DYNAMIC MECHANICAL-PROPERTIES OF ANISOTROPIC NETWORKS FORMED BY LIQUID-CRYSTALLINE ACRYLATES

Thermomechanical properties of oriented polymer networks, which had been obtained by photopolymerization of liquid crystalline acrylates, were investigated. The networks exhibited three mechanical loss peaks which were associated with the relaxation of the whole network, relaxation of the central aromatic unit of the molecules and the crankshaft motion of the methylene groups. Tensile modulus and the strength of the oriented networks were anisotropic and highly temperature dependent. The oriented networks also showed an anisotropic thermal behaviour, contracting in the direction of molecular orientation while expanding in the lateral directions with increasing temperature. The anisotropic properties of the oriented networks have been interpreted in terms of the molecular structure and grouping of the molecules formed after polymerization.