Exploring the Influence of Various Filler Modification Techniques on the Biocomposites Properties Derived From Lignocellulosic Hazelnut Waste Shells

Abstract

Biocomposites exhibit a wide range of properties and can compete with non-biodegradable polymers across various industrial fields. This study presented research results using hazelnut shell waste (HShW) as a biofiller in an epoxy matrix. HShW was modified using sodium hydroxide and several acids, including ethylenediaminetetraacetic (EDTA), acetic (AA), acrylic (AcA), and linoleic (LA). The modification process increased cellulose content, while lignin and hemicellulose contents decreased. This study explored the effects of filler content and modification type on the composites' mechanical, thermal, dynamic mechanical, water sorption, chemical resistance, and hygrothermal aging properties. The distinct X-ray diffraction (XRD) peaks around 22 degrees confirm that Cellulose I retains its original crystal structure within the composites. All modifications improved the tensile strength of the biocomposites, particularly at 20-30 wt%, ranging from 4.65 % to 53.49 %. The LA-HShW composites displayed the highest tensile strength (101-132 MPa), thermal stability, and glass transition temperature (Tg) values of 101.1 degrees C (DMA) and 66.4 degrees C (DSC). The AcA-and LA-modified HShW composites exhibited the lowest mass loss rate at 379.2 degrees C among the composite materials. All composites demonstrated greater resistance to alkali and acids such as hydrochloric and sulfuric, while showing lower resistance to acetone. In addition, hygrothermal aging increased moisture uptake (2.45-5.68 %) in biocomposites and reduced Tg values. A decrease in the Tg values of DMA and DSC was between 4.80 and 18.71 % and 7.01-18.29 %, respectively. The 20 wt% LA-HShW composite demonstrated significantly greater stability to aging, exhibiting the highest storage modulus (0.85 GPa), loss modulus (0.06 GPa), and DSC Tg (58.2 degrees C) compared to the other composites.