PHOTOCHEMISTRY OF POLY(BUTYLENETEREPHTHALATE) .1. IDENTIFICATION OF THE IR-ABSORBING PHOTOLYSIS PRODUCTS

The photolysis of poly(butyleneterephthalate) was carried out under radiation of long wavelength (lambda greater-than-or-equal-to 300 nm) and short wavelength (lambda = 254 nm) in vacuum atmosphere. Photolysis products, formed by irradiation of thin polymer films, were investigated by FTIR spectroscopy. Specific chemical and physical treatments were developed in order to identify the photoproducts. The main groups involved in the photochemical evolution have been identified to be end-group species, i.e. benzoic acid, benzaldehyde, gamma-butyrolactone, formate and aliphatic alcohol, as well as chain m-biphenyl structures. It was shown that the repartition of photolytical species in the polymer was heterogeneous. On the basis of photoproducts identification, a general scheme accounting for the main routes of poly(butyleneterephthalate) photolysis was proposed.