A STUDY ON THE STRUCTURE OF DEGRADED PVC BY PHOTOACOUSTIC-SPECTROSCOPY

Photoacoustic spectroscopy (PAS) is used to study polyene structures i n degraded PVC, and the PA spectra without deviation caused by solvent s can be obtained. In the PA spectra, it is shown that polyenes with c onjugated number n from 4 to 9 have definite absorption peaks in the 3 00-500 nm region. The relationship between the position of absorption peak lambda(max) and conjugated number n is discussed. Analyses of PA spectra combined with FTIR spectra enable an investigation of structur al influences of some stabilizers. The influences on conformation inte rfere with the propagation of polyenes and give PVC extra thermal stab ility. (C) 1997 Elsevier Science B.V.