Xiaodong Liu, Jia Guo, Wufei Tang, Jun Sun, Hongfei Li, Xiaoyu Gu, Sheng Zhang*. Enhancing the flame retardancy of thermoplastic polyurethane by introducing montmorillonite nanosheets modified with phosphorylated chitosan. Composites Part A 2019, 119, 291-298

https://doi.org/10.1016/j.compositesa.2019.02.009

Abstract

Phosphorylated chitosan (PCS) was applied to decorate montmorillonite under ultrasonic catalysis to prepare organically modified exfoliated montmorillonite (PMT). It was demonstrated that PMT had better synergi** with aluminum hypophosphite (AHP) than MMT in improving the fire resistance of thermoplastic polyurethane (TPU) composites. By the presence of 9% AHP and 1% PMT, the limiting oxygen index of TPU composites was increased to 28.4%, the UL-94 rating was achieved to V-0. The peak heat release rate and total **oke release were reduced from 1090 kW/m² and 831 m²/m² of control TPU sample to 195 kW/m² and 91 m²/m² of the TPU/AHP/PMT sample respectively. The char residue after cone calorimetry demonstrated PMT nanoplatelets were well dispersed in the polymer matrix, which served as the thermal insulation layer to shield the underlying matrix from the exterior heat irradiation.