Study On The Production Technology Of Veneer Polymer Composites By Heat Initiation

With the decrease of high-quality timber and the increase of people consumption demand,making the low-grade wood to be superior quality utilization has important strategic significance to construct resource-conserving society and environment protection in our country.In this paper,in order to improve wood performance and realize it high value-added utilization,we made monomer liquid to immerse into wood and polymerize in the wood by heat initiation.Research mainly involves the key industrialization technology of veneer-WPC prepared by heat-initiation:optimization of the impregnation liquid ratio,impregnation technology and curing process,as well as the design and use of the production equipment,and the application and fire-retardant of veneer polymer composite etc.Through laboratory group research and industrialized pilot,the optimized impregnation liquid formulation to produce veneer polymer composite by heat initiation,its composition is methyl methacrylate(MMA)as primary monomer,styrene monomer(St)amount to 20%,maleic anhydride(MAn)dosage of 5%,azobisisobutyronitrile(AIBN)dosage of 0.25%;the optimized curing process parameters is former vacuum of-0.09MPa,time of 10?30min;impregnation pressure of 1.0MPa,time of 30?90min;Heating curing temperature of(85±5)?,time of about 100?150min,pressure of 0.8?1.OMPa.The use of special equipment—vacuum pressure impregnation/heat curing chamber for WPC production,combined with special design of the veneer frame and collecting liquid board,which realizes monomer utilization rate over 88%.We produced veneer polymer composite by the industrialization of heat initiation method.Scanning electron microscopy(SEM)has indicated that the impregnation liquid was penetrated into wood lumen and intercellular,and polymerized in them,moreover well-distributed.The results of performance of veneer polymer composite indicated that,compared with the original wood,the static intensity,the static elastic modulus,the impact strength,the acid and alkali resistance and the dimension stability were higher obviously,surface wettability was slightly lower but it did not affect agglutination and paint.Through treating wood veneer by FRW fire-rctardant and additioning dimethyl methyl-phosphonate(DMMP)fire-retardant,the results of vencer polymer omposite fire-retardant indicated that it had no effect on polymerization performance of impregnation liquid of veneer polymer composite.Veneers were treated by FRW fire-retardant and at the same time treated the impregnation liquid of additioning DMMP fire-retardant,its flame retardant performance is optimum.Optimized flame retardant FRW loading is 12%,and the amout of DMMP is 15%;FRW fire-retardant treatment had an adverse effect on mechanical properties of veneer polymer composite;however DMMP fire-rctardant treatment improved mechanical properties of veneer polymer composite.Veneer polymer composites were used as panel and separately glued with poplar floor base-material and wood/plastic composite based on polyethylene(wood flour/polyethylene composite,HDPE-WF).Developed two new high grade floors:veneer polymer composite consolidated compound floor and veneer polymer composite/WPC compound floor,optimized to the production processes.