Polyitaconic acid dimethyl ester explosion suppression material

Abstract

The invention discloses a dimethyl polyitaconate explosion suppression material, and belongs to the technical field of explosion suppressant preparation. The preparation method of the polyitaconic acid dimethyl ester comprises the following steps: uniformly mixing a dispersing agent, a surfactant and a solvent, then adding dimethyl itaconate (DMI) and an initiator, uniformly mixing, heating to react, and purifying to obtain the polyitaconic acid dimethyl ester. The polyitaconic acid dimethyl ester disclosed by the invention can play a physical inhibition role and a chemical inhibition role on combustion of dust, and has a very good explosion suppression effect.

Description

Technical Field

[0001] The invention relates to the technical field of explosion suppressant preparation, in particular to a polydimethyl itaconate explosion suppressant material. Background Art

[0002] When metal dust encounters open flames or high-temperature heat sources in the air, a violent combustion reaction may occur, producing high-temperature and high-pressure gas and flames, forming metal dust explosion. Metal dust explosion is a serious industrial safety accident that will not only cause casualties and equipment damage, but also cause secondary accidents, such as fires and toxic gas leaks. At present, there are mainly the following methods at home and abroad to prevent and suppress dust explosions: first, eliminate the ignition source; second, avoid the formation of dust clouds; third, adopt a series of protective measures such as isolation, discharge, and ventilation; fourth, add explosion suppressants. However, due to the large number of potential ignition sources in industrial production, and there are many unavoidable electrostatic environments and electrostatic effects, it is almost impossible to eliminate the ignition source. During powder processing, a large amount of dust will be 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 a dust cloud. Taking a series of protective measures such as ventilation, discharge, and isolation can indeed effectively reduce the possibility of dust explosions, but if these protective measures fail, the consequences will be unimaginable. Although adding explosion suppressants can prevent dust explosions to a certain extent, there is a lack of efficient, environmentally friendly and economical explosion suppressants. Summary of the invention

[0003] The purpose of the present invention is to provide a polydimethyl itaconate explosion suppression material to solve the problems existing in the above-mentioned prior art.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] One of the technical solutions of the present invention is to use dimethyl polyitaconate as an explosion suppression material, wherein the structural formula of dimethyl polyitaconate is as shown in formula (1):

[0006]

[0007] Among them, n is 100~300.

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

[0009] Furthermore, the preparation method of polydimethyl itaconate comprises the following steps:

[0010] The dispersant, the surfactant and the solvent are mixed evenly, and then dimethyl itaconate (DMI) and the initiator are added and mixed evenly, and the mixture is heated for reaction and then purified to obtain the polydimethyl itaconate.

[0011] Furthermore, the dispersant includes basic magnesium carbonate; the surfactant includes sodium dodecylbenzene sulfonate (SDBS); and the initiator includes dimethyl azobisisobutyrate (AIBME).

[0012] Furthermore, the application method specifically includes: mixing the metal dust and the polymethyl itaconate evenly to achieve explosion suppression.

[0013] The second technical solution of the present invention: an explosion suppression material, the main component of which includes dimethyl polyitaconate.

[0014] The present invention discloses the following technical effects:

[0015] The polymethyl itaconate of the present invention can physically and chemically inhibit the combustion of dust, as follows:

[0016] Physical inhibition: PDMI particles have a large specific surface area and a strong adsorption effect 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 confined space, the energy generated by it can be blocked by PDMI particles between aluminum powders, weakening the transfer of heat. At the same time, the thermal decomposition temperature range of PDMI is relatively wide, mainly 260-420℃, and the maximum decomposition rate is around 315℃. The thermal decomposition of PDMI particles between aluminum powders can absorb the heat released in the combustion reaction zone, reduce the flame temperature of aluminum dust combustion, weaken the thermal decomposition of unburned aluminum powder particles, and reduce the thermal decomposition oxidation rate of aluminum powder particles. In addition, the decomposition of PDMI particles will produce 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.

