Flame retardance stabilization, polymer

Bagdanova, V. V. Fedeev, S. S. Lesnikovic, A. I. Klimovtsova, I. A. Sviridov, V. V. The formation of antimony oxychloride in flame retardant mixtures and its influence on flame retardant efficiency, Polymer Degradation and Stability, 1985, 11, 205-210. 

Anna, P., Marosi, Gy., Csontos, I., Bourbigot, S., Le Bras, M., and Delobel, R. 2001. Influence of modified rheology on the efficiency of intumescent flame retardant systems. Polymer Degradation and Stability 74(3) 423M-26. 

S. Zhang, A.R. Horrocks, T.R. Hull, and B.K. Kandola, Flammability, degradation and structural characterization of fiber-forming polypropylene containing nanoclay-flame retardant combinations, Polym. Degrad. Stabil., 2006, 91 719-725. 

Applications In 1994 about half of the Phosphorus(III) chloride consumed in the USA was utilized in the manufacture of the intermediate phosphorous acid, a further 19.4% to phosphorus(V) oxychloride. Di and trialkylphosphonates, triarylphosphonate, pho.sphorus(V) sulfochloride and phosphorus(V) chloride are also manufactured directly from pho.sphorus(III) chloride. Broken down according to the field of application of the end products, the consumption of phosphorus(IIl) chloride is the USA in 1994 53.6% was utilized for pesticide production (mainly for glyphosphate), 18% for the manufacture of water treatment chemicals (phosphonic acids) and tensides (acid chlorides of fatty acids and secondary products), 17.1% in the manufacture of polymer additives (flame retardants, stabilizers etc.) as well as small quantities for the production of hydraulic fluids, lubricants and additives for lubricating oils. 

Zhu, S. and Shi, W. Flame retardant mechanism of hyperbranched polyurethane acrylates used for UV curable flame retardant coatings. Polymer Degradation and Stability, 75, 543-547 (2001). 

Lin and co-workers [51] observed that cnring phenolic resins with epoxies instead of with hexamethylene tetramine yields polymers which have almost the same flame retardance as polymers produced with hexamethylene tetramine curing. They also have toughness, stiffness, good thermal stability, excellent flame retardance and low glass transition temperature (Tg). 

The influence of phosphorus incorporated through a reactive approach on the flame retardancy of polymers is reviewed in Chapter 12 by Sonnier et al. It is notably demonstrated that phosphorus has an influence on the degradation pathway of the polymer and hence its thermal stability and charring. 

Although the polyhalophosphazenes have potentially useful physical and mechanical properties, their chemical reactivity and hydrolytic instability rule out their practical use. Luckily, however, an important aspect of the phosphazene polymer system is the relative ease with which the properties can be modified by the introduction of different side groups. Useful properties of such organopoly-phosphazenes include resistance to water, solvents, oils, and so on non-inflanunability and flame retardancy stability to visible and ultraviolet radiation high thermal stability (>200 C) and low-temperature flexibility and elasticity. 

Low melting temperature phases (glasses) have long been considered as flame-retardant polymer additives. Low melting temperature glasses can improve the thermal stability and flame retardance of polymers by... 

The SEM image of the residue of the PP/Ceo sample showed that Ceo crystals only aggregated rather than forming a compact and continuous network. Thus, it was not the char residue that was responsible for the enhanced thermal stability and improved flame retardancy of PP/Ceo nanocomposites. Because the char residue could not confer flame retardancy on polymers, possible reasons may be concealed in the primary state or in the heating or combustion of polymer materials. 

Because of their unique layered structure and highly tunable chemical composition based on different metal species and interlayer anions, LDHs have many interesting properties, such as unique anion-exchanging ability, easy synthesis, high bond water content, memory effect, nontoxicity, and biocompatibility. Based on these properties, LDHs are considered as very important layered crystals with potential applications in catalysis [6], controlled drugs release [7], gene therapy [8], improvement of heat stability and flame retardancy of polymer composites [9], controlled release or adsorption of pesticides [10], and preparation of novel hybrid materials for specific applications, such as visible luminescence [11], UV/photo stabilization [12], magnetic nanoparticle synthesis [13], or wastewater treatment [14]. 

