Thermal, morphological and mechanical properties of composites based on polyamide 6 with cellulose, silica and their hybrids from rice husk

Abstract

The use of cellulosic fibers from different natural sources as fillers in polymer matrices to improve their properties has been extensively studied in the last years. It is mainly due to the vast availability of natural fibers as well as their biodegradability. The purpose of this present work was to extract cellulose, silica, and cellulose-silica fillers – these last called “hybrids” – from rice husk through delignification and subsequent oxidation and, then, prepare composites with polyamide 6 and improve mainly its thermal-mechanical properties. The content of 10 wt.% of fillers was inserted in PA 6 matrix. Infrared spectroscopy pointed the main characteristic peaks of cellulose and silica of hybrids, as thermogravimetric analysis showed high thermal stability of fillers, allowing their incorporation in PA-6 matrix by extrusion method. Thermo dynamic-mechanical analysis showed, in a general overview, a significant improvement of mechanical properties of composites, as elastic modulus, compared with neat polyamide-6, mainly the one with 2.5 wt% of silica and 7.5% of cellulose. This last also showed increasing of degree of crystallinity, measured by differential scanning calorimetry, showing the extraction efficiency of fillers from rice husk as well as the potential application of composites as structural components in automotive parts.