make them versatile and valuable for a wide range of applications. Understanding the principles of polymer science and engineering is essential for developing innovative solutions to address the challenges of today's society. One of the key aspects of polymer science is the structure-property relationship,which explores how the arrangement of polymer chains influences their physical and chemical properties. By manipulating the molecular structure through synthesis and processing techniques, researchers can tailor the properties of polymers to meet specific requirements. For example, the addition of crosslinking agents can enhance the mechanical strength of polymers, making them suitable for structural applications in construction and manufacturing. In addition to their mechanical properties, polymers also exhibit unique thermal, electrical, and optical characteristics that make them ideal for a wide range of applications. For instance, polymers such as polyethylene and polypropylene are excellent insulators, making them valuable materials for electrical and electronic devices. On the other hand, polymers like polycarbonate and acrylics are transparent and lightweight, making them suitable for optical and display technologies. The field of polymer engineering focuses on the design and optimization of polymer-based materials and products. Engineers leverage their knowledge of polymer science to develop new materials with enhanced performance and functionality. By incorporating additives, fillers, and reinforcements, engineers can improve the mechanical, thermal, and chemical properties of polymers to meet the demands of specific applications. For example, the addition of carbon nanotubes can enhance the conductivity of polymers, making them suitable for advanced electronic devices. Moreover, polymer engineers play a crucial role in sustainability efforts by developing biodegradable and recyclable polymers that reduce environmental impact. With the increasing awareness of environmental issues, there is a growing demand for eco-friendly alternatives to traditional plastics. Polymer engineers are at the forefront ofresearch and development, exploring new materials and processes to create sustainable solutions for a greener future. In conclusion, polymer science and engineering are interdisciplinary fields that drive innovation and progress in various industries. By understanding the structure-property relationship of polymers and leveraging engineering principles, researchers and engineers can develop advanced materials with tailored properties for diverse applications. From improving mechanical strength to enhancing thermal conductivity, polymers offer endless possibilities for innovation and sustainability. As we continue to push the boundaries of polymer science and engineering, we pave the way for a brighter and more sustainable future.。
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Shear band and Craze
剪切带和银纹
Shear band 剪切带
剪切带是韧性聚合物在单向拉伸至屈 服点时出现的与拉伸方向成约45° 服点时出现的与拉伸方向成约 ° 角倾 斜的剪切滑移变形带 剪切带的厚度约1 ， 在剪切带内部， 剪切带的厚度约 m， 在剪切带内部 ， 高分子链沿外力方向高度取向 剪切带内部没有空隙， 因此， 剪切带内部没有空隙 ， 因此 ， 形变过 程没有明显的体积变化 剪切带的产生与发展吸收了大量能量。 剪切带的产生与发展吸收了大量能量 。 同时， 由于发生取向硬化， 同时 ， 由于发生取向硬化 ， 阻止了形 变的进一步发展
cos α
0
Aα F//
α
Aα =
F⊥ = F cosα
σ=
F A
F⊥
F
σ⊥ =
F⊥ F = cos 2 α = σ 0 cos 2 α Aα A0
A0
F F 1 σ // = // = sin α cos α = σ 0 sin 2α Aα A0 2
Analysis of the stress during tensile test
9.3 Fracture Theory of Polymers
