Study on Chain Extension of PET Flakes by Reactive Extrusion with Chain Extenders

The chain extension of recycled PET flakes was studied via reactive extrusion using diisocyanatotoluene(TDI),antimony trioxide(Sb2O3),phthalic anhydride,pyromellitic dianhydrde(PMDA),and naphthalenetetra carboxylic dianhydride(NTDA) as chain extenders.It was found that effects of TDI,Sb2O3,phthalic anhydride and NTDA were weak,while PMDA could increase the intrinsic viscosity of the material obviously.A mixture of PMDA and phthalic anhydride provided the best chain extension.The intrinsic viscosity of the material reached 0.96 dL/g when the content of PMDA and phthalic anhydride was 0.3 % and 0.2 %,respectively.