Fire retardant action of mineral fillers

Endothermically decomposing mineral fillers, such as aluminium or magnesium hydroxide, magnesium carbonate, or mixed magnesium/calcium carbonates and hydroxides, such as naturally occurring mixtures of huntite and hydromagnesite are in heavy demand as sustainable, environmentally benign fire retardants. They are more difficult to deploy than the halogenated flame retardants they are replacing, as their modes of action are more complex, and are not equally effective in different polymers. In addition to their presence (at levels up to 70%), reducing the flammable content of the material, they have three quantifiable fire retardant effects: heat absorption through endothermic decomposition; increased heat capacity of the polymer residue; increased heat capacity of the gas phase through the presence of water or carbon dioxide. These three contributions have been quantified for eight of the most common fire retardant mineral fillers, and the effects on standard fire tests such as the LOI, UL 94 and cone calorimeter discussed. By quantifying these estimable contributions, more subtle effects, which they might otherwise mask, may be identified

Curing of epoxy resins by complex based on monoamide of phosphonic acid and ammonium chloride

Reaction of epoxy-diane resin with complex based on monoamide of phosphonic acid and ammonium chloride (MODAF) is studied. It is established that the MODAF equivalent in the reaction with epoxy resin is equal to 1/5 of its molecular weight. Epoxy resin is cured via the reactions of both monoamide and ammonium chloride. The dependence of the epoxide and hydroxyl groups has a stepped character over time, which is probably due to the existence of certain threshold concentrations of the curing coefficients. The investigated reaction is a new example of macroscopic coherence manifestation. © 2010 Pleiades Publishing, Ltd

Determination of hydroxyl groups in epoxy resins by potentiometric titration using a reaction with maleic anhydride

A reaction of maleic anhydride with epoxy-dian resins in methyl ethyl ketene was investigated. It was shown by potentiometric titration that the resulting maleic esters are stable to hydrolysis in acid and weakly acid organic solutions. This reaction can be used for the quantitative determination of hydroxyl groups in epoxy resins. Epoxy groups do not interfere with the formation of maleic esters under the conditions of determination. The optimal reaction conditions were found. The reaction kinetic was investigated, the reaction rate constants were determined at various temperatures, and the activation energy was found. The value of the activation energy indicates that the reaction is characterized by a low potential barrier. © 2001 MAIK "Nauka/Interperiodica"

Curing of epoxy resins by complex based on monoamide of phosphonic acid and ammonium chloride

Reaction of epoxy-diane resin with complex based on monoamide of phosphonic acid and ammonium chloride (MODAF) is studied. It is established that the MODAF equivalent in the reaction with epoxy resin is equal to 1/5 of its molecular weight. Epoxy resin is cured via the reactions of both monoamide and ammonium chloride. The dependence of the epoxide and hydroxyl groups has a stepped character over time, which is probably due to the existence of certain threshold concentrations of the curing coefficients. The investigated reaction is a new example of macroscopic coherence manifestation. © 2010 Pleiades Publishing, Ltd