scholarly journals ПІДВИЩЕННЯ ВОГНЕЗАХИСНОЇ ЕФЕКТИВНОСТІ ІНТУМЕСЦЕНТНИХ ЕПОКСИДНИХ ПОКРИТТІВ СПОЛУКАМИ ІНТЕРКАЛЬОВАНОГО ГРАФІТУ

2021 ◽  
Vol 152 (6) ◽  
pp. 55-65
Author(s):  
Л. М. Вахітова ◽  
В. П. Плаван ◽  
В. І. Шологон ◽  
К. В. Калафат ◽  
Н. А. Таран ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Oxidative Degradation ◽  
Fire Retardant ◽  
Ammonium Polyphosphate ◽  
Thermal Oxidative Degradation ◽  
Char Residue ◽  
Temperature Range ◽  
Char Layer ◽  
Polymer Component ◽  
Intumescent System

Investigation of the effect of nitrate oxide graphite on the parameters of char layer, obtained from the system of ammonium polyphosphate / melamine / pentaerythritol / epoxy resin under the influence of temperatures of 200–800 °С.  Methodology.  A  fire  retardant  mixture  was  chosen  as  a  model  intumescent  system  ammonium polyphosphate / melamine / pentaerythritol. As a polymer component was used bisphenols A / F epoxy resin together with a polyamidoamine hardener. Nitrate oxide graphite was obtained by oxidation of natural scaly graphite  with fuming  nitrogen  acid.  The  effect  of  impurities  of  nitrate  oxide  graphite  was  determined  by thermogravimetry  on  the  intumescence  coefficient  of  intumescent  compositions  and  the  mass  of  the  char residue intumescent compositions in temperature range of 200–800 °С.  Findings. The influence of nitrate oxide graphite on the characteristics was studied of char layer of epoxy intumescent system ammonium polyphosphate / melamine / pentaerythritol / epoxy resin. The study of thermal  oxidative  degradation  was  carried  out  intumescent  compositions  in  the  temperature  range  200–800 °С. It was shown that intercalated graphite compounds increase the thermal stability of the formed char layer at temperatures > 600 °С. Determined intumescence coefficients and thermogravimetric analysis of modified intumescent systems was performed nitrate oxide graphite with different degrees of intercalation, in the conditions of 200–800 °С. It was established that the optimal parameters of the char layer are in terms of volume intumescence coefficient and mass of the char residue are provided by graphites, which contain 15–25% of intercalant in its composition. But the results obtained allow us to determine nitrate oxide graphite as a promising modifier of epoxy intumescent systems to increase its fire protection efficiency. Originality.  The  influence  of  degree  of  intercalation  of  nitrate  oxide  graphite  was  studied  on  the characteristics of char layer of epoxy intumescent system for the first time.  Practical value. The optimal content of intercalant in nitrate oxide graphite was established for the development of formulations of intumescent epoxy coatings with increased fire retardant properties.

FIRE PROTECTIVE EFFICIENCY OF INTUMESCENT TYPE EPOXIDE COATING

2021 ◽  
pp. 143-153
Author(s):  
Lyubov Vakhitova ◽  
◽  
Nadiya Taran ◽  
Konstantin Kalafat ◽  
Volodymyr Bessarabov ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Epoxy Resins ◽  
Flame Retardants ◽  
Practical Importance ◽  
Fire Retardant ◽  
Practical Significance ◽  
Protective Efficiency ◽  
Intumescent Coating ◽  
Polymer Component ◽  
Intumescent System

Purpose. The purpose of this work is to study the thermal degradation of epoxy polymers and nanocomposites based on them in a fire retardant intumescent coating having a composition – ammonium polyphosphate / melamine / pentaerythritol. Methods. Thermogravimetric studies have been performed on the device “Thermoscan-2”, fire tests were performed by the method of “Bunsen burner”. Results. The influence of the structure of epoxy resin as a polymer component of the intumescent system on oxidative thermal destruction and fire retardant efficiency of reactive coating has been researched. The obtained results allow us to state that the best result has been demonstrated by Araldite GY 783 – epoxy resin of bisphenols A/F with a reactive solvent. The thermal properties of various epoxy resins and nanocomposites based on them with organomodified montmorillonite have been studied. It was found that montmorillonite in the nanocomposite increases the decomposition temperature of epoxy resin. Scientific novelty. It has been shown that the variation of the polymer component of the intumescent coating has little effect on the swelling rate, but the fire retardant efficiency of the intumescent composition containing epoxy resin of bisphenols A/F is higher than the same characteristic for the composition based on epoxy resin of bisphenol A. It has been established that the exclusion of pentaerythritol from the formulation of the epoxy intumescent system causes the formation of a more regular and durable char insulation layer. It has been proved that the use of additional, including nanostructured flame retardants, namely, modified montmorillonite, can increase the fire retardant efficiency of the coating. Practical significance. The obtained results are of practical importance for the development of new scientific approaches to the design of fire-fighting materials with improved performance characteristics through the use of polymers that provide the construction of a thermostable thermal insulation char layer. Through a series of systematic tests, it has been demonstrated that the use of nanoclay and nanocomposites based on epoxy resins allows to improve the formulations of intumescent coatings with high performance with the help of budget nanotechnologies.

