东华大学高分子材料《文献检索》期末作业

智能型水凝胶的制备
高分子0902 陈骏091100117
摘要智能型水凝胶是一类具有广泛应用前景的功能高分子材料, 但由于传统水凝胶存在一些缺点因而限制了其应用, 因此近年来围绕提高传统水凝胶的性能做了大量研究工作。

本文从四个主要方面综述了近年来智能型水凝胶制备的研究进展。

关键词水凝胶微凝胶IPN水凝胶快速响应性
智能型水凝胶是一类对外界刺激能产生敏感响应的水凝胶, 外界刺激可以是温度、pH 值、溶剂、盐浓度、光、化学物质等。

根据对外界刺激的响应情况, 智能型水凝胶分为: 温度响应性水凝胶、pH2响应性水凝胶、光响应性水凝胶、压力响应性水凝胶、生物分子响应性水凝胶、电场响应性水凝胶等。

由于智能型水凝胶的独特响应性, 在化学转换器、记忆元件开关、传感器、人造肌肉、化学存储器、分子分离体系、活性酶的固定、组织工程、药物载体等方面具有很好的应用前景, 因而对于这一类物质的研究引起越来越多科学家的注意。

但由于传统水凝胶存在一些缺点(例如机械性能比较差, 响应速度慢等) , 因而大大限制了水凝胶的应用; 因此近年来围绕提高水凝胶的响应速度、机械强度等性能问题, 科学家展开了一系列广泛的研究工作, 这方面的研究报道与日俱增。

智能型水凝胶近年来的发展主要可归结为以下四大方面。

1快速响应性水凝胶
传统水凝胶溶胀速度较慢, 吸收水的时间需要几小时甚至几天。

虽然慢的溶胀对于许多应用是有利的, 但也有许多场合需要高分子网络能很快地溶胀。

为了提高水凝胶的响应速度, 在传统水凝胶的基础上制备了几种新型水凝胶。

2物理交联水凝胶
由于交联剂不仅会影响包埋物质的完整性, 而且经常是有毒的化合物, 因此化学交联水凝胶使用之前必须除去未反应的交联剂。

而制备物理交联凝胶则可以避免使用交联剂, 因此近年对于物理交联水凝胶的兴趣越来越浓。

物理交联水凝胶的另一个优点是可以原位形成凝胶: 物理交联水凝胶在一定条件下是高分子溶液, 当条件(如温度、pH 等) 改变时, 形成凝胶。

因此, 物理交联水凝胶可用于制备可注射式药物缓释体系, 即: 使药物在温和的条件下混合在高分子溶液中, 然后注射到身体的一定部位, 在一定的生理条件下高分子溶液形成水凝胶, 其中的药物通过凝胶的分解或以其它方式缓慢释放, 从而达到控制药物释放的目的。

3具有规则构造的水凝胶
溶胀的水凝胶通常是无定型的, 因此没有特别的分子水平的有序结构, 这可能是合成高分子水凝胶缺乏机械强度以及快速响应的原因之一。

生物凝胶通常能形成非常有序的聚集体, 从而使得生物器官具有足够的机械强度和灵活的功能。

因此合成具有规则构造的水凝胶也是智能型水凝胶改性的一个主要研究方向。

4互穿聚合物网络( IPN)水凝胶
高分子水凝胶的应用已引起越来越多人的兴趣, 尤其是在药用和医用方面, 但它们的许多潜在应用却因其机械强度低而受到限制。

为提高凝胶的机械性能, 现已开发了许多新类型的凝胶。

在这些工作中许多是倾向于合成有微观相分离形态的高分子, 比如嵌段共聚物(其中亲水微区和疏水微区交替出现) , 这种多微区结构似乎能够满足血液相容性, 且机械性能得到提高。

