微米长刨花骨伤成组固定夹板造型设计研究

根据夹板造型成型原理,在分析微米长刨花材料的特性及其设计参数的基础上,结合微米长刨花这种材料的性能,提出了骨伤固定夹板的造型设计理论,探讨了微米长刨花在骨伤固定夹板造型设计上的可行性,总结了微米长刨花具有环保、绿色、与人体皮肤相容性好等优点.采用微米长刨花夹板造型可以设计出完全符合人体手腕形状复杂变化的夹板,使骨伤病人的舒适性大大提高.     

脱硫石膏刨花板制造工艺的初步研究

脱硫石膏为燃煤电厂烟气脱硫处理的一种化学副产物。本文分析讨论了脱硫石膏的性能及其与木材刨花混合制造石膏刨花板的可行性,初步探讨了脱硫石膏刨花板的制造工艺。结果表明,脱硫石膏用于制造石膏刨花板完全可行,其性能优于天然石膏生产的石膏刨花板,以木膏比０．１８生产的石膏刨花板材的各项性能均优于木膏比０．２２生产的板材。     

微米木纤维颈椎夹板的研制

以微米木纤维为材料替代国内外广泛采用的塑料与石膏而制作颈椎夹板,具有环保、绿色、与人体皮肤相容性好等优点。微米木纤维颈椎夹板是一种规则空间曲面加工的木质工件,为解决其双曲面造型的加工难题,目前这种复杂的夹板造型多先在专用模压机床上直接加工出不同曲线形状的夹板,之后使用普通数控机床或加工中心来进行形状修正。而建立微米木纤维颈椎夹板空间曲面的通用数学模型,利用模型参数驱动的通用性,直接由模型方程输入人体颈部相关尺寸参数,即可获得不同人群所需的加工尺寸,实现在一台机床上完成不规则曲面自动加工,可保证颈椎夹板造型的美观,并降低生产成本。VC++6.0对微米木纤维颈椎夹板造型进行的仿真验证表明,所建立的数学模型具有良好的精确性、通用性和实用性,为微米木纤维颈椎夹板加工系统的开发奠定理论基础。     

石膏刨花板研究综述

石膏板具有优异的抗火性能,在轻型木结构中主要用作楼板和墙板的抗火覆面板。通过在石膏基体中复合木材刨花等植物纤维制备石膏刨花板,可不改变板材原有的生产制备工艺而提高其力学性能。生产石膏刨花板的石膏原料主要来源于工业石膏,刨花主要为农业或工业副产品,兼顾变废为宝和材料成本可控等优势,因此具有广泛的应用前景。文中综述了石膏刨花板中不同缓凝剂的作用机理、不同植物纤维类型的增强效果、后处理方式和外加剂对板材性能改善的机理等板材制备工艺,以及石膏刨花板的物理力学性能和抗火性能等研究现状,指出目前土木工程用石膏刨花板存在的不足及需进一步研究的方向,可为石膏刨花板的进一步系统研究以及工程应用提供参考。     

不同单元形态木材增强重组竹结构材料抗弯性能的研究

根据混杂复合材料理论,探讨将几种不同单元形态的木材:木束、木刨花和木纤维与重组竹的基本单元--竹束,采用均匀混杂方法制备增强型重组竹结构材料的可行性,研究木束-竹束、木刨花-竹束以及木纤维-竹束的混杂比对增强重组竹结构材抗弯性能的影响.结果表明:与重组竹相比,当刨花-竹束以及纤维-竹束混杂比分别为10%、5%时,在垂直加载和水平加载方向上竹木复合重组结构材料的静曲强度和弹性模量综合增强效果最为明显,而随着木束-竹束混杂比增加,木束增强重组竹结构材料的弹性模量和静曲强度呈现先下降再上升的趋势,当混杂比为33%时负增强效应最大.     

石膏刨花板的生产工艺及其应用前景

石膏刨花板是以建筑石膏为胶凝剂, 以刨花为加强材料的新型建筑板材.本文叙述了石膏刨花板的特点和生产工艺; 介绍了芬兰、挪威等国石膏刨花板的生产现状, 论述了我国发展石膏刨花板的可能性和必要性, 并提出了几点建议.     

石膏刨花板的密度、木膏比和水膏比与其性能关系的初步研究

本文通过一系列的工艺试验对石膏刨花板的密度、木膏比和水膏比与其性能的关系进行了初步的研究。结果表明：1．密度的增加会导致石膏刨花板强度的显著增加；2．提高木膏比会使静曲强度等随之上升，但对弹性模量和平面抗拉强度影响不大；3．水膏比在0．30－0．40范围内对板子性能无显著影响；4．三个因子间无交互作用。     

刨花板板坯预压回弹率的研究

本研究对刨花大小与形态，密度，施胶量，以及预压温度，保压时间，压缩厚度六个因素与板坯预压后厚度回弹率的关系进行了试验。试验结果证明，木材的材料属性和刨花刚性下降是引起回弹的主要原因，刨花的大小与形态、密度，胶施量等预压条件对板坯的回弹率都产生影响。适当的工艺措施可以减少预压板坯的厚度回弹率。     