scholarly journals ПОРІВНЯННЯ АМІНІВ ЯК ГАЗОУТВОРЮВАЧІВ ВОГНЕЗАХИСНИХ КОМПОЗИЦІЙ ІНТУМЕСЦЕНТНОГО ТИПУ

2022 ◽  
pp. 69-80
Author(s):  
LIUBOV VAKHITOVA ◽  
KONSTANTIN KALAFAT ◽  
NADIYA TARAN ◽  
VOLODYMYR BESSARABOV
Keyword(s):  
Infrared Spectroscopy ◽  
Fire Protection ◽  
Ammonium Polyphosphate ◽  
Char Residue ◽  
Protection Efficiency ◽  
Blowing Agents ◽  
Char Layer ◽  
Intumescent Coatings ◽  
Intumescent System ◽  
Residue Mass

Purpose. Study of influence of blowing agents amines structure on the construction processes of thermal insulating char layer of intumescent system ammonium polyphosphate/pentaerythritol/amine and fire protection efficiency of this system at high temperatures. Methodology. A fire retardant mixture of ammonium polyphosphate/pentaerythritol/amine was chosen as a model intumescent system. Dispersion of vinyl acetate copolymer with vinyl ether of versatic acid was used as a polymeric component. A step-by-step study of the characteristics of the char layer of the intumescent composition was applied in the study, consisting in the analysis of the characteristics of the char formed after keeping the intumescent composition samples at a certain temperature between 100 and 800 °C, char residue mass (m, %), structure and density of the formed char layer. The method of infrared spectroscopy was used for identification of products of thermolysis of intumescent systems. Determination of fire protection efficiency of intumescent coatings was carried out in a mini-oven under standard fire conditions. Findings. The influence of the structure of amines blowing agents on the formation of char layer of intumescent system ammonium polyphosphate/pentaerythritol/amine was studied. Physico-chemical parameters of char layer formed during high temperature swelling of intumescent system components with varying amine: urea, melamine, dicyandiamide, guanidine, thiocarbamide, formylthiosemicarbazide, thiosemicarbazide, phenylethylcarbamide have been determined. In the temperature range 200–400 oC for systems with linear amines (urea, thiocarbamide, thiosemicarbazide), there is a rapid formation of insulating layer with intense outgassing (high intumescent coefficients K) and the same rapid its destruction with significant losses of char residue mass (Δm). The presence of melamine, dicyandiamide and guanidine in intumescent system provides constancy of intumescent coefficient at minimal mass loss. Chemical transformations of intumescent systems were studied by the method of infrared spectroscopy when the investigated amines were varied. It was found that linear diamines do not form stable spatially branched phosphamide compounds with phosphates as the basis of a thermostable heat-insulating frame. At the same time in IR spectra of char residue systems with melamine, dicyandiamide and guanidine the absorption bands of P-N-C bonds (1070–1050 cm-1) and P-N (980–950 cm-1) up to 600–700 oC are observed. Fire tests proved that melamine, dicyandiamide and guanidine are blowing agents providing maximum protection of metal against fire and can be used for composition of fire retardants for steel constructions.Originality. It has been proved that amines in intumescent polyphosphate system perform at least two functions: blowing agents by means of thermal destruction to incombustible gases and nucleophilic compound that takes part in char layer formation by aminolysis of electrophilic substrates.Practical value. The optimum amine blowing agents for developing formulations of intumescent coatings with enhanced flame retardant properties have been established.

scholarly journals Effect of char layer on transient thermal oxidative degradation of polyethylene