另一种实现这一目标的方法是通过形成互穿聚合物网络来提高水凝胶的机械强度。

IPN是由两种或两种以上聚合物通过网络互穿缠结而形成的一类独特的聚合物共混物或聚合物合金。

IPN 特有的强迫作用能使两种性能差异很大或具有不同功能的聚合物形成稳定的结合, 从而实现组分之间性能的互补; 同时IPN 的特殊细胞状结构、界面互穿、双相连续等结构形态特征, 又使得它们在性能或功能上产生特
殊的协同作用。

同嵌段共聚物相比, 这些体系的相形态相对于环境的变化较稳定, 因为它是通过交联作用而固定的。

5结束语
智能型水凝胶在许多应用方面具有很大的潜能, 如pH2敏感和温度敏感水凝胶可用于靶向药物的控制释放; 对特定分子(如葡萄糖、抗原) 响应的水凝胶, 既可用于生物传感器也可用于药物释放体系; 光敏感性、压力响应性及电敏感性水凝胶也有用于药物释放和生物分离的潜力。

虽然从理论上来说实现这些应用是可行的, 但实际应用还要求对水凝胶的性能进行很大的改进。

所有这些刺激响应性水凝胶的最显著的缺点是它们的响应速度太慢, 因此制备快速响应性水凝胶是智能型水凝胶研究领域的一个重要课题。

实现这一目标的最简单的方法是制备较薄和较小的水凝胶, 但这种水凝胶往往没有足够的机械强度以满足实际应用。

另外用于药物载体的智能型水凝胶还要求有生物相容性, 合成具有更好生物相容性和生物降解性的新的高分子和交联剂对于成功的应用是最基本的。

总之, 研究开发具有优异性能的智能型水凝胶是一个富有挑战性的任务, 如果能及时总结已有的成果并将其应用于未来的研究中, 有可能制备出一系列具有所期望性能的智能型水凝胶。

参考文献
[ 1 ] 查刘生,王秀琴,邹先波,陆晨. 智能纳米水凝胶的制备及其刺激响应性能和应用研究进展[J]. 石油化工,2012,(2).
[ 2 ] 杨银,邵丽,邓阳全,张志斌. 智能水凝胶的制备及其在生物医学中的应用[J]. 化工新型材料,2010,(1).
[ 3 ] 郭艳,李树斌,王志龙. 丙烯酸／α-甲基丙烯酸／丙烯酰胺共聚物智能水凝胶的合成及评价[J]. 精细石油化工进展,2006,(2).
[ 4 ] 孙希孟,石军,曹少魁. 交联型温度/pH双敏水凝胶的设计与制备[J]. 高分子通报,2009,(10).
[ 5 ] 俞玫. 壳聚糖接枝聚丙烯酰胺水凝胶的制备及性质研究[J]. 天津化工,2006,(3).
[ 6 ] 肖慧,刘兆民. 环境敏感性水凝胶的制备和应用[J]. 上海大学学报(自然科学版),2003,(1).
[ 7 ] 孙成栋,赖小林,赵文军,文彬,高林. 苯乙烯/马来酸酐共聚物智能水凝胶的制备与性能[J]. 功能高分子学报,2008,(3).
[ 8 ] 林权,姜英男,杨旭东,马骋,杨柏. 荧光智能温度响应聚合物水凝胶微球的制备与性质研究[A]..[C].: ,2011:576. [ 9 ] 张建合. 智能型水凝胶的合成及其刺激响应性[J]. 信阳师范学院学报(自然科学版),1998,(2).
[10] 单军. 智能性高聚物水凝胶的种类及其合成方法[J]. 化工新型材料,1996,(4).
智能型水凝胶的制备
高分子0902 陈骏091100117
一
Title-题名: 智能纳米水凝胶的制备及其刺激响应性能和应用研究进展
Author-作者: 查刘生;王秀琴;邹先波;陆晨;
Organ-单位: 东华大学纤维材料改性国家重点实验室;
Source-文献来源: 石油化工
Keyword-关键词: 智能纳米水凝胶;;沉淀聚合;;反相乳液聚合;;交联;;刺激响应性能
Summary-摘要: 粒径为1～1 000 nm的智能纳米水凝胶是近年来受到国内外普遍关注的智能聚合物纳米材料。

