PROBLEMS OF AGING AND STABILIZATION OF POLY(VINYL CHLORIDE)

We have investigated plasticized poly(vinyl chloride) (PVC) samples ag ed in natural and artificial conditions, and samples recovered after u se for a long time (15-30 years) at 253-301 K. The predominant process in dark, low temperature ageing of plasticized PVC is loss of plastic izer by desorption. In photo-ageing the main process is degradation of both polymer and plasticizer, proceeding generally on the irradiated side of the sample and depending on the spectral distribution of the l ight. Washing off of stabilizers from the polymer occurs in contact wi th water. With consideration of the experimentally determined empirica l kinetic equations for mass loss or degradation during use or artific ial exposure we can determine the conditions of ageing. Based on an an alysis of the use conditions, one can deduce predictive equations for the description of degradation. (C) 1996 Elsevier Science Limited