Flame retardance, polyvinylchloride

M. Brebu, T. Bhaskar, K. Murai, A. Muto, Y. Sakata, and M.A. Uddin, The individual and cumulative effect of brominated flame retardant and polyvinylchloride (pvc) on thermal degradation of acrylonitrile-butadiene-styrene (ABS) copolymer, Chemosphere, 56(5) 433 440, August 2004. 

Several organizations have initiated projects to investigate and compare the choices of flame-retardant laminates for PWB. These projects include the predominant flame-retardant used in FR-4 PWB, tetrabromobisphenol A (TBBPA). Some of these projects also address all brominated flame-retardants and polyvinylchloride (PVC) usage in all components of electronics. Projects include the following ... 

The synthesis as well as the recycling and disposal of halogenated compounds such as Polyvinylchloride (PVC), flame retardants (for example Tetrabromobisphenol A), y-Hexachlorocydohexane (y-HCH), Hexachlorobenzene (HCB) leads to the formation of byproducts and residues. Polymers, for example, as well as printed circuit boards or shredder residues include problematic substances which, for ecological reasons, cannot be passed on to the environment but have to be supplied to a specific and proper recycling or disposal process. Prior to this background so called "Supercritical Fluids" are of special interest. Supercritical fluids can be used for the synthesis of polymers in an enviromentally friendly way as well as for recycling and disposal processes. 

MAJOR USES Used in the manufacture of carbon tetrachloride, trichloroethylene, chlorinated hydrocarbons, polychloroprene, polyvinylchloride, hydrogen chloride, hypochlorous acid, ethylene dichloride, metallic chlorides, chlorobenzene, chloroacetic acid, chlorinated lime, chloroform Used in the manufacturing process of water purification, flame retardant compounds, paper products, textiles, petroleum products, medicines, antiseptics, insecticides, solvents, paints, plastics, disinfectants, synthetic rubber. 

Polyvinylchloride is very popular in flame resistant applications because of its intrinsic protection due to its high content of chlorine (57%). At the same time, PVC is a rigid material and requires plasticizers to produce flexible articles. Addition of plasticizers reduces chlorine content and some form of enhancement of flame retardancy is required. Chloroparaffins were commonly used as secondary plasticizers due to their very high chlorine content (up to 70%) but some chloroparaffins are now on the hsts of restricted... 

Representatives of various industries [17] have examined some smoke depressants and flame retardant resins introduced by various US Companies in relation to US legislation. These include smoke suppressed polyvinylchloride (PVC) (BE Goodrich) and polyurethane (PU) foams (Mobay Chemical), and smoke suppressant additives from Climax Molybdenum, and Sherwin-Williams (molybdenum compounds), Solem Industries, and Alcoa Chemicals (aluminium trihydrates, for polypropylene (PP) and PVC), Dover Chemical Corp., (aromatic bromine compound for PP), and US Borax (zinc borate). 

Various workers have discussed the fire retardancy of polyvinylchloride (PVC) [55-59] using ammonium treated clay montmorillonite nanocomposites [52], hydroxyapatite nanocomposites [56] and antimony trioxide [57]. Lum [60] examined the effect of flame retardant additives on polymer pyrolysis reactions with a PVC composition containing 3 phr of SbiOs. It is well known that a synergistic flame retardancy effect is observed when SbiOs is incorporated into organic halide materials such as PVC. 

---