Linking the flame‐retardant mechanisms of an ethylene‐acrylate copolymer, chalk and silicone elastomer system with its intumescent behaviour

Abstract

SUMMARYIn this paper the flame-retardant mechanisms of a flame-retardant system consisting of ethylene-acrylate copolymer, chalk and silicone elastomer are linked to its foaming process and to its formation of a final intumescent structure. Thermocouples were placed inside and at the surface of cone calorimeter test specimens in order to measure the temperature at different depths during the formation of the intumescent structure. The temperature and visual observations of the foaming process were then linked to chemical reactions seen with thermogravimetric analysis and also coupled with earlier knowledge of the flameretardant mechanism.A correlation is seen between the chemical reactions, the temperature (inside and at the surface of a cone calorimeter test specimen) as measured by thermocouples and visual observations in the intumescent process. Further, the outcome of this study provides useful information for achieving a deeper understanding of the flame-retardant mechanisms of the ethylene-acrylate copolymer, chalk and silicone elastomer system.

Enhanced fire behavior of Casico-based foams

“…As was previously reported [4,5], calcium silicate is formed through a sintering reaction between CaO and SiO 2 . Since the amount of CaO is higher than SiO 2 , CaO is also present in the final residue.…”

“…The following two weight loss stages (step 2 and step 3, see Table 4) occurred in all formulations and are typical of unfoamed Casico [4,5]: between 300 and 500 ºC, the higher weight loss stage (step 2) was registered and related to ethylene copolymer pyrolysis with the formation of butene and carboxylic acid groups:…”

“…Polymeric formulations based on ethylene acrylate copolymer-silicon-chalk have been developed in the last two decades as an alternative to the halogenated and high load magnesium hydroxide composites for cable insulation and jacket production [4][5][6][7][8].…”

Flame Retardants: Overview

“…Polymer nanocomposites, where the polymer is combined with nanoscale spheres, rods, or plates, form a new material that is predominantly interfacial polymer throughout the material (62)(63)(64). They provide a variety of benefits over traditional composites including enhanced mechanical, thermal, electrical, and fire properties (61)(62)(63)65). This last property enhancement, fire performance, has been noted in just about every type of nanocomposite produced to date, with a few minor exceptions (64,66).…”

“…Notable examples include oragnosilicones in polycarbonate and the calcium silicon carbonate (CASICO) system used in wire and cable materials (26,27,(59)(60)(61).…”