Uso de aditivos na compatibilização de blendas PP/PBAT.

Abstract

In this work, several PP/PBAT blends containing PP-g-MA (0 and 5%w/w) as an additive as well as three types of lubricants (stearates) (0 and 0.5%w/w) were prepared by twin-screw extrusion under a single processing condition. The samples obtained were characterized by torque rheometry, melt flow index (MFI), infrared spectroscopy (FTIR), mechanical properties (tensile and impact), heat deflection temperature (HDT), x-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), thermal degradation and biodegradation. The results of torque rheometry suggest degradation during processing. Melt flow index increased with stearate incorporation. Mechanical properties and HDT values of PP decreased with the addition of both PBAT and additives to polypropylene. XRD data showed that the degree of crystallinity of the blends increased with the addition of the compatibilizer (PP-g-MA) and of the stearates, while that of DSC indicated that the degree of crystallinity of the blends decreased with PBAT addition and increased with the incorporation of additives. SEM images showed that the particle size of the biodegradable polymer diminished upon addition of the stearates use in the PP/PBAT blends. TG data showed a reduction in the thermal stability of the systems containing PBAT and stearates. All samples, particularly those containing stearates, strongly thermally

degraded. The blends investigated biodegrade, provided that the material is pre- degraded before burial. The rate of degradation is higher in systems with stearates,

which was attributed to the pro-oxidant action of these substances. The incorporation of the PP into PBAT and stearates is a less harmful alternative to the environment when compared with neat polypropylene since, under ideal conditions, it is easily degraded after disposal.