Liang H, Shi WF (2004) Thermal behaviour and degradation mechanism of phosphate di/triacrylate used for UV curable flame-retardant coatings. Polymer Degradation and Stability 84(3), 525-532. [In English]
flame-retardant; phosphate; UV curing; thermodegradation; chromatography-mass spectrometry; polymers; ftir;
Abstract: Tri(acryloyloxyethyl) phosphate (TAEP) and di(acryloyloxyethyl)ethyl phosphate (DAEEP) were synthesized from phosphorus oxychloride and hydroxylethyl acrylate and used as flame retardant multifunctional monomers for UV curable systems. The UV cured TAEP and DAEEP films have limiting oxygen indexes of 36 and 29, respectively. Their thermal behaviours were studied by thermogravimetric analysis, and they show three characteristic degradation temperature regions, attributed to the decomposition of phosphate, thermal pyrolysis of acrylate side chains, and decomposition of unstable structures in char, respectively. This was further demonstrated by in situ Fourier-transform infrared and direct pyrolysis/mass spectrometry measurements, and monitored by inductively coupled plasma-atomic emission spectrometry. As flame-retardant mechanism it is proposed that the degraded products of phosphate form poly(phosphoric acid), which further catalyses the breakage of carbonyl groups to form an intumescent char, preventing the samples from further burning. (C) 2004 Elsevier Ltd. All rights reserved.