介绍了制备智能纳米水凝胶的4种方法:沉淀聚合/交联法、反相乳液聚合/交联法、自组装/交联法和微模板成型/交联法,评述了这些制备方法的优缺点;同时论述了温度、pH、光、磁场和分子识别等单刺激响应性智能纳米水凝胶以及多重刺激响应性智能纳米水凝胶的研究进展情况;最后简单介绍了智能纳米水凝胶在药物输送与可控释放、医学诊断、生物传感器、智能微反应器和吸附与分离等方面的应用。

PubTime-发表时间: 2012-02-15
Year-年: 2012
Period-期: 02
PageCount-页码: 131-142
二
Title-题名: 智能水凝胶的制备及其在生物医学中的应用
Author-作者: 杨银;邵丽;邓阳全;张志斌;
Organ-单位: 西南交通大学生物工程学院;
Source-文献来源: 化工新型材料
Keyword-关键词: 智能;;水凝胶;;生物材料;;生物医学
Summary-摘要: 智能水凝胶对于外界微小的物理化学刺激,如温度、电场、磁场、光、pH、离子强度或压力等能够感知并在响应过程中有显著的溶胀行为或响应性。

本文介绍了智能水凝胶的分类及其合成方法,同时综述了智能水凝胶在药物控释、医用敷料、组织工程、角膜接触镜材料以及作为组织充填材料方面的应用,并对其发展趋势及应用前景作了简单的评述。

PubTime-发表时间: 2010-01-15
Year-年: 2010
Period-期: 01
PageCount-页码: 11-13+63
三
Title-题名: 丙烯酸／α-甲基丙烯酸／丙烯酰胺共聚物智能水凝胶的合成及评价
Author-作者: 郭艳;李树斌;王志龙;
Organ-单位: 河南油田勘探开发研究院,长江大学化学与环境工程学院,长江大学化学与环境工程学院南阳473132 长江大学化学与环境工程学院,荆州434023,荆州434023 湖北信息工程学校,荆门448000,荆州434023 Source-文献来源: 精细石油化工进展
Keyword-关键词: 水凝胶;;pH敏感性;;温度敏感性;;溶胀比;;丙烯酸;;α-甲基丙烯酸;;丙烯酰胺
Summary-摘要: 由丙烯酸(AA)、α-甲基丙烯酸(MAA)和丙烯酰胺(AM)合成了具有很好pH敏感性和一定温度敏感性的智能水凝胶,考察了合成温度、丙烯酰胺、交联剂和引发剂用量对制备的水凝胶溶胀性能的影响。

结果表明,在60℃下,单体AA和MAA用量分别为100 mmol和75 mmol时,单体AM、交联剂和引发剂用量分别为反应
物总质量的32．8％、0．2％和0．4％时,制备的水凝胶溶胀性能最好。

考察了介质的离子浓度、pH值和温度对水凝胶溶胀比的影响,结果表明,离子浓度越大,水凝胶的溶胀比越小;水凝胶具有一定的pH可逆性。

PubTime-发表时间: 2006-02-25
Year-年: 2006
Period-期: 02
PageCount-页码: 36-39
四
Title-题名: 交联型温度/pH双敏水凝胶的设计与制备
Author-作者: 孙希孟;石军;曹少魁;
Organ-单位: 郑州大学材料科学与工程学院;郑州大学化学系;
Source-文献来源: 高分子通报
Keyword-关键词: 智能水凝胶;;温度/pH响应;;共聚;;接枝;;互穿聚合物网络(IPN)
Summary-摘要: 刺激响应型水凝胶是其结构和性能随环境条件的变化而发生改变的一类智能高分子材料。