石膏刨花板生产技术的有关问题

以石膏为胶凝材料,用木质碎料刨花（木材刨花和非木材植物纤维,如棉秆、蔗渣、芦苇、竹材、麻秆等纤维碎料）为增强材料,外加适量的水和化学助剂,经强制性的搅拌混合形成半干性混合均匀料,在成型压力机内以２,０～３．５ＭＰａ的压力,在受压状态下完成石膏与木质材料的水化团结,所形成的板材就是石膏刨花板。这种成型方法为半干法。 基于这种板材的主要原料石膏是低能耗的生产原料（石膏煅烧,能耗为９２０～１０４５ｋＪ／ｋｇ,约为水泥煅烧能耗的１／４）;板材的生产过程只用少量的水,且石膏是水硬性材料,不产生污水;在板材…     

几种树种木材制造石膏刨花板的适应性

本文论述了挪威云杉、山杨、白桦和柞木及山杨、白桦、柞木的混合刨花制造石膏刨花板的适应性。结果表明,在工艺参数相同的情况下,木材密度越大的树种制成的板材强度越低,挪威云杉板强度最大,山杨板次之,柞木板极低。挪威云杉和山杨是制造石膏刨花板的优质树种。改变木膏比、刨花体积和对刨花进行水抽提均没有使白桦和柞木制成合格的石膏刨花板。混合刨花干扰石膏刨花板的凝固时间,致使板子强度低劣,在生产中应予避免。     

竹木混合水泥刨花板工艺初步研究

研究了热压法制造竹木混合水泥刨花板工艺并对影响板材性能的因素进行探讨。结果表明:竹刨花水煮预处理后所制备的板材性能较好;本实验范围内,竹木混合水泥刨花板较合适的工艺参数为竹木比1∶3、灰木比4∶1、热压时间1～2min/mm板厚、CaCl2用量为灰重的5%、水灰比0.4。     

稻壳形态对稻壳--木材复合材料性能的影响

测试了稻壳形态对稻壳-木材复合材料物理力学性能的影响。试验结果表明，以20网日、30网日和40网目的稻壳为补充材料制备的密度为0．80g／cm^3的板的物理力学性能均达到国标二级品的要求。确立20网目的稻壳适宜于稻壳-木材复合材料。     

淀粉/木粉复合材料的制备与性能研究

以淀粉和木粉为原料,甘油为增塑剂,通过挤出成型制备淀粉/木粉可生物降解复合材料,重点研究淀粉/木粉混合比例对复合材料性能的影响。采用扫描电镜（SEM）、X射线衍射仪（XRD）和热重分析（TGA）对复合材料进行表征,并对复合材料的力学性能和吸水性能进行测试。实验结果表明：木粉的加入破坏热塑性淀粉的连续性,使复合材料的结晶度增大。复合材料的拉伸强度、吸水率和吸水厚度膨胀率随着木粉比例增大逐渐增大,断裂伸长率却逐渐降低。TGA测试结果表明,随着木粉加入比例增大,复合材料的热分解起始温度逐渐降低,但热分解的终止温度逐渐升高,淀粉和木粉两相依赖性逐渐减弱。     

A THEORY OF DETERMINING MASS TRANSFERPARAMETERS FOR WOOD PARTICLE MATERIALS

INTRoD[JCTIONTllcrcsearcI1OI1tl1ctI1c111opl1}'sIcalprop-crtiesofl1catandl11asstransfcrproccsscsi11``oodparticlcl11atcrlalsisratllcrlll11ltcdcur-rcntI}O11l}afct`papcrssofarasconccn1slllnybclbund(Slla11g.19(j()).Ho\tc\cr'tl1cullll,attol1a11dtI1cproductionof\"oodcl1ipa11dx`oodslla\lngctc.Asra\`matcrlals(Sl1ang*I()9l)forpulpandpapcr'paniclcboards'\\'oodfucl(Martalcna.l988)ort\'oodpaFticlc111atc-rialhascdcom6ositcproductsarcincrcasil1goxcrtllcx"orldTllccfficicnttechnolog1caIllandlil1gofth…     

Effects of wood species,particle sizes and dimensions of residue obtained from trimming of wood–cement composites on physical and mechanical properties of cement-bonded particleboard

Abstract

The present work was conducted to study the effects of wood species, particle size and residue particle size obtained from trimming of wood–cement composites on physical and mechanical properties of cement-bonded particleboard (CBPB). Particleboard was manufactured with a wood/cement ratio of 1:3 and specific gravity 1200 kg m^?3. After manufacturing, the boards were tested. The second order plan was used to test the significant difference between factors and levels. It was shown that slenderness and compaction ratio increased and bulk density and specific surface decreased with the increase of particle size. With the increase in slenderness ratio and compaction ratio and decrease in bulk density and specific surface, thickness swelling and mechanical properties improved, but water absorption by the board increased. The addition of 6% of 5/3 fraction size of particle obtained from trimming of boards improved significantly the properties of the boards. The optimized panel properties, obtained using poplar particles with a fraction size of 7pass/on5, exceeded the BISON type HZ and EN Standard for Wood Particleboard. CBPB made of alder or poplar particles with 5/3 fraction size of residue exceeded the BISON type HZ. All CBPB with 5/3 fraction size of residue showed lower mean values of thickness swelling, well below the maximum requirements of both standards. In addition, wood species, fraction size of particles and residue size are believed to have been the main cause of change in the properties of the boards.     

