Structure-property-processing studies of polymer nanocomposites

• Main Authors: Loo, Leslie Sun Sun, Zhang, Xingui
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Research Report
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Chemical engineering::Polymers and polymer manufacture
• Online Access: http://hdl.handle.net/10356/42262
• Institution: Nanyang Technological University

A novel amorphous polyamide/montmorillonite nanocomposite based on poly(hexamethylene isophthalamide) was successfully prepared by melt intercalation. Wide angle X-ray diffraction and transmission electron microscopy showed that organoclay containing quaternary amine surfactants with phenyl and hydroxyl groups was delaminated in the polymer matrix, resulting in well-exfoliated morphologies even at high montmorillonite content. Differential scanning calorimetry results indicated that clay platelets did not induce the formation of a crystalline phase in this amorphous polymer. Tensile tests demonstrated that the addition of nanoclay caused a dramatic increase in Young’s modulus (almost twofold) and yield strength of the nanocomposites compared to the homopolymer. The nanocomposites exhibited ductile behavior up to 5 wt% of nanoclay. The improvement in Young’s modulus is comparable with semicrystalline aliphatic nylon 6 nanocomposites. Both the main chain amide groups and the amorphous nature of the polyamide are responsible for enhancing the dispersion of the nano-fillers, thereby leading to improved properties of the nanocomposites. The structure-property relationship for these nanocomposites was also explored. Thermal oxidative degradation of the polymer nanocomposites was studied by thermogravimetric analysis (TGA). TGA results demonstrated that the addition of organoclay resulted in a substantial increase (30°C) in the onset degradation temperature of the nanocomposites as compared to the homopolymer. The protective effect is mainly due to the confinement and barrier effect of the nanoclay. Nylon 6/nanoclay nanocomposites exposed to oxygen plasma also showed better abrasion resistance compared to pure nylon 6.