Avaliação da influência de óleos vegetais como foto-estabilizantes em polipropileno reciclado

Abstract

The objective of this research was to verify the action of three different vegetable oils (grape seed oil, Brazil nut oil and castor oil) as potential antioxidant additives and photostabilizers for recycled polypropylene (PP rec.). Oils were incorporated into the PP rec. in variable amounts of 0.5, 1.0 and 1.5 phr. After processing carried out by a twin-screw extruder and fabrication of plates, in a hydraulic press, fragments were removed from each particular sample; then, thermal analysis, thermogravimetry (TGA), in oxidizing conditions, was conducted at three heating rates (3°C/min, 6°C/min and 12°C/min). Analysis of the experimental data and implementation of ANOVA methodology allowed select to grape seed oil as the most promising in the antioxidant role. Subsequently, specimens of PP rec./OSU compositions have undergone 45 days of exposure to ultraviolet (UV). Thermal analysis by TGA was again conducted, and the kinetic study of the photo-oxidative degradation, in conjunction with ANOVA methodology, it allowed determining that OSU is acting as photostabilizer, but only when it is used in low content (0.5 phr) and sample is subjected to low heating rate (3°C/min).