Nghiên cứu xây dựng hệ chất hoạt động bề mặt bền nhiệt ứng dụng trong công nghệ sản xuất chất tạo bọt chữa cháy TT TIENG ANH

MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY  NGUYEN THI NGOAN RESEARCH ON BUILDING HEAT-RESISTANT SURFACTANTS SYSTEM APPLIED IN FIRE FIGHTING FOAM PRODUCTION TECHNOLOGY Major: Chemical engineering Code : 9.52.03.01 SUMMARY OF CHEMICAL DOCTORAL THESIS HA NOI – 2021 This thesis was completed at Graduate University of Science and Technology – Vietnam Academy of Science and Technology Supervisors: Dr Le Van Thu Dr Nguyen Thi Mua Examiner 1: Examiner 2: Examiner 3: The thesis defense was monitored by the Graduate University level Board of Examiner, held at: Graduate University of Science and Technology – 18 Hoang Quoc Viet – Cau Giay – Ha Noi at ,…………………… 2021 Hardcopy of the thesis can be found at: - Library of Graduate University of Science and Technology - National Library of Vietnam INTRODUCTION The acceptability of the thesis Fire is a threat to humans The consequences, damage to people and property caused by fire and explosion are enormous Fire can happen anywhere and in all fields Water is used to extinguish forest fires, house fires, boat fires… Today, it is still the primary fire extinguishing agent with good cooling and low cost However, water is ineffective against burning gasoline, oil, or other flammable liquids because water has a greater density than these fuels Fire derived from liquid fuels is characterized by a fastburning rate, a long time, and a risk of strong thermal radiation, which can lead to serious damage to the surrounding environment Therefore, the research and manufacture of effective fire extinguishing agents and quick extinguishers are important Nowadays, fire fighting foam has been produced into many types to meet each purpose of fire fighting Fire-fighting foaming agents are used to extinguish fires and prevent re-burns in fuel fires With fast, popular firefighting properties, fire-fighting foam is currently the most widely used on the market In our country, the research and production of fire fighting foam products are limited, mainly imported Special, a product line of aqueous film-forming foam (AFFF) and alcohol - resistant aqueous film-forming foam concentrate (AR-AFFF) Therefore, it is necessary to research and manufacture fire fighting foam products to meet the needs of using and actively produce domestically Therefore, the implementation of the thesis topic "Research on building heat-resistant surfactants system applied in fire fighting foam production technology" is topical has scientific and meaningful meaning in practice The research objectives of the thesis - Building heat-resistant surfactants system from some surfactants, suitable for the high-temperature conditions and characteristics of each fire object; - Optimization of the built-in heat-resistant surfactant system, applied in the production of aqueous film-forming foam (AFFF) and alcoholresistant aqueous film-forming foam (AR-AFFF), meets TCVN; - Evaluate the applicability of some silicon-containing compounds to improve fire suppression efficiency for aqueous film-forming foam AFFF The main research contents of the thesis - The study analyzes, evaluates, and selects surfactants suitable to the harsh conditions of the fire (high temperature, powerful heat radiation, long burning time ) to improve fire extinguishing efficiency; - Study physical and chemical properties, compatibility, and heat stability; - Research to optimize the mixing ratio of surfactants suitable for the AFFF and AR-AFFF fire extinguishing foam and the lowest surface tension; - Research on using surfactants with some silicon compounds to improve the fire extinguishing efficiency of the AFFF CHAPTER OVERVIEW The overview consists of four main parts: Part overview of the fire fighting foaming agent: general introduction about AFFF and AR-AFFF foam Part studies, learns about the composition of fire fighting foam the and application of some silicon-containing compounds in fire fighting foam Part introduces the role and principle of extinguishing