Characterization of Recycled/Virgin Polyethylene Terephthalate Composite Reinforced with Glass Fiber for Automotive Applications

Abstract

The use of recycled polyethylene terephthalate (PET) as a matrix for composite materials based on glass fiber reinforced virgin PET could be a cost-effective and environmentally friendly way to upgrade the bottle-grade recycled PET into engineering-grade PET for injection molding. In this work, a commercial virgin PET reinforced with 50%wt of glass fibers was compounded by mechanical mixing with a recycled PET, in order to minimize breakage of the glass fibers. The obtained compound, composed by 60%wt of recycled pet and 40%wt glass fiber reinforced virgin PET, was injection molded at three different mold temperatures (4, 40 and 80 °C) to analyze the effect of crystallization of the material during the production process. The results in terms of thermal and mechanical properties were compared with those obtained from recycled PET molded in the same conditions. The flexural tests and the analysis of thermal resistance showed that by adding 40%wt of glass fiber reinforced virgin PET to the recycled PET causes a noticeable improvement of crystallization kinetics and of mechanical properties with respect to that of the pure recycled PET, making it suitable for technical applications.