Effect of wood/basalt hybridization on crystallization and mechanical properties of PLA

In this study hybrid composites based on polylactide were reinforced with wood and basalt fibres. Composites have undergone physical and mechanical tests and the water absorption after 1 and 14 days as well as the effect of biodegradation on strength properties have been determined. Additionally the effects of annealing and temperature of tests on mechanical properties were investigated. The addition of fibres considerably increased the susceptibility of the tested composites and for composites with addition of 7.5 wt% of each wood and basalt fibres increased by more than 35% at +23 degrees C and was by 12 times higher at 80 degrees C. Heat treatment of composites positively influenced the results, mainly at elevated test temperatures. For pure PLA, the increase in Young's modulus was over 22 times (from 157 MPa to 3 473 MPa). The addition of fibres resulted in a reduction of the differences between the materials before and after annealing. Impact strength was more than double for composites after heat treatment at room temperature.