foam Part presents the research situation of foaming agents in the world and Vietnam CHAPTER EXPERIMENT AND METHODOLOGY 2.1 Chemical and equipment 2.2 Evaluation and analysis method 2.2.1 Method for determining the chemical and physical properties of the fire fighting foam Determine the parameters: - Interfacial tension, surface tension and spreading coefficient, viscosity, expansion and 50 % drainage time, pH, and freezing temperature 2.2.2 Method of determining the stability of the foam The technique using two syringes used to create foam and to assess foam stability 2.2.3 Method for determining compatibility and heat resistance Compliance and heat stability were investigated by isothermal incubation at 150°C for hours Observe the turbidity, measure the surface tension and the pH of those solutions 2.2.4 Experimental planning method and optimization Design matrix of experimental plans according to Box - Hunter model The optimal composition and concentration of a surfactant system are determined when the surface tension reaches the minimum value 2.3.5 Test method Evaluate the fire extinguishing effect of foam solution fabricated according to TCVN - 7278: 2003 standard 2.3 Experimental The general research process for manufacturing the firefighting foaming agent system is as follows: Selection of fluorinated surfactants and hydrocarbons Determination of compatibility and heat resistance of mixtures of surfactants Determination of foam properties and fire test Formulate the formulation of a firefighting foaming agent Optimized mixing of surfactants Study selection additives the of 2.3.1 Manufacture of aqueous film-forming foam 2.3.2 Dispersion of silicon compounds in AFFF foam 2.3.3 Manufacture of alcohol-resistant aqueous film-forming foam CHAPTER RESULTS AND DISCUSSION 3.1 Aqueous film-forming foam AFFF 3.1.1 Study and selection of surfactants Table 3.1: Results of investigating the expansion and half-life of hydrocarbon surfactants Expansion 50 % drainage time No Surfactants (times) (minute: seconds) Branched alkyl benzene 6.2 2:48 sulfonate (BAS) Ethoxylated Sulfate (EOS) 3.1 2:02 Propoxylated Sulfate (POS) 3.8 2:56 Alkyl polyglucosides (APG) 5.8 4:01 Nonylphenol ethoxylates (NPE) 5.5 4:11 Lauryl hydoxysulfo betaine 5.4 4:19 (LHSB) Selection of hydrocarbon surfactants: Alkyl polyglucosides (APG), Nonylphenol ethoxylates (NPE), and Lauryl hydoxysulfo betaine (LHSB) with the parameters of expansion times greater and 50 % drainage time of more than minutes SCBM (mN/m) Sức căng bề mặt (mN/m) 16,5 3,5 16 15,5 2,5 15 14,5 14 0,035 1,5 0,04 0,045 0,05 0,055 0,06 Nồng độ DCF (%) Figure 3.1 The effect of the DCF concentration on the surface tension of the water Sức căng bề mặt liên diện (mN/m) SCBM liên diện (mN/m) 17 Table 3.2: Expansion and 50 % drainage time of solution DuPont™ Capstone® fluorosurfactant 1440 (DCF) Concentration % 0,03 0,035 0,04 0,045 0,05 0,055 0,06 Expansion (times) 3.2 3.7 4.2 4.8 4.2 5.6 6.3 50 % drainage time (minute: seconds) 3:23 4:07 4:23 4:52 5:21 5:56 6:28 Spreading coefficient 5.4 5.8 6.1 6.6 7.4 7.6 8.0 The results in figure 3.1 and table 3.2 show that fluorinated surfactant DuPont™ Capstone® fluorosurfactant 1440 (DCF) is suitable for researching the manufacture of aqueous film-forming foam Figure 3.2: Graph showing surface tension of surfactants by concentration The results in figure 3.2 showed that hydrocarbon surfactants are capable of reducing the surface tension of water to about 28 - 33 mN/m Meanwhile, fluorinated surfactants reduce water surface tension about 1516 mN /m lower than hydrocarbon surfactants On the other hand, DCF is heat stable under high-temperature conditions because it contains C-F bonds Therefore, DCF is selected as the main ingredient in the fire fighting foam formulation 3.1.2 Determination of compatibility and heat resistance of mixtures of surfactants From the results of evaluating the compatibility and heat stability of a mixture of 2, 3, and surfactants, it is found that the system of substances is capable of reducing the surface tension of the system to a low value The changes