The Properties Of The Regenerated Particles By Steam Explosion And The Particleboard Manufacture Technology

More and more people are paying attention to the recycling and reusing of the used wood around the word. A large amount of waste wood is generated from many natural, commercial and domestic sources each year in China. The recycled wood can not only decrease the impact to the environment, but also can produce attractive products and relieve the scarcity of wood resources.The used particle board is always regenertated by the mechanic method which results in the serious damage to the shaving shape, the low quality and the poor process ability of the regenerated particle board. So the steam explosion technology of regenerating particle was studied in the paper, the characteristics of the regenerated particle were evaluated, and the optimization of the hot process are also discussed in the paper.Different technological conditions were selected including the time of steam treatment and the steam pressure. SEM, FTIR, elemental analysis, water absorption, and the analysis of the chemical component were used to evaluate the effect of explosion on the microscopic structure, chemical composition and physical properties to evaluate the properties of the regenerated particles. Orthogonal experiments were designed to prepare the regenerated particleboard. MOR, MOE, IB, TS of the board were examined to optimize the conditions, the array is designated by the Orthogonal Test L16 (45) involving four factors:the percent of regenerated particles(A), glue content (B), wax content (C) and hot pressing time (D). The effect of mechanical process and explosion process on the properties of regenerated particleboard was investigated by using the different ratios of recycled wood shavings and fresh shavings to produce the particleboard; and the significant findings were as follows:1) It was found that the regenerated wood shavings were better in maintaining the original shape and the quality of the following products after the explosion treatment than that after mechanical process. So explosion treatment is useful in the process of recycling of waste particleboard.2) The study on the characteristics of the regenerated wood shavings revealed that the explosion treatment caused two results to the used particleboard. On one hand, the adhesive was softened and destroyed, which can been seen from the amount changes of functional group including methyl, methylene and amino-group and the element N of the regenerated shavings; on the other hand, the explosion treatment had influence on the wood, the microscopic structure was destroyed with the increasing of the intensity of explosion. The content of semi-cellulose and lignin decreased, the content of cellulose and crystallinity of cellulose increased after the explosion treatment.3) The urea-formaldehyde resin of waste particle board could be destroyed and the shaving shapes could keep perfect under the certain explosion conditions because the stability of urea-formaldehyde resin to the steam was less than that of the wood. At the same time, the content of formaldehyde decreased with the damage of the urea-formaldehyde resin adhesive, which was benefit for the decreasing of the formaldehyde of the following products.4) The MOR, MOE and IB of the particleboard prepared from the recycled wood shavings using explosion process were better than that using mechanical process. The optimum conditions were as follows:the percent of regenerated particles 40%; adhesive content 10%; wax content 0.7% and hot pressing time:35s/mm.