由于温度和pH值是生物和化学系统的两个重要因素,也是人体的重要生理指标,因此温度/pH双重响应型水凝胶的制备及其在医药领域的应用研究具有重要的理论和现实意义。

论文综述了近年来国内外温度/pH双敏水凝胶的设计与制备方法,并对其制备与应用的发展方向进行展望。

PubTime-发表时间: 2009-10-15
Year-年: 2009
Period-期: 10
PageCount-页码: 30-37
五
Title-题名: 壳聚糖接枝聚丙烯酰胺水凝胶的制备及性质研究
Author-作者: 俞玫;
Organ-单位: 天津大学药学院天津300072
Source-文献来源: 天津化工
Keyword-关键词: 壳聚糖;;丙烯酰胺;;智能水凝胶
Summary-摘要: 通过接枝共聚反应制备了几种壳聚糖接枝聚丙烯酰胺水凝胶,其中过硫酸钾为自由基引发剂,亚甲基双丙烯酰胺或甲醛为交联剂,并研究了实验因素,如交联剂浓度和单体比率对水凝胶溶胀能力的影响。

实验表明水凝胶具有离子强度、pH值和温度敏感性。

这种可随外界因素响应及“开关”的性质,使此类智能水凝胶有望成为生物制品载体,例如药物载体。

PubTime-发表时间: 2006-05-30
Year-年: 2006
Period-期: 03
PageCount-页码: 1-3+51
六
Title-题名: 环境敏感性水凝胶的制备和应用
Author-作者: 肖慧,刘兆民
Organ-单位: 上海大学射线应用研究所,上海大学射线应用研究所上海201800 ,上海201800
Source-文献来源: 上海大学学报(自然科学版)
Keyword-关键词: 温敏;;pH敏;;水凝胶
Summary-摘要: 该文综述了温敏水凝胶、pH敏水凝胶、温度和pH双重敏感性水凝胶近年来的研究情况,比较了化学法和辐射法制备的不同.该类水凝胶具有传感、处理和执行外界刺激的功能,作为智能材料具有良好的应用前
景.
PubTime-发表时间: 2003-02-28
Year-年: 2003
Period-期: 01
PageCount-页码: 67-72
七
Title-题名: 苯乙烯/马来酸酐共聚物智能水凝胶的制备与性能
Author-作者: 孙成栋;赖小林;赵文军;文彬;高林;
Organ-单位: 中国科学院新疆理化技术研究所;
Source-文献来源: 功能高分子学报
Keyword-关键词: 苯乙烯/马来酸酐共聚水凝胶;;pH敏感性;;温度敏感性;;离子强度敏感性;;动态溶涨性能Summary-摘要: 合成了苯乙烯/马来酸酐共聚物接枝聚乙二醇400(PEG400)水凝胶。

研究了环境pH、温度、离子强度对该凝胶溶涨性能的影响,并对凝胶的动态溶涨行为进行了分析。

结果显示该水凝胶对环境pH、温度、离子强度等变化均作出体积相转变响应,表现出了智能高分子凝胶的特性。

PubTime-发表时间: 2008-09-15
Year-年: 2008
Period-期: 03
PageCount-页码: 270-274
八
Title-题名: 荧光智能温度响应聚合物水凝胶微球的制备与性质研究
Author-作者: 林权;姜英男;杨旭东;马骋;杨柏;
Organ-作者机构: 吉林大学超分子结构与材料国家重点实验室;
SrcDatabase-来源数据库: 中国会议
City-会议地点: 中国辽宁大连
Meeting-会议名称: 2011年全国高分子学术论文报告会
Keyword-关键词: 智能;;聚合物微球;;荧光;;温敏
Summary-摘要: <正>敏感性高分子水凝胶表现出的智能特性,使其在药物释放、生物标记、荧光探针、传感器和仿生人工肌肉等方面具有非常广阔的应用前景。

本文首先通过无皂乳液共聚合的方式,两步法制备得到以硬质的PS-co-PNIPAM(聚苯乙烯-N-异丙基基丙烯酰胺)微球
PageCount-页码: 576
Year-年: 2011
九
Title-题名: 智能型水凝胶的合成及其刺激响应性
Author-作者: 张建合
Organ-单位: 信阳师范学院学报编辑部
Source-文献来源: 信阳师范学院学报(自然科学版)
Keyword-关键词: 智能水凝胶；合成；刺激响应性；溶胀；相转变
Summary-摘要: 本文综述了智能型水凝胶的制备方法及该凝胶对环境的刺激响应性，重点介绍了该凝胶的温敏效应、压敏效应、光敏效应及直流电场效应。