in pH and surface tension after the annealing are not significantly changed, indicating that the system is thermally stable The ratio of DCF: APG: LHSB: NPE studied was 1: 3: 2: Table 3.10 Investigating the expansion, 50 % drainage time No of the surfactant system Expansion Surfactant (times) DCF : APG 6.6 DCF : APG : LHSB 6.2 DCF : APG : NPE 4.2 DCF : APG : LHSB : NPE 5.4 50 % drainage time (minute: seconds) 3:46 3:59 4:51 5:36 3.1.3 Optimizing of the surfactants system The regressive equation corresponds to the emirical variables: Ŷ = 42.81 – 5.324*10-2Z1 – 8.279*10-2Z2 – 0.1118*Z3 4.69*10-5Z1Z2 + 6.56*10-5Z1Z3 – 7.19*10-5 Z2Z3 + 2.423*10-4Z12 + 2.07*10-4 Z22 + 2.733*10-4Z32 The corresponding optimum concentration of surfactants is as follows: DCF = 103.74 ≈ 104 g/kg APG = 251.02 ≈ 251 g/kg LHSB = 150.01 ≈ 150 g/kg NPE = 74.94 ≈ 75 g/kg The surface tension reached the smallest is σ = 17,06 mN/m a b c Figure 3.3: 3D graph showing σ according to values of surfactant concentration Figure 3.4: Contour lines represent the value of σ according to the concentration of surfactants 3.1.4 Research and selection of additives The changes in pH and surface tension of the surfactant system when having 5.0% butyl diglycol, 2.5% glycerin, 1.5% Ure and 1.0% HEC have a slight change, indicating that the research material system is relatively thermally stable Heat resistance will be studied more carefully by fire tests according to Vietnamese standards 3.1.5 Study to investigate the mix order Through experiments investigating the mixing order of surfactants, it was found that bisexual surfactants such as LHSB should be added first with the fluorinated surfactant then to the last nonion active substance Table 3.20: The results of surveying the mixing order of the AFFF DCF + H2O A B C D E F Note: Mix order APG APG NPE NPE LHSB LHSB NPE LHSB APG LHSB APG NPE LHSB NPE LHSB APG NPE APG Δt (°C) Solution state 0.2 0.3 0.1 0.1 0.3 0.2 ++ ++ +++ +++ +++: the solution is completely clear and little foam forms ++-: the solution has many small bubbles -: the solution has a lot of foam, durable Continue to study the additive composition, based on the parameters of Nonylphenol ethoxylates Lauryl hydoxysulfo betaine 4.4 4.0 245 285 The results in table 3.25 show that, there are five surfactants: Sodium lauryl ether sunfat (SLES); Sodium lauryl sulfate (SLS); Alkylphenol ethoxylate (APE); Nonylphenol ethoxylates (NPE) Lauryl hydoxysulfo betaine (LHSB) has satisfactory 50% drainage time and expansion Selection of fluoroalkyl betaine (FB) to research and manufacture an alcohol-resistant aqueous film-forming foam Investigate the compatibility of fluorinated surfactants and hydrocarbon surfactants in the ratios of 1:4, 1:3, 1:2, 1:1, 3:1, 2:1 with a total concentration of 0.2% in water incubated at 150°C for hours The results are as follows: Table 3.24: Compatibility of the surfactant mixtures Ratio Mixture FB : SLES FB : SLS FB : APE FB : NPE FB : LHSB Comment 1:4 1:3 1:2 1:1 2:1 transparent transparent transparent transparent transparent transparent transparent transparent transparent turbidity transparent transparent transparent transparent turbidity transparent transparent transparent transparent transparent turbidity turbidity turbidity turbidity turbidity The mixtures were mixed with a total concentration of 0.2% 3:1 transparent turbidity turbidity transparent turbidity Through experiments found that the mixture FB: SLS; FB: APE and FB: LHSB after hours of incubation shows that the solution is turbidity That indicates that the mixtures have poor compatibility and heat stability The mix of FB: SLES and FB: NPE was completely clear after hours of incubation Therefore, the research team identified two surfactants: Sodium lauryl ether sulfate (SLES) and Nonylphenol ethoxylates (NPE) for the next study For alcohol-resistant foaming agents, it is extremely important to use a combination of water-soluble, alcohol-insoluble, and fluorinated polymers Select partially fluorinated acrylic copolymer (PFAC) fluorinated polymer product - the ingredient that increases heat resistance, to