单电子转移活性自由基聚合制备星形聚合物及性能研究

As a polymerization method replacing atom transfer radical polymerization(ATRP), single electron transfer living radical polymerization(SET-LRP), which is the latest research result for living radical polymerization, is entirely different from ATRP in the catalytic process and has many advantages such as little dosage of transition metal, short reaction time, being operated at (or below) room temperature, and so on. Similar to ATRP, the average molecular weight and molecular weight distribution of polymers synthesized by SET-LRP can be controlled, the length of polymer chain is more homogeneous and the weak link of which may be subtracted. Star polymers are comprised of multiple arms or branches radiating from a central point or core and have been of huge scientific interest since they were first prepared sixty years ago, as a result of their unique physical properties. Star polymers are not just an academic curiosity, but are currently employed or under investigation in a wide range of industries and commercial materials ranging from engine oils and coating technologies to contact lenses and biomedical devices. Although there are many different types of star polymers and methods for their synthesis, recent advances in the field of controlled radical polymerisation have enabled the facile production of complex star polymer architectures from a large range of monomer families, without the requirement of highly stringent reaction conditions. By document retrieval, it was found that, up to now, the research about SET-LRP to synthesis water-soluble star polymer has not been reported publicly. In this topic, acrylamide-based monomers by SET-LRP will be researched. Meanwhile, the polymerization technology will be confirmed and the properties of target products will be researched. The work has great significance in the academic for the development of SET-LRP and application field of ionic liquid.

单电子转移活性自由基聚合（SET-LRP），一种代替原子转移自由基聚合（ATRP）的方法，其催化过程与ATRP完全不同，具有过渡金属用量少，反应时间短，并可在室温或低于室温下操作等优点，是活性自由基聚合的最新研究成果。与ATRP方法一样，该法合成的聚合物平均分子量及其分布等可控，链长更均匀或可消减链中薄弱环节等。星形聚合物是由线性高分子链连接于一中心核而形成的星形大分子，与传统的线性高分子相比，三维的星状高分子具有高溶解度、低粘滞性和非晶化等特点。通过文献检索，发现迄今为止，国内外有关星形水溶性聚合物的SET-LRP的研究报道尚未见到。本课题通过研究适合丙烯酰胺类单体聚合的催化-引发体系，进而确定星形水溶性聚合物合成的聚合反应工艺，并研究目标产物的性能，对于拓展单电子转移活性自由基聚合法的应用领域具有重要的科学意义。

该项目通过研究适合水溶性类单体聚合的催化-引发体系，进而确定星形水溶性聚合物合成的聚合反应工艺，并研究目标产物的性能，对拓展单电子转移活性自由基聚合法的应用领域具有重要的科学意义。采用2-溴异丁酰溴(BIB)对聚氧乙烯甘油醚、聚乙烯亚胺、淀粉大分子端基进行改性，合成了系列水溶性星形支化大分子引发剂，并将该系列引发剂用于单电子转移活性自由基法制备水溶性星形聚合物，分析星形聚合物结构与性能之间的构效关系。.以四氯化碳(CCl4)为引发剂，Cu0粉/Me6-TREN为催化体系，在水溶液中实现了NaAA和AM的单电子转移活性自由基聚合(SET-LRP)，得星形 P( AM-co-AA) 。考察了引发剂用量、催化剂用量、失活剂用量及引发温度和反应物浓度对共聚物黏均分子量的影响，得到分子量高达331万的部分水解星形聚丙烯酰胺。以HPEI1800In8为大分子引发剂，引发DMAEMA的SET-LRP，在0 ℃下成功实现了DMAEMA的水相可控活性自由基聚合。研究表明：物料加入量等都对聚合反应有影响，其配比存在最优值。扩链实验结果表明：通过SET-LRP得到的PDMAEMA具有活性并可引发单体继续聚合。所得的聚合物在选择性溶剂中自组装，用浊度法和透射电镜研究了不同臂数星形PDMAEMA的响应行为。以Gly-Br3作为大分子引发剂，引发NIPAM的SET-LRP，通过扩链反应(DP=120- 360)研究了这一聚合反应的活性特征，结果表明：单体转化率在30 min内可达100%且聚合产物分子量分布小于1.18。通过连续加料链延伸的方法，分别加入NIPAM，DMAEMA，NVP，合成嵌段聚合物，对嵌段星形共聚物的响应行为进行研究，随着pH值降低，其临界溶解温度升高。当pH=3.0时，表现出弱的热响应行为，随着pH值增加（pH=8.6和10.0），表现出强的热响应行为，可形成较大的球形胶束及囊泡。以SET-LRP法在水溶液中合成含纳米二氧化硅的新型星形共聚物。结果表明，纳米SiO2 功能单体(NSFM)成功地参与该反应。通过正交试验确定聚合反应最佳物料摩尔比，当剪切速率大于100 s-1时，星形共聚物表现出剪切增稠的流变性能。