Evaluation of sugar mill lime waste in biobased epoxy composites

Abstract

In this study, precipitated calcium carbonate‐lime waste (LW) from sugar beet production was recycled as a raw material for the preparation of composite materials. Epoxidized soybean oil (ESO) was used as a co‐matrix in 50 wt% with bisphenol A‐type epoxy resin (ER). The composites were prepared with LW in varied per cent values (10 − 50 wt%) using the casting technique. The morphology of the composites was characterized by X‐ray diffraction and scanning electron microscopy. Effects of ESO and LW amounts on the mechanical and thermal properties of the composites were investigated. Modification with ESO remarkably enhanced the plasticity of the material, but decreased the curing degree about 2%. The modified ER shows about 13% increase in elongation at break over the pure epoxy matrix. Density and hardness of neat epoxy matrices were observed to increase with the LW content in the composite. Tensile strengths of all composites are higher than that obtained with neat epoxy. The thermogravimetric analyses show that ESO and LW significantly improve the thermal stability of neat ER at the temperatures above 300°C. The best thermal results were obtained with the composites containing 40‐ and 50 wt% LW. The residual weights of the composites are higher than that of neat ER and ER‐ESO, and increases with the increasing LW amount. The T5, T10 and T50 data of the composites are higher than those of neat ER and ER‐ESO. The water sorption values of the ER‐ESO matrix composites are in the range of 1.0 − 2.9 wt%. POLYM. COMPOS., 39:924–935, 2018. © 2016 Society of Plastics Engineers