Synthetic hydromagnesite as flame retardant. Evaluation of the flame behaviour in a polyethylene matrix

Ibarra, Laia Haurie; Fernández, A. Inés; Velasco, José Ignácio; Chimenos, J.M.; Cuesta, José‐Marie Lopez; Espiell, F.

doi:10.1016/j.polymdegradstab.2005.08.009

Cited by 114 publications

(77 citation statements)

References 13 publications

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“…However, the suitability of both synthetic and natural hydromagnesite as a fire retardant for polymers could improve the cost effectiveness of the plan and lead to a future commercial source of hydromagnesite. There has also been interest in the literature [25,[27][28][29][30][31] in synthetic hydromagnesite as a fire retardant.…”

Section: Sources Of Hydromagnesite and Huntitementioning

confidence: 99%

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The thermal decomposition of huntite and hydromagnesite—A review

2010

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Naturally occurring mixtures of hydromagnesite and huntite are important industrial minerals. Their endothermic decomposition over a specific temperature range, releasing water and carbon dioxide, has lead to such mixtures being successfully used as fire retardants, often replacing aluminium hydroxide or magnesium hydroxide. The current understanding of the structure and thermal decomposition mechanism of both minerals and their combination in natural mixtures is reviewed. The crystalline structure of both minerals has been fully characterised. The thermal decomposition of huntite has been characterised and is relatively simple. However, the thermal decomposition mechanism of hydromagnesite is sensitive to many factors including rate of heating and the composition of the atmosphere. The partial pressure of carbon dioxide significantly affects the decomposition mechanism of hydromagnesite causing magnesium carbonate to crystallise and decompose at a higher temperature instead of decomposing directly to magnesium oxide.Keywords: hydromagnesite, huntite, fire, flame, retardant, mineral This review critically examines the sometimes conflicting reports in the published literature. It draws together current knowledge of the structure and thermal decomposition of hydromagnesite and huntite, in order to provide an insight into the thermal behaviour of mixtures of these minerals and to optimise their selection and applications. Industrial use of Mineral Fillers as Fire Retardant AdditivesThe largest group of mineral fire retardants are metal hydroxides. Their endothermic decomposition and associated release of inert gasses or water vapour, above the processing temperature but below the thermal decomposition temperature of polymers suppresses the ignition, while the accumulation of a solid inert residue on the surface of the burning polymer reduces the heat release rate. Aluminium hydroxide (ATH) and magnesium hydroxide are the most widely used [1]. Globally aluminium hydroxide is the highest tonnage fire retardant [2,3]. It decomposes according to the following reaction:The endothermic loss of water resulting from the thermal decomposition of ATH has been variously reported [3][4][5] between 1170 and 1300 Jg Magnesium hydroxide is used less widely than ATH. It decomposes through a similar endothermic mechanism to ATH, giving off water. Mg(OH) 2(s) → MgO (s) + H 2 O (g)The endotherm for this reaction is quoted at values between 1244 to 1450 Jg -1 by various authors [3,[5][6][7]. It starts to decompose at about 300 -330°C giving off water [5]. L.A. Hollingbery, T.R. Hull / Thermochimica Acta 509 (2010) 1-112 Although ATH and magnesium hydroxide are the most well known mineral fire retardants, Rothon [5] has identified a number of minerals (Table 1) that could be of potential benefit in polymers. Each decomposes endothermically with the evolution of either carbon dioxide, water or both. Of these minerals, hydromagnesite is the one that has probably seen most commercial interest. Hydromagnesite is naturally occurring...

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Section: Sources Of Hydromagnesite and Huntitementioning

confidence: 99%

“…More recently Haurie et al [29] studied the use of synthetic hydromagnesite with the following chemical formula:…”

Section: Comparison Of Synthetic Hydromagnesite With Naturally Occurrmentioning

confidence: 99%

The thermal decomposition of huntite and hydromagnesite—A review

2010

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“…Haurie [62] has also looked at magnesium hydroxide, synthetic hydromagnesite and natural hydromagnesite/huntite blends, each in a 50/50 mix with ATH. This work was done in a 75/25 LDPE/EVA blend.…”

Section: Fire Retardant Behaviour Of Hydromagnesite / Huntite Blends mentioning

confidence: 99%

“…It is stated that "since hydromagnesite has a release temperature of 320 -350°C, we used Mg(OH) 2 as the hydroxide control sample". It has been shown by many authors [24,25,29,33,[35][36][37][38][39]62] that hydromagnesite decomposes over a range of about 220 -550°C. Morgan also states that in his electron micrographs the hydromagnesite particles "can be clearly seen amongst the larger huntite particles".…”

Section: Heat Release Studies By Cone Calorimetrymentioning

confidence: 99%

The fire retardant behaviour of huntite and hydromagnesite – A review

Hollingbery

Hull

2010

Polymer Degradation and Stability

133

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Naturally occurring mixtures of hydromagnesite and huntite have found important industrial use. Their endothermic decomposition over a temperature range similar to that of commonly used polymers and their release of water and carbon dioxide, has led to such mixtures being successfully used as fire retardants. They have replaced aluminium hydroxide and magnesium hydroxide in many applications. The current understanding of the thermal decomposition mechanism of both minerals and their combination in natural mixtures has been reviewed and related to their fire retardant action. Both minerals contribute to the reduction in flammability of polymers although the extent of these interactions has not been fully investigated. However, the fire retardant mechanism of these minerals appears more complicated than either aluminium hydroxide or magnesium hydroxide. This paper critically examines the literature on the fire retardant behaviour of mixtures of hydromagnesite and huntite, providing information of particular use to formulators of fire retardant polymers using these minerals. It also highlights the gaps in understanding of the fire retardant mechanisms of mixtures of hydromagnesite and huntite and areas that require further research.

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“…Crosslinking can be a suitable method for this purpose [24,25]. Using of some other new synthetic fire retardants has also been reported [26,27]. In our previous papers, factors affecting silane grafting and water crosslinking and mechanical and thermal properties of XLPE were investigated [28,29].…”

Section: Introductionmentioning

confidence: 99%

Silane crosslinking of polyethylene: the effects of EVA, ATH and Sb2O3 on properties of the production in continuous grafting of LDPE

Azizi

Barzin²,

Morshedian³

2007

Express Polym. Lett.

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Abstract. In this study, thermal, mechanical and fire retardant properties of silane-crosslinked low-density polyethylene (XLPE) containing ethylene-vinylacetate (EVA) copolymer, alumina trihydrate (ATH) and antimony trioxide (Sb2O3) have been studied. Samples were prepared in a single-screw extruder and the silane type was vinyltrimethoxy silane (VTMOS). Incorporation of ATH and Sb2O3 into polyethylene at sufficiently high loading introduces good fire retardancy expressed by limiting oxygen index (LOI). However, some tensile properties decreased. These limitations could be overcome by silane crosslinking. By incorporation of EVA into XLPE gel content increased and curing time decreased. Differential scanning calorimetric (DSC) analysis indicated the existence of two distinct melting endothermic peaks corresponding to two different crystalline phases. Results from mechanical properties showed that mechanical properties of XLPE/EVA blends improve by increasing EVA content up to 15 wt%.

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Synthetic hydromagnesite as flame retardant. Evaluation of the flame behaviour in a polyethylene matrix

Cited by 114 publications

References 13 publications

The thermal decomposition of huntite and hydromagnesite—A review

The thermal decomposition of huntite and hydromagnesite—A review

The fire retardant behaviour of huntite and hydromagnesite – A review

Silane crosslinking of polyethylene: the effects of EVA, ATH and Sb2O3 on properties of the production in continuous grafting of LDPE

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