洋麻芯刨花板的试制

洋麻(Hibiscus cannabinus)是一种传统的造纸纤维作物。笔者利用洋麻芯分别试制了单层和 3 层结构刨花板,单层结构采用3% pMDI或6% PF的施胶量,设计密度为0.25~0.85 g/cm3;3层结构刨花板采用施胶量3% pMDI,设计密度为 0.85 g/cm3,粗细刨花分层铺装,表芯层原料质量比分别为 3∶7,5∶5, 和2∶1。分析了板的常规物理力学性能(MOE,MOR,IB,TS,LE)及端面密度梯度(VDP)。结果表明:采用洋麻芯为原料制造的刨花板,具有较好的力学性能,但吸湿变形明显,这主要决定于密度和施胶量两大因子;单层结构具有非对称性;采用“细-粗-细”的分层结构可以有效改善单层结构的不对称性,表芯比为 5∶5 时3层结构刨花板的综合性能最佳。

A Laboratory Trial of Manufacturing Kenaf Core Particleboard

Kenaf(Hibiscus cannabinus) is a warm weather and fast growing fiber crop ,which is often used in paper making .In this study, single-and three-layer kenaf core particleboards(KPB) were made with polymeric methylene diphenyl diisocyanate (pMDI,3%) and phenol formaledgyde (PF,6%) resins .density levels were specified as 0.25,0.40,0.55,0.70and strength ,thickness swelling (TS) ,linera expansion (LE),and vertical density profile (VDP)were assessed. The data were compared with properties specified in ANSI/A208.1 for woodbased particleboard (WPB). It was shown that kenaf core could be made into standard-satis-fied particleboards.Density and resin content were two primary factors deciding the performances of KPB.KPBdensere than 0.70g/cn3 and with 6% PF met the standard specifications. KPB with 3%pMDI failed to achieve the standard unless slightly higher resin content and /ordensity were used. TS and LE of single -alyer KPB had a dissymmetric sturcture in thickness direction. Threelayer construction improved MOE, MOR and IB strengths ,and effectively avoided the unbalanced sturcture of sing-layer KPB in thickness direction. KPB with a 5:5 surface-to-core ratio had the best comprehensive performances.