Investigations of the ultrasounds velocity and its relation to the heterophase structure of multiblock elastomers consisting of poly(butylene terephthalate) and poly(1,2-oxypropylene) or dimerized fatty acid
Polimery 2002, No 9, 630
Investigations concern analysis of chosen multiblock elastomers differing with chemical structure of flexible segments [poly(1,2-oxypropylene) (PO3) or dimerized fatty acid (DFA)] and rigid segments content — poly(butylene terephthalate) (PBT). The dependences of ultrasounds velocity (v) on the temperature (T) and rigid segments content (wh) haye been characterized. The results of the trials of experimental results' fitting to those calculated from the formerly proposed two-layer model of elastomer have been presented. That model based on the data concerning ultrasounds attenuation while recently it was tested with results of utrasounds velocity investigations. An explanation of observed imperfection of the model has been proposed. It appeared that — for two-phase multiblock elastomers — dependences v = f(T) can be approximatively linked to wh values in the frame of the model. However this model should be treated as a frontier one in simplified interpretation of a structure of investigated elastomers because of their complicated morphological structure and various degrees of microphase separation. The microphase separation has been estimated on the base of investigations of crystalographic structures fromed in various conditions of samples cooling.
Keywords: multiblock thermoplastic elastomers, ultrasonic investigations, heterophase structure of elastomers, two-layer structural model