THE EFFECT OF BRANCHING ON THE MECHANICAL-PROPERTIES OF HBA HNA COPOLYMER/

The mechanical properties of aligned fibres and monofilaments of rando m copolyesters of 4-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoi c acid (HNA) with and without the inclusion of a trifunctional branchi ng monomer have been investigated using both macroscopic and X-ray tec hniques. Results for unbranched samples are in line with previous work while including the branching monomer reduces both the shear and tens ile moduli as measured macroscopically. Annealing the samples increase s the moduli. On the scale observed by X-ray diffraction the inclusion of branching has little effect whereas annealing increases the sinuos ity of the chains and hence reduces the apparent chain modulus determi ned by X-ray measurements on samples under stress. Copyright (C) 1996 Elsevier Science Ltd.