Deformation studies of thermotropic aromatic copolyesters using NIR Raman spectroscopy

Near infrared (NIR) Raman spectroscopy has been used to investigate the def ormation behaviour of highly oriented fibres and tapes made from thermotrop ic aromatic copolyesters. It has been found that a number of Raman bands of thermotropic aromatic copolyesters show Linear shifts towards lower wavenu mbers with stress and strain following tensile deformation. The strain and stress dependencies of the 1600 cm(-1) band due to stretching of the p-phen yl ring, have been studied in detail and discussed in relation to values re ported for high-performance aromatic polymer fibres. The behaviour has been discussed in terms of the microstructure of the thermotropic aromatic copo lyester materials compared with that of other highly-oriented aromatic poly mer fibres. (C) 2001 Elsevier Science Ltd. All rights reserved.