Study on Crystallization, Thermal and Flame Retardant Properties of Nylon 66/Organoclay Nanocomposites by in situ Polymerization

Exfoliated Nylon 66/organoclay (PA66/OMT) nanocomposites were synthesized based on adipic acid, hexamethylendiamine, and organoclay (organically modified montmorillonite, OMT) modified by protonated aminocaproic acid via in situ polymerization. X-ray diffraction and transmission electronic microscopy were used to characterize their morphologies. Results confirmed that the exfoliated nanocomposites with different organoclay content were obtained. The crystallization behavior, thermal stability, and flame retardant properties of the PA66/OMT nanocomposites were investigated through thermogravimetry, differential scanning calorimetry and cone calorimetry experiments. The addition of OMT can induce the generation of γ-crystalline phase, increase the crystallization temperature and affect the crystallinity in PA66 matrix. The exfoliated nanocomposites have enhanced thermal stability and flame retardant properties compared with pure PA66. And it shows that a synergistic effect occurred between nanoscale clay layers and flame-retardant melamine polyphosphate.