聚氨酯/二氧化硅包覆多壁碳纳米管复合材料的导热与电绝缘性能

通过溶胶-凝胶法制备了厚度为30nm-50nm的二氧化硅(SiO2)包覆多壁碳纳米管(SiO2-MWNTs),并与聚氨酯(PU)复合制备了PU/SiO2-MWNT复合材料。研究了SiO2-MWNTs对PU导热电绝缘性能的影响。结果表明,SiO2包覆层增强了MWNTs与PU之间的界面相互作用,促进了MWNTs在PU中的分散。由于SiO2包覆层的电绝缘作用,PU/SiO2-MWNT复合材料保持了PU的电绝缘性能。同时SiO2包覆层作为过渡层,降低了PU与MWNTs间的模量失配,减少了声子的界面散射,提高了PU/SiO2-MWNT复合材料的导热性能。当SiO2-MWNTs的质量分数为0.5%和1.0%时,PU/SiO2-MWNT复合材料的热导率分别提高了53.7%和63.8%。

Thermal Conductivity and Electrical Insulation of Polyurethane/Silica-Coated Multi-Walled Carbon Nanotube Composites

30 nm～50 nm thick silica coated multi-walled carbon nanotubes(SiO2-MWNTs) were synthesized by sol-gel method,and compounded with polyurethane(PU) to prepare the PU/SiO2-MWNT composites.The effect of SiO2-MWNTs on the thermal conductivity and electrical insulation of PU was investigated.The results show that the silica layer improves the interfacial interaction between MWNTs and PU,and enhances the dispersion of MWNTs in PU matrix.Due to the electrical insulation of silica layer,PU/SiO2-MWNT composites almost show the same electrical insulation as neat PU.At the same time,the silica intermediate layer alleviates the modulus mismatch between the stiff MWNTs and the soft PU,decreases the scattering of phonons,and enhances the thermal conductivity of the PU/SiO2-MWNT composites.By adding 0.5% and 1.0% SiO2-MWNTs,the thermal conductivity of the PU/SiO2-MWNT composites is increased by 53.7% and 63.8% respectively.