Estimation of the Homogenization Temperature of a 1.2 Polybutadiene/1.4 Polybutadiene Diblock Copolymer Using Rheological Testing Methods

摘要

Four samples containing various proportions of 1.2 and 1.4 polybutadiene were subjected to a series of rheological tests in which the dynamic storage modulus was determined over a range of temperature (30 C-160 C) and frequently (0.1-100 rad/sec). Isochronal plots of G' vs temperature showed that one of the samples (diblock 30/50, containing 38% 1, 2 polybutadiene) was substantially different in its rheological behavior. Appropriate treatment of the data revealed a 'rubberlike' plateau at low frequencies which began to disappear around 70 C and was completely missing at 100 C and above. From these results it was tentatively concluded that this sample undergoes a transition from a heterogeneous to a homogeneous morphology between 70 C and 100 C. (Author)