Synthesis and investigation of polyphenyldimethylsiloxane block copolymerswith bimodal chain length distribution of oligodimethylsiloxane blocks

Siloxane block copolymers containing linear dimethylsiloxane (DMS) and cycl olinear phenylsilsesquioxane blocks were synthesized. A peculiarity of the copolymers is a bimodal distribution of linear DMS blocks in the polymer ch ain. The results of X-ray diffraction, thermomechanical, and DSC studies of bimodal block copolymers indicate a higher degree of microphase separation of the blocks as compared to unimodal block copolymers.