Preparation And Performance Of Composites Using Waste Non-metallic Materials Recycled From Printed Circuit Boards

The non-metallic materials recycled from waste printed circuit boards (WPCBN) arethermosetting characteristics, consisting of thermosetting resins, glass fibers, and a smallamount of metal components. In this thesis, the extrusion molding method was employedto prepare several kinds of composites by polypropylene recycled from waste bumper(WPP), polyvinyl chloride recycled from waste window frame (WPVC) and WPCBN.Mechanical properties of composites prepared by PP and WPCBN were studied. It ishelpful for the improvement of the mechanics performance when the particle size ofWPCBN is less than or equal to150micrometer. The tensile strength and impact strengthdecrease with increasing amount of WPCBN filling. By contrast, flexural strength andmodulus can be significantly improved by adding WPCBN. The thermogravimetric (TG),oxygen index (OI) and vicat softening temperature (VST) analysis indicate that thepresence of WPCBN can effectively enhance the flame retardant and thermal propertiesof WPP/WPCBN composites for their potential applications. The VST and OI increasesby5°C and15%, when the content of0.150mm non-metal fillers approaches30phr.To raise the interfacial adhesion between WPCBN and WPP, a compatilizers,maleic-anhydride-modified polypropylene (MAPP), and a surface treatment (KH550) areused to treat the WPCBN. Furthermore, the surface chemistry of the treated non-metallicmaterials and composites are evaluated using Fourier-transform infrared (FTIR)techniques. The effect of surface treatment on the mechanical properties of thecomposites is investigated. Also, fracture surfaces and fracture mechanism of thecomposites are examined and discussed in this thesis. It demonstrates that the compositesthat contain WPCBN treated with MAPP followed by KH550are characterized byexcellent mechanical properties. The maximum increments of the tensile strength and flexural modulus of the composites are found to be48.29%and22.73%, respectively.Compared with New polypropylene (NPP)/WPCBN composites, the tensile and flexuralstrength of WPP/WPCBN are only reduced by16.8%and20.4%, the impact strength ofthe two kind of composites are in an equally close.Composites are prepared with WPP/WPVC polymer blend instead of WPP. Theeffects of WPCBN and MAPP on composites mechanical properties were investigated.WPCBN reaches an excellent dispersion between WPP and WPVC. The tensile, flexuraland impact properties of the composites were improved after the addition of MAPP.When the dosage of MAPP is6phr, the maximum impact strength and flexural modulusare5.53kJ/m2and2459.81MPa, respectively. When the dosage of MAPP is9phr, thevalues of tensile and flexural strength reach the peaks, being26.57MPa and39.043MPa.A comparison between WPP/WPVC/WPCBN and WPP/WPCBN composites shows thatthe maximum increment of the flame retardant properties, flexural strength and flexuralmodulus are20.69%,31.85%and17.39%, respectively.