Compósitos de poli (butileno adipato-co-tereftalato) e fibra de babaçu: efeito do processamento e do tipo e teor de carga.

Abstract

The effect of the processing, type and content of two variations of a plant fiber extracted from babassu coconut and the type of processing in the structure, thermal, rheological, mechanical properties, water absorption and biodegradability of poly (butylene adipate-co-terephthalate) – PBAT/babassu compounds were evaluated. PBAT composites with 10, 20 and 30% of micronized fiber from the mesocarp and epicarp fiber of babassu coconut were produced in an internal laboratory mixer, and characterized by torque rheometry. The compositions were extruded, injection molded and characterized by FTIR, MO, MEV, MFI, DSC and TGA. Water absorption, mechanical properties and soil biodegradability were also determined. The effect of the type of processing adopted was evaluated by parallel plate rheometry, melt flow index, MO and DSC. Results show that, in the extrusion process, the specific energy is dependent on the type of filler employed and independent of its content. The rheological study allowed to estimate the degradation of the PBAT and the composites during processing, which was shown to be dependent on fiber type and content. Optical microscopy evidenced the morphological difference between the loads and that this is preserved in the composites. The type and loading content, as well as the type of processing, affected the crystallization and melting parameters of the composites. Fiber incorporation stiffened and weakened the PBAT, and mechanical properties were were dependent on load content. The presence of vegetable fibers significantly increased the capacity and rate of water absorption, which were shown to be dependent on the type and content of filler. Babassu incorporation tends to accelerate PBAT biodegradation. Higher processing intensity resulted in lower viscosity, higher dispersion of the vegetable load and had a moderate effect on the thermal characteristics of the systems. PBAT/babassu based products are biodegradable, environmentally friendly and economical and their properties allow them to be used in different applications. Babassu fillers can be used to produce lower cost composites without significant damage to the properties of PBAT.