A study on the phase behavior of poly(epsilon-caprolactone)-poly(butadiene) diblock copolymers: The influence of relatively low-molecular-weight block copolymers on the order-disorder transition behavior

作者：Takagi Hideaki^*; Yamamoto Katsuhiro; Okamoto Shigeru; Sakurai Shinichi

来源：Polymer, 2015, 67: 20-27.

DOI：10.1016/j.polymer.2015.04.041

• Block copolymer
• Order-disorder transition
• Fluctuation

The phase behavior in relatively low-molecular-weight poly(epsilon-caprolactone)-poly(butadiene) diblock copolymers (PCL-PB) were investigated using small angle X-ray scattering (SAXS). The temperature dependence of x was determined from the curve fitting of SAXS profiles using random phase approximation in the disordered state. The phase diagram for PCL-PB was constructed. Generally, according to Fredrickson-Helfand theory, the product (chi N)(ODT), where N is the degree of polymerization and chi is the Flory-Huggins interaction parameter at the order-disorder transition temperature, is considered to be shifted toward upper side in phase diagram due to the existence of fluctuation. However, in PCL-PB, the significant increase of (chi N)our was not apparently observed. In order to compare (chi N)(ODT) values with theoretical and many experimental studies, we calculated (chi N)(ODT) which was obtained from 19 earlier reports. We picked out 69 samples which formed lamellae morphology and had nearly symmetric composition. In the region of relatively low-molecular-weight, it was found that the increase of (chi N)(ODT) was not clearly seen in the almost all of investigated articles.

• 出版日期2015-6-12