ARTIFICIALLY WEATHERED PVC FILMS

Specimens made from plasticized and rigid PVC were subjected to artifi cial weathering at an average temperature of 60-degrees-C. The result of that were reduced elongation at break and work of fracture. The rea son for that are corresponding changes in the thermodynamic characteri stics. In plassticized PVC the increase in the modulus of elasticity i s the consequence of the increase in the degree of crystallinity up to a certain point during the exposure; after that it is controlled by t he evaporation of plasticizer. The plasticizer loss above the glass tr ansition temperature turns out to be a process which is controlled by vaporization.