Natural Fiber-Reinforced Recycled Polypropylene: Microstructural and Mechanical Properties

Abstract

This article deals with short spruce fiber-reinforced recycled polypropylene materials. Polypropylene has been subjected to n extrusion and crushing cycles, in order to simulate the recycling process. Recycling consequences have been studied on five times and 10 times-recycled PP. Then, short spruce fibers have been added in the 10 times-recycled PP, with different fiber weight fractions: 10, 30, and 40%. For microstructural aspects, results obtained by DSC and WAXS show that added fibers lead to an increase of the polymer degree of crystallinity, and to the development of a new crystalline phase with the β form. Tensile tests have shown that fiber presence obtains high rigidity values, but embrittles materials. Fracture tests coupled with digital image correlation technique have also been performed. Results show the better accommodation of overstrains at the crack tip in the composite material. Thus, this new type of composite, made of recycled polymers and natural fibers, seems to be full of promise.