Effect of crosslinking density on the viscoelastic properties of unsaturated polyesters
Effect of crosslinking density on the viscoelastic properties of unsaturated polyesters
复制标题
交联密度对不饱和聚酯粘弹性能的影响
DOI：
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发表时间：
1965
期刊：
影响因子：
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通讯作者：
Y. Suzuki
中科院分区：
文献类型：
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作者：
K. Shibayama;Y. Suzuki
研究了不饱和聚酯在玻璃化-橡胶化转变区的粘弹性能与比容的温度依赖性的关系。通过使用琥珀酸和富马酸的混合物作为二元酸组分，制备了在交联密度方面同源的聚酯。通过折射率测量确定比容的温度依赖性，假定比活度与温度无关。在恒定频率下测量了动态粘弹性的温度色散。结果总结如下。比容和玻璃化温度与交联密度的对数呈线性关系。随着交联密度的增加，粘弹性分散体的热膨胀系数和陡度减小。由WLF方程计算的自由体积分数和自由体积膨胀系数与比容的温度依赖性符合较好。结果表明，交联的效果主要归因于聚合物网络中自由体积的数量和分布的变化。
Viscoelastic properties of unsaturated polyesters were investigated in the glass-rubber transition region in relation to the temperature dependence of specific volume. Polyesters which are homologous with respect to crosslinking density were prepared by using mixtures of succinic and fumaric acid as the dibasic acid component. The temperature dependence of the specific volume was determined by refractive index measurement, the specific refractivity being assumed to be independent of temperature. The temperature dispersion of dynamic viscoelasticity was measured at a constant frequency. Results are summarized as follows. Specific volume and glass temperature are linearly related to the logarithm of crosslinking density. The thermal expansion coefficient and steepness of viscoelastic dispersion decrease with increasing crosslinking density. Fractional free volume and expansion coefficient of free volume, both of which were calculated by WLF equation, are in good agreement with the temperature dependence of specific volume. The results indicate that the effect of crosslinking is largely attributable to the change in amount and distribution of free volume in polymer networks.