The Study On Wood-Rubber Multifunctional Environmental Composite Panel

With soaring development of automobile industry, problems of polluted environment and lack of resource are more and more remarkable in the globe. It is one efficient way to reducing "black pollution" and saving forest resources, which using waste tire and wood make new composite materials.Main purpose of the thesis was to that material comprising of larch (Larlx gmelini) wood particle and waste tire rubber, adopting a polymeric methylene diphenyl diisocyanate (PMDI) and urea-formaldehyde (UF) combination binder system manufacture low cost, environmental wood-rubber functional composite. Manufacturing technology was complete studied. Preceding parameter including PMDI/UF, wood particle-to-rubber crumb ratio, and size of rubber crumb, density, on the physical and mechanical properties of the composite panel have been fully developed. Optimization of processing variables in wood-rubber composites was performed by using some mathematical and statistic methods, based on a large number of trials, and optimal board manufacturing technology was obtained. Microcosmic structure of composite and relation between microcosmic structure and mechanical properties was probed by SEM. It is innovative study to probe the properties of damp shock absorption and sound insulation of wood/rubber composites. The main results and highlight from this study can be summarized as follows:1. The effects of main experimental variables, including PMDI, UF, wood particle-to-rubber crumb ratio, and size of rubber crumb, density, on the physical and mechanical properties of the composite panel have been fully investigated. The results indicated that the wood particle-to-rubber crumb ratio and density are the most significant variable that impacts on the composite performance. The physical and mechanical properties of the composite will be predominant with increacing wood particle-to-rubber crumb ratio and density, followed by the level of PMDI usage. The UF resin content and size of rubber crumb have a less influence on the panel properties.2. In terms of formaldehyde emission (FE) of the composite, the results showed that the ratio of wood particle and rubber crumbs is the most significant variable, followed by the UF content, The amount of PMDI has a less influence, while the size of rubber crumb has no influence on composite properties. The formaldehyde emission value (FE) was greatly reduced in the rubber-wood composite panel, and 7.1 mg/100g was obtained in this study.3. Based on the mechanical properties and cost analysis of composite panel and the optimal parameters of manufacturing composite panel were 60/40 wood particles/rubber crumbs, 6% PMDI, 10% UF, and 5-mm rubber crumbs. These results provide basic and useful information for commercial production of wood/rubber composite panel in the future.4. The board performance was evaluated by measuring internal bond (IB) strength, modulus of rupture (MOR) and modulus of elasticity (MOE). Based on the analyses of board properties, board density, pressing time and pressing temperature were identified as independent variables that had significant influence on board performace. A mathematical simulation or response surface models were developed to predict the board properties (MOR, MOE and IB). The suggested optimal board manufacturing conditions were about 170℃, for pressing temperature, 300 seconds for pressing time, and 1000 kg m～(-3) for board density.5. Microcosmic properties of structure in composite: interface areas in composite were performed between wood particle and wood particle, between wood particle and rubber crumb; Vertical density profile of wood/rubber composite panel was formed proceeding load affect on composite; wood particles/fibers usually were destroy in heavy vertical density profile and high level of PMDI/UF; wood particles/fibers usually were draw out or pull out from matrix in light vertical density profile and low level of PMDI/UF; 6. With advanced experimental methods and test facilities, damp shock absorption and sound insulation of composite panel were investigated. Testing results exhibited that wood/rubber composite panel has better damp shock absorption and sound insulation properties than wood-based particleboard. An increase in the quantity of waste tire rubber in the composite panel significantly improves damp shock absorption and sound insulation properties. The size of rubber crumbs also has certain influence on these board properties. Therefore, adjusting the quantity and size of rubber crumbs in the composite panel allows producing different quality panels for different applications.