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Bulk Structure and Rheological Properties of Poly (macromonomer)s Associate with Multibranched Structure of High Branch Density

与高支化密度多支化结构相关的聚（大分子单体）的整体结构和流变性能

基本信息

批准号：
09650997
负责人：
TSUKAHARA Yasuhisa
金额：
$ 1.86万
依托单位：
Kyoto Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

Dynamic shear moduli of multibranched polystyrenes were measured as functions of frequency and temperature using a parallel-plate rheometer to investigate the effect of the multibranched structure of polymer molecules on the rheological properties. The multibranched polystyrenes are poly(macromonomer)s of omega-methacryloyloxyethyl polystyrene macromonomers (MA-PSt)s and statistical copolymers of the MA-PSt with methyl methacrylate (MMA) monomer. The dynamic shear moduli of a linear polystyrene were also measured under the same conditions for comparison. The master curve of the storage dynamic shear modulus G' for the poly(macro-monomer)s did not show the so-called plateau region and the G' gradually decreased from the edge of the glass transition region to the terminal zone. In this region, the loss modulus G" was always larger than G'. The plateau region became clear in the copolymers with less branch density. These results indicate that the intermolecular chain entanglement is restricted in the poly(macromonomer) system due to the multibranched structure of high branch density. Film forming properties of the branched polymers such as brittleness are consistent with the results of rheological properties, thus, can be ascribed to the absence of the intermolecular chain entanglement.

利用平行板流变仪测定了多支化聚苯乙烯的动态剪切模量随频率和温度的变化规律，研究了聚合物分子多支化结构对其流变性能的影响。多支聚苯乙烯是omega-甲基丙烯酰氧乙基聚苯乙烯大单体（MA-PSt）的聚（大单体）和MA-PSt与甲基丙烯酸甲酯（MMA）单体的统计共聚物。在相同的条件下，还测量了线性聚苯乙烯的动态剪切模量，以进行比较。聚（大单体）s的存储动态剪切模量G′的主曲线没有出现所谓的平台区，从玻璃化过渡区边缘到终端区G′逐渐减小。在这一区域，损耗模量G‘ ’始终大于G‘ ’。在分支密度较小的共聚物中，高原区变得明显。这些结果表明，在高分子体系中，高分支密度的多分支结构限制了分子间链纠缠。支化聚合物的成膜性能，如脆性，与流变性能的结果一致，因此，可以归因于分子间链纠缠的缺失。