Flame retardants magnesium hydroxide based,

Other flame retardants and/or smoke suppressants can also be used such as magnesium hydroxide, magnesium carbonate, magnesium-zinc complexes and some tin-zinc compositions. Zinc oxide is a common ingredient in many rubber base formulations used as part of the curing system. At the same time, the action of zinc oxide is similar to that of antimony trioxide, but less effective. 

The traditional flame retardant is based on organobromine compounds together with antimony trioxide as a synergist. Magnesium hydroxide is a good flame retardant due to its high decomposition temperature and smoke suppression properties. It is widely used in thermoplastic materials. However, magnesium hydroxide must be added in portions of some 60% to achieve a reasonable effect. 

J.P. Lv and W.H. Liu, Flame retardancy and mechanical properties of EVA nanocomposites based on magnesium hydroxide nano-particles/microcapsulated red phosphorus, J. Appl. Polym. Sci., 2007, 105 333-340. 

Additive flame-retardants may be more easily incorporated in polyurethane formulation. Several class of compounds have been used to improve flame retardancy of PU foams such compounds are halogen- (very often chloroalkyl-phosphate) or phosphorous-based compounds, although also other substances, like as EG, melamine, aluminum trihydrate and magnesium hydroxide, may be used. 

Special considerations presence of zinc, copper, iron and nickel compounds accelerated dehydrochlorination combination of basic magnesium carbonate and aluminum hydroxide is used as flame retardant and smoke supressant chlorinated polyethylene adsorbs on the surface of titanium dioxide forming a layer 1-20 nm thick depending on the aciii/base interaction parameter of titanium dioxide ... 

Manufacturers of various fillers continue studies on altemative systems. Most antimony oxide used as a fire retardant can be replaced by a combination of zinc borate without the loss of other properties (in some cases improvements are reported). Another option is to use the same filler systems which are used in polyethylene insulated cables and wires. These are based on magnesium hydroxide and aluminum hydroxide. These systems pcrfoim as flame retardants but require a high filler concentration which affects jacket resistance and mechanical performance. Recently, new coated grades have been developed which can be used at up to 65 wt% without the loss of properties or productivity (extrusion rates 2,500 m/min of cable are possible). ... 

The flame-retardant effect of magnesium hydroxide and ATH is based on the endothermic decomposition to magnesium or aluminum oxide, see reactions (11.1) and (11.2). This decomposition effectively acts as a heat sink cooling the surface of the polymer. 

Obviously, ATH cannot be used in thermoplastics other than polyethylene and PVC, and in the respective plastic-based composite materials. A common disadvantage of ATH and MDH (magnesium hydroxide) is that in order to provide a sufficient level of flame retardancy, they have to be used in large amounts, such as 50-65% and not below 40%. 

Fire retardants used in polystyrene (PS) include montmorillonite clay, polytetrafluoro-ethylene (PTFE) [8], bromine-based flame retardants such as brominated bisphenol A [9], brominated phenyl oxide or tetrabromophthalic anhydride, or magnesium hydroxide [10,11]. Sanchez-Olivares and co-workers [12], in their study of the effect of montmorillonite clay on the burning rate of PS and PS-polyethylene terephthalate blends, showed that increased combustion rate accompanied the incorporation of montmorillonite particles in high-impact polystyrene (FlIPS) formulations. 

Intumescents are said to have a key advantage over filler-type non-halogenated flame retardants in that they are effective at lower addition levels than traditional materials. For example, an intumescent based on ammonium polyphosphate will achieve the same level of protection at addition levels of 25 to 35 parts by weight (pbw) as atypical non-halogenated flame retardant, such as alumina trihydrate or magnesium hydroxide, at between 60 and 70 parts by polymer weight. 

In the present chapter, we report some of om study on both raw and surface-modified Grewia optiva fiber-reinforced UPE matrix-based composites, which possess enhanced mechanical and physico-chemical properties when compared with UPE matrix. In addition to the effect of flame retardants, i.e., magnesium hydroxide and zinc borate, on flame resistance, the behavior of resulted Grewia optiva fiber-reinforced composites have also been evaluated and was foimd to be improved. A significant discussion on the work of other researcher s work has also been added in the chapter. 

Synergistic flame retardancy Nanocomposites have been demonstrated to reduce flammability, particularly through lowering peak heat release in cone calorimeter experiments. In combination with conventional flame retardants such as magnesium hydroxide or aluminum trihydrate, several polyolefin-based wire and cable products have been developed that incorporate 5% nanoday to reduce the use of conventional fire retardant agents and to improve physical properties [14, 15]. 

These may present some problems in incorporation into compounds while maintaining the desired physical properties, but a zero-halogen magnesium hydroxide flame-retardant concentrate on a polyolefin base (by Uvtec under the name Safe FR 5000) can easily be dispersed into polyolefin products. It is predispersed to run on existing PVC production equipment and is non-corrosive and non-abrasive to processing equipment. It is halogen free, with low smoke and no acid combustion gas. There is no leaching of the flame-retardant component and it is recyclable and environmentally safe, available in UV-stabilized formulations. 

Fillers may promote char magnesium hydroxide, zinc borate, antimony oxides require high loadings and can degrade mechanical and other properties. Toxicity of antimony-based retardants is a concern. Can be used with other flame retardants synergistically. 

Hassel [103] has compared DSC, TG, thermal evolution analysis, TMA and DMA in evaluating flame retardant textiles based on different polyester fibres. Also the thermoanalytical analysis (DSC, TGA) of a sisal reinforced flame retardant poly-ester/(DBDPO, Sb203) formulation has been described [104]. Larcey et al. [105] have reported use of a simultaneous TG-DSC system (STA) to investigate the suitability of using magnesium hydroxide as a flame retardant and smoke suppressant in PP formulations. 

Since NBR/PVC has basic good flame resistance it may be used in hose and belt applications where this is a requirement. A 70/30 or 50/50 NBR/PVC base elastomer should be selected and use non-black fillers, including alumina trihydrate (e.g.. Hydrated Alumina 983), magnesium hydroxide, and zinc borate (e.g., Firebrake ZB) as flame retardant fillers. Calcium carbonate will assist in reducing smoke emission. In addition a phosphate plasticizer such as Kronitex 100 or chlorinated paraffin like Chlorowax 40 should be used as the only plasticizer types. 

To overcome environmental and health issues flame retardants based on metal hydroxides like magnesium hydroxide and aluminum trihydroxide were developed and used to reduce flammability of polymeric materials. The major drawback of metal hydroxide-type conventional fillers is the high concentration (usually above 50 wt.%) requirements to obtain satisfactory flame-retardant effects. Such high filler loadings consequently... 

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