Hura crepitans L. Seed Oil-Based Medium Oil Alkyd Resin/Calcined Clay Reinforced Bio-Composites: Synthesis, Characterization and Molecular Weight Determination

Abstract

Research on producing high-quality bio-based products from locally sourced, environmentally friendly materials for the surface coating industry has been revitalized by the Sustainable Development Goals and the concept of green chemistry, promoting both environmental and economic sustainability. This research aims to synthesize bio-composites of alkyd resin from locally sourced Hura crepitans L. seed oil (HCSO) and calcined clay (CC) as reinforcing agents for use as binders in surface coating products. Three samples of 50% oil-length HCSO solvent-borne alkyd resin bio-composites with different weight percentages of CC, HOA-1 (2 wt.% CC), HOA-2 (3 wt.% CC), and HOA-3 (5 wt.% CC), were prepared via an in-situ two-stage alcoholysis-polyesterification process. In contrast, the ordinary alkyd resin HOA-Z was prepared without CC to serve as a control. The effect of CC loading on the appearance, surface morphology, number-average molecular weight, thermal stability, and intercalation with the alkyd sample was investigated. The bio-based products were characterized using standard methods. The colour of the final products ranges from dark brown to light brown. The viscosity of the bio-composites decreases from 17430.0 to 737.5 mPa.s. A morphological study showed the homogeneous dispersion of the CC in the alkyd resin. The molecular weight decreases with an increase in wt.% of CC, while the flammability property increases with increased CC loading. The tensile strength increases with the addition of CC from 18 MPa (HOA-Z) to 44 MPa (HOA-3). Processed clay minerals can serve as a better reinforcement agent for the preparation of polymer bio-composites.