Polyamides, phosphorus containing

Phenothiophosphine ring-containing polyamides and polyesters were also prepared by the polycondensation of 2,8-bischloroformyl-lO-phenylphenothiophos-phine 5,5, 10-trioxide with aromatic diamines such as 4,4 -diaminodiphenyl ether and 4,4 -diaminodiphenyl-methane, and bisphenols such as 4,4 -dihydroxybiphe-nyl and 4,4 -dihydroxydiphenylmethane, respectively [159]. These polymers are soluble in polar aprotic solvents and also exhibit good heat and fire resistance. Phosphorus containing high performance polymers are shown in Table 6. 

Padbury, S.A., Horrocks, A.R., and Kandola, B.K. 2003. The effect of phosphorus-containing flame retardants and nanoclay on the burning behaviour of polyamides 6 and 6.6. Proceedings of the 14th Conference Advances in Flame Retardant Polymers, Stamford, Norwalk, CT Business Communications 2003. 

Oligomer 163 represents a stabilizer having PA chain with pendant phenolic moiety [31], Pendant hindered piperidine or piperazine moieties were attached to oligomeric stabilizers having polysulfonamide, polyurea (e.g. 164), or PA (e.g. 165) unis [213]. Polyhydrazide 166 was tested as HD AO and copper deactivator in PP [214]. Poly (nitrophenylene-carbazide disulfide) 167 was prepared for thermal stabilization of PVC. Phosphorus containing crosslinkable polymers having polyamide, polyimide and polyurea chains were prepared for flame and heat resistant applications [215]. 

A HALS-based additive system has been developed by Clariant based on salt-like reaction products of HALS with phosphorus-containing organic acids [199] or carboxylic acids [200]. Despite their salt-like character, these additives are said to stabilise in the normal HALS manner, and additionally provide improved processing, mechanical properties and appearance. They are specifically aimed at polyesters and polyamides. An example of one of these compounds is the... 

As previously noted (Introduction) a number of metal-containing polyesters have been synthesized employing organometallic dihalides and salts of dicarboxylic acids. Further the synthesis of phosphorus-containing polyesters and polyamides has also been accomplished (for instance 11-15). Previous attempts by our group to synthesize the analogous phosphorus anhydrides failed. 

Several classes of P- and N-containing polymers have been reported in literature. These include polybenzimidazoles, polyester-imides, polyamide-imide, polyanhydride-imides, polyurethanes, polyamides, and polymaleimide-amines. Heretofore, phosphorus-containing bisimide resins have received little attention. Bisimide monomers, which cure by addition-type polymerization without the elimination of volatile products, are suitable as matrix resins for fabrication of graphite-fabric reinforced composite materials. 

The action of inhibitors phenol derivatives,aromatic amines, sulfur-and phosphorus-containing compounds was studied in conjunction with polyamide. 

Part 2 includes chapters on specific classes of cyclic monomers and their polymerization mechanisms and kinetics, their main (co)polymer architectures and related products, as well as current and future applications. Hence, siloxane-con-taining and sulfur-nitrogen-phosphorus-containing polymers are described in Chapters 3 and 4, respectively, while the polymerization of cyclic depsipeptides, ureas and urethanes, of polyethers and polyoxazolines, and of polyamides are detailed in Chapters 5, 6 and 7, respectively. Chapters 9, 10, 11 and 12 include details of polyesters prepared from either P-lactones, from dilactones, from larger lactones and from polycarbonates, while the polymerization of cycloalkanes is described in Chapter 13. It should be noted that, slightly out of place . Chapter 8 covers the subject of ring-opening metathesis polymerizahon. 

The red allotropic form of phosphorus is relatively nontoxic and, unlike white phosphorus, is not spontaneously flammable. Red phosphorus is, however, easily ignited. It is a polymeric form of phosphorus, thermally stable up to ca. 450°C. In its finally divided form, it has proved to be a powerful flame-retardant additive.18 Elemental red phosphorus is a highly efficient flame retardant, especially for oxygen-containing polymers such as polycarbonates and polyethylene terephthalate). Red phosphorus is particularly useful in glass-filled polyamide 6,6, where high processing temperature (about 280°C) excludes the use of most phosphorus compounds.19 In addition, coated red phosphorus is used to flame retard nylon electrical parts, mainly in Europe and Asia.20... 

Using this method, a number of poly-isophthalamides with trifunctional monomers [18] or poly-trimethyl and fert-butylhydroquinone aromatic polyamides can be prepared [19]. Another interesting example of the use of Yamasaki s reaction is the preparation of organosolu-ble aromatic polyamides containing phosphorus [20] or the preparation of polyamides with a diamantane moiety embedded in the structure of the principal chain [21]. 

Zinc borate can be used as a fire retardant in PVC, polyolefins, elastomers, polyamides, and epoxy resins. In hal( en-containing systems, it is used in conjunction with antimony oxide, while in halogen-free systems it is normally used in conjunction with other FRs such as aluminum trihydrate, magnesium hydroxide, or red phosphorus. In a small number of specific applications, zinc borate can be used alone. 

With halogen-containing systems, zinc borate can partially or completely replace the antimony synergist in PVC, notably wire and cable, wallcoverings, roof membranes and tarpaulins. It is also effective in polyolefins, elastomers, polyamides and epoxy polymers while, in halogen-free systems, it can be used in conjunction with alumina trihydrate, magnesium hydroxide or red phosphorus. 

Phosphorus compounds may bond various impurities contained in the polyamides, which might catalyze the process of polyamide destruction at high temperatures [39]. 

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. 

Gonoshilov, D. G., Keibal, N. A., Bondarenko, S. N., Kablov, V. F. (2010). Phosphorus Boron Containing Fire Retardant Compounds for Polyamide Fibers Proceedings of the 16th International Scientific and Practical Conference Rubber industry Raw materials. Manufactured materials. Technologies, Moscow, 160-162. 

Red phosphorus is the most concentrated source of phosphorus for flame retardancy. In fact, it is very effective in some polymers, such as thermoplastic polyesters or polyamides, where self-extinguishing UL-94 V-0 performance can be achieved at loadings of less than 10 wt%. Despite the apparent chemical simplicity of this additive, its mechanism of action is not completely understood. Most researchers agree" ° that in oxygen- or nitrogen-containing polymers, red phosphorus reacts with the polymer and induces char formation. Although there is a belief that red phosphorus is oxidized and hydrolyzed by water before it... 

In the work of Liu and Tsai, TG thermograms revealed that all the aromatic polyamides with bulky cyclic groups containing phosphorus began to degrade at about 310 "G [a.341]. The decomposition temperatures of the polymers at 10% weight loss were 340-390 "C as shown on Table 8. 

---