Accelerated aging of polymer composite from Pennisetum purpureum fibers with recycled low-density polyethylene

Abstract

The use of natural fibers (NF) as reinforcement in polymer composites have been an interesting option to improve their mechanical properties and to decrease production costs since several crops can produce large amounts of NF with low cost. This is particularly attractive for polymer waste recycling that depends of the production of cheap materials to be economically viable. Elephant grass ( Pennisetum purpureum schum) is a tropical climate plant of fast growth with high potential for production of NF. However, studies on the use of P. purpureum fibers as reinforcement in polymers, mainly for recycled polymers, have been restricted. The aims of this study was to evaluate the action of the P. purpureum fibers on the properties of composites using matrix of low-density polyethylene waste (LDPE-w) as well as to verify the behavior of recycled polymer when submitted to the accelerated photochemical aging using UVA radiation. LDPE-w and LDPE-w composite with P. purpureum fibers (LDPE-composite) were analyzed at different aging times by tensile and impact tests, melt flow rate, scanning electron microscopy and Fourier transform infrared. It was verified that P. purpureum fibers induce defects in matrix of LDPE-w, decreasing the performance of mechanical properties. Similar effect also occurs when LDPE-w is submitted to the first hours of accelerated aging. On the other hand, effects of stabilization of the degradation on the polymer matrix can be attributed to the P. purpureum fibers at high aging times. Thus, P. purpureum presents high potential for use as reinforcement in recycled thermoplastic waste.