2007 ◽  
Vol 11 (2) ◽  
pp. 23-36 ◽  
Author(s):  
Javad Esfahani ◽  
Ali Abdolabadi
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Solid Phase ◽  
Early Stage ◽  
Radiation Heat Transfer ◽  
Oxidative Degradation ◽  
Degradation Process ◽  
Thermal Oxidative Degradation ◽  
Char Layer ◽  
Effect Of Oxygen

A transient one dimensional model has been presented to simulate degradation and gasification of polyethylene, in early stage of fire growth. In the present model effect of oxygen on degradation and rate of polymer gasification while the sample is subjected to an external radiative heat source is numerically investigated. This model includes different mechanism, which affect the degradation process, such as in depth thermal oxidative decomposition, in depth absorption of radiation, heat transfer, volatiles advection in solid phase and convective heat transfer on surface. Also effects of radiative parameters, due to formation of char layer such as surface reflectivity and absorptivity on thermal degradation of polyethylene are investigated. The results for 40 kW/m2 heat source are reported and yielded realistic results, comparing to the published experimental data. The results show that an increase in oxygen concentration leads to considerable increase in gasification rate and also leads to sharp increase of surface temperature. .

Synergistic Effect of Nano Fe2O3 on Intumescent Flame Retardant Polypropylene Systems

2013 ◽  
Vol 669 ◽  
pp. 233-238 ◽  
Author(s):  
Wei Zhao ◽  
Ji Ping Liu
Keyword(s):  
Mechanical Properties ◽  
Fire Retardant ◽  
Thermal Stabilization ◽  
Flame Retardance ◽  
Melamine Phosphate ◽  
Char Layer ◽  
Flame Retarded ◽  
Char Structure ◽  
Intumescent System ◽  
Thermal Stability Of

Nano Fe2O3 were added into polypropylene (PP) / ammonium polyphosphate (APP) / melamine phosphate (MPOP) / 1-oxo-4-hydroxymethyl-2,6,7-trioxal-phosphabicyclo-[2.2.2]octane (PEPA) to prepare intumescent flame-retarded nanocomposites. The flame retardance and thermal stabilization and intumescent char layer have been investigated by UL-94 test, TGA and SEM. Result showed that the behavior of this intumescent system can be enhanced significantly by the addition of small amounts of nano Fe2O3. TGA results present higher thermal stability of the PP-IFR-Fe2O3 in high temperature when compared with the PP-IFR. SEM indicated the char layer from the PP-IFR-Fe2O3 system has a compact and tough char structure compared with the PP-IFR. Adding 0.3 wt% and 27 wt% IFR into PP, the PP-IFR-Fe2O3 system provided good fire retardant behavior, mechanical properties and achieved UL94 V-0 rating.

scholarly journals INVESTIGATION OF THE FIRE-RETARDANT EFFECTIVENESS OF PHOSPHORUS-CONTAINING IMPREGNATING COMPOUNDS FOR WOOD

2020 ◽  
pp. 93-97
Author(s):  
N. A. Keibal ◽  
V. F. Kablov ◽  
V. S. Boyarkin
Keyword(s):  
Flame Retardant ◽  
Fire Resistance ◽  
Comparative Studies ◽  
Oxidative Degradation ◽  
Fire Retardant ◽  
Thermal Oxidative Degradation ◽  
Phosphorus Containing

The paper presents the results of comparative studies of the flame-retardant effectiveness of impregnating compounds based on a phosphor-containing oligomer and dimethylphosphite. It is shown that phosphorus-containing impregnating compounds increase the resistance to thermal-oxidative degradation, as well as the fire resistance of wood.

Thermal oxidative degradation of an epoxy resin

1993 ◽  
Vol 42 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Nathalie Rose ◽  
Michel Le Bras ◽  
René Delobel ◽  
Bruno Costes ◽  
Yves Henry
Keyword(s):  
Epoxy Resin ◽  
Oxidative Degradation ◽  
Thermal Oxidative Degradation

scholarly journals Technology and Properties of Chondroitin Sulfate from Marine Hydrobionts

2020 ◽  
Author(s):  
Irina Konovalova ◽  
Vitaliy Novikov ◽  
Yuliya Kuchina ◽  
Nataliia Dolgopiatova
Keyword(s):  
Chondroitin Sulfate ◽  
Thermal Destruction ◽  
Oxidative Degradation ◽  
Bound Water ◽  
Cartilage Tissue ◽  
Thermal Oxidative Degradation ◽  
Temperature Range ◽  
Chondroitin Sulfates ◽  
Polar Functional Groups ◽  
Differential Thermogravimetry

