碳纳米管/环氧树脂复合材料性能研究

Study on properties of carbon nanotubes/epoxy resin composites

研究的碳纳米管/环氧树脂复合材料是导电复合材料中研究较多的材料体系。实验中为了降低体系的黏度,方便搅拌和固化成型,使用50%(质量分数)环氧稀释剂669混合E44环氧树脂作为基体。固化剂选择了常用的甲基四氢苯酐,同时添加了促进剂DMP-30,实验中采用的分散方法是普通的搅拌和超声分散。实验结果显示,碳纳米管的加入大大增加了材料的力学性能。抗弯强度从81.72 MPa增大到了130 MPa,增加了60%左右。同时碳纳米管加入后起到了增韧作用,材料的韧性明显提高。比较不同浓度下的抗弯强度可以发现,碳纳米管的浓度变换对复合材料的整体抗弯强度影响并不大。从扫描电镜照片来看,本实验制备的碳纳米管/环氧树脂复合材料的分散性并不好,碳纳米管呈现聚集分布。在电学性能上,由于碳纳米管的分散不够,导致材料的电导率偏低。阻抗分析显示,渗流阈值在0.50%(质量分数)以上。在碳纳米管分散性较好的情况下,由于碳纳米管的长径比较大,渗流阈值一般在0.1%(质量分数)以下。在介电性能方面,本实验发现碳纳米管可以显著增加材料在低频下的相对介电常数。

Carbon nanotubes/epoxy resin composites studied in this paper are widely studied in conductive composites.In order to reduce the viscosity of the system and facilitate stirring and curing,50%(mass fraction)epoxy diluent 669 mixed with E44 epoxy resin is used as the matrix.The commonly used methyl tetrahydrophthalic anhydride is chosen as curing agent,and DMP-30 is added as accelerator.The dispersing method used in the experiment is ordinary agitation and ultrasonic dispersion.The experimental results show that the addition of carbon nanotubes greatly increases the mechanical properties of the material.The bending strength increases from 81.72 MPa to 130 MPa,increasing by about 60%.At the same time,carbon nanotubes play a toughening role,and the toughness of the material is obviously improved.Comparing the bending strength of the composites at different concentrations,it can be found that the concentration change of carbon nanotubes has little effect on the overall bending strength of the composites.Scanning electron microscopy photographs show that the dispersion of carbon nanotubes/epoxy resin composites prepared in this experiment is not good,and carbon nanotubes show aggregation distribution.In terms of electrical properties,due to the insufficient dispersion of carbon nanotubes,the conductivity of materials is low.Impedance analysis shows that the percolation threshold is above 0.50%(mass fraction).In the case of good dispersion of carbon nanotubes,the percolation threshold is generally less than 0.1%(mass fraction)because of the high L/d of carbon nanotubes.In terms of dielectric properties,it is found that carbon nanotubes can significantly increase the relative dielectric constant of materials at low frequencies.