Investigation of mechanical and thermal properties of hazelnut shell and talc filled polypropylene composites

In PP matrix polymer composites, hazelnut shell can be used as an organic filling material as an alternative to inorganic filling material. In our country, hazelnut shell is preferred as a filling material in polymer matrix composites due to the abundance of hazelnut production and, accordingly, the easy availability of hazelnut shells, their low cost and unique colour. In this study, organic and inorganic additive polymer hybrid composite was obtained by adding talc, SEBS, SEBS-g-MA to PP in different proportions from hazelnut shells, which do not produce any added value to our country's economy in the form of waste and are consumed by burning. Mechanical properties (tensile, bending, impact, hardness measurement, etc.), thermal properties (HDT, VICAT, DSC, MFI, TGA, etc.) and formed microstructures (SEM) of hybrid composites with hazelnut shell were experimentally investigated. When hazelnut shell and talc were added to PP, the tensile strength of the prepared mixtures decreased, and the tensile elasticity module increased. However, a decrease was observed in the tensile modulus of elasticity after the addition of SEBS and SEBS-g-MA. While there was a positive increase in the bending strength and bending modulus of elasticity in general, a decrease was observed in the elasticity modulus when SEBS and SEBS-g-MA were added. Impact strength decreased with the addition of hazelnut shell and talc, but an increase in impact strength was observed in mixtures with SEBS and SEBS-g-MA ratio more than 3%. The highest impact strength was obtained from mixtures with 9% SEBS-g-MA added. In general, the density, HDT, VICAT, crystal melting initiation and crystallization temperature of the mixtures prepared with the addition of hazelnut shell and talc increased, while a decrease was observed in the MFI value and Tm temperature. In the hardness measurements, there was a slight increase in Shore D hardness in all mixtures, but it was determined that the hardness decreased when SEBS and SEBS-g-MA were added to the mixture. In the surface gloss measurement, lower GLOSS value was measured in all samples compared to the reference sample, depending on the hazelnut shell colour. It was concluded that the residual amounts remaining in the TGA and ash test were directly proportional to the talc and the mixtures were made homogeneously. As a result, it is thought that hazelnut shell can be used as a filling material in the production of polymer composites, the mechanical and thermal properties of hybrid composites produced by adding different inorganic materials to the structure can be improved, and more economical products compatible with the environment can be produced.