Resinification of NaOH-catalyzed phenolated wood–phenol mixture with formalin for making molding materials

NaOH-catalyzed phenolated wood-phenol-formalin co-condensed novolak type resin was prepared in two stages. Birch wood meal was first phenolated by using NaOH as a catalyst at an elevated temperature (i.e. 250 °C), and then formalin solution together with oxalic acid was added to the phenolated wood-phenol mixture obtained. The relationships among reaction parameters and phenolation/ resinification yields, flow properties of the resinified phenolated wood, and the physico-mechanical properties of the resinified phenolated wood-based molding materials were studied. The yields obtained due to resinification of the phenolated wood were found to depend, greatly, on the phenol-formalin molar ratio. Moreover, the melt flow properties (i.e. flow properties and viscosity) of the resinified NaOH-catalyzed phenolated wood reached or slightly exceeded those of commercial novolak resin and was greatly improved in comparison to the NaOH-catalyzed phenolated wood-based molding materials alone. Furthermore, the flexural properties of the resinified phenolated wood-based molding materials were determined to be much similar to or better than those of commercial novolak resin-based molding materials and much greater than those of NaOH-catalyzed phenolated woodbased molding materials alone. On the other hand, the resinified phenolated wood-based molding materials were more hydrophobic and biodegradable than those of commercial novolak resin-based molding materials and less hydrophobic and biodegradable than NaOH-catalyzed phenolated woodbased molding materials alone.     

Effect of Wood Fibers on the Rheological and Mechanical Properties of Polystyrene/Wood Composites

The effects of wood fibers on the rheological and mechanical properties of polystyrene/wood (PS/wood) composites were investigated. The composites with different ratios of PS and wood were prepared by means of internal mixer and, additionally, two different sizes of the wood particles were used, such as ～100 and ～600 µm. The rheological properties were studied using capillary rheometer, apparent shear rate, apparent shear stress, apparent viscosity, power law index, and flow activation energy at a constant shear stress were determined. The rheological results showed that the shear stress–shear rate variations obeyed a power law equation, and the composites exhibited shear thinning. The flow activation energy of the composites increased with the addition of wood particles. Mechanical results showed that stress at break of the composites was higher than that of pure PS, whereas the strain at break and impact strength of the composites were lower than that of PS. In addition, the mechanical properties of the present composites were improved when the small size of wood particles were incorporated.     

PBAT/木粉复合材料的制备

以木粉和聚己二酸/对苯二甲酸丁二酯(PBAT)为原料,添加硅烷偶联剂,混合均匀后,在开炼机中混炼一定时间制备PBAT/木粉复合材料,从偶联剂种类及其用量、加工温度、加工时间4个方面探讨了制备PBAT/木粉复合材料的最佳工艺条件。研究结果表明,加入的硅烷偶联剂KH–560用量为木粉和PBAT总质量的2%,与木粉和PBAT在130℃下混炼10 min,制备出的PBAT/木粉复合材料的相容性较好,且复合材料的拉伸性能达到最优,拉伸强度和断裂伸长率分别达到12.42 MPa和56.58%。SEM分析表明,添加KH–560后,PBAT/木粉的相容性得到了明显改善,耐水性更好,吸水率从13.04%下降到10.39%,制备出的PBAT/木粉复合材料的耐热性能较原料木粉也得到了较大的提高,在395℃时仅分解40%。     

户外木塑复合材料的研究进展

综述了户外木塑复合材料的发展现状,介绍了木塑复合材料在户外环境真菌、湿度、紫外线、冰冻-解冻气候条件下性能的变化,总结了木粉种类、含量和成型方法对其户外使用性能的影响,并详述了用于户外木塑复合材料的原材料包括树脂基体和助剂的研究情况。     

Comparative Study of Water Absorption Behavior of Wood and Wood Plastic Composites of Simul Using Film Neutron Radiography

Abstract

The film neutron radiography method was adopted for a comparative study of water absorption behavior in wood and wood plastic composites (WPC) of Simul using the thermal neutron radiography facility of 3 MW TRIGA MARK-II research reactor at Atomic Energy Research Establishment, Savar Dhaka, Bangladesh. Variations of optical density values due to water absorption of these samples were measured from neutron radiographic images. The WPC samples were prepared with impregnating monomer methylmethacrylate (MMA) under gamma radiation in order to study their water absorption behavior. The water absorption nature of Simul wood (Salmalia mamabrarica) and its composites, with and without urea as additive, was monitored by optical density measurements. The absorption of water in wood increases continuously with time. Where as, the water absorption by wood plastic composites is less compared to virgin wood; the composites with additive urea showed less water absorption than did those of virgin wood and the composites without urea.     

