Investigation of the effect of graphene nanosheets on the properties of beech/polylactic acid flour composites

In this study, the effect of different amounts of graphene on the physical and mechanical properties of polylactic acid beech wood fiber composites were investigated. Beech flour and graphene were used as reinforcing phases with different weight percentages (0, 0.5, 1.5 and 2.5%). Samples were prepared by solution method and after pressing, mechanical properties such as flexural strength, flexural modulus, impact resistance and tensile strength and physical properties including differential scanning calorimetry test (DSC) and X-ray scattering test were measured. The results of analysis of variance showed that the effect of treatment was significant for flexural strength ( p < .05) and flexural modulus, impact resistance and tensile strength ( p < .01). The highest flexural strength, flexural modulus and tensile strength were related to treatment 8, which included 30% beech flour, 67.5% polylactic acid and 2.5% graphene, and the highest impact resistance was related to treatment 2, which included 20%. The weight of beech flour was 79.5% by weight of polylactic acid and 0.5% by weight of graphene, which were significantly different from other treatments ( p < .05). Based on the DSC, the melting temperature of the polymer matrix was transferred to higher temperatures by adding graphene nanosheets. The results of X-ray diffraction test showed that for all three treatments there is a similar trend in terms of peak graph and with increasing the concentration of graphene nanoparticles, only the peak intensity changed. It can be said that the addition of nanographene to beech-polylactic acid flour composites has improved the mechanical and physical properties.