Obtenção de celulose a partir da casca de arroz e sua utilização como carga em compósitos com matriz de polietileno de alta densidade

Abstract

Composites formed by a matrix of high density polyethylene (HDPE), reinforced with cellulose obtained from the rice husk, were prepared and studied with the aim of using raw materials from renewable sources, as well as the production of materials efficient and inexpensive, through the use of natural resources. The obtaining of cellulose from the rice husk was carried out through alkaline treatment and bleaching for the removal of lignin, impurities, silica and hemicellulose. The crystallinity and surface of the cellulose were studied by infrared spectroscopy with fourier transform (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. After its obtaining the cellulose was incorporated into the polymer matrix through the mixing method in the molten state. Composites were prepared with different amount of cellulose (5, 10 and 15 wt% by mass) and their mechanical, structural and thermal properties were investigated and correlated with their morphology. It was observed that the treatment used to obtain the cellulose was effective. The results of FTIR and XRD demonstrated a reduction of non-cellulosic constituents and an increase in crystallinity. SEM analysis for cellulose revealed a structure with a rough surface after successive chemical treatments. Also it was possible to observe that the addition of the load array promoted a slight improvement on thermal stability and the data of differential scanning calorimetry (DSC) did not show a significant change in the results obtained for the composites in relation to the pure polymer. The mechanical tests of composites obtained indicated an improvement of its properties in relation to the neat HDPE. The micrographs of SEM, weak adhesion array-strengthening. The cellulose for being a biodegradable material and present such features can be applied as cargo in HDPE matrix composites to promote an improvement of their thermal and mechanical properties contributing to future applications in the field of packaging.