聚[4-(4′-八甲基四硅氧基)二苯醚]分子量与特性粘数的关系

本工作对本体聚合的交替共聚物,聚[4-(4′-八甲基四硅氧基)二苯醚]作了重沉淀分级,再用粘度法、动态渗透压,光散射及GPC对级分和未分级试样作了分子量和分布宽度的测定。实验数据经多分散性改正后,得到该共聚物单分散的特性粘数-分子量关系式: [η]=2.33×10~(-3)M~(0.88)(毫升/克,25℃,四氢呋喃)该共聚物在四氢呋喃溶液中的第二维利系数A_2随分子量的增加而降低,依从A_2=3.60×10~(-2)的关系. 该共聚物在水中加热后放置几天会产生降解。紫外和红外光谱说明降解后共聚物的化学组成没有明显变化。

INTRINSIC VISCOSITY-MOLECULAR WEIGHT RELATIONSHIPFOR POLY [4-(4''-OCTAMETHYLTETRASILOXANYL)DIPHYNYLETHER]

A poly [4-(4'-octamethyltetrasiloxanyl) diphynylether] alternating copolymerprepared by bulk polymerization, has been fractionated by repeated precipitation method. All fractions together with unfractionated sample have been characterized by viscometry, dynamic osmometry, light scattering and GPC. After correction for polydispersity, a monodispersed [η] -M relationship has been obtained:[η] = 2.33 × 10-3 M0.88 (ml/g, at 25℃, in THF)For the copolymer in THF, The second virial coefficient A2 decreases as the molecular weight increases. The relationship is:We found that degradation occured to some extent when the copolymer was heated then kept for a few days in water. The results of investigation by UV and IR have shown that the chemical composition of the copolymer has not changed noticeably during degradation.