Modification of poly(propylene) through grafting with dimethyl itaconate in solution

Abstract

Functionalization of isotactic poly(propylene) (PP) with dimethyl itaconate (DMI) as functional polar monomer using 2,5-dimethyl-2,5 -bis(tert-butylperoxy)hexane (L101) as radical initiator was carried out in both boiling xylene and decalin as solvent media. The effect of DMI and the initiator concentration on the extent of grafting was studied by varying reaction time and temperature. It was found that temperature affects the percentage of DMI grafted onto PP, which is slightly higher for reactions carried out in xylene than in decalin. The results also show that the amount of DMI incorporated is proportional to the initial DMI and initiator concentrations used in the grafting reaction up to certain concentrations, and thereafter a decrease in the percentage of grafting (G in wt.-%) was found. The maximum value of grafting obtained was 0.7 wt.-%. The melt flow index (MFI) values increase with increasing initial amount of initiator used in the grafting reaction. The degradation of the PP chain is higher when xylene is used as solvent. MFI values of 20-100 were found for modified PP compared with 11.4 for the unmodified polymer.