Polydimethyl citraconate explosion suppression material

Abstract

The application discloses a polydimethyl itaconate explosion suppression material and belongs to the technical field of explosion suppressant preparation. A preparation method of the polydimethyl itaconate comprises the following steps: uniformly mixing a dispersing agent, a surfactant and a solvent, then uniformly mixing dimethyl itaconate (DMI) and an initiator, and purifying after heating reaction to obtain the polydimethyl itaconate. The polydimethyl itaconate has physical and chemical inhibition effects on dust combustion and has a good explosion suppression effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of explosion inhibitor preparation, in particular to a polydimethyl citraconate explosion inhibitor. BACKGROUND

[0002] Metal dusts can cause violent combustion reaction when encountering open flames or high-temperature heat sources in the air, producing high-temperature and high-pressure gas and flame, forming metal dust explosion. Metal dust explosion is a serious industrial safety accident, which not only causes casualties and equipment damage, but also causes secondary accidents such as fire and toxic gas leakage. At present, there are mainly the following methods to prevent and inhibit dust explosion at home and abroad: first, eliminate ignition sources; second, avoid the formation of dust clouds; third, take a series of protective measures such as isolation, discharge, ventilation, etc.; fourth, add explosion inhibitors. However, due to the large number of potential ignition sources in industrial production, and the existence of many unavoidable electrostatic environments and electrostatic effects, it is almost impossible to eliminate ignition sources. When powder processing, a large amount of dust is exposed to the air to form a dust cloud that can cause an explosion, so it is also very difficult to avoid the formation of dust clouds. Taking a series of protective measures such as ventilation, discharge, and isolation can indeed effectively reduce the possibility of dust explosion, but if these protective measures fail, the consequences will be unimaginable. Although the use of explosion inhibitors can prevent dust explosion to some extent, there is a lack of efficient, environmentally friendly and economical explosion inhibitors. SUMMARY

[0003] The purpose of the present application is to provide a polydimethyl citraconate explosion inhibitor to solve the problems existing in the prior art.

[0004] To achieve the above purpose, the present application provides the following solutions:

[0005] One of the technical solutions of the present application is the application of polydimethyl citraconate as an explosion inhibitor. The structural formula of the polydimethyl citraconate is shown as formula (1):

[0006]

[0007] Wherein, n is 100-300.

[0008] Further, the number average molecular weight of the polydimethyl citraconate is 20000-40000 g / mol, the weight average molecular weight is 10000-41567 g / mol, and the polydispersity coefficient is 1.51-2.

[0009] Further, the preparation method of the polydimethyl citraconate comprises the following steps:

[0010] The dispersant, the surfactant and the solvent are mixed uniformly, then dimethyl itaconate (DMI) and the initiator are added and mixed uniformly, and after heating reaction, purification is carried out to obtain the dimethyl itaconic acid ester.

[0011] Further, the dispersant comprises basic magnesium carbonate; the surfactant comprises sodium dodecyl benzene sulfonate (SDBS); and the initiator comprises dimethyl azobis isobutyrate (AIBME).

[0012] Further, the application method specifically comprises: uniformly mixing the metal dust and the dimethyl itaconic acid ester to achieve the explosion suppression effect.

[0013] The second technical scheme of the application is an explosion suppression material, and the main component comprises dimethyl itaconic acid ester.

[0014] The application discloses the following technical effects:

[0015] The dimethyl itaconic acid ester can physically and chemically suppress the combustion of the dust, and the specific effects are as follows:

[0016] The physical suppression effect: the PDMI particles have a large specific surface area and a strong adsorption effect with the aluminum powder, so that the aluminum powder can be adsorbed on the surface of the PDMI particles, the surface area of the aluminum powder in contact with oxygen is reduced, and the violent oxidation reaction of the aluminum powder is suppressed. In addition, when the aluminum powder explosion reaction occurs in a closed space, the energy generated by the aluminum powder can be blocked by the PDMI particles, and the heat transfer is weakened. Meanwhile, the thermal decomposition temperature range of the PDMI is relatively wide, mainly 260-420 DEG C, and the maximum decomposition rate is about 315 DEG C. The thermal decomposition of the PDMI particles between the aluminum powders can absorb the heat released in the combustion reaction zone, reduce the aluminum dust combustion flame temperature, weaken the pyrolysis of the unburned aluminum powder particles, and reduce the pyrolysis and oxidation rate of the aluminum powder particles. Moreover, the decomposition of the PDMI particles produces non-combustible gaseous products (thermal decomposition products) such as CO2 and H2O (g), which can dilute the oxygen concentration and block the violent reaction of the unburned aluminum powder with oxygen.