高分子的断裂理论
Griffith Fracture Theory
Griffith断裂理论 该理论由Griffith于60年前为解释玻璃纤维的 于 年前为解释玻璃纤维的 该理论由 断裂强度而提出， 断裂强度而提出 ， 目前广泛应用于金属和非 金属材料的断裂现象 Griffith认为， 实际的脆性固体在受到外力作 认为， 认为 用时， 由于局部不均匀性， 用时 ， 由于局部不均匀性 ， 会在垂直于主应 力方向上产生裂缝， 力方向上产生裂缝 ， 在裂缝的两端产生应力 集中。 当局部应力超过材料的内聚力时， 集中 。 当局部应力超过材料的内聚力时 ， 就 会导致裂缝增长并进而使材料断裂
l l0 l ε= = l0 l0
Tensile strain
拉伸应变
l0 l l F
True stress
真应力
F σ’ = A
Typical stress-strain curve
Y: yield point
σy: yield strength 屈服强度 σ εy: elongation at yield 屈服伸长率 σy σb σb: break strength 断裂强度 εy: elongation at break 断裂伸长率
软~硬：模量 硬
强~弱：拉伸强度 弱
韧~脆：断裂能 脆
True stress-strain curve
真应力-应变曲线
True stress
真应力
F σ′ = A
无体积变化 且均匀变形
σ
σ′
σy
A0l0 A0 A= = l 1+ ε
σ ε
F (1 + ε ) σ′ = = σ (1 + ε ) A0
Principle of Yielding
σ ⊥ = σ 0 cos 2 α
σ // = σ 0 sin 2α
1 2
屈服原理
σ⊥ = σ0
σ⊥ = σ0
2
α =0
α = 45
o
σ // = 0
σ // = σ0
2
α = 90 o
σ // = 0
σ⊥ = 0
韧性材料拉伸时， 韧性材料拉伸时 ， 斜截面上的最大切应力首先增加到材料的剪切 强度，因此材料屈服，并出现与拉伸方向成45° 强度，因此材料屈服 ，并出现与拉伸方向成 °角的剪切滑移变形 进一步拉伸时， 剪切带中由于分子链高度取向强度提高， 带 。 进一步拉伸时 ， 剪切带中由于分子链高度取向强度提高 ， 暂 时不发生进一步的变形。 而其边缘则进一步发生剪切变形。 同样， 时不发生进一步的变形 。 而其边缘则进一步发生剪切变形 。 同样 ， 在135°的斜截面上也发生剪切变形，因而试样逐渐生成对称的细颈， °的斜截面上也发生剪切变形，因而试样逐渐生成对称的细颈， 直至细颈扩展至整个试样 脆性试样在最大切应力达到剪切强度之前， 脆性试样在最大切应力达到剪切强度之前 ， 横截面上的法向正应 力已达到材料的拉伸强度， 因此试样还来不及屈服就断裂了， 力已达到材料的拉伸强度 ， 因此试样还来不及屈服就断裂了 ， 而 且断面与拉伸方向相垂直。 且断面与拉伸方向相垂直。
σ t = I(σ y , σ b )
断裂点 屈服点
Y Y’ B’ B
B: break point
Tensile strength 拉伸强度
α
0
Young's Modulus 杨氏模量
E = tan α
εy
εb
ε
Fracture energy 断裂能: OYB面积
Molecular motion during tensile test 拉伸过程中高分子链的运动
剪切带
Shear band and Craze
剪切带和银纹
Craze 银纹
裂缝
银纹是聚合物在应力作用下， 银纹是聚合物在应力作用下，于材料的某些 银纹 薄弱环节出现应力集中而产生局部的塑性形 变和取向， 变和取向，以至于在材料表面或内部垂直于 应力方向上出现的微细的空化条纹状形变区 银 纹 的 长 约 100m 、 宽 约 10m 、 厚 约 1m ， 外 形 与 裂 缝 （Crack）相似，但裂缝内部是空的，而银纹内部有许多高 ）相似，但裂缝内部是空的， 度取向的聚合物微纤， 度取向的聚合物微纤，这些微纤把银纹体的两个面连接起来 并沿外力方向取向，微纤之间为空隙隔开。 并沿外力方向取向，微纤之间为空隙隔开。银纹体中聚合物 的体积分数约为40~60%。 银纹进一步发展 ， 以至于微纤断 的体积分数约为 。 银纹进一步发展， 裂时， 裂时，就成为裂缝 银纹形变导致的体积增加， 银纹形变导致的体积增加，而截面积基本不变 银纹的产生与发展吸收了大量能量
Shear band and Craze
剪切带和银纹
银纹和剪切变形带是聚合物形变的两种主要形式 某种聚合物采取什么形式主要取决于其临界缠结分子量 Mc ， 非晶态聚合物的分子量达到 c 以上时就会产生分 非晶态聚合物的分子量达到M 子间缠结， 子间缠结，形成物理交联点 PS等脆性聚合物的 c（19000）较大，缠结点密度低， 等脆性聚合物的M ） 较大， 缠结点密度低， 等脆性聚合物的 缠结链伸长的长度大， 缠结链伸长的长度大，容易产生银纹 PC等韧性聚合物的 c （ 2490）较小 ， 缠结点密度高 ， 等韧性聚合物的M 等韧性聚合物的 ） 较小，缠结点密度高， 缠结链伸展较困难，容易发生应变硬化， 缠结链伸展较困难，容易发生应变硬化，这种情况下银 纹化形变不会得到充分发展， 纹化形变不会得到充分发展，当应力增大到剪切屈服应 力时，试样即可产生剪切形变 力时，
Banding 弯曲
强度，模量
Friction 摩擦
摩擦系数，磨损量…
…
9.1 Stress-Strain Behavior Stressof Polymers
高分子的应力高分子的应力-应变行为
Stress-strain curve
Tensile stress
拉伸应力
应力-应变曲线
A A0 F
F σ= A0
Polymer Physics
高分子物理
9 Mechanical Properties of Polymers
高分子的力学性能
Mechanical Properties
Tensile 拉伸
拉伸强度，拉伸（杨氏）模量，断裂伸长率， 屈服强度，100％定伸应力…
Impact 冲击
悬臂梁，简支梁，落锤… 缺口，无缺口
ε
Types of stress-strain curve
应力-应变曲线的类型
序号 类型 曲线 模量 拉伸强度 断裂伸长率 断裂能 实例 高 中 小 小 PS PMMA 酚醛树脂 高 高 中 中 硬PVC AS 高 高 大 大 PC ABS HDPE 低 中 很大 大 硫化橡胶 软PVC 低 低 中 小 未硫化橡胶 齐聚物 1 硬而脆 2 硬而强 3 强而韧 4 软而韧 5 软而弱
Stress Concentration
应力集中
在无限大的平板上刻一椭圆孔。 在无限大的平板上刻一椭圆孔。在垂直于长轴方向施以均 匀张应力，则在椭圆孔附近存在应力集中， 匀张应力，则在椭圆孔附近存在应力集中，两端的应力最 大。Lnglis导得 导得
2a σ m = σ 0 1 + b
σ0
断裂产生的新表面所需要的表面能是由材料内部的 弹性储能的减少来补偿的 裂缝附近集中了大量的弹性储能， 裂缝附近集中了大量的弹性储能，所以材料在裂缝 处先行断裂
σm
2b 2a
椭圆
a >> b
σ m ≈ 2σ 0
a
ρ
σ0
Stress distribution near an ellipsoid
裂缝
裂缝尖端 曲率半径
Griffith Equation
Griffith方程 Griffith方程
Griffith线弹性断裂理论从能量平衡的观点分析 线弹性断裂理论从能量平衡的观点分析 断裂过程。 断裂过程。认为
Principle of Yielding
屈服原理
聚合物为什么会屈服？屈服后为什么会产生细颈？ 聚合物为什么会屈服？屈服后为什么会产生细颈？
韧性聚合物在屈服点时常可看到试样 上出现与拉伸方向成约45° 上出现与拉伸方向成约 ° 角倾斜的 剪切滑移变形带（ 剪切滑移变形带 （ Shear band)， 并 ， 且逐渐生成对称的细颈 F// = F sin α A
σ ε