| Printed circuit board (PCB) was an integral part of electronic products. In recent years, wastedPCB (WPCB)amount wasgrowing rapidly with the high renewal speed of electrical and electronic products.The recycling of the WPCB has been developing into an emerging industry in the world. In this thesis, a forecast for the amount and distribution of of WPCB in Fujian province was proposed by combination of the actual survey and mathematic modelanalysis. The status of WPCB recycling in Fujian province was also reviewed. Besides, the technology of appling recycled PCB powder (r-PCB) on the recycled polyethelen (r-PE) was investigated.Firstly, the amount of the WPCB obtained from "the four machine and a computer" inFuzhou,Quanzhou, Xiamen and Zhangzhou in Fujian province in 2012-2020were proposed via on-the-spot investigation and questionnaire survey. It wasclear that the stocks of WPCB inFuzhou, Xiamen, Zhangzhou and Quanzhou are of 6308t,3983 t,2026 t and 2184t respectively. The total amount of the WPCB recycled in the electronic production dismantling enterprises in the four cities wereof 800 t,415 t,370t and 700t, respectively. Moreover, based on the survy data, the amount and distribution of the WPCB in all Fujian province were forecasted using the the function estimation model. The results show that the amount of WPCB in Fujian province in 2015 wouldreatch to 3020.5t, in whichFuzhou, Xiamen, Zhangzhou and Quanzhouare of 782.79t(25.9%), 453.02t(15.0%),369.11 t(12.2%)and 683.26 t(2.6%).Secondly, the recycled PCB (r-PCB)powder was obtained from WPCB by crushing, grinding and eddy current separation process. The composition, structure and thermal stabilityof the r-PCB powder were investigated using X-ray fluorescence spectrometer, infrared spectroscopyand thermogravimetric analyzer respectively. Moreover, r-PE/r-PCB composite was prepared on a double-screw extruder. The results showed that the r-PCB powder wasinriched ofhydroxyl and ether bond, which provides a possibility for r-PCB surface modification.Themelt flow rate,torque, tensile strength and bending strengthof r-PE/r-PCB composite increase with the dosage of r-PCB, whereas, the notched impact strength decreases.The tensile strength of the composite reaches to 11.96 MPa, which is 11.5% higher than that of the pure r-PE.Thirdly, the compatibilizingefficiency of compatibilizer and the dosage on the r-PE/r-PCB compositewas investigated. And the copporleaching testsfrom the r-PE/r-PCB composite were carried out using sulfuric-nitric acid and acetic acid respectively. The results show that all compatibilizers used in the experiment give obviouscompatibilizing effect for the composite, in which POE-g-MAH shows the most efficient.5 phr of POE-g-MAH introduced in the r-PE/r-PCB compositeresults in increasing the impact strength to the maxmum 4.39 kJ/m2,43.5% higher than that of the composite without any compatibilizer. Moreover, the Cu leaching level of the composite was determined to be far lower than the value limitedby therelative standards in China.Finally, the effect of the compound additives on the mechanic property of the composite was studied. It wasclear that the notched impact strength of the composite can be improved using compound additives. The introduction of EM/OM (0.6/9.0), acid/OM (0.4/9.0) and acid/EM/OM (0.4/0.4/9.0) into the composite cause to increase in the notched impact strength of the composite by 111.8%,129.7% and 111.8% respectively. Besides, the compound additives also can leads to increasing the tensile strength of the composite in some extent. The results of accelerated weathering test showed that notched impact strength of the composite decline obviously with the testing time. The composites with PEW-g-MAH/POE-g-MAH(0.6/5.0), citric acid/POE-g-MAH(0.4/5.0) andcitric acid/PEW-g-MAH/POE-g-MAH(0.4/0.6/5) give decreaments of notched impact strengthby 49.8%,57.3%and 51.6%in weathering test for 15 h. |
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