Thermal Stability and Flame Retardation

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. 

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. 

Their general thermal stability and flame retardancy have been recently reviewed.52... 

Flame-retardant epoxy resins with different silicon contents were prepared using silicon-containing epoxides or silicon-containing prepolymers. The thermal stability and flame-retardant properties of the produced epoxide systems were evaluated and related to the silicon content. The char yields under nitrogen and air atmospheres increased with increase in silicon content. The authors pointed out that the silicon-containing resin has improved flame retardancy over the silicon-free resin as evidenced by the LOI. LOI values increased from 24 for a standard commercial resin to 36 for silicon-containing resins.35... 

Zhu, J., Start, R, Mauritz, K. A., and Wilkie, C. A. Thermal stability and flame retardancy of poly(methyl methacrylate)-clay nanocomposites, Polym. Degrad. Stab. (2002), 77, 253-258. 

L. Haurie, A.I. Fernandez, J.I. Velasco, J.M. Chimenos, J.M. Lopez-Cuesta, and F. Espiell, Thermal stability and flame retardancy of LDPE/EVA blends filled with synthetic hydromagnesite/aluminium hydroxide/aluminium hydroxide/ montmorillonite mixtures, Polym. Degrad. Stabil., 2007, 92 1082-1087. 

A. Laachachi, M. Cochez, E. Leroy, P. Gaudon, M. Ferriol, and J.M. Lopez-Cuesta, Effect of A1203 and Ti02 nano-particles and APP on thermal stability and flame retardance of PMMA, Polym. Adv. Technol. 2006, 17 327-334. 

Among inorganic heterocycles, perhalogenated cyclic phosphazenes occupy a very prominent place as the precursors for polyphosphazenes whose properties can he tuned by changing the substituents on the phosphorus sites (J). The heterocycles, as such, provide a robust framework for building a variety of novel molecules that have high thermal stability and flame retardancy, and have also been used recently to prepare a variety of dendrimers (2). The most widely studied among these are the perchlorinated cyclophosphazenes. Their syntheses reactions, properties, and application potential have been well documented a, 3-7). 

Aromatic polysulfones are a commercially important class of thermoplastic polymers [127]. They have highly desirable qualities such as chemical inertness, thermal stability, and flame retardency [128,129]. Although a number of methods are available for the synthesis of polysulfones [130,131,132], step polymerization methods are the most widely used industrially [127]. Polysulfones have been synthesized with the involvement of sulfonylium cations as propagating species. 

Vothi, H., Nguyen, C., Lee, K., Kim, J. Thermal stability and flame retardancy of novel phloroglucinol based organo phoshorous compoimd. Polym. Degrad. Stab. 95, 1092 (2010)... 

Imide-Modified Isocyanurate Foams. The imide linkage is a thermally stable linkage, and therefore, imide-modified isocyanurate foams have higher thermal stability and flame retardance than urethane-modified isocyanurate foams. R. Grieve (114) prepared such foams in a one-shot process by reacting a polycarboxylic acid anhydride with an organic polyisocyanate in the presence of a catalytic amount of a monomeric homocyclic polyepoxide and a tertiary amine. 

Some three decades ago, scientists from the Du Pont company developed polycondensation methods which allowed the preparation of high molecular weight wholly aromatic polyamides. The first commercially produced wholly aromatic polyamide fibre was poly(m-phenyleneisophthalamide) (Nomex, Du Pont, 1967) [la, c]. Some years later, development of the preparation and processing of poly(p-phenyleneterephthalamide) (PPTA) led to the commercialization of the para product Kevlar (Du Pont) in the early seventies [lb, c]. While Nomex shows excellent thermal stability and flame-retardance, and indeed is referred to as a heat and flame resistant aramid fibre, Kevlar fibre also has similar properties, but in addition it has exceptional tensile strength and modulus, and is referred to as an ultra-high strength, high modulus aramid fibre. 

D. K. Chattopadhyay and D. C. Webster, Thermal stability and flame retardancy of polyurethanes , Prog Polym Sci, 2009,34,1068-133. 

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 addition of unmodified MWCNTs has a negative effect on thermal stability of the epoxy nanocomposites. This is due to the poor affinity between as-received MWCNTs and epoxy resin matrix, which increases vacancies or voids in the nanocomposite. However, the addition of amine-modified MWCNTs enhances the values of the first and second decomposition temperatures, which indicates the thermal stability improvement of the nanocomposite. The reason may be attributed to the fact that amine-modified MWCNTs have a better affinity for the polymer matrix than unmodified MWCNTs. Similar results are reports from Yang and Gu [51] using modified MWCNTs. TGA analysis indicates the thermal stabiUly improvement of the epoxy/MWCNTs nanocomposite. The reason may be due to the fact that triethylenetetramine TETA-grafted MWCNTs possess a good affinity to the epoxy matrix. The incorporation of functionalized CNTs into resin promoted the thermal stability and flame retardancy of the epoxy. 

Epoxy group functionalized polyphenylsilsesquioxane oligomers were used for modification of phenol-formaldehyde oligomer (novolac resin -SF-0112) for increasing their flexibility, their hydrophobic surface properties, thermal stability and flame-retardant properties. Novolac resin - SF-0112 contains a little amount of free phenols (0.9%) compared with other phenol-formaldehyde oligomers. 

Properties affected Stiffness, hardness, shrinkage/dimensional stability thermal stability and flame retardancy may also be improved. 

Ma C M, Lee C and Wu H (1998), Mechanical properties, thermal stability, and flame retardance of pultruded fiber-reinforced poly(ethylene oxide)-toughened novolak-type phenolic resin , J Appl Polym Sci, 69, 1129-1136. 

PCT displays a high deflection temperature (HDT) consistent with its high melting point which enables it to be used in glass-fiber reinforced formulations resistant to elevated temperatures. Usual formulations for injection molding contain 30-40 % of glass fiber as well as other additives, such as low molecular weight aliphatic polyesters, in order to increase the crystalizability of PCT. In some applications, thermal stabilizers and flame retardant bromide and antimony aromatic derivatives are also added (14,118). 

Due to the ongoing miniaturization trend of electronic devices and for meeting some critical application requirements, several techniques and approaches for improving the thermal stability and flame retardancy of the epoxy resins have been employed. Actually, all the modern-day electronic devices contain at least one printed wired board to support... 

The use of bifunctional protonated titanium-containing aminopropylisobutyl POSS (Ti-NH3POSS) to intercalate synthetic sodium saponite leads to significant thermal stabilization of PS nanocomposites [30] (Table 3.1). The catalytic activity of the Ti centers leads to the formation of stable charring products by secondary reactions. This causes significant improvement of the thermal stability and flame retardancy of the nanocomposite. 

Nylons are often used in electrical products, such as electrical connectors, terminal blocks, smah electrical housings, switch components, wire ties, and other industrial parts, where thermal stability and fire resistance are priorities. Because of this practical interest, the thermal stability and flame retardancy of nylons have been studied extensively. Halogen compounds are effective flame retardants for polyamides [14-17], but they have limited utility because their combustion products are toxic. Alternative flame retardants are used with polyamides, such as phosphorus- and nitrogen-containing substances. The most important organic nitrogen-containing flame retardants are melamine and its derivates [14, 18-20]. However, these traditional flame retardants are outside the scope of this chapter. 

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