Effects of dowels produced from various materials on withdrawal strength in MDF and Pb

Wood dowels are commonly used in the construction furniture, but little information is available about the additive effects of dowels on the ultimate withdrawal strength of single or multidowel joints. This study was carried out to determine the tensile strength of 10‐mm‐diameter dowels produced from medium‐density fiberboard (MDF), plywood, scotch pine (Pinus sylvestris L.), and beech (Fagus orientalis lipsky), bonded parallel and vertical to the surface of MDF and particleboard (Pb) with poly(vinyl acetate) (PVAc) and Desmodur‐VTKA (D‐VTKA). Tensile strength was applied to the dowels according to the procedure in the ASTM‐D 1037 standard. The effects of dowel species, direction of tensile, composite material, and type of adhesive on tensile strength were determined. The results showed that the highest tensile strength was obtained in beech dowels bonded vertically with PVAc adhesive to the surface of MDF at 7.91 N/mm². If the dowels used in furniture production are subjected to great tensile strength, beech dowels bonded with PVAc adhesive on MDF should be used. However, when dowels produced from MDF and plywood waste are used, they also can produce positive results. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 531–535, 2003     

MDF水泥的玻璃纤维增强研究

研究了中碱和抗碱玻璃纤维作为ＭＤＦ水泥的增强材料的可行性以及它的增强效果，试图通过向ＭＤＦ水泥中引入玻璃纤维来改善它的耐水性能。研究结果表明：中碱和抗碱玻璃纤维作为ＭＤＦ水泥的增强材料具有较好的耐久性，并能显著提高ＭＤＦ水泥的抗弯强度、断裂韧性和耐水性能；玻璃纤维的Ｌ／Ｄ制约着其掺量Ｖｆ对ＭＤＦ水泥的物理性能的影响，并决定着该材料的结构特征；采用本文介绍的工艺，在制备ＭＤＦ水泥材料时，玻璃纤维长度以５ｍｍ为宜。     

精制水泥制品的工程性质和潜在应用

“精制水泥制品”指一类用较高技术制成的超高强水泥基材料。本文介绍了精制水泥制品的工程性质,以及在声学、低温学、装甲、电磁幅射屏蔽、电器和高放废物固化处理方面的潜在应用。     

聚丙烯酰胺──铝酸一钙水化过程的一些特性分析

本文研究了聚丙烯酰胺与铝酸一钙水化过程中的液相离子浓度、水化热的变化规律，对反应体系的物相变化进行了ＸＲＤ分析，比较了掺入与不掺聚合物两种反应体系的差别，讨论了水化过程的特点，为聚合物与水泥间的反应机理提供了直接的实验证据。     

MDF水泥材料的稳定性及改性研究

本文探讨了不同改性剂及其掺量和聚合物不同含量对ＭＤＦ水泥材料力学性能及显微结构的影响，并且提出了ＭＤＦ水泥材料的稳定机理．     

AN INVESTIGATION OF BONDING BEHAVIOUR ON THE INTERFACE OF POLYACRYLAMIDE-ALUMINOUS COMPOSITES

MDF cement material,a new kind of highstrength polymer cement,has an exellent proper-ty of bending strength.It is supposed that thisproperty attributes to the mechanism of improv-ing interface strength.In this paper,the bondingbehaviours on the composite interface betweenpolyacrylamide and aluninous cement are studiedwith microimage,XPS surface analysis tech-nique and fracture surface analysis.Actions onthe improving interface in this material are dis-cussed.     

合理选择中密度纤维板生产工艺的思考与探讨

根据我国中密度纤维板生产线建设实践,就剥皮与水洗、干燥与施胶、铺装与预压、热压与砂光等工序生产工艺的合理选择提出了看法与建议。     

Termite Resistance of MDF Panels Treated with Various Boron Compounds

In this study, the effects of various boron compounds on the termite resistance of MDF panels were evaluated. Either borax (BX), boric acid (BA), zinc borate (ZB), or sodium perborate tetrahydrate (SPT) were added to urea-formaldehyde (UF) resin at target contents of 1%, 1.5%, 2% and 2.5% based on dry fiber weight. The panels were then manufactured using 12% urea-formaldehyde resin and 1% NH₄Cl. MDF samples from the panels were tested against the subterranean termites, Coptotermes formosanus Shiraki. Laboratory termite resistance tests showed that all samples containing boron compounds had greater resistance against termite attack compared to untreated MDF samples. At the second and third weeks of exposure, nearly 100% termite mortalities were recorded in all boron compound treated samples. The highest termite mortalities were determined in the samples with either BA or BX. Also, it was found that SPT showed notable performance on the termite mortality. As chemical loadings increased, termite mortalities increased, and at the same time the weight losses of the samples decreased.     

抑烟剂对阻燃中纤板的燃烧性能影响研究

文章主要就抑烟剂对阻燃中纤板的燃烧性能影响进行了研究,最后研究出了一种低烟毒阻燃中纤板.经测试在阻燃剂添加量30 kg/m3情况下,当复合抑烟剂添加量2％时阻燃中纤板的氧指数为37.5％,UL94点燃续燃时间为3.5 s,阴燃时间为11.2 s,烟密度等级SDR由5.7下降到4.0.经GB8624-2012对阻燃中纤板进行燃烧性能测试,结果表明未发生火焰的横向、纵向蔓延,具有较好的阻燃、成炭性能.