HOMOGENEOUS AND HETEROGENEOUS BLENDS OF POLYBUTADIENE, POLYISOPRENE, AND CORRESPONDING DIBLOCK COPOLYMERS

The miscibility of homogeneous diblock copolymers of 1, 4-polybutadiene and cis-l, 4-polyisoprene with either or both of the corresponding linear homopolymers was found to depend upon the relative lengths of the block segments and upon the coordinates of the binary or ternary mixture on the appropriate triangular composition diagram. Evidence from a variety of experiments was used to draw overall conclusions regarding the location of the diblock in these blends and its influence on physical properties. Experimental methods employed were transmission electron microscopy on suitably stained specimens, thermomechanical analysis at a heating rate of 5 °C/min, and dynamic mechanical testing at 3.5 Hz over a temperature range from -130 to 40 °C. © 1979, American Chemical Society. All rights reserved.