甲基丙烯酸甲酯與乙烯酚之共聚物中序列分佈與分子量分佈對氫鍵強度的影響

Abstract

本論文以第三丁基氧苯乙烯(4-tert-Butoxystyrene)、乙醯氧基苯乙烯(4-Acetoxystyrene)及甲基丙烯酸甲酯(Methyl methacrylate)作為單體，並以陰離子、自由基、原子轉移自由基三種聚合反應及一水解反應去除保護基，合成一系列的Poly(vinylphenol-co-methyl methacrylate)團聯式及雜亂式共聚物，並由紅外線光譜證明因兩者的序列分佈不同，團聯式共聚物內會有分子內屏幕效應，以致於相同PVPh含量的PVPh-b-PMMA及PVPh-r-PMMA中，PVPh-r-PMMA內C=O基形成氫鍵的比例較高且其分間作用平衡常數也較大；此外，分子量分佈(PDI)狹小的PVPh-b-PMMA其玻璃轉移溫度(Tg)較相同PVPh含量的PVPh-r-PMMA高。

A series of poly(vinylphenol-co-methyl methacrylate) block and random copolymers were prepared by anionic、free radical and atom transfer radical polymerizations of 4-tert-butoxystyrene、4-acetoxystyrene and methyl methacrylate, followed by selective removal of the 4-tert-butoxystyrene and the 4-acetoxystyrene protective group by hydrolysis reaction, respectively. Infrared spectra provide positive evidence that the random copolymer has higher fraction of hydrogen bonded carbonyl group and larger inter-association equilibrium constant with similar vinylphenol content than the block copolymer due to the different sequence distribution, which may come from the so called intramolecular screening effect. However, the block copolymer with the lower polydispersity index has the higher glass transition temperature than the random copolymer under the same composition.