Aumento da massa molar e restituição das propriedades reológicas do PET pós-consumo pelo uso de extensor de cadeia epoxídico.

Abstract

This study is concerned with the effect of a styrene-acrylic multifunctional oligomer (POLYAD PR 002), marketed as a chain extender for condensation polymers, in the increase of molecular weight of poly (ethylene terephthalate) (PET) and, consequently, the restitution of their rheological properties. This behavior was analyzed in post-consumer PET (PETPC) from colorless bottles collected in the State of Paraíba, as well as in virgin PET (PETV) for comparison. The polymers were processed with and without the incorporation of the chain extender additive at different levels to facilitate developing different grades of PET. An internal mixer coupled to the torque rheometer Haake Rheomix 3000QC of PolyLab QC, with roller type rotors operating at 265ºC and 60 rpm was used. In the first stage, processing was performed during 16 min, with different additive concentrations (1.5%, 3% and 5% by weight) and in a second stage, polymers with and without the incorporation of additive concentrations 1.5 and 3% by weight were processed and reprocessed during 30 min. The samples were characterized by torque rheometry. From torque and temperature measurements was possible to evaluate molar masses. According to the results, it is evident that estimates based on realtime torque measurement are fast and accurate indicators of the effectiveness of chain extension, and that the incorporation of the additive to PETV and PETPC had a strong effect in increase its molar mass