The effects of solvent type on the concentration dependence of the compression modulus of thermoreversible isotactic polystyrene gels
The effects of solvent type on the concentration dependence of the compression modulus of thermoreversible isotactic polystyrene gels
复制标题
溶剂类型对热可逆全同立构聚苯乙烯凝胶压缩模量浓度依赖性的影响
DOI：
10.1002/polb.1988.090260205
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
J. Guenet
中科院分区：
文献类型：
--
作者：
G. McKenna;J. Guenet
将全同立构聚苯乙烯在反式十氢萘或1-氯十烷中的溶液在高温(约180℃)淬火至−20°C时转变为凝胶，在0.04g/g至0.40g/g的浓度范围内测量了这些凝胶的压缩松弛系数，在22℃时，凝胶呈现双对数应力松弛速率m，高于聚氯乙烯和明胶凝胶体系。1 2 0 S等时模数浓度图表现出非幂规律的行为，即不仅有双对数斜率随浓度增加而减小的总趋势，而且还存在着在浓度较小范围内发生模数突变的区域。与之前在等规聚苯乙烯/顺式十氢林凝胶中发现的相比，这些特征在浓度依赖的模数中不那么明显。这一行为被解释为与凝胶结构的流苏胶束图片不一致。初步研究结果表明，聚合物含量和凝胶形成温度对凝胶的模数有显著影响。
Solutions of isotactic polystyrene in either trans-decalin or 1-chlorodecane were transformed into gels by quenching from a high temperature (ca. 180°C) to −20°C. The relaxation modulus in compression of these gels was measured over a range of concentrations of from 0.04 g/g to 0.40 g/g. At 22°C, the gels show a double logarithmic stress relaxation rate, m, which is higher than for PVC and gelatin gel systems. 120 s isochronal modulus concentration diagrams exhibit non-power law behavior, i.e., not only is the general trend such that the double logarithmic slope decreases with increasing concentration, but there are also regions in which abrupt changes in modulus occur over narrow ranges in concentrations. These features in the concentration dependence of the modulus are less pronounced than those found previously1 in isotactic polystyrene/cis-decalin gels. The behavior is interpreted to be inconsistent with a fringed micelle picture of the gel structure. Preliminary results are reported indicating that polymer fraction and temperature of gel formation can significantly affect the modulus of the gels.