川大高分子复试专外(川大DR给的)

聚氯乙烯polyvinyl chloride聚丙烯Polypropylene聚苯乙烯Polystyrene 聚碳酸酯P olycarbonate线性低密度聚乙烯L inear low- density polyethylene聚酰胺Polyamide 结晶度Crystallinity粘弹性行为Viscoelastic behavior蠕变creep热变形温度Heat distortion temperature热降解Thermal d egradation 玻璃化转变温度Glass transition temperature 老化ageing弹性行为e lastic behavior拉伸强度tensile strength粘弹性Viscoelasticity 冲击强度impact strength 应力应变曲线Stress-strain curves注射成型Injection Molding 双螺杆挤出机twin-screw extruder 传递模塑Transfer molding 螺槽深度flight d epth压缩段compression section 计量段metering section模具型腔浇口gate吹塑成型Blow Molding 热成型Thermoforming旋转模塑Rotational molding-压延c alendering•Polyamide 聚酰胺Macromolecule 大分子•Amorphous 非晶Infrared spectroscopy 红外分光•X-ray Diffraction X光衍射disentanglement 解缠•Melt strength 熔体强度Reciprocating screw 往复螺杆•Polyurethane 聚氨酯Viscoelastic behavior粘弹性行为•Differential Scanning Calorimetry 示差扫描量热法•Coefficient of thermal expansion热膨胀系数•Vicat softening temperature 维卡软化温度•Molecular weight distribution分子量分布•Compression molding压缩模塑•Liquid crystal 液晶•Yield strength 屈服强度•Ejection system 顶出系统1.In some cases, the polymer molecules can pack together into regular, repeatingstructural patterns. These regularly packed regions are called crystals or crystalline regions. Although no polymer is completely crystalline, those with large part of crystalline areas are said to be crystalline or semicrystalline.有时，聚合物分子是由有一定规律的重复结构单元组成，这些区域叫做晶体或结晶区域。

虽然没有聚合物是完全结晶的，但我们仍然把那些具有大面积结晶区域的聚合物叫做晶体或半晶体。

2.Polymer chains are generally so long that significant intermolecular entanglement existseven in the liquid state. This entanglement in the liquid state is exhibited in the high viscosity of the polymer melts and solutions and in a property called melt strength3.An important thermal transition in the crystalline polymers is at the meting point,where the polymer molecules can move freely. Beyond the melting point, furtherheating will eventually cause the molecule to degrade because the thermal energy is sufficient to break the primary bonds of the molecules.晶态聚合物在熔点时，会发生一个重要的热转变，此时，聚合物分子能够自由运动。

在高于这温度时，断续加热会聚合物分解，因此此时热能足以使分子链发生断裂。

4.Most viscoelastic materials will also show significant deformations with static loads butover long period of time. This property is called creep, defined as the gradual deformation of a material under a static load.大部分粘弹性材料在恒定应力长期作用下，也会发生明显形变，这种性能叫做蠕变。

他是材料在静态力作用下发生的逐步形变。

5.An important parameter associated with the screw is the ratio of the length of theflighted portion of the screw to the inside diameter of the barrel or the outside diameter of the screw. This ratio is called the L/D ratio of the screw, which is a measure of the capability of the screw to mix materials and of the ability of the screw to melt certain hard-to melt materials.螺杆的一个重要参数是螺杆有螺纹部分长度和螺杆内径或外径的比值。

这个比值叫做螺杆长径比。

长径比是衡量螺杆混合能力和熔化难熔物料能力的重要指标。

6.The key to success in injection molding are (1) the proper machine for good melting andinjecting of the resin, (2) the proper resin for appropriate part performance, (3) good mold for part definition and removal, and (4) proper operation for efficient molding cycles.成功进行注射成型的重要因素是（1）合适的成型机械，进行良好的熔化和注射树脂，（2）选择合适的树脂以满足制品性能，（3）好的模具来保证尺寸精度和脱模，（4）合适的工艺来保证高效的模塑周期。

7.Plastics are very large molecules that are synthetic and can be or have been shaped.This definition generally excludes unmodified or slightly modified natural polymers. If the natural polymer has been substantially modified, the materials can be considered a plastic, assuming it is formable.8.The most important (but not the only) feature of a polymer that determines whether itwill be amorphous or crystalline is the shape of the polymer repeat unit. If the repeat unit is complex, especially with large pendant groups, the polymer cannot pack tightly together and will be amorphous. Some of the most common amorphous polymers are polystyrene, acrylic, polycarbonate, and most copolymers.9.When polymers are heated, the basic nature of the polymer is to move internally toabsorb the energy input. This internal motion can be molecular twisting, vibrating, stretching, translation and other movements. The extent of the motions is detected bya rise in the temperature of the polymer.当对聚合物加热时，聚合物内部会发生运动以及吸收输入的能量，这种运动有：分子扭曲、振动、拉伸、平动和其他分子运动。

分子运动程度通过聚合物温度的提高来检测。

10 .The complexity in polymers arises because solid polymeric materials can exist, in twovery distinct types of structures. In one type, the polymer molecules are randomly coiled about each other with entanglement. This structure type is called amorphous. In the second type of configuration, the polymer molecules can pack together into regular, repeating structural patterns. These regularly packed regions are called crystals or crystalline regions.11.In addition to the shaping of parts, extrusion is the most efficient and widely used method for melting plastic resin as part of the process of adding or mixing fillers, colorants, and other additives into the molten plastic. When used for shaping, the process is called extrusion molding.12.The injection molding process is conceptually simple. A plastic is melted and then forced into the cavity of a closed mold, which gives shape to the plastic. After sufficient time for the plastic part to solidify, the mold is opened and the part is removed.注射成型过程在概念上是很简单的，首先吧一种塑料熔化，在注射进闭合的模具空隙进行成型，经过足够长的时间，让塑料固化，再打开模具，进行脱模操作取出制件。