该类凝胶具有传感、处理和执行功能，作为智能材料具有良好的应用前景。

PubTime-发表时间: 1998-04-15
Year-年: 1998
Period-期: 02
PageCount-页码: 87-91
十
Title-题名: 智能性高聚物水凝胶的种类及其合成方法
Author-作者: 单军
Organ-单位: 合肥工业大学化工学院高分子材料专业
Source-文献来源: 化工新型材料
Keyword-关键词: 智能材料，高聚物水凝胶，刺激响应性
Summary-摘要: 本文简述了智能性高聚物水凝胶的发展及其刺激响应性。

着重介绍了至今已合成的高聚物水凝胶的种类和制备方法。

PubTime-发表时间: 1996-04-25
Year-年: 1996
Period-期: 04
PageCount-页码: 20-22+19
Preparation of Intelligent Hydrogel
高分子0902 陈骏091100117
一
Title: Synthesis of a chemically-crosslinked thermo-sensitive hydrogel film and in situ encapsulation of model protein drugs
Author: Biaobing Wang, Wen Zhu, Ying Zhang, Zigang Yang, Jiandong Ding
Source: Reactive and Functional Polymers
Keywords: Hydrogel; Biodegradable polymer; Protein; Controlled-release
Abstract: An intelligent and biodegradable hydrogel film was prepared via polymerization of a
well-designed macromer, and in situ encapsulation of model protein drugs in the hydrogel was performed in this paper. Hydrogels were prepared by polymerization of a synthetic macromer, in which the central part is a temperature-sensitive triblock copolymer composed of poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide), the extension along each end is biodegradable oligo (ε-caprolactone) (oligoCL) terminated with an acrylate group. The biodegradability of the resultant hydrogels was confirmed. The swelling/deswelling experiments revealed the negative and reversible
temperature-sensitivity of the hydrogels. The volume phase transition temperature is between the refrigerator temperature and human body temperature. Four model protein drugs (insulin, lysozyme, SOD and BSA) were encapsulated into the hydrogel via in situ polymerization of macromer aqueous solutions mixed with proteins. Proteins were found to be controlled released and the release rate was strikingly influenced by temperature. The in vitro release profiles of proteins of different molecular weights (MW) were measured. The half release time is found to be positively related to the molecular weight of examined model proteins. The novel chemically crosslinked hydrogels might be prospective as controlled-release carriers of biomacromolecular drugs.
Volume: 66
Issue: 5
PubTime: May 2006
Pages: 509-518
ISSN: 1381-5148
二
Title: Synthesis and degradation of intelligent hydrogels containing polyacetal segments
Author: Juan Du, Xiaobin Ding, Zhaohui Zheng, Yuxing Peng Source: European Polymer Journal Keywords: Intelligent hydrogel; Degradation; Poly(1,3-dioxolane)
Abstract: Intelligent hydrogels were first obtained by copolymerization of telechelic poly(1,3-dioxolane) (pDXL) with acrylic acid, acrylamide, N-isopropylacrylamide respectively. The synthesis and characterization of the networks were discussed. The swelling behavior of the hydrogel was dependent on the solubility parameter of the solvents and hydrogels. The networks containing polyacetal segments (pDXL) can degrade by acid in different solvents. DXL and few other cycle molecules measured by
GC–MS analysis were formed after degradation. According to the degradation products, the polymerization mechanism can be testified.
Volume: 38
Issue: 5
PubTime: May 2002
Pages: 1033-1037
ISSN: 0014-3057
三
Title: Synthesis and characterization of partially biodegradable, temperature and pH sensitive
Dex–MA/PNIPAAm hydrogels
Author: Xianzheng Zhang, Daqing Wu, Chih-Chang Chu Source: Biomaterials
