Some properties of particleboards produced from Rhizophora spp. as a tissue-equivalent phantom material bonded with Eremurus spp.

The objective of this study is to evaluate the mechanical and physical properties of the particleboard manufactured from Rhizophora spp. in three particle sizes bonded with powdered Eremurus spp. root as a bio-based adhesive in two adhesive treatment levels. The samples acquired high internal bond strength values when the Rhizphora spp. particle size was reduced and the adhesive treatment level was increased. Dimensional stability normally increased with the reduced Rhizophora spp. wood particle size. The hydrophilic property of Eremurus spp. indicates that dimensional stability also increased with decreased adhesive treatment level. However, dimensional stability is affected by the adhesive treatment level when the wood particle size is smaller than that of the adhesive particle. The density distributions of the fabricated particleboards were evaluated using Surfer8 software, which showed significant homogeneity in all samples. The microstructures of the fabricated particleboards were investigated by field emission scanning electron microscopy, which refers to the better surrounding adhesive with bigger particles than Rhizophora spp. particles. This study indicates the potential of Eremurus spp. root as a bio-adhesive, which improved the characterization of Rhizophora spp. particleboard.     

Effect of Synthesis Variables on Tack in Urea-Formaldehyde Resin

The degree of tack-the ability of resin to adhere to another surface under light pressure and over short time-in urea-formaldehyde resin varies throughout the particleboard manufacturing process and affects mill maintenance and board quality. A three-part study was conducted to evaluate the effects of certain synthesis variables-molar formaldehyde:urea ratio, ingredient concentration, reaction pH, and reaction catalyst-on tack of urea-formaldehyde resin in particleboard manufacturing. Southern pine particleboard mats were formed and prepressed in the laboratory, and tack was evaluated with the push-off method. Reaction pH significantly affected tack and viscosity, which were highly related. On the average, reducing formaldehyde:urea ratio and ingredient concentration increased tack; these two variables may be significant to tack development and resin morphology. Reaction catalyst did not affect tack or other resin morphology. Reaction catalyst did not affect tack or other resin characteristics, but resin surface tension contributed significantly to tack development. Further study should better define optimum manufacturing time and make tack development in particleboard manufacturing more predictable.     

Some chemical properties of hazelnut husk and its suitability for particleboard production

Hazelnut husk is a renewable natural resource that has not industrial utilization yet. The objective of this study was to examine some chemical properties (holocellulose, cellulose, lignin and ash contents, alcohol–benzene, hot and cold water solubility and solubility in dilute alkali (1% NaOH)) of hazelnut husk and to evaluate its suitability to produce composite panels. For this study, particleboards were produced using hazelnut husk as an alternative raw material for the forest products industry. Two panel density levels (0.6 and 0.7 g/cm³) and three types of resins (urea-formaldehyde (UF), phenol formaldehyde (PF), melamine-formaldehyde (MUF)) were selected as treatments. The findings indicated that hazelnut husk waste is a valuable renewable natural resource for particleboard production and could be utilized as a substitute for wood in board production. Its shortcomings, such as higher water absorption and thickness swelling could easily be controlled by adding water repellent chemicals in production. The bending and the internal bond strength properties of the hazelnut husk boards produced met the requirement for the general purpose product standards (TS-EN 312-2) at 0.70 g/cm³ density.     

Particleboard from Cashew Nut Shell Liquid

Cashew nut shell liquid (CNSL) is a cheap agro by-product and a renewable resource, which consists mainly of substituted phenols. A CNSL-based reactive resin was used in this study as binder for particleboards. The resin was prepared by heating a mixture of CNSL, phenol, and hexamethylenetetramine. Properties of the board, viz. water absorption, tensile strength parallel to the surface, tensile strength perpendicular to the surface, and compressibility are determined. The effect of the resin content, P:F ratio of resin, and CNSL:P ratio of resin on the properties of particleboard are also studied. It is found that about 15% resin in the molding formulation is essential to give a board of acceptable quality. It is possible to include up to 20% CNSL without any deterioration in the properties of the board. This is significant from the conservation viewpoint.     

异氰酸酯在麦秸刨花板制造中粘板问题的研究

研究了在使用异氰酸酯胶粘剂生产麦秸刨花板中粘板问题的防治 ,并得到了良好的、廉价的、可工业使用的脱膜剂。     

刨花板端面和平面甲醛散发的分布

通过实验分析了刨花板端面和平面甲醛散发的分布特征，给出了数学模型。作者认为，注意甲醛散发试件的取样位置是必要的。     

Characterization of date palm lignocellulosic by-products and self-bonded composite materials obtained thereof

In the present work, we investigated the possibility of valorizing four date palm tree by-products: leaflets, rachis, leaf sheath and fibrillum as self-bonded materials. First, their chemical composition and morphological properties were studied and showed high neutral detergent fiber values for all samples (65–91%) as normally required for self-bonding adhesion. Particleboard composites were then manufactured by thermopressing without any pretreatment or addition of synthetic binders. The properties of the resulting composites were assessed using bending test, internal bonding measurement, thickness swelling, water absorption and dynamical mechanical analysis. The fibrillum, leaflets and rachis based- composites have sufficient modulus of rupture to meet the Japanese Industrial Standard. However, only the fibrillum panels meet the French Standards. Furthermore, the results of dynamic mechanical analysis of leaflets composites reveal a relaxation peak which could be attributed to higher molecular weight carbohydrates. These preliminary results will allow to discriminate the various sources of fibrous particles on the same tree and to choose adequate preprocessing for further research.     

Effects of urea–formaldehyde resin mole ratio on the properties of particleboard

The use of urea–formaldehyde (UF) resins with lower contents of free formaldehyde in the board industry has led to products with very low emissions of formaldehyde. This study gives a detailed account of the influence on the mechanical and physical properties of the particleboard using UF resins with different mole ratios of formaldehyde:urea within the range 0.97–1.27. The mole ratio influenced not only the thickness swelling (TS) and water absorption (WA) but also the internal bond strength (IB) and the modulus of rupture (MOR) if the manufacturing process was optimized. The investigation revealed clearly that at mole ratios of formaldehyde giving the emission class El the MOR, IB, TS, and WA of particleboard deteriorated. Compensation for the deterioration could be provided through a higher dosage of resin or through the modification of UF resin. However, both alternatives meant that the product would be more expensive.     

我国创花板发展现状与发展趋势分析

本文根据详实调查和有关文献,对我国刨花板工业发展情况进行了详实的总结,并提出刨花板工业的未来发展趋势。     

刨花板用异氰酸酯胶粘剂合成工艺的研究

就刨花板用异氰酸酯树脂胶粘剂的合成工艺进行了广泛深入的研究。探讨了异氰酸酯树脂胶粘剂的合成工艺操作条件,其中主要讨论了利用不同种类的异氰酸酯和多元醇合成的异氰酸酯树脂胶粘剂的性能和影响因素及其对刨花板物理力学性能的影响。