Q. Wu and B. J. Qu, Synergistic effects of silicotungistic acid on intumescent flame-retardant polypropylene. Polymer Degradation and Stability, 74 (2001), 255-61. 

DPPES was grafted onto the surface of GNO by condensation to form a synergistic phosphorus/silicon-containing GNO flame retardant (DPPES-GNO). A series of nanocomposites that contained 0,1,5, and 10 wt% DPPES-GNO was prepared. XPS, FTIR, Raman spectroscopy, and TEM verified that DPPES covalently bonded to GNO. Furthermore, the addition of DPPES-GNO (up to 10 wt%) to neat epoxy significantly increased its thermal stability and improved the char yield and LOI by 42% and 80%, respectively. The phosphorus, silicon, and GNO layer stmctures of DPPES-GNO caused the continuous and insulating char layer to protect the inner polymer matrix. The approach that is described herein has great potential for the development of a novel synergistic phosphorus/silicon—GNO flame retardant with polymer nanocomposite applications. 

An excellent review of the work on the flame retardancy of polymer nanocomposites was published in 2007 [3]. This chapter will focus on the evaluation of the proposed mechanisms for enhanced thermal stability of polymer-clay nanocomposites, the proposed relationships between enhanced thermal stability of polymer-clay nanocomposites and flame retardancy, and the synergies that develop between traditional flame retardants for polymers and polymer-clay nanocomposites. 

The full complement of commercially available polymer types has been evaluated for flame retardancy as polymer-clay nanocomposites by cone calorimetry [3]. The type of polymer is a significant independent variable as regards the flame-retardant behavior of the polymer-clay nanocomposite. All of the significant independent variables that were discussed above that relate to thermal stability of the polymer-clay nanocomposites are applicable to flame-retardant behavior. 

These variables that relate to increased thermal stability of the polymer in polymer-clay nanocomposites extrapolate directly to improved flame retardancy of polymer-clay nanocomposites. The improvement in flame retardancy provided by polymer-clay nanocomposites does not completely satisfy the criteria found in the definitions for traditional commercial flame retardants. Lower ignition temperatures, no change in the total heat release, and no change in total mass loss as measured by cone calorimetry of the polymer-clay nanocomposites when compared to the pure polymer prevent the classification of clay in polymer-clay nanocomposites as a flame retardant. Flame-retardant synergies between commercial flame retardants and polymer-clay nanocomposites have mitigated some of the flame-retardant deficiencies of the polymer-clay nanocomposites and allow for their commercial introduction into products. 

Because of the multifaceted features of clay as a nanoparticle, the benefits in polymer-clay nanocomposites range from increased mechanical performance, barrier performance, and thermal stability. A systems approach to the design of polymer-clay nanocomposites with excellent flame retardancy will provide superior solutions in relation to formulating existing flame retardants with polymer-clay nanocomposites. Providing surface modifications for the clay with higher thermal stability that will not compromise the mechanical and barrier performance of... 

Based on these properties, LDHs are considered as very important layered crystals with potential applications in catalysis,controlled drugs release, gene therapy, improvement of heat stability and flame retardancy of polymer composites,controlled release or adsorption of pesticides, preparation of novel hybrid materials for specific applications, such as visible lumines-cence, UV/photo-stabilization, and magnetic nanoparticle synthesis and wastewater treatment. ... 

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. 

Noryl. Noryl engineering thermoplastics are polymer blends formed by melt-blending DMPPO and HIPS or other polymers such as nylon with proprietary stabilizers, flame retardants, impact modifiers, and other additives (69). Because the mbber characteristics that are required for optimum performance in DMPPO—polystyrene blends are not the same as for polystyrene alone, most of the HIPS that is used in DMPPO blends is designed specifically for this use (70). Noryl is produced as sheet and for vacuum forming, but by far the greatest use is in pellets for injection mol ding. 

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. 

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