| Thermosetting plastic, as one large category of plastic, generally applied in structural parts, stress parts and functional parts, its products have been widely permeated into every realm of society, such as in producing of construction formwork, automotive components, electronic components, printed circuit boards (PCB) and so on. The amount of waste thermosetting plastic, especially cured epoxy resin which applied in manufacturing of electronic components, is increasing dramatically as the growing of production scale and demanding for thermosetting plastic, let alone the arrival of discarding peak of various electronic and electrical products. The waste is now mainly treated by simple landfill or incineration, which can not meet the requirement of sustainable development. Owing to non-melt and indissoluble properties of thermosetting plastic, its waste can not be recycled by re-melting method, which is commonly applied to reclaim waste thermoplastics. Either from resource-recycling, or from environmental protecting view of point, as the increasing level for utilization rate of e-waste around the world, it is an imperative issue to develop environment-friendly and economically feasible recycling technologies of waste cured epoxy resin.In this paper the recycling and reutilization of waste cured epoxy resin have been studied. The research object in this thesis was the mold residue of epoxy molding compound, which was generated as industrial waste in the molding process of electronic components packages. A physical method has been applied for reusing waste cured epoxy resin powders (waste epoxy powders) into poly (vinyl chloride) (PVC) blend to prepare composites. The relationships between the structure and the properties of the composites have been studied, both of the formulations and process conditions have been optimized, meanwhile a regenerative product has been preliminary developed, with the aim to reclaim waste cured epoxy resin and maximize its reutilization. Furthermore, a coupling agent has also been applied and studied to improve properties of the composites.The components and properties of waste epoxy powder have been studied by using infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray energy spectrum analysis (EDS). The results showed that waste epoxy powders mainly consisted of irregular cured epoxy resin particles with rough surface, and spherical silica powder. There are active and polar functional groups on the surface of the powder, such as hydroxyl groups, ether bonds, carbonyl, epoxy groups and so on, which make the powders have a certain activity. All the above functional groups make it possible to have both physical and chemical interactions between PVC chain and waste epoxy powders, which would contribute to miscibility between different phases in the blends, consequently the feasibility of blending waste epoxy powder with PVC resin, even at a high portion, was proposed.In the laboratory stage, waste cured epoxy resin was reused to produce regenerative composites by compression molding method. The effects of filler size and content on the mechanical properties of composites were investigated; the optimized molding parameters have been explored. The results showed that the smaller size of waste epoxy powder was benefit to mechanical properties of the composites. Simply blending of waste epoxy powder without any surface modification and PVC would result in the significant decline of the mechanical properties of the composites, especial for the impact strength. When the powder content was up to 60wt%, under optimized molding conditions, waste epoxy powder/PVC composites showed excellent mechanical properties, with tensile strength of 34.65MPa, impact strength of 5.2 KJ/m2, flexural strength of 60.94MPa and flexural modulus of 6.1GPa, which displayed much better mechanical performance than ordinary wood-plastics composites. It should be noticed that when waste epoxy powders are added at high ratio (>50wt%), the powders can not be counted as a filler component of "PVC composites", but become the main material, while PVC and other additives only play the role of adhesive in the composites to bond the powders together. Compared to be just as a general filler in thermoplastic, waste epoxy powder can be the main material to be reused, which indicates a distinguished increment of reutilization rate and shows its good practical sense.The structure and properties of the interface in waste epoxy powder/PVC composites have been studied; the mechanism of surface grafting reaction was also discussed. After dissolved PVC of the blends by Soxhlet extraction, the final residue was tested by FT-IR spectrometer, the results indicated that PVC chain had grafting onto the surface of waste epoxy powder, and concluded that the grafting reaction may attribute to nucleophilic substitution, which occur between hydroxyl or epoxy and PVC chain labile sites. A stable boundary layer structure was constructed, because there was not only the main physical adhesion (secondary bond force) existed, but also the strong chemical binding (primary bond force) existed between waste epoxy powder and PVC. SEM photos showed partly strong interfacial bonding, and crosslinking points on the interface, however, the interfacial cracking and debonding indicated that further improvement of interfacial bonding could be made in future.In order to prepare for the next trial in workshop, it is very important to understand the roles of each component in formulations and their interactions to each other. The effects of different additives on rheological behavior of waste epoxy powder/PVC blends have been studied by torque rheometer. It can be concluded that the processing aid ACR-401 promotes the fusion of PVC mainly in initial stage; the impact modifier CPE-135A could shorten the fusion time, and improves the impact strength meanwhile decreases the tensile strength of the composites, in this experiment the proper content was 4-6 phr; the internal and external lubricating effects of the various lubricants are weakened by waste epoxy powder, due to its high portion and absorption of lubricants; When CaSt2 and wax with equivalent ratio are added, the best impact property of composites can be reached.A practical product trial has been done in workshop, with the aim to develop a new process for making regeneration products by conical twin-screw extruder. In this paper, a kind of freight pallet has been developed successfully. The results of heap pressure, impact strength, heat and acid resistance tests showed that the produced pallet with static loading of 2000kg, dynamic loading of 1000kg, and good heat and acid resistance, all of which could meet the requirements for container transportation pallet. Results of simple cost-benefit analysis indicated that the developed regeneration technology would bring wonderful economic, social and eco-benefits.Application of coulping agent on improving waste cured epoxy resin regeneration composites has been investigated. Take silane coupling agent KH-550 as an example, the effects of KH-550 and its coulping mechanism have been studied and analyzed. The results displayed that KH-550, could not only strengthen and toughen the composites, but also help improving plasticizing and processing stability of the blends; SEM photos also showed that KH-550 improved the interfacial bonding between waste epoxy powder and PVC, which leaded to better mechanical performance. Both of the tensile strength and flexural strength of the modified composites exceeded the requirements for national ordinary engineering plastic, which meant that higher value-added products could be manufactured and further scope of application would be prospected.Dynamic mechanical thermal analysis(DMA) and Vicat softening temperature(VST) of the composites were measured. It can be concluded, in one aspect, the unmodified waste epoxy powder has some properties of strengthen and heat resistance, which could improve storage modulus, Tg and VST of the composites; in the other aspect, interfacial layer was formed owing to interactions between waste epoxy powder and PVC, and the interfacial layer was strengthened by adding KH-550, with declining trend of loss modulus and loss factor peak of the composites, it also indicated the improvement of rigidity and heat resistance of the composites after using KH-550.
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