Chemical modification of styrene–butadiene block copolymers and the structural, thermal and morphological characterisation of the products

Abstract

Kraton D1101 and D1102, poly(styrene)–poly(butadiene)–poly(styrene)(PS–PBD–PS), and Kraton G1651, poly(styrene)–poly(hydrogenated butadiene)–poly(styrene)(PS-HPBD-PS) block copolymers have been chemically modified in high conversion to yield novel linear soluble block-copolymer materials. Specifically the PS block in G1651 has been nitrated, and the PBD block in D1101 has been brominated and chlorosulfenylated. The species from the latter modification have also been oxidised quantitatively to yield block copolymers with pendant aromatic sulfone substituents. Transmission electron microscopy has shown that in the solid state the new materials retain the microphase-separated structure of the parent block copolymers, although the precise morphology changes. The latter is discussed in the light of current thinking in the literature. Glass-transition and thermal-decomposition data have also been obtained for the new materials.