Synthesis and properties of homogeneously dispersed polyamide 6/MWNTs nanocomposites via simultaneous in situ anionic ring-opening polymerization and compatibilization

• Published in: Journal of applied polymer science 2009-06, Vol.112 (6), p.3620-3626
• Main Authors: Yan, Dongguang, Yang, Guisheng
• Format: Article
• Language: English
• Subjects: Applied sciences; carbon nanotubes; Composites; Exact sciences and technology; Forms of application and semi-finished materials; in situ compatibilization; in situ polymerization; nanocomposites; polyamides; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.29783

Toluene 2, 4-diisocyanate (TDI) functionalized multiwalled carbon nanotubes (MWNTs-NCO) were used to prepare monomer casting polyamide 6 (MCPA6)/MWNTs nanocomposites via in situ anionic ring-opening polymerization (AROP). Isocyanate groups of MWNTs-NCO could serve as AROP activators of ε-caprolactam (CL) in the in situ polymerization. Fourier transform infrared (FTIR) showed that a graft copolymer of PA6 and MWNTs was formed in the in situ polymerization. MWNTs-PA6 covalent bonds of the graft copolymer constituted a strong type of interfacial interaction in the nanocomposites and increased the compatibility of MWNTs and MCPA6 matrix. The nanocomposites were characterized for the morphology, mechanical, crystallization, and thermal properties through field emission transmission electron microscopy (FETEM), tensile testing, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). FETEM analysis showed that MWNTs were homogeneously dispersed in MCPA6 matrix. The initial tensile strengths and tensile modulus of the nanocomposite with 1.5 wt % loading of MWNTs were enhanced by about 16 and 13%, respectively, compared with the corresponding values for neat MCPA6. DSC analysis indicated that the crystallization temperature of the nanocomposites was increased by 8°C by adding 1.5 wt % MWNTs compared with pure MCPA6. Besides, it was found that the thermal stability of MCPA6 was improved by the addition of the MWNTs.