[0017] The chemical suppression effect: the free radicals (hydrogen radicals and carbon radicals) generated in the pyrolysis process of the PDMI particles can also combine with OH and H free radicals in the aluminum powder explosion space, capture the free radicals required for the aluminum powder explosion, reduce the concentration of the combustion reaction free radicals, and block the explosion chain reaction, so as to chemically suppress the explosion. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 IR spectra of dimethyl itaconate (DMI) and polydimethyl itaconate (PDMI) prepared in Example 1;

[0020] Figure 2 1H NMR spectra of dimethyl itaconate (DMI) and polydimethyl itaconate (PDMI) prepared in Example 1, wherein (a) is dimethyl itaconate and (b) is polydimethyl itaconate;

[0021] Figure 3 Thermal analysis curves of polydimethyl itaconate prepared in Example 1 under different atmospheres, wherein (a) is a nitrogen atmosphere and (b) is an air atmosphere;

[0022] Figure 4 It is the flame propagation process of aluminum powder explosion and combustion;

[0023] Figure 5 This is the flame propagation process of aluminum powder explosion and combustion after adding 20wt% polymethyl itaconate. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0026] All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains unless otherwise specifically defined herein. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All documents mentioned herein are incorporated by reference to disclose and describe in full the methods and / or materials which are described therein. In case of conflict between the content of the specification and that of any document incorporated herein by reference, the content of the specification prevails.

[0027] Many modifications and variations of the present application described in the specification are possible without departing from the scope or spirit of the application. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples are illustrative only.

[0028] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean inclusion, but not limited to, the listed materials and methods.

[0029] Example 1

[0030] A polydimethyl itaconate explosion suppression material:

[0031] (I) Preparation method of polydimethyl itaconate:

[0032] 15wt% dispersant (basic magnesium carbonate, amount is 15% of the mass of dimethyl itaconate) and 2wt% sodium dodecyl benzene sulfonate (SDBS, amount is 2% of the mass of dimethyl itaconate) were added to a 250mL three-necked flask containing 80mL deionized water, nitrogen was introduced and stirred for 30min, then 15.82g of dimethyl itaconate (DMI) and 1wt% of dimethyl azobis isobutyrate (AIBME, amount is 1% of the mass of dimethyl itaconate) were added to the three-necked flask and mixed uniformly, the stirring was continued and the temperature was raised to 70℃ for 9h, after the reaction was completed, the product was washed with appropriate amount of 10wt% dilute hydrochloric acid and deionized water, dissolved in dichloromethane and precipitated in ethanol, after suction filtration, it was dried in a vacuum oven at 60℃, ground and sieved through a 40 mesh sieve to obtain polydimethyl itaconate (PDMI).

[0033] The chemical reaction equation is as follows:

[0034]

[0035] The infrared spectrum (FTIR) of dimethyl itaconate (DMI) and polydimethyl itaconate (PDMI) is shown in Figure 1 .

[0036] As can be seen from Figure 1 , the peak at 2956cm-1 The stretching vibration absorption peak of methyl CH is at 2847 cm -1 The stretching vibration absorption peak of methylene CH is at 1737 cm -1 is the stretching vibration absorption peak of C=O, 1438cm -1 The peak at 1198 cm is the CH bending vibration absorption peak. -1 Nearby is the stretching vibration absorption peak of CO, at 1639cm -1 The disappearance of the C=C stretching vibration absorption peak at 370 nm indicated the successful synthesis of poly(dimethyl itaconate).

[0037] H NMR spectra of dimethyl itaconate (DMI) and polydimethyl itaconate (PDMI) ( 1 HNMR) see Figure 2 . Figure 2 In the figure, (a) is the H NMR spectrum of dimethyl itaconate, and (b) is the H NMR spectrum of dimethyl polyitaconate.

