Thermal stability flame retardancy

In the case of composites, the surface modification leads to a good dispersion of the inorganic material in polymers matrices and, depending on the nature of the dispersed phase, imparts improved chemical and physical properties such as mechanical properties, UV attenuation, flame retardancy, thermal stability, thermal and electrical conductivity, gas barrier properties, superhydrophobicity, antimicrobial properties, etc. 

RYTON polyphenylene sulfide resins and compounds are engineering thermoplastics developed by Phillips Petroleum Company. Available in both molding and coating grades, these materials feature excellent dimensional stability, inherent flame retardancy, thermal stability, chemical resistance, desirable electrical properties and ease of processing. 

Shukor F, Hassan A, Islam MS, Mokhtar M, Hasan M. Effect of ammoninm polyphosphate on flame retardancy, thermal stability and mechanical properties of alkali treated kenaf fiber filled PLA biocomposites. Mater Des 2014 54 425-9. 

The presence of siloxane along with phosphorus moiety in bifunctional epoxy system exhibited synergism in establishing flame retardancy, thermal stability and mechanical properties. Hence, we extended our investigation to find out the effect of siloxane and phosphorus moiety and POSS... 

K. Antos, J. Sedldf. Influence of brominated flame retardant thermal decomposition products on HALS. Polymer Degradation and Stability 90(1), 188-194 (2005). 

The high degree of crystallization and the thermal stability of the bond between the benzene ring and sulfur are the two properties responsible for the polymer s high melting point, thermal stability, inherent flame retardance, and good chemical resistance. There are no known solvents of poIy(phenyIene sulfide) that can function below 205°C. 

Cblorina.ted Pa.ra.ffins, The term chlotinated paraffins covers a variety of compositions. The prime variables are molecular weight of the starting paraffin and the chlorine content of the final product. Typical products contain from 12—24 carbons and from 40—70 wt % chlorine. Liquid chlotinated paraffins are used as plasticizers (qv) and flame retardants ia paint (qv) and PVC formulations. The soHd materials are used as additive flame retardants ia a variety of thermoplastics. In this use, they are combiaed with antimony oxide which acts as a synergist. Thermal stabilizers, such as those used ia PVC (see vinyl polymers), must be used to overcome the inherent thermal iastabiUty. 

Red Phosphorus. This aHotropic form of phosphoms is relatively nontoxic and, unlike white phosphoms, is not spontaneously flammable. Red phosphoms is, however, easily ignited. It is a polymeric form of phosphoms having thermal stabiUty up to ca 450°C. In finely divided form it has been found to be a powerful flame-retardant additive (26,45—47). In Europe, it has found commercial use ia molded nylon electrical parts ia a coated and stabilized form. Handling hazards and color have deterred broad usage. The development of a series of masterbatches by Albright Wilson should facihtate further use. 

This dicarboxyhc ester is then copolycondensed with the other reactants in PET manufacture to produce a flame-retardant polyester [63745-01-7]. The advantage of this rather unusual phosphinate stmcture is its high thermal and hydrolytic stability. The fabric is probably used mainly for flirnishings in pubhc buildings in Japan. 

Poly(vinyl chloride). PVC is one of the most important and versatile commodity polymers (Table 4). It is inherently flame retardant and chemically resistant and has found numerous and varied appHcations, principally because of its low price and capacity for being modified. Without modification, processibiUty, heat stabiUty, impact strength, and appearance all are poor. Thermal stabilizers, lubricants, plasticizers, impact modifiers, and other additives transform PVC into a very versatile polymer (257,258). 

Minor and potential new uses include flue-gas desulfurization (44,45), silver-cleaning formulations (46), thermal-energy storage (47), cyanide antidote (48), cement additive (49), aluminum-etching solutions (50), removal of nitrogen dioxide from flue gas (51), concrete-set accelerator (52), stabilizer for acrylamide polymers (53), extreme pressure additives for lubricants (54), multiple-use heating pads (55), in soap and shampoo compositions (56), and as a flame retardant in polycarbonate compositions (57). Moreover, precious metals can be recovered from difficult ores using thiosulfates (58). Use of thiosulfates avoids the environmentally hazardous cyanides. 

