Use of amino silane coupling agent to improve physical and mechanical properties of UF-bonded wheat straw(Triticum aestivum L.) poplar wood particleboard

We evaluated the potential use of amino silane coupling agent （SiNH） to improve physical and mechanical properties of UF-bonded wheat straw （Triticurn aestivum L.） poplar wood particleboard. We examined the effects of varied content of silane coupling agent content and ratios of straw to poplar wood particles on particleboard prop- erties. The ratios of straw to poplar wood particles were 100：0, 85：15, 70：30 and 55：45. Silane coupling agent content was tested at three levels, 0, 5 and 10 %. The experimental panels were tested for their mechanical strength, including modulus of elasticity （MOE）, modulus of rupture （MOR）, intemal bonding （IB） and physical properties according to procedures specified in DIN 68763 （Chipboard for special purposes in building construction： concepts, requirements, testing, 1982-03, 1982）. All board properties were improved by the addition of silane cou- pling agent. The use of poplar wood particles had a positive effect on the mechanical properties of wheat straw parti- cleboard but had a negative effect on physical properties （thickness swelling and water absorption）.

The influence of silane coupling agent and poplar particles on the wettability, surface roughness, and hardness of UF-bonded wheat straw(Triticum aestivum L.)/poplar wood particleboard

We used silane coupling agents to improve the bonding ability between wheat straw particles and UF resin, and investigated surface properties （wettability and surface roughness） and hardness of parti-cleboard made from UF-bonded wheat straw （Triticum aestivum L.） combined with poplar wood as affected by silane coupling agent content and straw/poplar wood particle ratios. We manufactured one-layered particleboard panels at four different ratios of straw to poplar wood par-ticles （0%, 15%, 30% and 45% wheat straw） and silane coupling agent content at three levels of 0, 5% and 10%. Roughness measurements, average roughness （Ra）, mean peak-to-valley height （Rz）, and root mean square roughness （Rq） were measured on unsanded samples by using a fine stylus tracing technique. We obtained contact angle measurements by using a goniometer connected to a digital camera and computer sys-tem. Boards containing greater amounts of poplar particles had superior hardness compared to control samples and had lower wettability. Panels made with higher amounts of silane had lower Rq values.

Cement-bonded particleboard with a mixture of wheat straw and poplar wood

We investigated the hydration behavior and some physical/mechanical properties of cement-bonded particleboard （CBPB） containing particles of wheat straw and poplar wood at various usage ratios and bonded with Portland cement mixed with different levels of inorganic additives. We determined the setting time and compression strength of cement pastes containing different additives and particles, and studied the effects of these additives and particles on thickness swelling, internal bond strength and modulus of rupture of CBPB by using RSM （Response Surface Methodology）. The mathematical model equations （second-order response functions） were derived to optimize properties of CBPB by computer simulation programming. Predicted values were in agreement with experimental values （R2 values of 0.93, 0.96 and 0.96 for TS, IB and MOR, respectively）. RSM can be efficiently applied to model panel properties. The variables can affect the properties of panels. The cement composites with bending strength 〉 12.5 MPa and internal bond strength 〉 0.28 MPa can be made by using wheat straw as a reinforcing material. Straw particle usage up to 11.5% in the mixture satisfies the minimum requirements of International Standard, EN 312 （2003） for IB and MOR. The dose of 4.95% calcium chloride, by weight of cement, can improve mechanical properties of the panels at the minimum requirement of EN 312. By increasing straw content from 0 to 30%, TS was reduced by increasing straw particle usage up to 1.5% and with 5.54% calcium chloride in the mixture, TS satisfied the EN 312 standard.