Chondroitin sulfate was isolated from the cartilage tissue of salmon (Salmo salar), northern skate (Raja hyperborean) and black-shark (Galeus melastomus). The polysaccharide content is from 67.1% to 82.2% in the samples. FTIR spectra of the obtained samples contain peaks at wave numbers characteristic of chondroitin sulfates (1550, 1350–1300, 1160–1120 и 822 cм–1). The thermal properties of chondroitin sulfates were studied by differential thermogravimetry. It was shown that the weight loss of the samples in the temperature range of 40–600ºC occurs in several stages. At the first stage, desorption of physically bound water occurs to a temperature of 150–200ºC, which can be explained by the difficulty in breaking hydrogen bonds between water molecules and the polar functional groups of chondroitin sulfate. Thermal decomposition of the bulk of chondroitin sulfate samples is observed at temperatures from 230–530ºC. The presence of peaks on the TGA curves in the temperature range 236–330ºC is associated with the release of sulfate groups and carboxylic acids (thermal destruction of uronic acid and pyranose units). When samples are heated above 350–400ºC, thermal oxidative degradation of residual carbon and sulfur compounds develops. The mass loss rates in each region were determined and the activation energies of each event were calculated. The nature of the cartilage tissue from which chondroitin sulfate is isolated affects the rate of destruction. Thus, in the temperature range 236–244ºC, the lowest destruction rate is observed for samples of chondroitin sulfate from salmon cartilage.

scholarly journals ПОРІВНЯННЯ ПОЛІОЛІВ ЯК КАРБОНІЗУЮЧИХ АГЕНТІВ ВОГНЕЗАХИСНИХ КОМПОЗИЦІЙ ІНТУМЕСЦЕНТНОГО ТИПУ

2022 ◽  
pp. 27-36
Author(s):  
LIUBOV VAKHITOVA ◽  
KONSTANTIN KALAFAT ◽  
NADIYA TARAN ◽  
VOLODYMYR BESSARABOV
Keyword(s):  
High Temperatures ◽  
Fire Protection ◽  
Flame Retardants ◽  
Fire Retardant ◽  
Reaction Products ◽  
Protection Efficiency ◽  
Char Layer ◽  
Thermal Insulating ◽  
Intumescent Coatings ◽  
Intumescent System

Purpose. To study the influence of the carbonizing agent structure on the formation of thermal insulating char layer of intumescent system acid donor/polyol and on the fire protection efficiency of the system at high temperatures. Methodology. A fire retardant mixture of an acid donor (phosphates ammonium, urea, melamine)/ polyol was chosen as a model intumescent system. Dispersion of vinyl acetate copolymer with ethylene was used as a polymeric component. The study applied the characteristics of the char layer of the intumescent composition at a certain temperature. The volumetric intumescent coefficient (K, cm3/g), mass of char residue (m, %), structure and density of the char layer are proposed as the main estimated parameters of flame retardant effect. IR spectroscopy was used to identify products of thermolysis of intumescent systems. Determination of fire protection efficiency of intumescent coatings was carried out in a mini-oven under standard fire conditions. Findings. The influence of polyol structure on the formation of thermal insulating char layer of intumescent acid donor/polyol system and the prediction of fire protection efficiency of this system under high temperature conditions has been investigated. It has been shown that under conditions of thermal shock the fire protection efficiency is more dependent on the nucleophilic reactivity of the polyol towards the unsaturated phosphorus atom of the acid donor than on its thermal stability. It has been found that pentaerythritol, dipentaerythritol, starch, dextrin, xylitol and sorbitol are the most effective carbonizing agents, regardless of the structure of the acid donor. It has been proved by infrared spectroscopy that at high temperatures as a result of the decomposition of pentaerythritol one of the reaction products is the aldehydes interacting with pentaerythritol with the formation of oligomeric compounds with a simple ether bond C-O-C. At the same time, pentaerythritol can be considered as a universal source of carbon framework for intumescent flame retardants regardless of the phosphate structure used. Originality. It has been shown that an important factor to increase the fire protection efficiency of intumescent systems is the use of polyols with an increased nucleophilicity in the esterification between polyol and phosphoric acid.Practical value. The optimal polyols as carbonizing agents for formulation of intumescent coatings with enhanced fire protection properties have been determined.

Sign in / Sign up

Export Citation Format

Share Document