多壁碳纳米管在尼龙6基体中的异相成核作用

Heterogeneous Nucleation Effect of Multi-Walled Carbon Nanotube in PA6 Matrix

用柔和混合法制备尼龙6/多壁碳纳米管(PA6/MWNTs)复合材料,纳米粒子的良好分散使复合材料出现熔融双峰现象。采用调幅式差示扫描量热仪(MDSC)研究了熔融双峰产生的原因和降温速率、MWNT含量对复合材料熔融行为的影响。结果表明,降温过程中,良好分散的MWNTs在基体中既起显著的异相成核作用,促进基体结晶,又限制了分子链排入晶格,抑制了晶体的生长,导致熔融双峰的出现。同时,降温速率越快,基体结晶时间越短,使低温熔融峰向低温偏移。MWNTs含量增加,异相成核作用越明显,形成的晶体越完善,使低温熔融峰向高温偏移。

Nylon 6/multi-walled carbon nanotube （PA6/MWNT） nanocomposites were prepared by mild compounding method. The double melting peaks phenomena appeared, indicating the good filler dispersion. Modulated differential scanning calorimeter （MDSC） was used to study the double melting peaks, the impact of the cooling rate, and different multi-walled carbon nanotubes （MWNT） content on the double melting peaks. The results of MDSC show that MWNTs play an role of heterogeneous nucleation in the matrix to promote the crystallization of PA6, but limit molecular chain discharged into the lattice and inhibit the growth of crystal, which leads to the double melting peaks. Meantime, the fast cooling rate makes the crystallization time of the matrix shorter and the low temperature melting peak lower. If the content of MWNTs increases, the role of heterogeneous nucleation becomes more obvious, leading to more perfect crystals and making the low temperature melting peak shift to high temperature.