滑石粉对聚丙烯木塑复合材料性能影响的研究

研究了不同含量的滑石粉对聚丙烯木塑复合材料力学性能和加工性能的影响.结果表明:滑石粉能够在一定程度上改善聚丙烯木塑复合材料的力学性能和加工性能.硅烷偶联剂对复合材料的处理效果要优于钛酸酯偶联剂.     

木塑复合材料制备及其在建筑中应用进展

综述了木塑复合材料的生产工艺,分析了影响木塑复合材料力学性能和耐久性的因素,阐述了木塑复合材料在建筑工程中的应用,展望了未来木塑复合材料的研究方向。指出今后木塑复合材料的研究应主要集中在耐久性机理的进一步探索以及提高木塑复合材料耐久性的改性和结构设计方法。     

HDPE-g-MAH增容HDPE/木粉复合材料的制备及加工设备的研究

使用HDPE-g-MAH做增容剂,通过双螺杆挤出机制备了HDPE/木粉复合材料,对HDPE-g-MAH进行量变实验,通过力学性能测试确定了最佳用量,并利用SEM对材料微观形貌进行了观察。在此基础上又采用单螺杆挤出机、开炼机和密炼机等不同的加工设备分别制备了木塑复合材料,对力学性能进行了对比表征。结果表明:HDPE-g-MAH的加入很好地改善了木塑复合材料的界面相容性、力学性能和木粉的分散性,HDPE-g-MAH的最佳用量为5份;而且只有使用剪切效果优良的双螺杆挤出机才能制备出性能优异的木塑复合材料。     

木纤维增强热塑性复合材料的界面研究现状

综述了目前国内外关于木纤维增强热塑性复合材料界面的研究进展，介绍了常用的几种改善木塑复合材料界面相容性的方法，并分析了各自的优缺点。     

抗静电木粉/聚丙烯复合材料的研究

为了提高木粉/聚丙烯复合材料的抗静电性能,通过高速混合、挤出造粒以及热压成型的方式制备了4种抗静电木粉/聚丙烯复合材料,并比较了它们的体积电阻率和拉伸强度,结果表明:在4种抗静电复合材料中加入炭黑的复合材料体积电阻率最小,拉伸强度最大。探讨了炭黑用量对木粉/聚丙烯复合材料抗静电性能和力学性能的影响,结果表明:当炭黑用量增加时,复合材料的体积电阻率明显降低,拉伸强度和弯曲强度出现最大值,弹性模量和断裂伸长率呈下降趋势。     

利用木屑与木质素制仿木复合材料的研究

以木屑和黑液木质素为原料,加入废旧聚丙烯塑料和相容剂马来酸酐接枝聚丙烯MAH-G-PP,经搅拌混合、造粒、螺杆挤出而制得仿木复合材料。当混合料总量为100份时,木粉和木质素的加入量均为混合料质量分数的30%,废旧聚丙烯塑料为35%,相容剂为5%时,其抗压强度和抗拉强度分别为22.4和7.3 MPa。     

木塑复合材料应用现状及发展趋势

介绍了国内外木塑复合材料的应用现状及最新研究成果，总结了近年来木塑复合制品行业面临的问题，对木塑复合材料的发展前景进行了展望。     

木塑复合材料及其研究进展

在结合实践研究的基础上,总结并介绍了木塑复合材料的发展现状,在生产方法及工艺方面,研究了如何改善木塑复合材料界面相容性的问题,并对国内外研究进展及未来的发展方向作了论述。     

Durability of Wood Flour-Thermoplastic Composites under Extreme Environmental Conditions and Fungal Exposure

