Preparation and Characterization of Sawdust Granite Filler Reinforced Polybenzoxazine Composites

Abstract

The bisphenol-A aniline benzoxazine resin synthesized by Mannich condensation and newlineboth the type of composites prepared by solution blending technique. In the present research, two types of industrial wastes such as sawdust and granite dust utilized as reinforcement materials in the preparation of bisphenol-A aniline-based benzoxazine composites. The composites were prepared and characterized by varying the sawdust content from 20 - 45 wt% and the granite powder content from 10 40 wt%. The influence of the sawdust, granite powder on the physical, thermal, structural, morphological, dimensional, and mechanical properties of the composites are newlineinvestigated. Thermogravimetric analysis results showed significant compatibility between sawdust and polybenzoxazine from the considerable improvement in char yield from 22% (neat resin) - 36% (for highly filled) and the glass transition temperature from 151-165 oC. From the derivatives of thermogravimetric plots, the ultimate weight loss of the composites was evaluated. Limiting oxygen index of the composites raised with raise in the content of the filler from 28-32. Differential scanning calorimetry results showed sawdust has an insignificant effect on the cure newlinetemperature (219 oC) of the composites. The structure of benzoxazine, polybenzoxazine, composites, and sawdust were studied using Fourier transformation infrared spectroscopy. The morphology derived from scanning electron microscopy (SEM) show that composites have good interfacial adhesion between the polybenzoxazine and sawdust. A particle analysis test performed on the sawdust to examine the particle size. Water absorption tests showed less water uptake in the composites than the raw sawdust. Chemical contents of sawdust such as ash content, acid-insoluble lignin content, and holo-cellulose content were recorded as 4.7 ± 0.3, newline27.2 ± 0.1, and 65.1 ± 0.2. X-ray diffraction (XRD) studies exhibited the nature of sawdust, granite powder and the composites newline