Resource Utilization Of Non-Metallic Materials Recycled From Waste Printed Circuit Boards By Coating Modification In A Spout-Fluid BED

The non-metallic materials recycled from waste printed circuit boards (N-WPCB) was mainly composed of thermosetting resins and glass fibers, which was hard to realize resource utilization effectively. In this thesis, N-WPCB was modified by coating in a spout-fluid bed with draft tube. The modified N-WPCB was used as filler to fabricate PP/N-WPCB composites by extrusion and injection molding.The effects of N-WPCB particle size and dosage on mechanical properties of PP/N-WPCB composites were studied. The results showed that the optimal particle size of N-WPCB was less than or equal to 154 micrometer. The flexural strength and oxygen index (01) were improved with increasing N-WPCB dosage filling in PP/N-WPCB composites. However, the tensile strength and impact strength of the PP/N-WPCB composites were decreased by adding N-WPCB. On comprehensive consideration for the reuse of the N-WPCB and the mechanical properties of PP/N-WPCB composites, the optimum dosage of the N-WPCB was 40.0 phr.The effect of different modifiers on mechanical properties of PP/N-WPCB composites was investigated.3-Aminopropyltriethoxysilane (KH-550) was the best modifier for N-WPCB coating modification in a spout-fluid bed with draft tube. The cross-section morphologies and the surface functional groups were characterized by scanning electron microscopy and infrared spectroscopy. It demonstrated that modified N-WPCB improved the interface bonding between N-WPCB and PP, which enhanced the mechanical properties of PP/N-WPCB composites.To obtain the operating parameters range of the coating modification process, the effects of spray rate, atomizing gas velocity, bed temperature, spouting gas velocity, and fluidizing gas velocity on modifying were evaluated. The optimum parameters of the coating modification process were the spray rate of 3.2 cm·s-1, atomizing gas velocity of 58.98 m·s-1, bed temperature of 80?, spout gas velocity of 29.49 m·s-1, and fluidizing gas velocity of 0.048 m·s-1.To improve the fluidization quality of the N-WPCB particles in the process of coating modification, PP particles was used to reinforce the process of coating modification. It showed that PP assisted fluidization could improve the quality of fluidization, and the mechanical properties of PP/N-WPCB composites. At the mass ratio of PP particles with N-WPCB particles was 100:80, and the dosage of KH-550 was 4 phr, the flexural strength, tensile strength, impact strength of the composites were increased by 16.60%,23.22% and 23.64%, respectively.