The effect of urea pretreatment on the formaldehyde emission and properties of straw particleboard

For manufacturing low-formaldehyde emission particleboard from wheat straw and urea-formaldehyde （UF） resins using urea treatment for indoor environments, we investigated the influence of urea treatment on the formaldehyde emission, physical and mechanical properties of the manufactured particleboard. Wheat straws were treated at three levels of urea concentration （5%, 10%, 15%） and 95℃ as holding temperature. Wheat straw particleboards were manufactured using hot press at 180℃ and 3 MPa with two types of UF adhesive （UF-45, UF-91）. Then the formaldehyde emission values, physical properties and mechanical properties were considered. The results show that the for- maldehyde emission value was decreased by increasing urea concentration. Furthermore, the results indicate that the specimens under urea treatment have better mechanical and physical properties compared with control specimens. Also specimens under urea treatment at 10% concentration and UF-91 type adhesive have the most optimum physical and mechanical strength.

Gypsum-bonded particleboard manufactured from agricultural based material

Gypsum-bonded particleboard(GBPB) panels were made from various mixtures of particles of bagasse(Saccharum officinarum L.) and wheat straw(Triticum aestivum L.), bonded with different ratios of particle/gypsum. This study examined the feasibility of bagasse and wheat straw particles in the production of GBPB. One-layer experimental GBPBs with a density of 1.05 or 1.20 g·cm 3were manufactured at different ratios of bagasse/wheat straw, i.e., 100%/0%, 93.75%/6.25%, 87.5%/12.5%, 75%/25%, 50%/50%, 25%/75% and 0%/100% using two particle/ gypsum composite ratios, i.e., 1/2.75 and 1/3.25 by weight. Thickness swelling(TS), water absorption(WA), modulus of rupture(MOR), modulus of elasticity(MOE) and internal bond strength(IB) properties of the boards were evaluated and a statistical analysis was performed in order to examine the possible feasibility of these agricultural residues for use in commercial GBPB manufacturing. We determined that WA of panels decreases as the amount of straw increases to 100% and the LR/G(wood/gypsum) ratio decreases to 1/3.25, whereas the TS of panels decreases as the proportion of straw decreases to 0% and the LR/G ratio increases to 1/2.75. The experimental results also show that the MOR and MOE of panels containing 0%, 6.25% and 12.5% wheat straw with a LR/G ratio of 1/2.75 were higher than those of panels made from 25%–100% wheat straw with a LR/G ratio of 1/2.75, as well as those from all other percentages of straw with a LR/G ratio of 1/3.25. On the other hand, the IB of panels containing more than 12.5% straw with LR/G ratios of 1/2.75 and 1/3.25 were lower than those of panels made from 0–12.5% straw also with both LR/G ratios. Panels consisting of 0%, 6.25% and 12.5% wheat straw with LR/G ratios of 1/2.75 and 1/3.25 met the minimum EN standard requirements of mechanical properties for general purposes. All of the panels containing 0–100% wheat straw with a LR/ G ratio of 1/2.75 or 1/3.25 met the required level of TS for 24-h immersion.

Study on Homogeneous Particleboard of Wheat Straw

In the paper homogeneous particleboard of wheat straw is researched. The result shows the technology of homogeneous particleboard from cost and quality. The moisture content of straw particle is 2.0%~2.5 %. The temperature of hot-pressing is 150℃. The time of hot-pressing is 48 sec/mm ( panel thickness). The ratio between MDI and UF is 0.40. The glue content for surface layer of wheat straw particle is 10% (MDI 2.86%, UF 7.14%). The glue content for core layer of wheat straw particle is 8% (MDI 2.29%, U...

无机麦秸碎料板制备及性能

以麦秸碎料和无机胶粘剂为主要原料,通过冷压成型工艺制备无机麦秸碎料板,研究了胶草比及板材密度对板材性能的影响,并通过X射线衍射仪、热重分析仪及扫描电镜等仪器分析了胶草比及板材密度对无机麦秸碎料板性能影响机制。结果表明,胶草比增加,麦秸碎料对无机成分水化反应的"隔阻"效应减弱,水化反应速度加快,反应更完全,结晶更完整,胶凝材料生成量增加,板材IB增大,TS减小,MOR和MOE先增大后减小。胶草比增大,麦秸碎料在板材中的分布均匀性增加,界面接合性能变好,界面摩擦阻力增大,板材力学性能变好,热稳定性增加。板材密度增加可以促进并加速无机成分水化反应,胶凝材料生成量增加,板材MOR、MOE及IB增大,而TS减小。密度增大板材密实度增加,无机胶粘剂各晶相颗粒间的相互作用增强,界面摩擦阻力及热运动阻力增大,板材力学性能变好,热稳定性增加。

