Epoxy resin Phosphorus containing

Epoxy Resins, in the combustion of epoxy resins, phosphorus inhibits the evolution of fuel gases and increases char (176). Much attention has been given to phosphorus additives or reactives in epoxy resins used as coatings for the purpose of increased adhesion to surfaces (177,178) and for fire resistance. More recently, a great deal of attention has been given to phosphorus-containing, flame-retarded electrical/electronic laminates and encapsulated electronic parts. 

In a study of dental silicate cements, Kent, Fletcher Wilson (1970) used electron probe analysis to study the fully set material. Their method of sample preparation varied slightly from the general one described above, in that they embedded their set cement in epoxy resin, polished the surface to flatness, and then coated it with a 2-nm carbon layer to provide electrical conductivity. They analysed the various areas of the cement for calcium, silicon, aluminium and phosphorus, and found that the cement comprised a matrix containing phosphorus, aluminium and calcium, but not silicon. The aluminosilicate glass was assumed to develop into a gel which was relatively depleted in calcium. 

In 2000, NEC developed an epoxy resin with what it describes as a fire-retardant structure that avoids the need for either TBBA or phosphorus-based flame retardants in circuit boards. The new resin contains a metal hydroxide retardant. The company claims the new board is almost totally free of pollutants, and is easy to process and thermally recycle. By also integrating flame retardant properties within the board, use of the metal hydroxide is minimised, while offering good electrical properties, higher heat resistance and improved processing characteristics. ... 

Lin, C. H. and Wang, C. S., Novel phosphorus-containing epoxy resins part 1 Synthesis and properties, Polymer, 2001, 42, 1869-1878. 

Horold, S. and Kleiner, H. J., (Clariant GmbH), Phosphorus-containing dicarboxylic reaction product of epoxy resins and phosphorus acid (anhydride) with hardener, U.S. Patent, 1999 5 959 043. 

Lin, C. H., Synthesis of novel phosphorus-containing cyanate esters and their curing reaction with epoxy resin, Polymer, 2004, 45, 7911-7926. 

Perez, R. M., Sandler, J. K. W., Altstaedt, V., Hoffmann, T., Pospiech, D., Artner, J., Ciesielski, M., Doering, M., Balabanovich, A. I., Knoll, U., Braun, U., and Schartel, B., Novel phosphorus-containing hardeners with tailored chemical structures for epoxy resins Synthesis and cured resin properties, J. Appl. Polym. Sci., 2007,105, 2744-2759. 

Ren, H., Sun, J., Wu, B., and Zhou, Q., Synthesis and properties of a phosphorus-containing flame retardant epoxy resin based on bisphenoxy(3-hydroxy) phenyl phosphine oxide, Polym. Degrad. Stab., 2007, 92, 956-961. 

The formation of borophosphate partially explains the good performance when APP and boric acid are mixed together in the epoxy resin. Indeed, in that case good mechanical resistance of the intumescent char is observed as borophosphate is a hard material, which also shows a good thermal stability. As a conclusion, the boron containing compounds provide the good structural properties of the char, whereas the phosphorus ensures the adhesion of the char to the steel. 

Wang CS, Lin CH. Synthesis and properties of phosphorus-containing epoxy resins by novel method. J. Polym. Sci. Part A Polym. Chem. 1999 37 3903-3909. 

Liu YL. Flame-retardant epoxy resins from novel phosphorus-containing novolac. Polymer 2001 42 3445-3454. 

Harold, S. and Schmitz, H.-P., Phosphorus-modified Epoxy Resins Comprising Epoxy Resins and Phosphorus-containing Compounds, U.S. Patent 5,830,973, 1998. 

TABLE 8.1. Conditions for MNP Synthesis by ion impiantation into Poiyvinyiidene Fiuoride (PVF2), Polyimide (PI), Polymethyl-methacryiate (PMMA), Poiymethyimethacryiate with Phosphorus-Containing Fragments (PMMA -1- PF), Polyethylene (PE), Poly(ethyleneterephthalate) (PET), Silicone Polymer (Phenylmethyl-silane Resin with Tin Diethyidicaprilate), Epoxy Polycarbonate (PC), and Polyetherimide (PEI) ... 

Among phosphorus-containing additive flame-retardants, phosphates are mostly applied as secondary plasticizers in formulations of flame-retarded plasticized PVC. Other additive agents are admixed with natural and synthetic rubbers, polyester and epoxy resins, polyurethane foams, polystyrenes and polyethylenes, etc. 

