Mechanical properties investigation on virgin and recycled polypropylene / Nathan Martinus

Polymer blending can be an effective way of reducing large amount of plastic waste as well as a cost-effective method which can be highly beneficial to the manufacturing industries. Polypropylene (PP) is a versatile material that is capable of numerous commercial applications. This study is about the effect of composition between virgin and recycled polypropylene towards their mechanical properties. The effect of blending polypropylene product was investigated whether it can improve the performance of the material without deteriorating its original mechanical properties. Two mechanical testing were conducted according to ASTM D638 for tensile Test and ASTM D790 for flexural test. Fracture surface analysis on the tensile test and flexural test was performed to observe the behavior of the material at fracture. The results from tensile and flexural test reveal that polypropylene products VP75 which consist 75 wt% of virgin polypropylene and 25 wt% of recycled polypropylene were the optimum composition. The results for tensile test also revealed that blending polypropylene at VP75 had positive influence on tensile strength, percent of elongation at break and young modulus. Opposite trends were obtained from flexural test where both flexural strength and bending modulus performed slightly less compared to virgin polypropylene. However, the differences were not that distinct. The SEM results revealed that compressive force and tensile force can instantaneously change the microstructure of PP product which results in the failure of tensile and flexural specimens. Overall, blending virgin and recycled polypropylene together at any composition had no significant effect on the mechanical properties of the material in the comparison with the virgin polypropylene. Therefore, recycled polypropylene can be used in production without the need to sacrifice its mechanical properties which can reduce material costing and help to save the environment by reducing polypropylene waste.