聚乳酸/石墨/多壁碳纳米管复合材料的制备及性能

通过共溶剂法制备了由石墨(GN)和多壁碳纳米管(MWCNTs)掺杂的聚乳酸(PLA)纳米复合材料,借助扫描电镜等手段,研究了MWCNTs用量对复合材料微观结构、热稳定性、导热和导热性能及介电性能的影响。结果显示,MWC-NTs和GN在PLA基体中形成了稳定的导电和导热网络结构,从而导致复合材料具有较低的导电和导热逾渗阈值,其值约为MWCNTs/GN=0.5/1。MWCNTs和GN均匀分散和协同增强效应促使复合材料热稳定性、导热和导电性能明显提高。与纯PLA相比,填料在逾渗阈值附近的复合材料的初始分解温度提高了近16℃,导热系数提高了1倍,体积电阻降低了109数量级。

Preparation and Properties of Nanocomposites Based on PLA,Graphite Nanosheets and MWCNTs

Polylactide based nanocomposites were preparaed by using graphite nanosheets(GN) and multi-walled carbon nanotubes(MWCNTs) with solution-blending technique,and their morphology,structure,thermal stability,mechanical,dielectric properties and conductivity were investigated.The resultant nanocomposites were characterized and evaluated by means of scanning electron microscope and so on.The results indicate that thermal expanded GN facilitates the formation of a fitting conductive network in presence of MWCNTs in PLA matrix,which resultes in a relatively low percolation threshold for thermal and electrical conduction of nanocomposites,and the low percolation threshold is at MWCNTs/GN=0.5/1.The significant improvement in thermal and electrical conductivity,thermal stability,mechanical properties of nanocomposites obtained by the presence of both nanoparticles in PLA matrix are associated to the good co-dispersion and co-reinforcement effect.Compared with the raw PLA,the onset temperature of thermal degradation of composite is improved by 16 ℃,the thermal conductivity of composite increases by one time,and the electrical conductivity decreases by 109.