conduct 11 research Investigating the change of surface tension according to the concentration of surfactants gives the results as shown in figure 3.6 Figure 3.6: The graph shows the surface tension of surfactants according to concentration Hydrocarbon surfactants have higher surface tension than fluorinated surfactants, so in the construction of the dominant material system, the FB fluorinated surfactant is selected as the main ingredient 3.2.2 Determination of compatibility and heat resistance of mixtures of surfactants From the results of evaluating the compatibility and heat stability of a mixture of 2, 3, and surfactants, it is found that the system of substances is capable of reducing the surface tension of the system to a low value The changes in pH and surface tension after the annealing are not significantly changed, indicating that the system is thermally stable The ratio of FB : SLES : NPE : PFAC studied was : : : 3.2.3 Optimizing of the surfactants system The regressive equation corresponds to the emirical variables: Ŷ = 52.27 – 5.66*10-2Z1 – 0.1546Z2 – 0.1003Z3 +8.1*10-5 Z1Z2-8.44*10-5 Z1Z3+ 1.31*10-4 Z2Z3 + 1.706*10-4 Z12+1.94*10-4 Z22 +3.076*10-4 Z32 12 Figure 3.7: graph showing σ according to values of surfactant concentration Figure 3.8: Contour lines represent the value of σ according to the concentration of surfactants The corresponding optimum concentration of surfactants is as follows:: FB = 111.21 ≈ 111 g/kg SLES = 226.8 ≈ 227 g/kg NPE= 113.44 ≈ 113 g/kg PFAC = 105.78 ≈ 106 g/kg The surface tension reached the smallest is σ = 17.56 mN/m 3.2.4 Research and selection of additives Using the same additive composition as aqueous film-forming foam applied to the research of alcohol-resistant foaming agent The results showed that with the above optimal system and the concentration of additives as 1.6% xanthan gum, 5% butyl diglycol, 3% glycerin, 2.5% urea, 1.2% HEC, the best heat resistance system 3.2.5 Study to investigate the mix order Through experiments investigating the order of the assimilation of partial surfactants, it was found that two fluorinated surfactants, FB and PFAC, need to be assimilated first, then the SLES anion surfactant, and finally the NPE nonion active surfactants 13 Table 3.43: The results of surveying the mixing order Δt Mix order FB + Solution H2O ( C) state A SLES NPE PFAC 0.2 - B SLES PFAC NPE 0.3 - C NPE SLES PFAC 0.1 - D NPE PFAC SLES 0.3 - E PFAC SLES NPE 0.1 +++ F PFAC NPE SLES 0.2 ++- Continue to study the composition of mixing additives, based on the properties of 50 % drainage time, mixing time, and surface tension At the order of agitating; Butyldiglycol; Glycerin; Hydroxyethylcellulose + Xanthan gum; Urea corresponds to the order 1; 2; 3; for a shortest stirring time of 30 minutes Therefore, the mixing order of substances in the fabrication process of the alcohol-resistant aqueous film-forming foam products are arranged in the following order: Water, FB, PFAC, SLES, NPE, Butyldiglycol; Glycerin; Hydroxyethylcellulose + Xanthan gum; Urea 3.2.6 Examine the time and the speed of agitating The results show that when the stirring speed increases, the agitating time decreases, when the speed increases to 200 rpm, the agitating time does not decrease, to ensure the safety of the device and save energy consumption during the process fabrication process Therefore, choose a stirring time of 180 rpm for the production of an alcohol-resistant aqueous film-forming foam From the survey results, the formulation of alcohol-resistant aqueous film-forming foam 1% is presented in table 3.46 14 No Table 3.46 The formula for making AR-AFFF Concentration Composition (%) Fluoroalkyl betaine (FB) 11.1 Sodium laury ether sunfate (SLES) 22.7 Nonyl phenol ethoxylate (NPE) 11.3 Partially fluorinated acrylic copolymer (PFAC) 10.6 Hydroxyethyl cellulose (HEC) 1.2 Xanthan gum 1.6 Urea 2.5 Glycerine 3.0 Butyl diglycol 5.0 Use the above manufacturing process to make an alcohol-resistant aqueous film-forming foam sample, and check the main specifications of the product The obtained results are presented in table 