| Electronic waste (e-waste) is a heat topic during the management of solid waste. Waste printed wiring boards (PWBs) are the focal points for handling e-waste. Scrap PWBs are a compositing material of organic materials, metal, and glass fiber with lamination structure. Mechanical treatment technique which employs crushing and separation processes for PCBs recovery is becoming more in favor and widely used in industrial practice. The full separation or liberation of metal and non-metallic from PCBs greatly depends on the crushing process, which plays a key role in mechanical technologies. Moreover, there are other problems associated with the crushing process, such as the dust and noise pollution, high energy consumption. Thus, the improvement of crushing efficiency is becoming a crucial problem for the PWBs treatment by using mechanical technology.As the typical elements of a PWB (FR-4), the thermo-mechanical properties of copper foil, epoxy resin, and glass fiber are quite different. Consequently, a thermal shock method was firstly employed to pretreat waste PWBs for the physical change and microstructure-level breakage of whole board, with aiming at the improvement of crushing performance, specifically on the full liberation of metal and non-metallic materials. Meanwhile, the thermal-shocked mechanism leads the changes of PWBs has been studied from the micro-mechanical properties of macro-mechanical response. Combined with the tool of ANSYS finite element model of temperature/stress field evolution, the theoretical analysis is simulated to assess the effect of thermal-shocked treatment. Moreover, the environmental impact and pyrolysis characteristic within the low-temperature scope of PWBs has been discussed in the favor of thermogravimetry-differential analysis and thermal-degradation experiment. Finally, the reuse of non-metallic material separated from PWBs residues before and after thermo-shocked pretreatment has been investigated.The influence of the thermo-shocked process on interfacial modification and mechanical property attenuation of PWBs is significant. The appearance and layer spacing of the basal plane began to change clearly when the temperature reached to 525k, and apparent bulging, cracking, and delaminating have been observed. The PCBs that are heated until 525K achieved 100% liberation increasing linearly from 13.6% for unheated PWBs through a single-level shear-crusher (2mm mesh). The crushing efficiency is improved by thermo-shocked treatment, which resulted in an obvious reduction of energy consumption and noise by a 41.7% and 8.2% (dB) at 525K respectively. Tensile, flexural, impact and delaminating strength of PCBs was greatly reduced as shocked temperature rose gradually, with a reduction by 68.7%, 60.8%, 16.5% and 58.5% respectively at 525K from its unheated strength. Above-mentioned temperature condition successfully avoided the pyrolysis of resin contained in PWBs (545K), which improbably generates toxic gaseous substances. That means thermo-shocked is harmlessly performed from the aspect of environmental protection. This study indicated that the non-metallic-material filled polypropylene composites are promising candidates for structural applications where high stiffness and fracture resistance are required. It was found that the maximum amount of recyclate that could be added to a composite board was 30% of weight, with the additive agents of: Silane coupling agents, 1%; Lubricant agents (Zine stearate and Na stearate, 1%; Antioxidizing agents, 1%; Processing modifier, 5%.These achievements obtained from this thesis could be helpful to develop new technology and establish operational setup with industrial scale facilities for waste PCBs recovery. The results are also useful for the recycling and reclamation of laminated compositing materials waste.
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