با توجه خاص به اثرات زيست محيطي )PET( بررسي سيستم بازيافت پلي اتيلن ترفنالات

Feasibility Study of PET Bottle Recycling in Order to Produce Unsaturated Polyester Resin

Post-consumer waste poly (ethylene terephthalate), PET, scraps were glycol zed at different reaction times and different weight ratios of 37.5 to 62.5% PET by using propylene glycol, PG. It was shown that the effect of catalyst presence is significant upon the acceleration of depolymerization. Two grades of virgin and waste PET was used to compare the depolymerization behavior by using PG, which showed the exact similarity. The free glycol of the resulted glyco-esters was removed. FTIR, GPC and DSC techniques were used lo characterize the glycolization products, and hydroxyl value determination was used to specify the extent of the reaction. The results showed that the some PET chains have been broken down and hydroxyl-terminated end groups have been formed on the oligomeric chains. A relative decrease in molecular weight and viscosity at same PET concentrations by increasing the reaction time indicated that the PET chains have been broken The results of free glycol removal and hydroxyl value tests confirmed that about 12 to 25% of PG have been used up to break the PET chains. The resulted oligomeric glycolizates can be readily used informulation of unsaturated resins and specific types of polyurethanes.