Keywords: Biodegradable; Temperature and pH responsive; Hydrogel; Dextran–maleic acid; Abstract: The objective of the study is to impart temperature and pH-sensitive capabilities to polysaccharide-based hydrogels, so that they can change their swelling property upon external stimulation like temperature or/and pH. Dextran was chosen as the model polysaccharide compound for such a demonstration. A novel class of dextran–maleic anhydride (Dex–MA)/poly(N-isopropylacrylamide) hybrid hydrogels was designed and synthesized by UV photocrosslinking. The dextran-based precursor (Dex–MA) was prepared by substituting the hydroxyl groups in Dex by MA. This Dex–MA precursor was then photocrosslinked with a known temperature sensitive precursor (N-isopropylacrylamide, NIPAAm) to form hybrid hydrogels having a wide range of composition ratio of Dex–MA to NIPAAm precursors. Due to the biodegradable nature of dextran, these Dex–MA/PNIPAAm hybrid hydrogels are partially biodegradable. These smart hybrid hydrogels were characterized by Fourier transform infrared spectroscopy for structural determination, differential scanning calorimertry for thermal property, maximum swelling ratio, swelling kinetics, temperature response kinetics, and effect of pH. The data obtained clearly show that these new smart hybrid hydrogels were responsive to the external changes of temperature as well as pH. The magnitude of smart and hydrogel properties of these hybrid hydrogels were found to depend on the feed composition ratio of the two precursors. By changing the composition ratio of these two precursors, the phase transition temperature (lower critical solution temperature) of the hybrid hydrogels could also be adjusted to be or near the body temperature for the potential applications in bioengineering and biotechnology fields.
Volume: 25
Issue: 19
PubTime: August 2004
Pages: 4719-4730
ISSN: 0142-9612
四
Title: Synthesis of biodegradable thermo- and pH-responsive hydrogels for controlled drug release Author: Changwen Zhao, Xiuli Zhuang, Pan He, Chunsheng Xiao, Chaoliang He, Jingru Sun, Xuesi Chen, Xiabin Jing
Source: Polymer
Keywords: Double sensitive; Hydrogel; Controlled release
Abstract: Novel intelligent hydrogels composed of biodegradable and pH-sensitive poly(l-glutamic acid) (PGA) and temperature sensitive poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) (PNH) were synthesized and characterized for controlled release of hydrophilic drug. The influence of pH on the equilibrium swelling ratios of the hydrogels was investigated. A higher PNH content resulted in lower equilibrium swelling ratios. Although temperature had little influence on the swelling behaviors of the hydrogels, the changes of optical transmittance of hydrogels as a function of temperature were marked, which showed that the PNH part of hydrogel exhibited hydrophobic property at temperature above the lower critical solution temperature (LCST). The biodegradation rate of the stimuli-sensitive hydrogels in the presence of enzyme was directly proportional to the PGA content. Lysozyme was chosen as a model
drug and loaded into the hydrogels. The in vitro drug release experiment was carried out at different pH values and the release data suggested that both the pH and PNH content played important roles in the drug release behaviors of the hydrogels.
Volume: 50
Issue: 18
PubTime: 26 August 2009
Pages: 4308-4316
ISSN: 0032-3861
五
Title: Synthesis and characteristic of the thermo- and pH-sensitive hydrogel and microporous hydrogel induced by the NP-10 aqueous two-phase system
Author: Wei Li, Jianli Wang, Lizhuang Zou, Shuquan Zhu
Source: European Polymer Journal
Keywords: Thermo-sensitive hydrogel; pH-Sensitive hydrogel; Microporous hydrogel; Surfactant; Aqueous two-phase system
Abstract: A series of novel thermo- and pH-sensitive (NP10-AA TPS) hydrogels and microporous (NP10-AA MP) hydrogels, inducing by polyoxyethylene (10) nonyl phenyl ether (NP-10) aqueous
two-phase system, was designed and fabricated with acrylic acid (AA) as the monomer for the first time. The resultant NP10-AA TPS hydrogel, compared with the traditional TPS hydrogel, was more advanced in both of the high swelling ratio and the variable lower critical solution temperature (LCST). A simple synthesis technique of the NP10-AA MP hydrogel was developed. The thermo-sensitivity of the
