The mechanical properties of an oriented lamella stack formed from an S-B-S block copolymer

The microstructure and m of a material composed of an oriented lamella stack are described. The material used for these studies was an S-B-S block copolymer exhibiting a lamellar morphology. By processing this material, using a novel injection moulding procedure, large specimens can be produced in which the lamellar microphases are uniformly oriented. This provides a unique opportunity for studying the anisotropy of the mechanical properties of a well characterized lamella stack, in which the two phases are molecularly bonded together. The experimental data are compared with predictions derived from composite mechanics. Excellent agreement between theory and experiment is found and this provides information concerning Poisson's ratio for the rubbery phase.