Solution properties of polymacromonomers consisting of polystyrene - V. Effect of side chain length on chain stiffness
Solution properties of polymacromonomers consisting of polystyrene - V. Effect of side chain length on chain stiffness
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DOI：
10.1295/polymj.33.481
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发表时间：
2001-01-01
期刊：
影响因子：
2.8
通讯作者：
Norisuye, T
中科院分区：
文献类型：
--
作者：
Hokajo, T;Terao, K;Norisuye, T
对一系列由每个侧链中具有65个单体单元的聚苯乙烯组成的聚大分子单体样品的环己烷和甲苯溶液进行光散射和粘度测量，以确定Z-均方回转半径（s（2））和特性粘度[η]作为重均分子量的函数，范围为2.9 X 10（5）至8.6 X 10（6）。聚大分子单体在环己烷中的θ温度测定为34.5 ℃。该溶剂中34.5 ℃和甲苯中15 ℃的（s（2））（z）数据（一种良好的溶剂）定量描述的蠕虫状链与λ（-1）（库恩段长度）= 36 run和M-L（每单位轮廓长度的分子量）= 25000 nm（-1），在后者中λ（-1）= 75 nm，M-L = 25000 nm（-1）。在每种溶剂中的[η]的分子量依赖性也解释了这个模型链时，所产生的侧链附近的主链末端的末端效应被考虑在内。使用两种溶剂中的上述λ（-1）值和先前对具有较短侧链的聚苯乙烯聚大分子单体的估计来检查主链刚度对侧链长度的依赖性。结果发现，λ（-1）几乎线性增加的侧链分子量为两种溶剂，但在甲苯中比在环己烷中有更大的斜率。
Light scattering and viscosity measurements were made on cyclohexane and toluene solutions of a series of polymacromonomer samples consisting of polystyrene with 65 monomer units in each side chain to determine the z-average mean-square radius of gyration (s(2)), and the intrinsic viscosity [eta] as functions of the weight average molecular weight in a range from 2.9 X 10(5) to 8.6 X 10(6). The theta temperature for the polymacromonomer in cyclohexane was determined to be 34.5 degreesC. The (s(2))(z) data in this solvent at 34.5 degreesC and toluene at 15 degreesC (a good solvent) were quantitatively described by the wormlike chain with lambda (-1) (the Kuhn segment length) = 36 run and M-L (the molecular weight per unit contour length) = 25000 nm(-1) in the former and with lambda (-1) = 75 nm and M-L = 25000 nm(-1) in the latter. The molecular weight dependence of [eta] in each solvent was also explained by this model chain when the end effect arising from side chains near the main-chain ends was taken into account. The above lambda (-1) values in the two solvents and the previous estimates for polystyrene polymacromonomers with shorter side chains were used to examine the dependence of the backbone stiffness on side chain length. It was found that lambda (-1) increases almost linearly with the side-chain molecular weight for both solvents but with a larger slope in toluene than in cyclohexane.