NP10-AA TPS hydrogel including the initial swelling ratio, LCST, dehydrated efficiency, was depended strongly on the crosslinker (MBA), initiator (APS), NP-10 and AA concentration. The swelling rate of the NP10-AA MP hydrogel was much higher than that of AA hydrogel dehydrated in the same lyophilization condition.
Volume: 44
Issue: 11
PubTime: November 2008
Pages: 3688-3699
ISSN: 0014-3057
六
Title: Synthesis and properties of thermo- and pH-sensitive poly(diallyldimethylammonium
chloride)/poly(N,N-diethylacrylamide) semi-IPN hydrogel
Author: Jun Chen, Mingzhu Liu, Hongliang Liu, Liwei Ma, Chunmei Gao, Siying Zhu, Shaopeng Zhang Source: Chemical Engineering Journal
Keywords: Semi-IPN hydrogel; Thermosensitive; pH-sensitive; Fast response; Swelling kinetics Abstract: In this study, a novel semi-interpenetrating polymer network (semi-IPN) hydrogel of
poly(diallyldimethylammonium chloride)/poly(N,N-diethylacrylamide) (PDADMAC/PDEA) was prepared using ammonium persulfate as an initiator and N,N,N′,N′-tetramethylethylenediamide as an accelerator at room temperature. The influence of this additive on the property of resulting PDEA hydrogels was investigated and characterized. The interior morphology by scanning electron microscopy (SEM) revealed that PDADMAC introduced PDEA hydrogels have large and interconnected porous network structures. Differential scanning calorimetry (DSC) studies showed the difference in the state of the water between PDEA and semi-IPN hydrogels. The incorporating of PDADMAC significantly
improved the equilibrium swelling ratio of modified hydrogels when comparing with a normal PDEA hydrogel. The semi-IPN hydrogels exhibited improved thermosensitive characteristics, such as faster deswelling and swelling rates and great oscillating deswelling–swelling behavior, and the level of improvement depended on the PDADMAC content. The swelling dynamic transport of the hydrogels was analyzed based on the Fickian equation.
Volume: 159
Issues: 1–3
PubTime: 1 May 2010
Pages: 247-256
ISSN: 1385-8947
七
Title: Synthesis and properties of thermosensitive poly(N-isopropylacrylamide-co-methyl methacrylate) hydrogel with rapid response
Author: Xian-Zheng Zhang, Ren-Xi Zhuo
Source: Materials Letters
Keywords: Thermosensitive; Hydrogel; Phase separation; Rapid response; On–off switch
Abstract: Poly(N-isopropylacrylamide-co-methyl methacrylate) (P(NIPA-co-MMA)) hydrogel was synthesized by making use of the phase separation technique in the mixed solvent (distilled water/glacial acetic acid). This hydrogel responds to external temperature changes very quickly owing to its macroporous network structure formed during the copolymerization/crosslinking process. In this paper, the on–off switch behavior of the P(NIPA-co-MMA) hydrogel with different content of hydrophobic component (MMA) was further investigated and proved to be more sensitive. This fast responsive hydrogel with hydrophobic component and improved sensitivity of its on–off switch behavior would have potential applications in the field of drug-controlled release.
Volume: 52
Issues: 1–2
PubTime: January 2002
Pages: 5-9
ISSN: 0167-577X
八
Title: Synthesis and characterization of biodegradable pH-sensitive hydrogel based on
poly(ε-caprolactone), methacrylic acid, and Pluronic (L35)
Author: Ke Wang, Xu Xu, TingTing Liu, ShaoZhi Fu, Gang Guo, YingChun Gu, Feng Luo, Xia Zhao, YuQuan Wei, ZhiYong Qian
Source: Carbohydrate Polymers
Keywords: Biodegradable; pH sensitive; Degradation; Swelling/deswelling
