Thermal degradation behavior and flammability of polyurethanes blended with poly(bispropoxyphosphazene)
Resource
Polymer Degradation and Stability 66 (3): 307-315
Journal
Polymer Degradation and Stability
Journal Volume
66
Journal Issue
3
Pages
307-315
Date Issued
1999
Author(s)
Wang, Pin-Sheng
Chen, Leo-Wang
Denq, Bar-Long
Don, Trong-Ming
Chiu, Yie-Shun
Abstract
Polyurethanes containing different amount of flame retardant, poly(bispropoxyphosphazene), were synthesized by a two-step polymerization. The thermal degradation behaviors of these polyurethanes were then studied by the thermal gravimetric analysis (TGA), TGA coupled with Fourier transform infrared analysis and elemental analysis. A limiting oxygen index was used to evaluate the flammability of these polyurethanes. For these modified polyurethanes under nitrogen, a two-stage thermal degradation behavior was observed. The first stage was caused by the degradation of hard segments, whereas the soft segments were responsible for the second-stage degradation. The thermal degradation activation energies were calculated by using Ozawa's method. It was found that the addition of flame retardant caused a decrease of the activation energy in the first stage, but an increase in the second stage, which was probably due to the formation of a thermal stable structure. As for the flame retardany, the modified poly-urethanes have a higher char yield at 550°C, and a higher limiting oxygen index than the neat polyurethane.
SDGs
Type
journal article