3.47 Table 3.47 The properties of alcohol-resistant aqueous film-forming foam Concentration 1% No Properties Expansion (times) 5.6 5.5 50 % drainage time (minute: seconds) 4:28 4:37 pH 7.4 7.3 Density 250C (g/cm3) 1.032 1.030 Time to extinguish (seconds) 168 155 Burn-back time (seconds) 651 659 The results of determining the properties of the alcohol-resistant aqueous film-forming foam 1% meet the requirements according to TCVN 7278 - 3: 2003 3.3 Research on using some silicon-containing compounds to enhance fire fighting foam properties 3.3.1 Effect of some silicon compounds on AFFF solution properties When adding sodium silicate compounds, silica gel, or siloxane to the mixture of surfactants, it interacts with the surfactants changing the surface tension of the solution 15 Figure 3.11 Effect of the concentration of some silicon compounds on the surface tension of AFFF solution 3.3.2 Effect of some silicon compounds on foam stability Aqueous samples after foaming using two syringes are given to a glass vial Sample designation No is AFFF foam solution containing 1% sodium silicate; Sample is AFFF foam solution containing 1.5% silica gel; Sample is AFFF foam solution containing 1.5% siloxane All are mass concentrations, and sample is the AFFF reference solution In the beginning, the four foam samples were of the same volume minute minutes 10 minutes 15 minutes 20 minutes 25 minutes Figure 3.14 Foam patterns 16 The foam volumes of the four foam samples decrease over time as a result of increasing liquid escapes After the first minutes, more water was escaped in samples and than in samples and The foam height did not change After 10 minutes, sample had the least amount of water drained, but foam height decreased lower than samples 2, 3, and By the 15th minute of sample 3, the foam height began to come down gradually While samples No and 2, the amount of foam does not change compared with the initial time After 25 minutes, on samples and almost no foam, sample 2, the amount of foam begins to decrease, the bubbles inside have a larger size than the bubbles in sample That indicates that the nano-silica particles are more resistant to foam than conventional AFFF Although the half-life is faster than that of AFFF, the resulting bubbles are more durable Inside, AFFF foam solution containing sodium silicate with a concentration of 1% has the most stable foam minute minutes 10 minutes 20 minutes Figure 3.15 The foam bubble shape changes over time Figure 3.15 shows the change of bubble morphology over time In 17 which, sample is an AFFF solution containing 1% sodium silicate, sample is an AFFF solution containing 1.5% silica gel, and sample is a conventional AFFF solution The results showed that the silica nanoparticles had a significant effect on the foaming process and foam stability Figure 3.17 The mechanism by which the nanoparticle concentration influences foam stability The influence of nano-silica on foam stability was explained by a group of authors Y Sheng, shown in figure 3.17 In the absence of silica nanoparticles, the foam is stabilized by a mixture of hydrocarbon and fluorinated surfactants When adding low concentration silica nanoparticles, destroys the adsorption equilibrium of the surfactants, reducing the number of surfactant molecules at the interface The low concentration of silica nanoparticles is unable to delay the half-life of the foam film and foaming, resulting in poor foam stability As the concentration of silica nanoparticles increases, they gradually agglomerate in the foam membrane and the space between bubbles, slowing the drainage of the foam When the nano-silica concentration is high, it fills the membrane, and the gap between the bubbles, and the drainage and half-life slow down, resulting in a highly stable foam 3.4 Testing 3.4.1 Small-scale testing 3.4.1.1 Small-scale testing of AFFF 18 To evaluate the thermal stability of the studied foam system, test the effectiveness of fire extinguishing by forceful application and gentle application methods Test results on a scale of 0.6 m2 by forceful and gentle application