| Waste rubber powder (WRP) is granular powder which is made from waste rubber grinded by machines.Waste rubber powder (WRP) with dense cross-linked network structure has lost its surface activity, because waste vulcanized rubber is used by people for a long time. Therefore, when waste rubber powder (WRP) is applied for other materials, the compatibility beween WRP and the matrix material is very poor, so that the properties of composites is not ideal. However, surface modification of WRP is the key to solve this bottleneck. In this paper, for the problem of recycling WRP, a series of surface modification research were carried out. The methods of microwave desulfurization and mechanical force chemical modification of WRP were used, and then the modified rubber powder was applied for raw rubber. The desulfurized rubber powder (DRP)/natural rubber (NR) vulcanizates were prepared, and the modification effect of two methods were studied comparatively. Finally, to further expand the application field of WRP, the desulfurized rubber powder (DRP) acrylonitrile-butadiene rubber (NBR) foam materials were prepared, which DRP was modified by the mechanical force chemical method and the related properties were studied.In this paper, more than 90% purity of WRP as raw material was applied for the rubber matrix.(1) Vulcanizates with rubber power and raw rubber were prepared and the impacts of rubber powder content, the particle size and types of rubber powder and curing system on the physical and mechanical properties of vulcanized rubber were discussed. While, the properties of vulcanizates with WRP and other rubbers were further researched. The basic researches laid a foundation for further research of rubber power modification basis.(2) The microwave desulfurization method of WRP was used. By the orthogonal design method and with the microwave power, time and rubber powder particle size as factors, a better microwave desulfurization condition was got, which was microwave power: 750W, microwave time: 60s and rubber powder particle size: 80mesh. Under this condition, a series of microwave treatment experiments were carried out and DRP/NR vulcanizates were prepared. The physical and mechanical properties, compression set, mechanical and dynamic analysis were tested and the cross-linking density were calculated by swelling method and Flory-Rehner equation. The results showed that DRP/NR vulcanizates had good mechanical properties and greater degree of cross-linking.(3) The mechanical force chemical modification method is that WRP and chemical additives react upon mechanical shear force by mixing mill in order that some physical and chemical properties of WRP have changed. While, waste rubber powder has achieved from the particles into a plastic sheet to facilitate the industrial application. In this paper, DRP/NR vulcanizates were prepared by the mechanical force chemical modification method. The vulcanizates have excellent mechanical properties and tear strength, less compression set and higher cross-linking density.(4) DRP /NBR foam materials were prepared by the new foaming agent MSH-500 and rubber power modified by the mechanical force chemical method. It had been found that foaming agent MSH-500 had a certain foaming effect in the NBR matrix through the determination of its density and surface morphology by scanning electron microscopy and Correlations among content of MSH-500, contents and particle sizes of rubber powder and foaming effects in vulcanizates were dicussed respectively and then the physical and mechanical properties of foam materials were measured.In this paper, the application of the fine rubber powder in raw rubber was researched preliminarily. The researches have done some theoretical basis for industrialization of the modification method and have an important sense for domestic recycling of scrap rubber. At the same time, the study will promote the development of environment-friendly industry further. |
PDF Full Text Request