Caracterização reológica e térmica de blendas de pet pós-consumo/PEAD compatibilizadas com PE-g-MA e extensor de cadeia epoxídico.

Abstract

In this work, the effect of the compatibilizer polyethylene grafted whit maleic anhydride (PE-g-MA), the additive joncryl and the mixture of the two, on the composition of blends of virgin and recycled poly(ethylene teraftalate) (PET) with virgin high density polyethylene (HDPE), on their rheological and thermal properties was evaluated. For this purpose, blends of virgin PET and recycled PET were produced with 25, 50 and 75% virgin HDPE, which were made compatible with PE-g-MA, added with joncryl and made compatible and added at the same time, in an internal laboratory mixer, and the torque rheometry of these systems was analyzed. The compositions were also characterized by differential scanning calorimetry and thermogravimetric analysis. The effect of the compatibilizer on the melt temperature was minimal (1ºC), however, the effect of the additive affected moderately (3 to 4ºC), and the addition of the additive and the compatibilizer, was moderate in all blends (5 a 7ºC). With regard to the increase in viscosity, the compatibilizing agent increased moderately, but significantly (30 to 75%), the adjusted torque of all blends. These increases were practically independent of the blend's composition. The addition of joncryl significantly increased (50 to 500%) the adjusted torque of all blends. The increments depended on the blend composition, the greater the higher the PET content, indicating that the additive acted on the polyester. The joint incorporation of the compatibilizer and the additive increased the viscosity of the system, from 125 to 950%, revealing the synergistic effect between both. The joint effect was bigger in blends with recycled PET. Joncryl only affected the crystallization parameters of PET, due to interactions with this polymer. The addition of the compatibilizer had minimal effect on the HDPE crystallization parameters, but it significantly altered the crystallization of PET, mainly virgin PET. The incorporation of the additive and compatibilizer, together, showed a behavior similar to the addition of just the compatibilizer in crystallization. The samples of virgin PET and recycled PET showed similar results of mass loss. HDPE and PE-g-MA also showed similar results of mass loss. The thermal stability of the blends tested was similar to that of pure PET and slightly higher than that of HDPE.