Fastener pull-out resistance of recycled polymer composites

Abstract

The problem of waste plastics has created a need to find new and innovative ways to keep discarded products out of landfills and turn waste materials into new products of value. By combining carpets made from poly(ethylene terephthalate) (cPET) or polypropylene (cPP) with pellets of recycled poly(ethylene terephthalate) (rPET), recycled polyolefins (rPO), or recycled high density polyethylene (rHDPE) through compression molding recycled composite materials were made and tested to investigate their suitability for use in light structural applications. For the recycled composites to be used in many structural applications they must have the ability to be cut to measured lengths and joined together using fasteners. In this study the pull-out resistance of wood screws, bolts, and nail fasteners was tested for three recycled carpet and pellet combinations, cPET/rPET, cPP/rPO, and cPP/rHDPE. It was found that the cPP/rPO and cPP/rHDPE composites have a stronger pull-out resistance than common pine wood for all fasteners tested. The cPET/rPET composites had a stronger pull-out resistance than common pine wood for screws and bolts, but was too brittle to have a nail driven through the material without cracking. These results show great promise for recycled composite materials to find use in light structural applications and avoid taking up space in landfills.