含氢键相互作用的IPN体系(Ⅴ)——体系组成变化对相结构和性能的影响

Interpenetrating Polymer Networks with Introduced Hydrogen Bonding ( Ⅴ ) ——The Effecct of Composition on Phase Structure and the Properties

研究了含引入氢键的PBA和PS(OH)组成的IPN体系,PS(OH)为含羟基的改性聚苯乙烯.与相应的非交联聚合物的共混体系不同,IPN均显示两相结构,一相几乎为纯PBA,另一相则是混合相;仅当PS(OH)中羟基含量高达30 mol％且其为IPN的主要成分时,才有相当量的PS(OH)溶入PBA为主的相.IPN的模量-组成行为可用Budiansky方程描述,表明两相的连续性,这一结论与透射电子显微镜的观察一致.

IPN's of polybutyl acrylate (PBA) and PS(OH), a copolymer of styrene and HFMS (a hydroxyl-containing monomer) were prepared by a sequential process, DSC and TEM show that all the IPN' s display two-phase structure even when the hydroxyl content in PS (OH) reached 30 mol%. The compositions of the two phases were calculated from the Tg values based on the “copolymerization equation”. It is found that there is no composition change of the two phases when the content oi PS(OH) in the IPN' s is less than 50%. Apparent Tg increase of the PBA-rich phase is found when the hydroxyl content in PS (OH) is as high as 30 mol% and PS (OH) becomes the major component in the IPN' s(>60%). This indicates that PS(OH) can be partially solubilized in the PBA-rich phase only when there are enough hydrogen bonds existing. The relative modulus of the IPN' s as a function of the total composition shows that in the composition range of PS(OH) about 30%-50% ?there is a drastic change of the modulus accompanying the variation of the phase structure. The modulus data are in good agreement with the Budi-ansky equation rather than the Kerner equation implying some extent of phase continuity.