Study On Bamboo/Wood Composite Strengthened Laminated Veneer Lumber Procedure By Impregnating Resin Method

As protecting nature forest project implemented, there were less and less superior-propertyand big-size wood in market, especially which could be used in construction such as woodbuilding and bridge etc, which were replaced by fast-growing plantation wood. The objectiveof this paper was to explore low-density and superior-property bamboo/wood compositestrengthened laminated veneer lumber(B/WCLVL) which used Moso bamboo(Phyllostachyspubescens)curtain and poplar (Populus spp.) veneer as raw material by low-molecular-weightwater -soluble phenol-formaldehyde(PF)resin impregnating process. This paper studied veneerand bamboo curtain impregnating technology, investigated the different assemble patterns andhot-pressing process effect on B/WCLVL properties. It also revealed the mat heat-transferringrules when in hot-pressing procedure, and got the optimized producing process of B/WCLVL.After studying, we got conclusions as the follows:1 The investigation of effect of impregnating time indicated that as the impregnating timeprolonging gained resin amount increased. The pressure procedure could improve thegained-resin amount significantly. Considered producing efficiency and the cost whenproduced B/WCLVL the pressure procedure was suggested.2 With the same adhesive amount, contrasting to the laminated veneer lumber properties whichmade by glue sizing and impregnating manner we got that by two manners the product hadthe same density, contrast to the laminated veneer lumber by glue sizing manner, MOE andMOR of laminated veneer lumber which made by resin impregnating manner were increasedby 20.17% and 44.7%, and thickness swelling decreased 21.76%.3. After studying poplar veneer impregnated-resin amount effect on LVL properties we got that:as the impregnated-resin amount increased, LVL density, MOE, MOR increased and TSdecreased. When the absorbed resin amount was 168%, the MOE and MOR of LVL were15.34GPa and 135MPa, which reached and exceeded Japan structural LVL standard140E(14GPa) and 180E (67.5MPa) respectively.4. The B/WCLVL heat-transferring rule in hot-pressing revealed that for the resin densifiedaction, with same adhesive amount, in resin impregnating manner the mat core layer had faster heat-transferring speed than adhesive sizing method, and increasing as veneerimpregnated-resin amount increased. When resin impregnated amount 130%, hot-pressingtemperature was 150℃, hot-pressing pressure was 1.0MPa, the c, ore layer temperaturereached to PF resin solidify temperature140℃needed 18min.5. After studying the B/WCLVL properties in 8 kinds assemble patterns the results indicatedthat the product had superior properties when surface was bamboo curtain. As veneerthickness was 2.0mm with surface was bamboo curtain, B/WCLVL MOE and MORincreased by 16% and 33% compared to LVL. The poplar veneer thickness didn't havenotable influence on B/WCLVL properties.6. The hot-pressing process effect on B/WCLVL indicated that with temperature andhot-pressing time and compressing ratio increased the properties of B/WCLVL improved.Above all the conditions, when manufactured B/WCLVL by resin impregnating manner,suggested the hot-pressing procedure parameters were hot-pressing temperature 140～160℃;hot-pressing time1.2～1.6 min/mm(product thickness); compression ratio 15～25%. And itcould be chose according to equipment condition and the product last utilization request.