双极性纳秒脉冲DBD等离子体改性增强BNNSs在环氧树脂中的分散性

Dispersion Enhancement of BNNSs in Epoxy Resin by Surface Modification with Bipolar Nanosecond Pulse DBD Plasma

在环氧树脂中添加氮化硼纳米片(boron nitride nanosheets,BNNSs)可获得某些优于常规材料的特性,但纳米粒子的“团聚”现象对改性效果有较大影响。为了增强BNNSs在环氧树脂(epoxy resin,EP)基体中的分散性,为此采用大气压Ar+HO双极性纳秒脉冲介质阻挡放电(dielectric barrier discharge,DBD)低温等离子体对BNNSs进行羟基化改性,再用硅烷偶联剂KH560修饰,使用X射线光电子能谱仪(X-ray photoelectron spectroscopy,XPS)、热重分析(thermogravimetric analysis,TGA)来研究等离子体改性前后BNNSs表面的元素及羟基含量和对偶联剂修饰的影响,利用面积分布概率和冲击强度对BNNSs分散性进行定量表征。测试结果表明,在20%的相对湿度下,等离子体改性后BNNSs表面的羟基含量提高近两倍,增强了BNNSs对偶联剂的吸附作用,相比于只用偶联剂改性的BNNSs,其表面偶联剂的包覆率提高了45%;在相同质量分数下,等离子体+偶联剂改性的BNNSs比只用偶联剂改性的BNNSs的分散性特征值增大10%以上。该研究为增强纳米粒子在基体材料中的分散性提供了一种新方法。

Filling epoxy resin with boron nitride(BN)nanosheets(BNNSs)can effectively improve the thermal conductivity of BN/EP nanocomposites,however,the severe agglomeration of BNNSs will significantly reduce the modification effects of the composites.In order to enhance the dispersion of BNNSs in epoxy resins,we adopted atmospheric pressure bipolar nanosecond pulse dielectric barrier discharge(DBD)Ar+HO low temperature plasma to hydroxylate BNNSs,then modified with silane coupling agent KH560.The elemental and hydroxyl content of BNNSs were investigated using X-ray photoelectron spectroscopy(XPS)and thermogravimetric analysis(TGA),respectively,and the dispersion of BNNSs was quantitatively characterized using area distribution probability and impact properties.The test results show that the hydroxyl content on the surface of BNNSs increases by nearly two fold after plasma modification at 20%relative humidity,which enhances the adsorption of BNNSs on coupling agent.The coating amount of silane coupling agent on the BNNSs surface increases by 45%after plasma modification compared with BNNSs modified with coupling agent only.The dispersion characteristic value of BNNSs treated by plasma and silane coupling agent is increased by more than 10%than that of silane coupling agent treated only at the same mass fraction.This study provides a new method for enhancing the dispersibility of nanoparticles in composite materials.