改性异氰酸酯施胶量及密度对麦秸刨花板性能的影响

用改性异氰酸酯胶黏剂制备麦秸刨花板,考察施胶量和密度对板材物理力学性能和热稳定性能的影响。通过扫描电子显微镜(SEM)观察和热重分析(TGA)探讨其胶接断面和热稳定性,研究其物理力学性能提高的原因。结果表明,随着施胶量增大,各项物理性能指标均有改善,热稳定性降低;随着麦秸刨花板密度增大,各项物理性能指标得到明显提高,热稳定性也逐渐提高;综合考虑麦秸刨花板性能和成本,当施胶量为4%,密度为0.8 g/cm3时,各项指标均最优,物理性能完全满足国家标准要求。

麦秸刨花板与木质普通刨花板的比较分析

对麦秸刨花板的生产工艺、产品性能与普通木质刨花板作了详尽的比较，分析了麦秸刨花板原料及生产工艺的特点，指出了该产品性能的优点，建议我国大力发展麦秸刨花板。

异氰酸酯胶麦秆刨花板生产成本分析

本文从生产规模、投资取向等方面入手，分析了异氰酸酯胶麦秆刨花板的生产成本，为异氰酸酯胶麦秆刨花板这一新产品的推广应用和工业化生产提供依据。

异氰酸酯胶麦秸刨花板密度对力学性能的影响

着重讨论了密度对异氰酸酯胶麦秸刨花板各项力学性能的影响。得出试验结论，密度与各项力学性能呈多项式回归关系；当施胶量为４％时，密度为０．６ｇ／ｃｍ３的麦秸刨花板的力学性能完全满足国家标准要求；生产０．６ｇ／ｃｍ３的麦秸刨花板，在技术上是可靠的，在经济上是合理的。

现有刨花板生产线生产麦秸均质板工艺设备适应性评价

对现有刨花板生产线进行改造 ,生产以麦秸为原料的麦秸均质板 ,是解决刨花板厂原料供应不足的有效途径之一。本文分析了我国目前刨花板厂的原料供应状况 ,对利用现有刨花板生产线生产麦秸均质板的工艺设备适应性进行了综合评价 ,并提出了设备改造方案。

处理麦秸制备麦草刨花板性能研究

本文以麦秸原料为研究对象,对麦草表面进行处理,采用异氰酸酯作为胶黏剂,制备麦草刨花板。系统研究麦草表面处理对刨花板的物理力学性能、吸水率等综合性能的影响。实验结果表明,水处理的麦秸制成的刨花板的物理力学性能提高,1%浓度的碱处理过的麦草刨花板的力学性能比5%碱处理过的麦草刨花板显著提高,但5%浓度的碱处理的刨花板的耐水性显著提高。扫描电子显微镜(SEM)结果表明:采用碱处理的麦草外表面蜡质层全部去除,接触角的测试结果进一步验证了碱处理方法能够降低麦草外表面的疏水性,提高润湿性,力学性能测试结果表明,采用不同处理方法进行麦草改性,其各种力学强度均能达到国家标准。