[0038] from Figure 2 As can be seen in Figure (a), characteristic peaks a (δ = 6.27 ppm) and b (δ = 5.67 ppm) correspond to the hydrogen protons of the vinyl group (CH2=C) on DMI. Characteristic peaks c (δ = 3.71 ppm) and d (δ = 3.64 ppm) correspond to the hydrogen protons of the methoxy (-OCH3) groups on the two side groups of DMI, respectively. Characteristic peak e (δ = 3.29 ppm) corresponds to the hydrogen protons of the methylene (-CH2-) group of DMI.

[0039] Figure 2 It can be seen from Figure (b) that the characteristic peak a (δ = 3.63ppm) and peak b (δ = 3.55ppm) correspond to the hydrogen protons of the methoxy group (-OCH3) on the polymer side chain, the characteristic peak c (δ = 2.61~2.70ppm) corresponds to the hydrogen protons on the methylene group on the PDMI side chain, and the characteristic peak d (δ = 2.34ppm) corresponds to the hydrogen protons of the methylene group (-CH2-) on the PDMI main chain. The above analysis illustrates the successful preparation of PDMI.

[0040] In addition, the number average molecular weight of PDMI was measured by gel permeation chromatography (GPC) and was M n =27516g / mol, weight average molecular weight is M w =41567 g / mol, polydispersity index PDI =1.51, further proving the synthesis of PDMI.

[0041] Thermal analysis curves of polydimethyl itaconate under different atmospheres are shown in Figure 3 . Figure 3 In the figure, (a) is nitrogen atmosphere, and (b) is air atmosphere;

[0042] From Figure 3 It can be seen from the (a) figure (thermal analysis curve of dimethyl polyoxymethylene citrate under nitrogen atmosphere) that under nitrogen atmosphere, from the TG and DTG curves, it can be seen that PDMI starts to thermally decompose at 257.3℃, the thermal weight loss rate reaches the highest at 319.7℃, and is basically completely decomposed at 487.3℃, and the final residue mass is 6.39%. And from the DSC curve, it can also be seen that there is an obvious endothermic peak at about 319.7℃, which also proves that the thermal decomposition of PDMI is an endothermic process, and therefore can be used as an explosion suppression material.

[0043] From Figure 3 It can be seen from the (b) figure (thermal analysis curve of dimethyl polyoxymethylene citrate under air atmosphere) that under air atmosphere, dimethyl polyoxymethylene citrate has no significant difference with the thermal analysis curve under nitrogen atmosphere before 420℃, indicating that the endothermic process of thermal decomposition in this temperature range is mainly the random chain scission and depolymerization of the polymer, and the residue mass at this stage is 6.95%. There is a difference between the thermal analysis curve under air atmosphere and that under nitrogen atmosphere above this temperature, and the DSC curve shows an exothermic peak at 432.5℃ and 483.2℃, proving that the residual product at this stage has undergone oxidation reaction, and the final residue mass is 0.52%, and the thermal decomposition is more complete.

[0044] (II) Explosion suppression effect of dimethyl polyoxymethylene citrate explosion suppression material

[0045] The flame propagation suppression effect of dimethyl polyoxymethylene citrate (PDMI) powder prepared in Example 1 on metal aluminum dust was tested by using Hartmann tube flame blocking device. The dimethyl polyoxymethylene citrate (PDMI) powder was added to the aluminum powder (the amount of PDMI was 20% of the mass of aluminum powder), and the mixture was mixed uniformly and then put into the dust bin.

[0046] After the experiment started, the mixed dust was first blown from the dust bin into the vertical combustion tube by using 0.2 MPa compressed air (the concentration of aluminum powder in the combustion tube was controlled to be 300 g / m 3 , and the concentration of PDMI was 60 g / m 3 ), to form a dust cloud. Then, 1000 mJ of ignition current was released by using 15 kV excitation voltage under an ignition delay time of 60 ms to ignite the dust cloud, so that the flame propagated upward.

[0047] A high-speed camera was used to record the flame propagation process at a shooting speed of 6000 frames, and the suppression effect of the inhibitor was judged based on the flame front, the average flame propagation speed, the flame brightness and other physical parameters.

