A novel polymeric intumescent ﬂame retardant containing phosphorus, nitrogen and sulphur (poly(ditrimethylolphosphono thiourea (PDTPT)) was synthesized, and its chemical structure was characterized by Fourier-transform infrared spectroscopy, ¹Hand ³¹P nuclear magnetic resonance spectroscopy and elemental analysis. The molecular weight and thermal properties of PDTPT were measured by using gel permeation chromatography and thermogravimetric analysis. PDTPT exhibited good thermal stability, char formation and swelling performance. The initial thermal decomposi-tion temperature and quality residual rate at 600°C of PDTPT were 282°C and 48.8%, respectively. When the mass fraction of PDTPT was 25 wt%, the limiting oxygen index-value of the cotton fabric/PDTPT composite was 27, an increase from 18 for the pure cotton fabric. Subsequent thermal analysis and scanning electron microscopy showed that PDTPT addition reduced the initial degradation temperature and the weight loss rate of the cotton fabric by forming a thick and tight carbon layer on its surface.
Volume 43, 2020
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