methods are present in table 3.49 Table 3.49: Test results to determine the time to extinguish of AFFF Time to extinguish (seconds) Burn-back time forceful gentle application (≥ 300 seconds) application (≤ 180 (≤ 300 seconds) seconds) 79 90 409 75 101 419 78 94 413 Average 77 95 414 Test results show that AFFF foam has a relatively fast extinguishing Test times time: 77 seconds for the forceful application method, 95 seconds for the gentle application method That proves the compatibility and heat stability of the mixture of surfactants and additives The burn-back time is 414 seconds compared to TCVN 7278 3.4.1.2 Small-scale testing of AR-AFFF The results of testing time to extinguish according to the scale of 0.25 m of the AR-AFFF are present in table 3.50 Table 3.50: Test results to determine the time to extinguish of AR-AFFF Test results Burn-back time (≤ 180 seconds) (≥ 600 seconds) 75 767 71 754 68 759 Average 71 760 The test results show that the AR - AFFF with time to extinguish is 71 Test times Time to extinguish seconds, the burn-back time is 760 seconds, meeting the standard TCVN 7278-3:2003 Therefore, it proves that the surfactant system is compatible and has good thermal stability 19 3.4.2 Test according to Vietnamese standards Test and evaluate the quality of fire-fighting foam products according to Vietnamese standards is an important step, and proving the practicality of the topic in applying products for fire prevention and fighting Test results for forceful application No Name of firefighting foam Aqueous filmforming foam Mixed rate Time to extinguish 0.5% 150 seconds Vietnamese standards 7278-1 : 2003 Fire extinguishing effect: class I (≤ 180s) Test results for gentle application No Name of firefighting foam Mixed rate Time to extinguish Burnback time Aqueous filmforming foam 0.5% 232 seconds 525 seconds Alcoholresistant aqueous filmforming foam 1% 165 seconds 716 seconds Vietnamese standards 7278-1 : 2003 and 7278-3 : 2003 - Fire extinguishing effect: class I (≤ 300s) - Burn-back level: D (≥ 300s) - Fire extinguishing effect: AR I (≤ 180s) - Burn-back level: B (≥ 600s) 3.4.3 Small-scale testing of a sodium silicate-containing AFFF foam Testing was conducted to evaluate the fire extinguishing efficiency of the sodium silicate AFFF foam 60s 75s 20 100s 130s Figure 3.18: Test the extinguishing effect of the AFFF foam containing the sodium silicate 0s 300s 540s 630 s Figure 3.19: Burn-back test of AFFF foam solution containing sodium silicate Results fire extinguishing time of the product is 63 seconds while the burn-back time is 585s 21 CONCLUSION The results of the thesis have included: Aqueous film-forming foam AFFF: Selection of surfactants including DuPont™ Capstone® fluorosurfactant 1440, Alkyl polyglucosides, Lauryl hydoxysulfo betaine, Nonylphenol ethoxylates with an optimum concentration of 104 g/kg respectively; 251 g/kg; 150 g/kg, and 75 g/kg ensure heat resistance and good compatibility At the optimal concentration of surfactants, the surface tension of the system reaches the lowest value of 17.06 mN /m The optimal mixing order was determined as follows: water; duPont™ capstone® fluorosurfactant 1440; lauryl hydoxysulfo betaine; nonylphenol ethoxylates; alkyl polyglucosides; butyl diglycol; glyxerin; hydroxyethyl cellulose; urea and agitating time is 40 minutes, agitating speed is 180 rpm Alcohol-resistant aqueous film-forming foam AR-AFFF: Selection of surfactants including Fluoroalkyl betaine, Sodium laury ether sunfat, Nonylphenol ethoxylates, Partially fluorinated acrylic copolymer with an optimum concentration of 111 g/kg; 227 g/kg; 113 g/kg 106 g/kg At the optimal concentration of surfactants, the surface tension of the system reaches the lowest value of 17.56 mN/m The optimal mixing order was determined as follows: water; fluoroalkyl betaine; partially fluorinated acrylic copolymer; sodium laury ether sunfat; nonylphenol ethoxylates; butyl diglycol; glyxerin; hydroxyethyl cellulose; xanthan gum; urea and agitating time is 50 minutes, agitating speed is 180 rpm Some silicon-containing compounds have been