Polymethylene Intermediates in Thermal and Photoinduced "Charge Transfer" Polymerization

热和光诱导“电荷转移”聚合中的聚乙烯中间体

• 批准号: 9216621
• 负责人: Henry Hall
• 金额: $ 27万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9216621&HistoricalAwards=false
• 关键词: Polymethylene; Intermediates; Thermal; Photoinduced; Charge

Spontaneous polymerizations, observed when electron-rich and electron-poor olefins are mixed, are initiated by tetramethylene intermediates which can be either zwitterionic or diradical in nature. Spontaneous free-radical copolymerizations have similarly been shown to compete with the Diels-Alder cycloadditions in reactions of dienes and olefins; these polymerizations are proposed to be initiated by 2-hexene-l,6-diradicals or zwitterions. To date, highly functionalized olefins have been used to obtain fast and clean reactions. These investigations will be extended to common industrial olefin/olefin reactions, such as styrene and acrylonitrile, and diene/olefin reactions, such as the isoprene/maleic anhydride system. Moreover, the effect of added Lewis acid to increase the electronphilicity of the electron-poor olefin will be studied in each case. The generation of diradicals or zwitterions from suitably substituted cyclopropanes and cyclobutanes will be used for initiation of polymerization of other monomers. The photochemical behavior of these systems will be compared to the thermal reactions and a uniform mechanistic picture will be established. This study is a continuation of the principal investigator's elucidation of the mechanism of spontaneous charge- transfer polymerizations. This research has as its aim to understand how, under certain well-defined conditions, some monomer pairs can polymerize in the absence of the usually needed initiating substances. Greater control of the kinetics of polymerization and the resulting structures is a likely outcome.

自发聚合，当富电子和 贫电子烯烃混合，由四亚甲基引发， 中间体可以是两性离子或双自由基， 自然 自发自由基共聚具有类似的 已被证明与Diels-Alder环加成竞争， 二烯和烯烃的反应;提出了这些聚合 由2-己烯-1，6-双自由基或两性离子引发。 到 迄今为止，高度官能化的烯烃已被用于获得快速的 干净的反应。 这些调查将扩大到 常见的工业烯烃/烯烃反应，如苯乙烯和 丙烯腈和二烯/烯烃反应，例如 异戊二烯/马来酸酐体系。 此外，添加的效果 刘易斯酸增加贫电子的亲电子性 将在每种情况下研究烯烃。 双自由基的产生 或来自适当取代的环丙烷的两性离子， 环丁烷将用于引发其它环丁烷的聚合。 单体。 这些系统的光化学行为将是 与热反应相比， 将建立。 本研究是主要的延续 研究人员对自发充电机制的解释- 转移聚合 这项研究的目的是了解在某些情况下， 在定义明确的条件下，一些单体对可以在 缺乏通常需要的引发物质。 更大 聚合动力学的控制和所得的 结构是可能的结果。