There is the possibiUty of a chemical reaction between a plastic and a colorant at processing temperatures. Thermal stabiUty of both the polymer and colorant plays an important role. Furthermore, the performance additives that may have been added to the resin such as antioxidants, stabilizers, flame retardants, ultraviolet light absorbers, and fillers must be considered. The suitabiUty of a colorant in a particular resin must be evaluated and tested in the final apphcation after all processing steps to ensure optimum performance. 

Phosphorus containing poly(maleimide-amines) were synthesized from N,N -bisdichloromaleimido-3,3 -diphenyl alkylphosphine oxides and aromatic diamines or piperazine [144]. The polymers prepared from piperazine are soluble in DMF, DM AC, DMSO, etc., but have poor thermal stability and flame retardancy. 

In recent years, many poly(phosphazenes), [RoPN]n, with a variety of substituents at phosphorus have been prepared and they often exhibit useful properties including low temperature flexibility, resistance to chemical attack, flame retardancy, stability to UV radiation, and reasonably high thermal stability. (1,2) Compounds containing biologically, catalytically, or electrically active side groups are also being investigated. (3,4)... 

Recently, several reports of the flame-retardant properties of boron-containing bisphenol-A resins have appeared from Gao and Liu.89 The synthesis of a boron-containing bisphenol-A formaldehyde resin (64 and 65) (Fig. 42) from a mixture of bisphenol-A, formaldehyde, and boric acid, in the mole ratio 1 2.4 0.5, has been reported.893 The kinetics of the thermal degradation and thermal stability of the resins were determined by thermal analysis. The analysis revealed that the resin had higher heat resistance and oxidative resistance than most common phenol-formaldehyde resins. 

Du, M.Gao and Jia, D. (2006) Thermal stability and flame retardant effect of halloysite nanotubules on Poly(propylene). European Polymer Journal, 42, 1362-1369. 

A detailed understanding of the course of a reaction between a polymer and an additive will permit one to use that information to design new flame retardants. The reaction between poly(methyl methacrylate), PMMA, and red phosphorus is described and that information used to determine that CIRh(PPh3)3 should be used as a flame retardant. The results of this investigation are then used to choose the next additive. A recurring theme is the efficacy of cross-linking as a means to impart an increased thermal stability. 

The previous conflicting investigations may now be rationalized. Red phosphorus is known to thermally convert to white phosphorus, which will burn in air. If white phosphorus is formed, a fire is expected and no flame retardant activity will be observed. On the other hand, if the phosphorus reacts with the polymer as in Scheme 1, then thermal stabilization is expected. The efficacy of red phosphorus seems to be closely related to the efficiency of mixing of the additive and the polymer, when they are well-mixed the phosphorus will react with the polymer and lead to flame retardant activity, if the mixing is poor then the phosphorus will be converted to the white allotrope and burning will result. Since all of the work reported herein was carried out in sealed tubes under vacuum, the phosphorus must react and lead to stabilization of the polymer against molecular weight loss and fuel production, i.e. thermal stabilization. 

Three flame retardants were compared in this study, namely, a brominated polycarbonate oligomer (58% bromine), a brominated polystyrene (68% bromine), and a brominated triaryl phosphate ester (60% bromine plus 4% phosphorus). These are described in Table I. Figures 1 and 2 compare the thermal stability of the brominated phosphate with commercial bromine-containing flame retardants by thermogravimetric analysis (TGA) and by differential scanning calorimetry (DSC). The brominated phosphate melts at 110°C and shows a 1% weight loss at 300°C. Brominated polycarbonate and brominated polystyrene are polymeric and are not as volatile at elevated temperatures as the monomeric flame retardants. 

Modified-polyphenylene oxide (or ether) is a blend of high impact polystyrene (PS) and polyphenylene oxide (PPO), plus thermal stabilizers and a triarylphosphate flame retardant. Studies of the mechanism of the flame retardant in modified-polyphenylene oxide have shown some evidence for both solid phase and vapor phase inhibition (4). Indeed, one is always interested to know whether flame retardant action is on the solid or vapor phase. 

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