利用热压还原法制备3D-W/rGO导电材料

利用木材天然多孔的网状结构及富含活性基团羟基和羧基的特性,通过冷热水循环结合冷冻处理的方式,提高了木材的渗透性;利用脉冲式真空浸渍法将氧化石墨烯(GO)与木材充分结合,再使用热压法将木材内部的GO还原,使木材具有三维导电性能。结果表明:当GO质量浓度为3 mg/m L,压缩率为45%,热压温度为220℃,热压时间为45 min时,木材/石墨烯三维导电材料(3D-W/r GO)性能最佳,纵向、径向和弦向体阻率分别为3.0×10²,7.0×10²和3.9×10³Ω·cm。对3D-W/r GO的形貌、结构和性能进行研究,激光共聚焦显微镜和扫描电子显微镜分析结果表明,还原性氧化石墨烯(r GO)在木材管道中均匀分布;X射线光电子能谱和傅里叶红外光谱表明,GO以酯键和氢键的形式与木材紧密结合,且r GO在木材机体中的还原程度较大;X射线衍射光谱分析显示,材料结晶度数值减小;综合热分析表明,材料的热稳定性有所提高。和木材相比,3D-W/r GO的力学性能及尺寸稳定性均有明显提升,是一种极具前景的导电材料。

Preparation of 3D-W/rGO conductive materials by hot-pressing reduction method

Functionality of wood’s natural porous network structure characteristics,and active groups hydroxyl(-OH) and carboxyl(-COOH) can make it to be a great matrix template for loading other materials.In this study,it was attempted to imbue electrical conductivity to the insulative wood by adding graphene into the wood matrix to form a conductive wood-graphene composite via a facile and environmentally benign fabrication technique.Firstly,a kind of wood sample with little inclusion was processed by water circulation combined with freezing treatment.Then the sample was combined with graphene oxide(GO) by the pulse vacuum impregnation method.Secondly,by hot-pressing,wood’s GO was pressed into graphene to obtain fine electrical conductivity.The conduction and bonding mechanism between graphene and wood were studied,and a series of characterization techniques were employed.The results showed that when GO’s mass concentration was 3 mg/mL,the compression ratio was 45%,the hot-pressing temperature was 220 ℃,and the hot-pressing time was 45 min,it could gain a wood/graphene three-dimensional conductive materials(3 D-W/rGO) with excellent electrical conductivity.Its longitudinal,radial and tangential volume resistivity values were 3.0×102,7.0×102 and 3.9×103 Ω·cm,respectively.More significantly,its highly unique three-dimensional anisotropic conductivity made this material to be a highly versatile conductor in various applications.Moreover, the morphology,structure and properties of 3 D-W/rGO were studied.The results of the laser confocal microscopy and scanning electron microscope showed that the reduced graphene oxide(rGO) was evenly distributed in the fiber lumen of wood.The mercury intrusion method isotherm showed that the 3 D-W/rGO’s total pore volume decreased by rGO’s growing in wood’s pores.Examinations of the X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy showed that GO was tightly combined with wood in the form of ester bond and hydrogen bond,and rGO had a greater degree of reduction in wood.The X-ray diffraction analysis showed that the crystallinity of material decreased and the comprehensive thermal analysis(TG-DSC) showed that the thermal stability of material was improved.3 DW/rGO not only had three-dimensional conductivity,but also significantly improved its mechanical properties and dimensional stability compared with wood.Using this treatment,wood and rGO can create a good combination effect,resulting in 3 D-W/rGO being a kind of promising conductive material.