Microstructures of Polymers Prepared by Free-Radical Polymerization

小行星9312048 本研究将致力于阐明聚醋酸乙烯酯、各种偏二氯乙烯聚合物和聚氯乙烯的详细结构和聚合机理。 所有这些聚合物都具有重大的技术意义，并且它们都是通过自由基聚合而商业化制造的。 大部分的努力将涉及到识别和定量的聚合物中的结构缺陷，如长和短的分支，长链端，外来不饱和，外来结构含氧，和来自溶剂的基团。 主要的分析工具将是高场核磁共振，聚氯乙烯和偏氯乙烯聚合物将首先化学转化为相应的“聚乙烯”，以便于分析。 将通过将聚合物光谱与在项目过程中合成的参考模型的光谱进行比较来确认共振归属。 在聚（乙酸乙烯酯）的情况下，一个主要的目标将是充分了解芳香族溶剂对聚合化学和动力学的显着影响。 对聚氯乙烯和偏二氯乙烯聚合物的研究将特别关注导致这些材料热不稳定性的结构缺陷。 从该项目获得的结果应建议修改聚合过程的方法，以形成具有改进性能的聚合物。 ***

9312048 Starnes This research will be directed toward the elucidation of the detailed structures and polymerization mechanisms of poly(vinyl acetate), various vinylidene chloride polymers, and poly(vinyl chloride). All of these polymers have great technological significance, and all of them are made commercially by free-radical polymerization. Much of the effort will relate to the identification and quantification of structural defects in the polymers such as long and short branches, long-chain ends, adventitious unsaturation, adventitious structures containing oxygen, and groups derived from solvents. The principal analytical tool will be high-field Nuclear Magnetic Resonance, and both the poly(vinyl chloride) and the vinylidence chloride polymers will first be converted chemically into the corresponding "polyethylenes" in order to facilitate the analyses. Resonance assignments will be confirmed by comparing the polymer spectra with those of reference models that are to be synthesized during the course of the project. In the case of poly(vinyl acetate), a major goal will be to understand fully the striking effects of aromatic solvents on the polymerization chemistry and kinetics. The work with poly(vinyl chloride) and the polymers of vinylidene chloride will be concerned especially with the structural defects that contribute to the thermal instability of these materials. Results obtained from the project should suggest ways of modifying the polymerization processes in order to form polymers with improved properties. ***