Investigation of mechanical and thermal properties of new type bio-composites containing camelina

Abstract

Increasing urbanization has made lightweight construction materials with low thermal conductivity important. One of these materials, which has gained importance recently, is bio-composite materials consisting of agricultural wastes. The usability of camelina stalks, an agricultural waste, in the production of bio-composite has not been studied. The aim of this research is to develop new lightweight bio-composites with camelina stalks filled. For this, 11 composite mixtures using unsaturated polyester resin as the binder were created. Camelina stalks at 25, 30, 35, 40 and 45 % substitution ratios were used in half of 10 mixtures outside reference. Later, five more different mixtures by adding expanded perlite (EP) up to 5 % of the amount of camelina stalks in each mixture were produced. The physical, mechanical and thermal properties of the bio-composites produced with polyester binder were examined and the microstructure analysis was performed by SEM. The results showed that thermal conductivity, unit weight, compressive strength and ultrasonic pulse velocity (UPV) decreased as the ratio of the camelina stalks increased. The lowest thermal conductivity value was determined as 0.0842 W/(mK) in the 45 % camelina + 5 % EP filled specimen. The highest compressive strength value of the mixtures excluding the reference specimen was found to be 35.78 MPa in the 25 % camelina + 5 % EP-filled specimen. The addition of EP to the composites increased the water absorption, UPV and compressive strengths, but decreased the thermal conductivity. The results showed that camelina stalks can be used to produce sustainable bio-composites.