The ageing of rigid polyvinyl chloride (R-PVC) aggravated by nitric and sulfuric acids was studied by IR

UV Spectroscopy

thermo-analysis and molecular weight determination. It was found that a number of groups

such as -NO2

-ONO2

-ONO were incorporated into the backbone of the PVC chain. These groups cause the fransition reaction of the instable bonding between the stabilizers and the PVC chain. This not only changes the composition of the materials but also changes the physical conformation. The latter deeply influence the duration of P-PVC Products used in chemical environment.