麦秸刨花板的吸水厚度变化模型

通过理论推导和实验数据的拟合曲线求得麦秸刨花板的吸水厚度变化模型。模型的应用结果表明：麦秸刨花板中胶粘剂的 ＭＤＩ用量越多，其最大的吸水厚度膨胀率越低，尺寸稳定性越高。当麦秸刨花板的密度从 ０．６５ ｇ／ｃｍ３增加到 ０．７５ ｇ／ｃｍ３时，其尺寸稳定性略有改进。厚度为 １０ ｍｍ的麦秸刨花板，当热压温度取 １５０℃，热压时间从 ６ ｍｉｎ增加到 １０ ｍｉｎ的过程中，麦秸刨花板的吸水厚度膨胀率开始呈下降趋势，随后增加。

无机麦秸碎料板制备与性能研究

以麦秸碎料和无机胶黏剂为主要原料,通过冷压成型工艺制备了无机麦秸碎料板,研究了麦秸碎料添加量对无机麦秸碎料板物理力学性能的影响,并通过X射线衍射仪、热重分析仪、差示扫描量热仪及扫描电镜等分析仪器分析了麦秸碎料添加量对无机麦秸碎料板性能影响机理。结果表明:随着胶草比增加,板坯养护期间,麦秸碎料对无机成分水化反应的"隔阻"效应减弱,无机麦秸碎料板坯中无机成分水化反应速度加快,反应更完全,结晶更完整,无机胶粘剂生成量增加,麦秸碎料与无机胶粘剂接合界面性能变好,无机麦秸碎料板的内结合强度(IB)逐渐增大,24 h吸水厚度膨胀率(TS)逐渐减小,静曲强度(MOR)和弹性模量(MOE)先增大后减小,板材热稳定性增加。综合考虑,优化的胶草比为2.1。

改性UF麦秸均质刨花板的工艺研究

通过试验确定了麦秸均质刨花板的主要工艺参数。其结果表明：１０ｍｍ厚麦秸均质刨花板的较优工艺参数为热压温度１５０℃、热压时间８ｍｉｎ、表层麦秸刨花的施胶量为１０％、芯层麦秸刨花的施胶量为８％、板密度０．７５ｇ／ｃｍ３、表芯层刨花比例为３：７。按照以上工艺条件压制的麦秸均质刨花板性能已达到均质刨花板的要求。

麦秸人造板工艺及生产问题分析

对我国大量的农业剩余物麦秸的最新用途——制造麦秸人造 (碎料 )板的生产工艺进行了阐述。对生产中存在的问题进行了分析并提出了建议。

API胶黏剂在麦秸刨花板上的应用

用API作胶黏剂制备麦秸刨花板,并对影响板材性能的因素进行了研究。实验结果表明,表、芯层施胶量均为2.5%时,所制得的板材性能均优于普通刨花板中优等品的指标,吸水膨胀性能的改善尤为显著。综合考虑板材性能及产品成本,API胶中交联剂的最佳用量为6%。

麦秸的酶处理研究

选择了 3种生物酶制剂对麦秸进行了处理。并用酶处理后的麦秸作原料 ,压制了脲醛树脂胶合的麦秸刨花板。结果表明 :在一定条件下 ,酶可以从细胞中分离出来 ,而不影响它的作用 :经纤维素和半纤维素的复合酶处理之后 ,麦秸表面的自由基都有了较大的提高 ;经脂肪酶处理后 ,可使麦秸的苯醇抽提物含量下降 ,处理时间延长 ,效果更好 ,这也间接地说明 ,脂肪酶处理麦秸 ,可降低其表面的蜡状物 ;用经酶处理后的麦秸作原料 ,可以压制出性能较好的脲醛树脂胶合的麦秸刨花板。其中 ,天津生物所研制的纤维素和半纤维素复合酶的效果最好。

基于表面处理的麦秸人造板力学性能研究

采用碱溶液对麦秸原料进行处理,以期改善其表面润湿性,提高与胶黏剂的结合强度。基于扩散-渗透理论,对碱溶液的处理效果进行了评价,并用处理过的麦秸压制刨花板。检测结果表明:与未处理麦秸刨花板相比,处理后板材的静曲强度、弹性模量略有下降,但内结合强度提高,吸水厚度膨胀率降低,各项指标均达到相关国家标准要求。