棉秆特性及其重组板材的研究

Research on characteristic of cotton-stalk and its scrimber

为探讨主要工艺参数对棉秆重组板材性能的影响,在分析棉秆构造和化学特性的基础上,分别在不同设计密度(0.6,0.7,0.8,0.9,1.0 g/cm3)、不同施胶量(60,80,100,120,140 g/kg)、不同防水剂施加量(0,5,10,15,20 g/kg)以及不同组坯方式(平行和垂直交叉)的条件下压制板材,并对其性能进行了检测。结果表明,棉秆主要由表皮部、木质部和髓芯部组成,棉秆中纤维素、木素的含量与木材相近,但灰分及抽提物含量明显高于木材;棉秆重组板材的静曲强度(MOR)随其密度的增加而增大;施胶量由60 g/kg增加到100 g/kg时,板材的静曲强度和内结合强度(IB)均明显升高,但当施胶量由100 g/kg升高到140 g/kg时,静曲强度变化不大,内结合强度则略有下降;增加石蜡用量能够提高棉秆重组板材的耐水性,施加量为15 g/kg时的2 h吸水厚度膨胀率(2 h TS)已达到刨花板国标的要求;平行组坯时,棉秆重组板材顺纤维方向的干缩率小于横向,横纹干缩率约为顺纹的2.31倍;重直交叉组坯时长宽方向的干缩率基本相同。棉秆是制造重组材的适用材料;以棉秆为原料、酚醛树脂(PF)为胶粘剂制造的棉秆重组材,其物理力学性能达到了刨花板的国标要求;板坯密度、施胶量、防水剂和组坯方式对棉秆重组材的性能影响较大,必须综合考虑来确定具体的数值或用量。

In order to study the principles that the main processing variables brought about influences on properties of cotton-stalk scrimber,the article analyzed the structure and chemical properties of cotton-stalk.Under the different conditions with different density（0.6,0.7,0.8,0.9,1.0 g/cm^3）,different glue consumption（60,80,100,120,140 g/kg）,different consumption of water repellent（0,5,10,15,20 g/kg）and different lay-up,the cotton-stalk scrimber was manufactured and its property was tested.The result showed that cotton-stalk consisted of epidermis,xylem and pith.Cellulose and lignin content of cotton-stalk were similar to those of wood.Ash and extractive content of cotton-stalk were much higher than those of wood.MOR of cotton-stalk scrimber increased with the increasing of its density.When the glue consumption increased from 60 g/kg to 100 g/kg,MOR and IB of panel increased obviously.MOR increased slightly and IB fell off slightly at the range of 100 g/kg to 140 g/kg of glue consumption.As the addition of paraffin increased,up to an value of 15 g/kg,2 h TS of panel could meet the standard requirement of particleboard.When the lay-up of panel was parallel,drying shrinkage rate of cross grain was 2.31 times as many as that of long grain.Drying shrinkage rates in the direction of the length and width were approximately equal when the lay-up was cross.It was concluded that cotton-stalk was suitable for making scrimber.The properties of cotton-stalk scrimber could meet the standard requirement of particle board.Density,glue consumption,water repellent and lay-up had great influences on properties of cotton-stalk scrimber,whose values could be given a synthetic consideration.