Liquid crystalline triblock copolymers. Mechanical behaviour and orientation under uniaxial strain

The stress-strain and orientation behaviour of side-chain liquid crystallin e(SLCP) ABA triblock copolymers with a backbone of polystyrene-block-1,2-po lybutadiene-block-polystyrene and a cyanobiphenyl mesogen in the side chain was investigated in dependence of molecular weight. The polymer shows the behaviour of a thermoplastic liquid crystalline elastomer(TPLCE) in the nem atic phase in a region between the glass transitions of the polystyrene blo ck and the SLCP. The ultimate properties and E-modulus is lower than for co nventional thermoplastic elastomers. Under uniaxial strain liquid crystalli ne order perpendicular to the direction of strain is induced.