Polymers halogen-free

For specific polymers, halogen-free and phosphorus-free plasticizers can reduce the oxygen index. The transparency can be altered if the compatibility is low and/or the refractive index is inadequate. 

PMVEMA, supphed as a white, fluffy powder, is soluble in ketones, esters, pyridine, lactams, and aldehydes, and insoluble in aUphatic, aromatic, or halogenated hydrocarbons, as well as in ethyl ether and nitroparaffins. When the copolymer dissolves in water or alcohols, the anhydride group is cleaved, forming the polymers in free acid form or the half-esters of the corresponding alcohol, respectively. Table 7 illustrates the commercially available alternating copolymers and derivatives. 

Use of higher-performance polymers may suppress the demand for FRs in business machines. Flame retardancy has recently been reviewed [39], as well as the technology of halogen-free FR additives [44]. The future technology of polymer flame retardancy has been described [45]. 

This material finds use as a sealing material in automotive applications and marine motor lead wire insulation. It has also been used as the base polymer for low flammability, halogen free, cable jacketing compounds. 

In halogen-free polymers, the zinc borate in combination with ATH at high loadings can also function as a flame retardant and smoke suppressant by releasing water and forming a porous ceramic residue, which acts as a thermal insulator. 

In general, tin compounds do not exhibit flame-retardant properties in halogen-free polymer systems, unless the composition contains a high inorganic filler loading. However, tin additives often act as smoke suppressants in non-halogenated polymers. 

Patent Number US 5554661 A 19960910 CLOSED CELL, LOW DENSITY ETHYLENIC POLYMER FOAM PRODUCED WITH INORGANIC HALOGEN-FREE BLOWING AGENTS... 

B. Perret and B. Schartel, The effect of different impact modifiers in halogen-free flame retarded polycarbonate blends - ii. fire behaviour, Polym. Degrad. Stab., In Press, Corrected Proof, 2009. 

Levchik, S. V., Levchik, G. F., Balanovich, A. I., Camino, G., and Costa, L., Mechanistic study of combustion performance and thermal decomposition behaviour of Nylon 6 with added halogen-free fire retardants, Polym. Degrad. Stab., 1996, 54, 217-222. 

Lu, S. and Hamerton, I., Recent developments in the chemistry of halogen-free flame retardant polymers, Prog. Polym. Sci. 2002, 27, 1661. 

There has been a great recent market demand for halogen-free fire-retardant polymers. Zinc borates are also multifunctional fire retardants in halogen-free polymers. They can promote char formation, reduce the Rate of Heat Release, smoke evolution, carbon monoxide generation, and afterglow combustion. When used in conjunction with metal hydroxides, they can also display synergy in fire test performance. 

The market demand for halogen-free fire-retardant polymers has been increasing steadily in applications such as electrical/electronics, transportation, and construction products. In wire and cable, the high loadings of ATH or MDH are required (60-70 wt.%). Recent developmental efforts... 

Both ammonium fluoroborate (NH4BF4) and potassium fluoroborate (KBF4) were reported to be flame retardants in both Cl/Br-containing and halogen-free polymers. Ammonium fluoroborate sublimes at 238°C and potassium fluoroborate has a melting point of 359°C. 

Zinc borate in conjunction with ATH or MDH is used in many halogen-free polymers. Based on DTA and DSC analyses, it was also demonstrated that the partial replacement of ATH with Firebrake ZB in cross-linked EVA can delay and reduce the thermal oxidative peak (Figure 9.17). The mode of action of this zinc borate and metal hydroxide is summarized as follows ... 

Qu, B. and Xie, R. 2003. Intumescent char structures and flame-retardant mechanism of expandable graphite-based halogen-free flame-retardant linear low density polyethylene blends. Polymer International 52(9) 1415-1422. 

Xie, R.C. and Qu, BJ. 2001. Synergistic effects of expandable graphite with some halogen-free flame retardants in polyolefin blends. Polymer Degradation and Stability 71(3) 375-380. 

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