Mechanical Properties of Rubber-toughened Post-industrial Glass-fiber-reinforced PA66

Abstract

Abstract When compounding engineering thermoplastics with glass fibers for reinforcement purposes, a tremendous amount of polymer-containing waste is generated. However, the polymer of interest is usually commingled with the polymer used to purge the extruder. Reclaiming valuable polymer from this waste is hindered by the incompatibility with the purging material since this leads to a blend system that has poor mechanical properties and low economic value. For this reason, this potentially valuable post-industrial polymer-waste is normally land filled. The current research is directed at the characterization and reuse of a post-industrial PA66 filled with glass fibers; this was separated from LDPE purge material and its impact resistance was modified through rubber toughening. Styrene-Ethylene-Butylene-Styrene and Ethylene-Propylene elastomers grafted with maleic anhydride (SEBS-g-MA and EP-g-MA respectively) were used as the toughening agents in this study due to their compatibility with PA. Izod impact strength, tensile strength and modulus, flexural strength, and elongation at break were used to characterize mechanical properties of the rubber-toughened recycled glass-filled PA66. The morphology of the fracture surfaces of the composites was examined by Scanning Electron Microscopy (SEM). It was found that both impact strength and elongation at break increase with increasing rubber content while flexural strength and tensile strength suffer upon incorporating rubber; however, by adding moderate amounts of rubber to the recycled glass-fiber-reinforced PA66 a balance between stiffness and toughness of the material could be obtained. For example, the addition of 10 wt.% of SEBS-g-MA to the recycled PA66 with 23.62 wt.% glass fiber loading resulted in a 27% and 151% increase in tensile strength and impact strength respectively of the blends when compared with neat PA66. This suggests that compounding both glass fibers and elastomers with PA66 is a useful strategy to recycle PA66, especially for reuse in under-the-hood automotive applications.