Acoholysis behavior of PET waste with hybrid fibers and their application in the synthesis of unsaturated resins

A novel fiber-derived unsaturated polyester resin (UPR) was synthesized through alcoholysis and polycondensation by using PET and hybrid fibers as raw materials. The effects of alcoholysis conditions including alcoholysis time, temperature, initiator concentration, type of alcoholysis agents and amount of hybrid fibers on the alcoholysis behavior were investigated by HPLC, LC–MS and GPC. A comprehensive analysis of the fiber-derived UPR was conducted under different reaction conditions and discussed by FTIR, viscosity, acid value and mechanical properties. HPLC results indicated a strong correlation between the maximal peak area in spectrometry and the yield of main glycol products. It was established that the alcoholysis of PET with hybrid fiber samples mainly obtain alcoholysis monomers and dimers by using glycol as an alcoholysis agent. It was discovered that less alcoholysis products was obtained with lower diethylene glycol. The molecular weight of glycolyzed products are oligomers based on a alcoholysis reaction time reached above 3 h. Under the optimal conditions, PET: EG: zinc acetate = 1.0: 2.0: 0.3 (wt%), 200 ℃, 3 h, PET/PU was completely alcoholyzed and produced oligomers. The performance of liquid UPR and its cured product have been investigated. The UPR prepared by PET/PU was utilized as a fiber source unsaturated resin, meeting the standards for organic artificial stone. This article highlighted the potential usage of PET with hybrid fibers in unsaturated resin.