Nonpolymerizable Monomers in Living Cationic Polymerization

活性阳离子聚合中的不可聚合单体

• 批准号: 9502777
• 负责人: Rudolf Faust
• 金额: $ 22.5万
• 依托单位: University of Massachusetts Lowell
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-07-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9502777&HistoricalAwards=false
• 关键词: Nonpolymerizable; Monomers; Living; Cationic; Polymerization

9502777 Faust Kinetic and mechanistic studies on the additions of 1,1- diphenylethylene and related highly reactive but non- polymerizable monomers to living cationic polymers will be carried out. Conductance measurement and UV-vis spectroscopy combined with structure analysis will determine the kinetics and mode of addition, the extent of chain end ionization and dissociation. The kinetics of the addition of diphenylcarbenium ions to monomers will also be studied, and the absolute rate constants will be determined for free ions and ion-pairs. The results will be used in the synthesis of well-defined block copolymers by sequential monomer addition when the reactivity of the second monomer is higher then that of the first monomer. The method involves capping with a reactive but non-polymerizable monomer such as 1,1-diphenylethylene, followed by tailoring the Lewis acidity to the reactivity of the second monomer by the addition of titanium(IV) alkoxide, by replacing the Lewis acid with a weaker one or by the use of a common ion salt. Another objective of the proposal is to explore the synthesis of end-functional polymers by in-situ functionalization (end-quenching) of the living ends. The last objective of the proposal is to investigate the combination of living cationic and living anionic-group transfer polymerization for the synthesis of linear and hetero-arm star block copolymers. Two different methods are proposed based on 1,1-diphenylethylene capping; one based on site transformation and the other based on mutual annihilation of the living polymer cations and anions. %%% This research provides a novel approach to the synthesis of various well-defined polymers with precisely known architecture. Such polymers are needed to study the fundamental physical properties as a function of structure. ***

9502777关于添加1,1-二苯基乙烯和相关的高反应性但不可聚合的单体与活阳离子聚合物的高度反应性但不可分之无效的单体的浮士德动力学和机械研究。 电导测量和UV-VIS光谱与结构分析相结合将决定添加的动力学和模式，链端电离和解离的程度。 还将研究将二苯基碳酸离子添加到单体中的动力学，并且将确定自由离子和离子对的绝对速率常数。 当第二个单体的反应性比第一个单体的反应性高时，结果将用于通过顺序单体添加定义明确的块共聚物的合成。 该方法涉及用反应性但不可聚合的单体（例如1,1-二苯基乙二基）封盖，然后通过添加钛（IV）烷氧化钛（IV）烷氧化物（通过较弱的氧化二氧化钛或用较弱的液体酸代替），或通过使用较弱的甲酸或使用共同的离子盐来定制第二个单体的反应性。 该提案的另一个目的是通过生存目的的原位功能化（最终激烈）来探索最终功能的聚合物的综合。 该提案的最后一个目标是研究生物阳离子和活阴离子组转移聚合的组合，以合成线性和异臂恒星块共聚物。 提出了两种不同的方法，基于1,1-二苯基甲基限值。一个基于位点转换，另一个基于生物聚合物阳离子和阴离子的相互歼灭。 %% %%这项研究提供了一种具有精确架构的各种定义明确的聚合物的合成的新方法。 需要这样的聚合物来研究基本物理特性随结构的函数。 ***