Development of glass fiber/polyester composites reinforced with bio-based calcium carbonate and aluminum trihydrate for the automotive industry

Nowadays, the transformation of natural wastes into high value-added materials has an important place in sustainable material development approaches. In this context, eggshell wastes, which are rich in calcium carbonate, are evaluated as a promising biofiller alternative for the purpose of reinforcing polymer-based composites in an environmentally friendly and cost-effective manner. In this study, glass fiber reinforced polyester composites reinforced with waste eggshell and aluminum trihydrate (ATH) were produced by hand lay-up method and the effects of additives on composite performance were investigated. For this purpose, in addition to composites containing only eggshell and only ATH as 10% of the total resin weight; hybrid composites with eggshell:ATH ratios of 5:5, 2.5:7.5 and 7.5:2.5 were prepared. In the lamination process, felt and plain woven glass fiber (300 gr/m²) reinforcements were used to obtain a composite consisting of a total of 7 layers, respectively. The structural properties of the composites were determined using Fourier transform infrared (FT-IR) spectrophotometer and the morphological properties were determined using scanning electron microscope (SEM). Tensile test, three-point bending test and impact tests were performed to examine the mechanical properties of the composites. UL94 horizontal fire resistance test was applied to the composites. As a result, only the addition of eggshell to the glass fiber reinforced polyester based composite increased the bending modulus, tensile and impact strength. While the tensile strength of the composites slightly increased with the combined use of eggshell and ATH, a decrease of approximately 45% was detected in the elongation values. When the combustion properties were examined, the combustion times of the composites were extended with the addition of additives. All composites were classified as slow burning (HB) materials.