Preparation And Properties Of Unsaturated Polyester Composites Modified With Waste Printed Circuit Board Powders

With the rapid development of information industry,renewal speed of electrical and electronic products is accelerating,and the corresponding electronic waste is also dramatically increasing.As the fundamental component for electric and electronic equipment,waste printed circuit boards(WPCB)is facing great pressure.Recently,the re-utilization of WPCB mainly concentrate on the high value-added metals.However,the nonmetals are usually landfilled or incinerated without any further disposal and reuse,causing severe environmental pollution and resources waste.Under the urgent pressure of global energy and environmental problems,it has great practical significance to realize the reuse of waste printed circuit boards powders(WPCBP).The compositions,surface morphology and particle size distribution of WPCBP were detailly analyzed.And the WPCBP were incorporated in room temperature cured unsaturated polyester(UPE)to investigate the effects of WPCBP on the mechanical properties and thermal stability of UPE composites.Results suggested that the smaller particle size of WPCBP give a positive effect on the mechanical properties of UPE composites,and it can act as strength enhancer to improve the tensile,flexural and heat distortion performance of UPE composites.Moreover,the thermal stability was dramatically improved.To strengthen the WPCBP-UPE interfacial interaction and achieve effective application of the high percent WPCBP in UPE composites,a novel type of polyurethane prepolymer(pre-pu)was prepared by the reaction of isophorone diisocyanate(IPDI)with polyethylene glycol(PEG).It was found that pre-pu was chemically bonded on the surface of WPCBP and a stronger interaction between WPCBP and UPE matrix was formed.The mechanical properties and thermal stability of UPE/prepu-WPCBP composites showed remarkable improvements compared with those of UPE/WPCBP composites.Based on the consideration of novel hybrid filler and interfacial interaction,sol-gel method was introduced to fabricate a new type of hybrid filler(WPCBP-SiO2)by immobolizing the nano Si O2 on the surface of WPCBP.Then WPCBP-SiO2 hybrid filler was modified with a silane coupling agent and incorporated in UPE matrix.The effect of WPCBPSiO2 hybrid filler on mechanical properties,interfacial bonding and thermal stability of UPEcomposites were comprehensively explored.It has been confirmed that WPCBP-SiO2 hybrid filler could form a strong interfacial interaction with polymer matrix,and markedly enhance the mechanical properties,thermal stability and wear resistance of UPE composites.Finally,WPCBP together with halloysite nanotubes(HNTs)were incorporated in UPE to prepare UPE/WPCBP/HNTs composites.Then the thermal stability and flame retardancy of UPE composites were systematically investigated.It has been confirmed that WPCBP and HNTs could markedly enhance the thermal stability and fire retrardancy of UPE,and HNTs gave a more positive contribution than WPCBP.The carbon layer became more stable and compact,which effectively prevented further combustion of polymer matrix and delayed the mass transfer process.It provided a new method and application direction for the high value utilization of waste printed circuit board.