[0048] When no explosion inhibitor is added, the dust cloud dispersed in the pipeline is ignited and rapidly spreads outward from the ignition center, the flame shape is relatively regular, the outline is clear, the flame front is relatively continuous, and the flame propagation speed is relatively fast. The flame brightness is relatively strong, indicating that the aluminum dust combustion and oxidation reaction is strong. When 20wt% of PDMI based on the mass of aluminum powder is added, the maximum height of the flame is significantly reduced, the flame brightness is significantly darkened, the flame emission area is significantly reduced, the flame front is broken, the flame becomes sparse and dispersed, and the propagation speed is reduced, indicating that PDMI effectively inhibits the explosion and combustion of aluminum powder and the propagation of the flame.

[0049] According to the TG curve (i.e. Figure 3 The analysis of the flame shape change and the TG and DTG curves shows that the explosion inhibition effect of PDMI particles (100-400 microns) is derived from the following two aspects: first, the physical inhibition effect. PDMI particles have a large specific surface area and strong adsorption with aluminum powder, which can make aluminum powder adsorbed on the surface of PDMI particles, reduce the surface area of aluminum powder in contact with oxygen, and inhibit the violent oxidation reaction of aluminum powder. In addition, when the explosion reaction of aluminum powder occurs in a closed space, the energy transfer between the aluminum powder can be blocked by PDMI particles, weakening the heat transfer. At the same time, the thermal decomposition temperature range of PDMI is relatively wide, mainly 260-420℃, and the maximum decomposition rate occurs at about 315℃. The thermal decomposition of PDMI particles between aluminum powder can absorb the heat released in the combustion reaction zone, reduce the aluminum dust combustion flame temperature, weaken the pyrolysis of unburned aluminum powder particles, and reduce the pyrolysis and oxidation rate of aluminum powder particles. Moreover, the thermal decomposition of PDMI particles produces non-combustible gaseous products (thermal decomposition products) such as CO2 and H2O(g), which can dilute the oxygen concentration and block the violent reaction of unburned aluminum powder with oxygen.

[0050] As for the chemical inhibition effect, the free radicals (hydrogen radicals, carbon radicals) produced during the thermal decomposition of PDMI particles can also combine with OH and H radicals in the explosion space of aluminum powder, capture the free radicals required for aluminum powder explosion, reduce the concentration of combustion reaction free radicals, and block the explosion chain reaction, thereby playing a chemical inhibition role in the explosion.

[0051] Comparative Example 1

[0052] Polydipropyl and polydibutyl of polyigkonate with more than 3 C in the side chain of monomer are viscous liquids, and it is impossible to form explosion inhibitor in the form of spraying. Polyigkonate diethyl is difficult to polymerize.

[0053] Comparative Example 2

[0054] Polyigkonate dimethyl with a number average molecular weight of less than 20000 g / mol is a viscous liquid, and it is impossible to form explosion inhibitor in the form of spraying.

[0055] The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification and improvement made by those skilled in the art to the technical solutions of the present application without departing from the design spirit of the present application shall fall within the protection scope of the present application.

Claims

1. An application of polydimethyl itaconate as an explosion suppression material, characterized in that: The structural formula of the polymethyl itaconate is shown in formula (1): Wherein, n is 100 to 300; The polydimethyl itaconate has a number average molecular weight of 20,000 to 40,000 g / mol, a weight average molecular weight of 10,000 to 41,567 g / mol, and a polydispersity coefficient of 1.51 to 2; The application method specifically includes: uniformly mixing the metal dust and the polydimethyl itaconate to achieve explosion suppression.

2. The use according to claim 1, characterized in that The preparation method of polydimethyl itaconate comprises the following steps: The dispersant, surfactant and solvent are mixed evenly, and then dimethyl itaconate and initiator are added and mixed evenly, and the mixture is heated for reaction and then purified to obtain the polydimethyl itaconate.

3. The use according to claim 2, characterized in that The dispersant includes basic magnesium carbonate; the surfactant includes sodium dodecylbenzenesulfonate; and the initiator includes dimethyl azobisisobutyrate.

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