结晶PMMA的NMR研究  

THE NMR STUDY OF CRYSTALLINE PMMA

作　　者：易菊珍[1] 冯汉桥[1] 

机构地区：[1]中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室

出　　处：《波谱学杂志》1999年第1期41-44,共4页Chinese Journal of Magnetic Resonance

基　　金：国家自然科学基金

摘　　要：用ＮＭＲ方法和ＤＳＣ技术研究了结晶聚甲基丙烯酸甲酯（ＰＭＭＡ）性质和玻璃化转变温度，并与无定形ＰＭＭＡ作了比较．通过１３ＣＣＰＭＡＳ谱，观察到了结晶ＰＭＭＡ与无定形ＰＭＭＡ的谱的线形，线宽，化学位移都十分类似，其中αＣＨ３分裂为两个峰，我们将它归属为γ旁式效应所对应的反式和旁式构象．而反门控碳谱显示ＰＭＭＡ中有四种状态，即等规ＰＭＭＡ结晶态和无定形态，间规ＰＭＭＡ结晶态和无定形态．通过测定Ｔ２（Ｈ）和旋转坐标系中质子的自旋晶格弛豫时间Ｔ１ρ（Ｈ），我们分别得到了两Ｔ２（Ｈ）值和两个Ｔ１ρ（Ｈ）值，对应于晶区与非晶区。The relaxation character and glass transition temperature of crystalline poly(methyl methacrylate)(PMMA) have been studied by means of NMR and DSC techniques. Compared with amorphous PMMA, the 13 C CP/MAS spectra of the crystalline one has similar band shape, band width and chemical shifts. α CH 3 carbon resonance exhibits two bands with a very asymmetrical shape, which may be related to conformational structure in sequence of the so called γ gauche effect. The two values of the proton spin lattice relaxation time in rotating frame T 1ρ (H) observed correspond to amorphous and crystaline structure respectively dectected by inverse gated decoupling. Aggregated structure wasn't detected by NMR means.

关 键 词：NMR弛豫时间 DCS 玻璃化 结晶 PMMA 

分 类 号：O632.52[理学—高分子化学]