Curing corrosion

Anhydride curing Corrosive, severe sensitizers Dusts may be sensitizers High toxicity... 

It is fair to say that some of the early reports were ill-founded, and magnified by rumour. There were also categorical reports from some users that molybdenum disulphide, even as free powder or burnished films, positively prevented or cured corrosion problems. These must in most cases have been equally ill-founded, although they provide an interesting parallel with the comments of Cramer in 1764, which were quoted in Chapter 1. 

Uses Epoxy for ambient-cured, corrosion-resist, coatings and powd. coatings additive to reduce meit mix vise, and improve flow and leveling Properties Gardner 1 max. soiid vise. 900-200 cSt (150 C) soften, pt. 84-94 C EEW 575-685... 

Chem. Descrip. Bisphenol A epoxy sol n. resin in rnethyi amyi ketone Uses Epoxy for ambienf-cured, corrosion-resist, coatings and metal primers... 

Uses Epoxy for ambient-cured, corrosion-resist, coatings and metal primers... 

Ahmad, S Ashraf S.M., Riaz. U and Zafar, S. (2008) Development of novel waterborne poly( 1-naphthylamine) / poly (vinylalcohol)-resorcinol formaldehyde-cured corrosion resistant composite coatings. Preg. Org. Coat, 62, 32-39. 

Furfural can be classified as a reactive solvent. It resiniftes in the presence of strong acid the reaction is accelerated by heat. Furfural is an excellent solvent for many organic materials, especially resins and polymers. On catalyzation and curing of such a solution, a hard rigid matrix results, which does not soften on heating and is not affected by most solvents and corrosive chemicals. 

The industrial value of furfuryl alcohol is a consequence of its low viscosity, high reactivity, and the outstanding chemical, mechanical, and thermal properties of its polymers, corrosion resistance, nonburning, low smoke emission, and exceUent char formation. The reactivity profile of furfuryl alcohol and resins is such that final curing can take place at ambient temperature with strong acids or at elevated temperature with latent acids. Major markets for furfuryl alcohol resins include the production of cores and molds for casting metals, corrosion-resistant fiber-reinforced plastics (FRPs), binders for refractories and corrosion-resistant cements and mortars. 

Because the heat distortion temperature of cured epoxy resins (qv) increases with the functionality of the curing agents, pyromellitic dianhydride is used to cross-link epoxy resins for elevated temperature service. The dianhydride may be added as a dispersion of micropulverized powder in liquid epoxy resin or as a glycol adduct (158). Such epoxies may be used as an insulating layer in printed circuit boards to improve heat resistance (159). Other uses include inhibition of corrosion (160,161), hot melt traffic paints (162), azo pigments (163), adhesives (164), and photoresist compounds (165). 

Diamine curatives were the first cross-linking agents for fluorocarbon mbbers. They are corrosive to mild steel molds and have been replaced in many appHcations by the bisphenol or other more recent cure systems. Nevertheless, some diamines are stiU used for food-contact appHcations of fluorocarbon mbbers and in zinc-free cures of halobutyl mbbers for pharmaceutical stoppers. Methylene dianiline and triethylene tetramine are cross-linking agents for ethylene—acryflc elastomers. 

The metallurgy of the cyclone equipment has in recent years focused primarily on type 304 H stainless steel. The 304 H material is durable and easy to fabricate and repair, withstands the high regenerator temperatures, and is oxidation- and corrosion-resistant. Essentially all internal surfaces of the cyclone that are subject to erosion are protected with a 2 cm layer of erosion-resistant lining. When installed and cured, most refractory linings are highly resistant to erosion. 

To improve the weatherabUity of epoxies, which normally chalk and yeUow, epoxy—polyester aUoys or hybrids are used. These powders with improved overbake resistance cure at temperatures as low as 130°C. They have film flexibiHty similar to epoxy resins, but their hardness is slightly decreased. Corrosion resistance is equivalent to epoxy powders in most cases, although solvent and alkaH resistance is inferior. 

It is claimed that the cured materials may be used continuously in air up to 300°C and in oxygen-free environments to 400°C. The materials are of interest as heat- and corrosion-resistant coatings, for example in geothermal wells, high-temperature sodium and lithium batteries and high-temperature polymer- and metal-processing equipment. 

Complexes of boron trifluoride and amines such as monoethylamine are of interest because of the very long pot lives possible. The disadvantages of these complexes are their hygroscopic nature and the corrosive effects of BF3 liberated during cure. 

Aliphatic and cycloaliphatic amine curing agents irritants, sensitizers, corrosive, absorbed through skin, respiratory irritants high toxicity... 

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