Abstract: A series of biodegradable and pH-sensitive hydrogels based on poly(ε-caprolactone) (PCL), Pluronic, and methylacrylic acid (MAA) were successfully prepared by UV-initiated free radical polymerization, which were further characterized by 1H NMR and FTIR. Swelling behavior in different aqueous media and pH-responsibility of the hydrogels were studied in detail. With increase in pH value of aqueous media from 1.2 to 7.2, swelling ratio of the hydrogels increased accordingly. The hydrolytic degradation behavior of these hydrogels was also investigated in detail. The biodegradable pH-sensitive hydrogel obtained in this work might have great potential application in drug delivery system. Volume: 79
Issue: 3
PubTime: 11 February 2010
Pages: 755-761
ISSN: 0144-8617
九
Title: Fast synthesis of temperature-sensitive PNIPAAm hydrogels by microwave irradiation
Author: Zhenxia Zhao, Zhong Li, Qibin Xia, Hongxia Xi, Yuesheng Lin
Source: European Polymer Journal
Keywords: PNIPAAm hydrogels; Microwave irradiation; Swelling ratio; Porous structure
Abstract: A novel method, microwave irradiation synthesis, is proposed for the preparation of
thermo-sensitive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels. The PNIPAAm hydrogels were separately synthesized by using microwave irradiation method and water-bath heating method. Chemical groups, lower critical solution temperature (LCST) and surface morphology of these PNIPAAm hydrogels were characterized by FT-IR, DSC and SEM. Swelling ratios of the gels were measured gravimetrically in the temperature range from 10.0 to 60.0&#xa0;°C. Results showed that (1) the use of microwave irradiation can greatly shorten the reaction time required for PNIPAAm hydrogel synthesis from several hours to several minutes in comparison with water-bath heating method, and obviously improve the yields of the PNIPAAm gels, which were up to 99% after a short reaction time; (2) SEM micrographs and textural measurement revealed that the gels synthesized using microwave irradiation had more porous structure, and their average pore sizes and specific surface areas were larger than those of the gels synthesized using water-bath heating method; and (3) the PNIPAAm hydrogels synthesized using microwave irradiation had much higher swelling ratios at 10.0&#xa0;°C below the LCST, and had lower swelling ratio at 60.0&#xa0;°C above the LCST compared to the hydrogels synthesized by water-bath method.
Volume: 44
Issue: 4
PubTime: April 2008
Pages: 1217-1224
ISSN: 0014-3057
十
Title: Synthesis and characterization of temperature sensitive P-NIPAM macro/micro hydrogels Author: P.E. JagadeeshBabu, R. Suresh Kumar, B. Maheswari
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects
Keywords: Hydrogel; Thermo sensitive; PNIPA; Water–oil emulsion; Micro particles
Abstract: A thermo responsive macro porous poly(N-isopropylacrylamide) hydrogel was synthesized using free radical polymerization. The reaction was optimized by varying the reaction temperature, monomer, cross-linker and initiator based on the strength and swelling characteristics of the hydrogel. The morphology of the macro hydrogel was observed using scanning electron microscope (SEM). The swelling behavior of the macro hydrogel was performed gravimetrically and found that the gel synthesized at 36&#xa0;°C had maximum deswelling ratio of 34.5 (–). These optimized values were further used to synthesis micro hydrogels using water–oil (w/o) emulsion technique. The morphology of the micro hydrogels were observed through SEM. Effect of water–oil ratio and stirrer speed on the mean particle size of the micro hydrogels were studied. Micro hydrogels synthesized at 1:1.5&#xa0;w/o ratio and at 800&#xa0;rp m had perfect spherical shape and had least particle mean diameter of 0.74&#xa0;μm,
with SD of 0.5. Dye release kinetics with respect to temperature and time were studied using methylene blue solution. The release kinetic studies of micro hydrogel showed higher sustained release for
56&#xa0;h compared to the macro hydrogel.
Volume: 384
Issues: 1–3
PubTime: 5 July 2011
Pages: 466-472
ISSN: 0927-7757。