木材水抽提物对石膏及石膏刨花板的凝固及其性能的影响

本文研究了在商用缓凝剂(Retardan P)的存在下木材水抽提物对石膏浆料和石膏刨花板凝固时间及其强度的综合影响。结果表明:1.木材水抽提物能使石膏浆料和石膏刨花板产生缓凝,并导致强度下降,其影响程度与树种和石膏质量均有关系。2.木材水抽提物能加强Retarda P的缓凝作用,并且用两者交互作用下石膏浆料的凝固时间,可以指示石膏刨花板的凝固时间。3.石膏刨花板的静曲强度受刨花树种的影响,但缓凝剂的添加量却无显著作用。     

麦秸/石膏复合材的工艺研究

以麦秸和石膏为原料,采用铺装生产工艺,通过单因子试验,研究原料形态、料膏比、乳白胶加入量和原料预处理方式等工艺因子对麦秸/石膏复合材性能的影响,并利用体视显微镜和扫描电子显微镜观察复合材的胶接状况。结果表明:料膏比10%、原料筛网目数10～20目、乳白胶的加入量12.5%、麦秸经热水处理3h,所制备的麦秸/石膏复合材各项物理力学性能较佳,指标可达到LY/T1598—2002石膏刨花板标准合格品的要求。     

Manufacture and properties of oil palm frond cement-bonded board

This study was designed to reveal the role of the cement/wood ratio in a hydration test of wood-cement mixtures. The compatibility of oil palm (Elaeis guineensis Jacq) fronds-cement mixtures was tested in the hydration test, with the addition of magnesium chloride as an accelerator at different water/cement ratios. To prove the findings on the hydration behavior of components, the cement-bonded boards were manufactured using a conventional cold-pressing method at different cement/wood ratios. Results indicated that the optimum weight ration of cement/wood increased with decreasing wood powder size based on the equal specific surface area ratio of cement/wood in the hydration test and board manufacturing. The addition of magnesium chloride improved the compatibility of oil palm fronds with cement; the compatibility factor (C _A) increased by more than 90% with the addition of 5% magnesium chloride. TheC _A factor increased proportionally with a higher magnesium chloride content and a higher water/ cement ratio. The addition of magnesium chloride also enhanced the cement hydration and ultimate board strength properties. However, the addition of 5% magnesium chloride did not improve the properties of boards sufficiently at a cement/wood ratio of 2.21.0.     

Properties of flat-pressed wood plastic composites as a function of particle size and mixing ratio

This paper presents the effects of particle size and mixing ratio on the properties including physical, mechanical, and decay resistance of wood plastic composites (WPCs). In addition, it also presents the effects of immersion temperatures on water absorption (WA) and thickness swelling (TS) of the WPCs. WPCs with a thickness of 6 mm were fabricated from Albizia richardiana King & Prain wood particles and recycled polyethylene terephthalate (PET) by the flat-press method. To prepare the WPCs, two different wood particle sizes (0.5–1.0 and 1.01–2.0 mm) were used along with four different mixing ratios (w/w). Subsequently, the physical properties include density, moisture content, WA, and TS, and mechanical properties include modulus of elasticity (MOE) and modulus of rupture (MOR) of the produced WPCs was evaluated. Furthermore, decay resistance was evaluated by the weight loss percentage method. Moreover, the effects of immersion temperatures on WA and TS of WPCs after 24 h of immersion in water at three different temperatures, i.e., 25, 50, and 75 °C were investigated. Results showed that the wood particle size had impact on WPC’s density (only 6% decreased with the increase of particle size); however, the density decreased by 29% when the wood particle content increased from 40 to 70%. The WA and TS gradually increased with the increase of particle content and decrease of particle size. In addition, WA and TS increased proportionately with increasing immersion temperature from 25 to 75 °C. Furthermore, the highest MOE (2570 N/mm²) was found for the WPCs fabricated from large wood particles having the ration of 50:50 (wood particle:PET). For decay resistance, WPCs consisted of larger particles and higher PET content showed greater resistance against decay. Therefore, it is comprehensible that fabrication of the WPCs from 50% large particles and 50% PET is technically feasible and further improvement of WPC performance like enhancement of MOE and reduction of density using coupling agent and agricultural waste fibers, respectively, in the WPC formulation is recommended.