¹³C, ²⁵Mg and ¹¹B solid‐state NMR study of a fire retarded ethylene‐vinyl acetate copolymer

Abstract

Flame retardance of ethylene‐vinyl acetate copolymer (EVA) can be achieved using magnesium hydroxide (Mg(OH)2) incorporated in the polymeric matrix. The adduct of small amount of zinc borate as synergistic agent in the formulation increases the fire‐proofing properties. Multinuclei solid‐state NMR appears as a powerful means to characterise materials before and after combustion. We show that endothermic dehydration, water vapour evolved and formation of a glassy coating provide the flame retardancy of interest to the polymeric matrix.

Intumescent ethylene-vinyl acetate copolymer: Reaction to fire and mechanistic aspects

“…The band assigned to CH is detected at 72 ppm [20]. The chemical shift at 170 ppm corresponding to C=O in the acetate group is not observed (except a tiny band for EVA-AP760, (Fig.…”

“…The non-degraded materials (t 0 ) with and without ZnCO 3 show the same 13 C NMR spectra. The resonance band at 21 ppm corresponds to the CH 3 -group of the acetic acid functionality of EVA [20]. The bands at 25, 30 and 35 ppm are attributed to the CH 2 -groups in the polymer backbone [21].…”

Recent Advances in Solid-State 25Mg NMR Spectroscopy

“…39 25 Mg NMR has been used to investigate the role of Mg(OH) 2 as a fire retardant in ethylene-vinyl acetate copolymers. 147 The very significant change in the lineshape indicated that on combustion a glassy phase was formed that was the source of the retarding action. 25 Mg NMR has been used to study the thermal decomposition of Mg(OH) 2 to MgO.…”

The fire retardant mechanism of ethylene vinyl acetate elastomer (EVM) containing aluminium trihydroxide and melamine phosphate

“…The spectrum corresponds to the data reported already in the literature for pure EVM. 17,[26][27][28][29][30] The peak at 20.8 ppm corresponds to the CH 3group of the acetic acid functionality of the polymer. 28 Those at 25.1, 29.8 and 34.5 ppm are attributed to the CH 2 -groups in the polymer backbone.…”

“…17,[26][27][28][29][30] The peak at 20.8 ppm corresponds to the CH 3group of the acetic acid functionality of the polymer. 28 Those at 25.1, 29.8 and 34.5 ppm are attributed to the CH 2 -groups in the polymer backbone. 27,31 The multiplicity of the peaks is due to the fact that when the VA monomer copolymerizes with ethylene, a random copolymer is obtained leading to several different monomer sequences in the chain.…”