Thermal decomposition behaviors of a self‐intumescent flame retardant epoxy resin
Cheng-shou Zhao, Hanming Yang, Yi‐Song Jiang, Hongwei Cui, Zhenjun Luo, Deyan Kong, Huaqiao Peng, Nima Esmaeili
Abstract
Abstract This paper focuses on revealing the thermal decomposition behaviors of a self‐intumescent flame retardant (IFR) epoxy (EP) resin (EP/15%APP‐Cu 2 O) employing 12 wt% ammonium polyphosphate (APP) as a halogen‐free flame retardant and 3 wt% copper (I) oxide (Cu 2 O) as char forming rate regulator. Initially, the thermal stability of EP/15%APP‐Cu 2 O was analyzed and compared to virgin EP resin and flame retardant EP (EP/15%APP) containing 15 wt% APP as flame retardant by thermogravimetric analysis test at different heating rates under nitrogen atmosphere. It was shown that the incorporation of APP altered the decomposition pathway of EP and decreased the onset decomposition temperature. Luckily, compared to EP/15%APP, the onset decomposition temperature of EP/15%APP‐Cu 2 O was just slightly reduced from 300.4 to 292.8°C. Then, the thermal degradation kinetics of EP, EP/15%APP and EP/15%APP‐Cu 2 O were further evaluated by Kissinger and Flynn‐Wall‐Ozawa methods. It was worth noted that the addition of APP or APP‐Cu 2 O enhanced the thermal degradation activation energies of EP, which contributed to the protective effect of the char formation. Particularly, the incorporation of 3 wt% Cu 2 O significantly decreased the thermal degradation activation energies at the early decomposition stage of EP. This may be the main contribution for intumescent char formation, which resulted in higher fire safety of EP/15%APP‐Cu 2 O compared to EP/15%APP. These information can potentially help to develop alternative IFR systems.