Synthesis and Photostability Study of Some Modified Poly(vinyl chloride) Containing Pendant Benzothiazole and Benzimidozole Ring

Abstract

The influence of introducing benzothiazole and benzimidazole as a pending groups into the repeating unit of PVC has been studied on the bases of photostability measurements. The photostability of modified polymers were studied by monitoring the carbonyl Index (I CO), polyene index (I po) and hydroxyl index (I OH), all results obtained indicated that PAA, PSS, PNN, PSA and PNA gave lower growth rate of I CO , I PO and I OH with irradiation time with respect to unmodified PVC film (control). The following trends of photostability are obtained PAA>PSS>PNN>PSA>PNA According to the experimental results several reaction mechanisms were proposed depending on the presence of benzothiazole and benzimidazole moieties in the polymer chain. The mode of chain scission was also investigated by measuring the variation of average viscosity molecular weight with irradiation time for modified PVC. The degree of deterioration (α) and the average number of chain scission (S) values were also calculated.