Synthesis of block and graft copolymers containing liquid-crystalline segments

Abstract

Block and graft copolymers bearing amorphous or semi-crystalline and liquid-crystalline moieties were obtained by means of non-traditional synthetic routes. Chemical modification of block and graft copolymer precursors by molecular liquid crystals and controlled radical block copolymerization between liquid-crystalline monomers and styrene were used for this purpose. Controlled radical polymerization was accomplished by means of stable free radical polymerization (SRFP) and by INIFERTER methodologies. In the former methodology, 2,2,6,6-tetramethyl-piperidinyl-1-oxy (TEMPO) was used to mediate the propagation. The INIFERTER technique comprised the polymerization reaction between a liquid-crystalline monomer and a sample of thiuram-terminated polystyrene promoted by UV radiation. The performance of these techniques was evaluated taking into account the chemical composition of the materials produced. The thermal properties were determined by DSC and were correlated to the chemical composition of the polymers obtained. © 1999 Society of Chemical Industry