Miscibility and crystallization in polycarbonate/poly(ε-caprolactone) blends:: Application of the self-concentration model
Miscibility and crystallization in polycarbonate/poly(ε-caprolactone) blends:: Application of the self-concentration model
复制标题
DOI：
10.1021/ma050481c
复制
发表时间：
2005-06-14
期刊：
影响因子：
5.5
通讯作者：
Lodge, TP
中科院分区：
文献类型：
--
作者：
Herrera, D;Zamora, JC;Lodge, TP
聚碳酸酯/聚（是己内酯的一种元素）（PC/PCL）共混物在没有进一步热处理的情况下被发现是可混溶的。PCL在含有60%或更少的聚碳酸酯的混合物中结晶，在这些条件下，所有混合物成分都保持无定形。由热激退极化电流实验确定的单一、广泛的量热玻璃转变和不同的组分动力学表明共混物的混相性和不同的平均局部成分的存在。将Lodge-McLeish模型应用于两种有效玻璃化温度的成分变化。通过调整自浓度值以最佳拟合实验点，得到了两个组分的定量一致。PCL的相关长度非常接近其库恩长度，而PC的最佳拟合导致特征长度略短。结果表明，在足够高的温度下退火后，PC发生结晶，从而在共混物的非晶态区域引起相偏析。
Polycarbonate/poly(is an element of-caprolactone) (PC/PCL) blends are found to be miscible when extruded samples are studied without any further thermal treatment. PCL crystallizes in blends containing 60% or less polycarbonate, a component that remains amorphous for all blend compositions under these conditions. Single, broad calorimetric glass transitions together with distinct component dynamics determined by thermally stimulated depolarization current experiments indicate the miscibility of the blends and the existence of different average local compositions. The Lodge-McLeish model is applied to the compositional variation of the two effective glass transition temperatures. Quantitative agreement is obtained for both components by adjusting the self-concentration values to best fit the experimental points. The relevant length for PCL is very close to its Kuhn length, whereas for PC the best fit leads to a slightly shorter characteristic length. It is shown that upon annealing at sufficiently high-temperature PC undergoes crystallization and thereby induces phase segregation in the otherwise amorphous regions of the blends.