Abstract

The main purpose of this research work was to investigate the response of wood flour reinforced polyethylene composites to 2 hours water boiling, five complete boiling and freezing cycles and fungal (Gloeophyllumm Traebum/Brown-rot fungus) exposure. Five composite formulations were manufactured and analyzed (0, 50, 60, 70 and copper carbonate treated 60% wood flour/polyethylene composites). The results showed that wood flour loading decreased the resistance of the composites to moisture and fungal environment. The exposure of the composites to 2 hours water boiling and five complete boiling and freezing cycles caused serious damage to the interfacial adhesion between wood flour and polyethylene matrix due to contraction and swelling stresses developed during cyclic exposure. The addition of 1 percent copper carbonate salt during compounding of wood flour and polyethylene prevented the colonization and proliferation of fungus on the surface of the composites, but had a negative effect on the water uptake and flexural properties of the composites.     

聚丙烯/木粉/纳米凹凸棒土复合材料性能研究

采用双螺杆挤出机制备了一系列聚丙烯(PP)/木粉/纳米凹凸棒土(AT)木塑复合材料(WPC.研究了AT用量对复合材料力学性能、热性能、加工性能的影响.结果表明,随着AT用量的增加,复合材料拉伸强度逐渐增加、冲击强度逐渐减小,硬度先增加后减小,AT用量为5份时复合材料硬度最大;复合材料维卡软化点不断提高;熔体流动速率(M...     

热塑性木塑复合材料研究进展

热塑性木塑复合材料（WPC）是一种兼有木材的力学性能和热塑性塑料易加工的新型材料。阐述木塑复合材料国内外最新研究进展和应用前景。指出热塑性木塑复合材料作为一种新型环保材料，具有广阔的应用前景。     

Preparation and characterization of LDPE and PP—Wood fiber composites

Natural fiber reinforced composites is an emerging area in polymer science. These natural fibers are low cost fibers with low density and high specific properties. These are biodegradable and nonabrasive. The natural fiber composites offer specific properties comparable to those of conventional fiber composites. However, in development of these composites, the incompatibility of the fibers and poor resistance to moisture often reduce the potential of natural fibers, and these draw backs become critical issue. Wood‐plastic composites (WPC) are a relatively new class of materials and one of the fastest growing sectors in the wood composites industry. Composites of wood in a thermoplastic matrix (wood–plastic composites) are considered a low maintenance solution to using wood in outdoor applications. WPCs are normally made from a mixture of wood fiber, thermoplastic, and small amounts of process and property modifiers through an extrusion process. In this study, Wood–plastic composites (WPC) are produce by adding a maleic anhydride modified low density polyethylene coupling agent to improve interfacial adhesion between the wood fiber and the plastic. Mixing is done with twin screw extruder. Subsequently, tensile strength, the modulus of elasticity, % elongation, hardness, Izod impact strength, melt flow index (MFI), and heat deflection temperature (HDT) are determined. Thermal transition temperatures and microstructure are determined with DSC and SEM, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

合成木材的应用研究

综述了合成木材研究开发技术进展,重点介绍了木塑复合材料的特点、配合、加工以及应用情况提出了未来木塑复合材料的发展趋势。     

松香超分散剂含量对塑木复合材料性能影响

以松香、二乙撑三胺和12-羟基硬脂酸为原料合成了松香超分散剂(RDH),研究不同RDH含量对塑木复合材料的力学性能、结晶性能及相容性的影响。结果表明,随着RDH加入量的增加,塑木复合材料的冲击强度、弯曲强度和弯曲模量都呈先增后减的变化趋势;当RDH质量分数为1.0%时,塑木复合材料的相容性较好。     

木塑复合材料的研究和应用进展

木塑复合材料(WPC)是一种新型的绿色环保复合材料,是木材的理想替代品,可以减少废弃木材和对环境的污染。本文简要地介绍了木塑复合材料的生产工艺和关键技术、挤出设备以及在国内外的应用发展现状,并对木塑复合材料发展趋势进行了分析,肯定了发展木塑复合材料的必要性和可行性。