Phosphorus and silicon containing epoxy resins Nil Flame retardant properties evaluated high LOI values indicated that epoxy resins containing hetero atoms are effective flame retardants [22]... 

Epoxy resins modified with polysiloxane containing organophosphorus and epoxide groups Pendant cyclic phosphorus containing groups LOI and cone calorimetry performed to evaluate flame retardancy [26]... 

Isobutyl bis(glycidylpropylether) phosphine oxide has been used as a crosslinking agent for phenolic novolac resin [77] in the production of phosphorus containing novolac-epoxy systems. It was shown that samples containing more than 2% phosphorus content produced a VO material, the industry standard for flame retardancy, bnt phosphorus-free polymers and those containing less than 2% phosphorus were consumed in the first ignition. 

The phosphorus-containing polyacroleine obtained in this way is used as an additive to paints, polyurethanes, and epoxy resins in order to increase their combustion resistance. 

G. Lligadas, J. C. Ronda, M. GaUa and V. Cadiz, Development of novel phosphorus-containing epoxy resins from renewable resources , / Po/ym Sci Part A Polym Chem,2006,44,6111-21. 

Nevertheless, some authors have provided some evidence of a flame inhibition effect of phosphorus. Schartel et al. have measured the EHC of epo y resins in a PCFC i.e. corresponding to complete combustion) and in a cone calorimeter. Epojy resins containing DOPO covalently linked to the network have been studied. All thermosets exhibited the same EHC in a PCFC (approximately 24 kJ g ), but in cone calorimeter tests the composites prepared from the phosphorus-containing resins (with 60 vol% of carbon fibers) exhibited a significantly lower EHC than the composite prepared from the phosphorus-free epoxy resin. In this study, a clear flame inhibition effect was evidenced. 

The major brominated flame retardant used with epoxy resins is TBBA. This is a reactive halogenated intermediate incorporated during resin preparation. However, other bromine containing species plus phosphorus containing monomers or curing agents may be reacted with the main epoxy resin eomponents during polymerisation. The latter may be alkyl or aryl phosphates. The best appear to be phenyl phosphate derivatives. 

A large number of organic phosphorus compounds are available to provide flame retardancy. However, it is known that such additives do not generally provide sufficient protection in epoxy resins. They are not resistant to migration and affect the mechanical properties. As a consequence epoxies are often proteeted by bromine containing types. 

Later work by the same team compared ODOPB and bis(3-dihydroxyphenyl) phenyl phosphate (BHPP) as reactive flame retardants in o-ciesol formaldehyde novolac epoxy resin. Since the ODOPB has a rigid, cyclic side chain sfructure, the resultant phosphorus-containing epoxy resin had a higher Tg, better flame retardancy properties, a higher modulus, and increased thermal... 

Flame Retardants. Flame retardance can be built into the epoxy resin by use of tetrabromobisphenol A or anhydride curing agents containing phosphorus or halogen. It can also be helped by nonreactive additives such as alumina trihydrate or organo-halogens + antimony oxide. 

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. 

Corrosion inhibitors in paints protect metallic surfaces from oxidation. Coating primers are used when there is continuous exposure to corrosive elements, e.g., in marine applications. Examples are coal-tar derivatives, epoxy resins and coal-tar modified epoxies. Primers that inhibit corrosion by anodic or cathodic polarization contain inorganic metallic pigments such as chromates or leads or both. Composite pigments containing calcium oxide, zinc, silica, and oxides of phosphorus and boron can also be used (Mathias 1984). Nowadays, powder paints such as polyester and epoxy powder paints can also be used for corrosion inhibition (Rose and Vance 1997). 

The chain extension of epoxy resins can be conducted with dihydric phenolic resins containing phosphate linkages. Bis(3-hydroxyphenyl) phenyl phosphate can be used as a chain extender for epoxy resins, and can afford a UL-94 V-0 level of flame retardancy with phosphorus content as low as 1.5% after cure (187) however, the glass-transition temperature (Tg) is lowered by the flexible phosphate group. 

Resins with improved flame-retarding properties were obtained from BMI containing phosphorus cured with different kinds of agents (Tsai et al. 2009) or by blending a commercial phenolic epoxy resin containing phosphorous and melamine phenol formaldehyde novolac with various amounts of BMI (Chiang et al. 2013). 

Phosphorus-containing flame retardants can be added to epoxy as additives, or they can be incorporated in an epoxy network by pre-reacting with epoxy resin or by using a phosphorus-based curing agent (Levchik and Weil 2004). 

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