Preparation And Properties Of A Main-Chain Smectic Liquid Crystalline Elastomer With Shape-Memory Ability

This article presents the preparation of a smectic liquid-crystalline elastomer from a main-chain polybibenzoate with cross-linkable methacrylate groups incorporated at the ends of the polymeric chains. The advantage of this functionalization is that it can be thermally cross-linked in the bulk state without initiator. Rheological experiments have established that temperatures around 2030 C above the isotropization point were found to be the most appropriate for the preparation of the network, leading to excellent sheets with a superior cross linking yield, and prepared in relatively short curing times. The DSC and X-ray diffraction experiments indicate that the network retains the liquid crystalline ability (with a slightly smaller order than that of the linear polymer). The shape memory behavior of the network has been determined from the well-known cyclic thermomechanical experiments. It follows that the investigated network shows a rather remarkable shape-memory behavior, with considerably good shape recovery and shape fixity values.