Evaluation of composite properties made of sunflower stem flour and natural poly lactic acid (PLA) polymer

In this research, the effect of using natural poly lactic acid polymer and the amount of MAPP coupling agent on the physical and mechanical properties of composite manufactured by sunflower stem flour was studied. For this purpose, three levels of PLA polymer including 50, 60 and 70% and tow levels of MAPP including 4 and 6 percent based on dry weight of polymer were used as variables. Then, the physical and mechanical properties of the test specimens including dimensional stability, resistance and tensile modulus, resistance and flexural modulus and impact resistance were measured. The results showed that increasing the amount of PLA polymer and reducing the share of sunflower stem flour and increasing MAPP up to 6 percent, increased the flexural, tensile and impact resistances and improved dimensional stability of the composites. But in contrast, the tensile and bending modulus of composites were reduced. However, by reviewing the results, it was found that the physical and mechanical properties of the composites made with this polymer and the particles of sunflower stem flour were competitive with other composites made with other chemical polymers and in some cases it was better than them.