studied and investigated to enhance fire fighting foam properties These compounds can improve fire extinguishing efficiency with stability for foam fire extinguishing products, and have great potential for developing environmentally friendly foam products in the future In which, sodium silicate 1% compound is more effective Fire-fighting foam product tested The results show that with the forceful 22 application method, the fire-extinguishing time of the aqueous filmforming foam AFFF foam retardant is 150 seconds With the gentle application method, the time to extinguish the fire and the burn-back time of AFFF is 232 seconds and 525 seconds, respectively; AR-AFFF is 165 seconds and 716 seconds These results meet the current TCVN 7278 AFFF foam containing sodium silicate 1% was tested with a fire extinguishing time under a gentle application method of 63 seconds, and the burn-back time was 585 seconds 23 THE NEW CONTRIBUTIONS OF THESIS The thesis researches heat-resistant surfactants of scientific significance for chemical engineering, contributing to clarifying their roles such as reducing surface tension, increasing thermal stability, compatibility, expansion in fire-fighting foam concentrates; Selected and optimized 02 heat-resistant surfactants system, helping to be proactive in the fabrication of aqueous film-forming foam concentrates (AFFF) and alcohol-resistant aqueous film-forming foam concentrates (AR- AFFF) meets TCVN 7278; Identified the active role of compounds containing silicon (sodium silicate, silica gel, siloxane) in the aqueous film-forming foam concentrates agent (AFFF) composition to increase the fire extinguishing effect of the product 24 LIST OF THE PUBLISHED WORKS Nguyen Thi Ngoan, Luong Nhu Hai, Do Son Hai, Vuong Van Truong, Nguyen Thi Mua, Le Van Thu, Study and selection of surfactant systems to use for manufacture aqueous film-forming foam concentrate (AFFF), Vietnam Journal of Chemistry, 56(3E1,2), 266-271, 2018 Nguyen Thi Ngoan, Luong Nhu Hai, Do Son Hai, Tran Van Chuc, Vu Dinh Ly, Le Van Thu, Tối ưu hóa hệ chất hoạt động bề mặt bền nhiệt sử dụng bọt chữa cháy tạo màng nước (AFFF), Hội nghị nhà khoa học trẻ lần thứ IV – Hanoi, 2018 Nguyen Thi Ngoan, Luong Nhu Hai, Do Son Hai, Vu Dinh Ly, Pham Thi Luu, Tran Van Chuc, Nguyen Thi Mua, Le Van Thu, Study and selection of surfactant systems to use for manufacture alcohol resistant aqueous filmforming foam concentrate (AR-AFFF), Vietnam Journal of Chemistry, 57(2e1,2), 149-154, 2019 Nguyen Thi Ngoan, Nguyen Van Thao, Luong Nhu Hai, Đo Son Hai, Vu Dinh Ly, Tran Van Chuc, Truong Hoang Son, Nguyen Thi Mua, Le Van Thu, Optimization of the surfactant systems for aqueous film-forming foam concentrates (AFFF), Vietnam Journal of Chemistry, 57(2e1,2), 316-321, 2019 Nguyen Thi Ngoan, Luong Nhu Hai, Do Son Hai, Vuong Van Truong, To Phuc Du, Truong Phuong Thao, Le Thi Thuy Hang, Le Van Thu, Study on the effects of sodium silicate to properties for aqueous film-forming foam concentrate, Vietnam Journal of Chemistry, 57(6E1,2), 59-63, 2019 Nguyen Thi Ngoan, Luong Nhu Hai, Do Son Hai, Nguyen Thi Mua, Le Van Thu, Optimization of the surfactant system for using in alcohol resistant aqueous film-forming foam concentrate (AR-AFFF), Vietnam Journal of Chemistry, 58(5E1,2), 126-130, 2020 Nguyen Thi Ngoan, Luong Nhu Hai, Do Son Hai, Nguyen Thi Mua, Le Van Thu, Study on the effects of foam stabilizers for aqueous film-forming foam concentrate, Vietnam Journal of Chemistry, 58(5E1,2), 131-135, 2020 25 ... Hai, Do Son Hai, Tran Van Chuc, Vu Dinh Ly, Le Van Thu, Tối ưu hóa hệ chất hoạt động bề mặt bền nhiệt sử dụng bọt chữa cháy tạo màng nước (AFFF), Hội nghị nhà khoa học trẻ lần thứ IV – Hanoi,... (%) Figure 3.1 The effect of the DCF concentration on the surface tension of the water Sức căng bề mặt liên diện (mN/m) SCBM liên diện (mN/m) 17 Table 3.2: Expansion and 50 % drainage time of solution... parameters of expansion times greater and 50 % drainage time of more than minutes SCBM (mN/m) Sức căng bề mặt (mN/m) 16,5 3,5 16 15,5 2,5 15 14,5 14 0,035 1,5 0,04 0,045 0,05 0,055 0,06 Nồng độ DCF (%)