|Article title||STUDY OF THE PYROLYSIS PROCESS AND COMBUSTIBILITY, PAINTS BASED ON VINYL ACETATE COPOLYMERS|
|Authors||M.N. Abdikarimov, B.A. Zhubanov|
|Section||SECTION VI. FIRE PROTECTION OF MATERIALS AND CONSTRUCTIONS|
|Month, Year||08, 2013 @en|
|Index UDC||691.57 + 698.1: 622.61|
|Abstract||The thermogravimetric and thermomechanical curves, the rate of burning and weight loss were determined for vinylacetate copolymer paints. These paints are applied for fire protection purpose on metal and wooden structures. The study was carried on the influence of the polymeric binders and various additives that are used for manufacturing of paints, varnishes and enamels on the mechanism and the rate of combustion. The kinetic curves of temperature change on a metallic substrate during the pyrolysis under propane/air flame were obtained. The observation has showed that adding the phosphoric acid to the vinylacetate – vinyl chloride copolymer paint leads the phosphorus remains in the condensed phase and enables the change in the combustion mechanism. At the same time the chlorine supports the tarring process in the condensed phase with the transform to the carbonized residue of fine structure as well as inhibition of combustion mainly in the flare, i.e. in the gas phase. In general, when combustion inhibiting paints based on VA-VCl copolymer with phosphorus-containing additives inhibiting mechanism is realized symbatically mixture P + Cl. Visco-elastic properties of the copolymer of VA-DM appear on the whole temperature range 0–90 оC, which leads to the possibility of its use as a polymeric binder for mono- lithic coatings. In the temperature range (43–46 оC) is equal to the glass transition temperature of the copolymer, BA-DM has inflection corresponding to 80 % strain. For polyvinylacetate observed three physical states: the glass (28–190 оC), highly elastic (190–370 оC) and viscous flow (370–430 оC). Differential thermal analysis showed that derivatogram characterized exothermic peaks at 300 (glass PVA), 500 (softening temperature of PVA), oxidation- 230о, 250о, 330о, 390о, 420о and 540о and exothermic peaks at 120о C (temperature strength PVA) 170о C (decomposition temperature) deep pyrolysis at 260о C, 300о, 400о and 440о C. Copolymers VA-VCl and VA-DM differ from PVA having high ink exo effect at 580о C, apparently, this is accompanied by a significant amount of heat during oxidative degradation, which causes the greatest weight loss at this temperature. The goal of this work – the study of the combustion mechanism and creation of fireretardant coatings based on polyvinyl acetate emulsion (PVA), and copolymers of vinyl acetate and vinyl chloride (VA-VCl), vinyl acetate and dibutylmaleate (BA-DM), grade 50 PD 35B for the printing industry (OST 6-05-637-78, and methylacrylate lacquer (MAC) with methyl methacrylate (MMA) – (MAC-MMA), chloroprene latex (Xl) with trihlorbutadienom (THB) – (Xl-THB) with various additives. Tasks of research – study pyrolysis combustion according to the nature of paint. Conducting fire tests at 11000C in a propane-air flame on a "Ceramic pipes" (CT) (GOST 745-73) with the measurement of the kinetic characteristics and weight loss samples vinylacetate copolymer paints with additives to assess the fire as fire protective coatings for metal and wood substrates. Thermogravimetric studies of samples in a stream of air and an inert gas at a heating rate of 100/min. Thermomechanical test plates to a thickness of 2 ± 0,1 mm at a load of 10 kg/cm2 and a heating rate 5–10о/min. Brief conclusions. The processes in the condensed phase pyrolysis and combustion of pro- pane-air flame with a temperature of 11000C and flame on a "Ceramic pipes" for the first time the possibility of obtaining slow-burning fire-retardant paints based on a copolymer of vinyl acetate and vinyl chloride. It was found that on a wooden substrate burning rate and weight loss of paint VA-VCl decrease with the introduction of various modifiers. Found that the rate of combustion nail MAC-MMA decreases in 4, loss of weight – 5 times with the introduction of blowing agents. Latex with chloroprene trihlorbutadien becomes slow-compounds in the presence of phosphorus compounds and the blowing agent. Sodium tungstate causes the appearance of a solid finely porous coke. Developed fire retardant foaming paint based on a copolymer of vinyl acetate for wood and metal surfaces.|
|Keywords||The thermogravimetric and thermomechanical curves; vinylacetate copolymer paints; the pyrolysis; the rate of burning, weight loss.|
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