Sreekanth M S, Panwar Ajay S, Pötschke Petra, Bhattacharyya Arup R
Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Phys Chem Chem Phys. 2015 Apr 14;17(14):9410-9. doi: 10.1039/c5cp00018a. Epub 2015 Mar 13.
Expanded graphite (EG) and multiwalled carbon nanotubes (MWNTs) based hybrid nano-composites were prepared with polyamide 6 (PA6) matrix via melt-mixing technique using a conical twin-screw micro-compounder. A novel organic modifier (lithium salt of 6-aminohexanoic acid; Li-AHA) was employed to modify MWNTs, which was utilized to intercalate Li-AHA modified MWNTs into the partially exfoliated EG gallery. Morphological investigation showed the intercalation of Li-AHA modified MWNTs into a partially exfoliated EG gallery in an EG/MWNTs-m2h hybrid, whereas the unmodified EG/MWNTs-h hybrid mixture exhibited a separate identity in the mixture. Improved interaction via melt-interfacial reaction between the acid end group of PA6 and the amine functionality of Li-AHA in the EG/MWNTs-m2h hybrid filler was confirmed by Fourier transform infrared spectroscopic analysis. The extent of melt-interfacial reaction was increased as a function of Li-AHA concentration in the filler. Wide angle X-ray diffraction analysis showed the existence of the α-crystalline phase of PA6. The incorporation of MWNTs, EG and EG/MWNTs hybrid in the PA6 matrix has favoured an α-crystalline structure of the PA6 phase. Crystallization studies have indicated a significant increase in the bulk crystallization temperature of the PA6 phase in the presence of MWNTs, EG and the EG/MWNTs hybrid filler. Moreover, the formation of PA6 'trans-crystalline lamellae' on the MWNTs surface was facilitated in the case of composites with MWNTs and the EG/MWNTs hybrid filler. An attempt has been made to investigate the role of the EG/MWNTs hybrid filler in influencing the crystallization behaviour of the PA6 phase in the hybrid nano-composites.
采用锥形双螺杆微型混合机，通过熔融混合技术制备了以聚酰胺6（PA6）为基体、膨胀石墨（EG）和多壁碳纳米管（MWNTs）为基础的混杂纳米复合材料。采用一种新型有机改性剂（6-氨基己酸锂盐；Li-AHA）对MWNTs进行改性，并将Li-AHA改性的MWNTs插入部分剥离的EG层间。形态学研究表明，在EG/MWNTs-m2h杂化物中，Li-AHA改性的MWNTs插入到部分剥离的EG层间，而未改性的EG/MWNTs-h杂化混合物在混合物中呈现出分离的状态。通过傅里叶变换红外光谱分析证实，EG/MWNTs-m2h杂化填料中PA6的酸端基与Li-AHA的胺官能团之间通过熔融界面反应实现了增强的相互作用。熔融界面反应的程度随填料中Li-AHA浓度的增加而提高。广角X射线衍射分析表明存在PA6的α晶相。MWNTs、EG和EG/MWNTs杂化物在PA6基体中的加入有利于PA6相形成α晶型结构。结晶研究表明，在存在MWNTs、EG和EG/MWNTs杂化填料的情况下，PA6相的本体结晶温度显著升高。此外，在含有MWNTs和EG/MWNTs杂化填料的复合材料中，MWNTs表面促进了PA6“横穿晶薄片”的形成。本文试图研究EG/MWNTs杂化填料在影响混杂纳米复合材料中PA6相结晶行为方面的作用。