[0017] Chemical inhibition: the free radicals (hydrogen free radicals, carbon free radicals) generated during the pyrolysis of PDMI particles can also combine with the OH and H free radicals in the explosion space of aluminum powder, seize the free radicals required for the explosion of aluminum powder, reduce the concentration of free radicals in the combustion reaction, and block the explosion chain reaction, thereby playing a role in chemical inhibition of the explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

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

[0020] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum 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 The 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 should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

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

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] Example 1

[0030] A polydimethyl itaconate explosion suppression material:

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

[0032] 15wt% dispersant (basic magnesium carbonate, 15% of the mass of dimethyl itaconate) and 2wt% sodium dodecylbenzene sulfonate (SDBS, 2% of the mass of dimethyl itaconate) were added to a 250mL three-necked flask containing 80mL of deionized water, and nitrogen was introduced and stirred for 30min. Then, 15.82g of dimethyl itaconate (DMI) and 1wt% of dimethyl azobisisobutyrate (AIBME, 1% of the mass of dimethyl itaconate) were added to the three-necked flask and mixed evenly. The mixture was stirred continuously and heated to 70°C for 9h. After the reaction, the product was washed with appropriate amounts of 10wt% dilute hydrochloric acid and deionized water, dissolved in dichloromethane and precipitated in ethanol, filtered and dried in a vacuum oven at 60°C, 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 spectra (FTIR) of dimethyl itaconate (DMI) and polydimethyl itaconate (PDMI) are shown in Figure 1 .

[0036] from Figure 1 It can be seen that 2956cm-1 The stretching vibration absorption peak of methyl CH is 2847 cm -1 The stretching vibration absorption peak of methylene CH is 1737 cm -1 is the stretching vibration absorption peak of C=O, 1438cm -1 The peak of CH bending vibration is 1198 cm -1 Nearby is the stretching vibration absorption peak of CO, at 1639cm -1 The disappearance of the C=C stretching vibration absorption peak at 147° indicated the successful synthesis of poly(dimethyl itaconate).

[0037] H NMR spectra of dimethyl itaconate (DMI) and polydimethyl itaconate (PDMI) ( 1 HNMR) 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), the 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. The characteristic peaks c (δ = 3.71 ppm) and d (δ = 3.64 ppm) correspond to the hydrogen protons of the methoxyl group (-OCH3) on the two side groups of DMI. The characteristic peak e (δ = 3.29 ppm) corresponds to the hydrogen protons of the methylene group (-CH2-) 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). n =27516 g / mol, weight average molecular weight is M w =41567 g / mol, polydispersity index PDI =1.51, which further proves the synthesis of PDMI.

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

[0042] from Figure 3 As can be seen from Figure (a) (thermal analysis curve of polydimethyl itaconate in nitrogen atmosphere), under nitrogen atmosphere, from the TG and DTG curves, it can be seen that PDMI starts to lose weight by thermal decomposition at 257.3℃, the thermal weight loss rate reaches the highest at 319.7℃, and it is basically decomposed completely at 487.3℃, and the final residue mass is 6.39%. From the DSC curve, it can also be seen that there is an obvious endothermic peak around 319.7℃, which also proves that the thermal decomposition of PDMI is an endothermic process, so it can be used as an explosion suppression material.

[0043] from Figure 3 It can be seen from Figure (b) (thermal analysis curve of polymethyl itaconate in air atmosphere) that in air atmosphere, there is no obvious difference between the thermal analysis curve of polymethyl itaconate and that in nitrogen atmosphere before 420°C, indicating that the endothermic process of thermal decomposition in this temperature range is mainly the random chain breaking and depolymerization of the polymer, and the mass of the residue at this stage is 6.95%. However, above this temperature, there is a difference from the thermal analysis curve in nitrogen atmosphere, and the DSC curve has exothermic peaks at 432.5°C and 483.2°C, 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 polydimethyl itaconate explosion suppression material

[0045] The inhibitory effect of the polymethyl itaconate (PDMI) powder prepared in Example 1 on the flame propagation of metal aluminum dust was tested using a Hartmann tube flame blocking device. Polymethyl itaconate (PDMI) powder was added to the aluminum powder (the amount of PDMI was 20% of the mass of the aluminum powder), which was fully mixed and then placed in a dust bin.

[0046] After the experiment started, the mixed dust was blown from the dust bin into the vertical combustion tube using 0.2MPa compressed air (the concentration of aluminum powder in the combustion tube was controlled to be 300g / m 3 , the concentration of PDMI is 60g / m 3 ), forming dust. Then the 15kV excitation voltage releases 1000mJ of ignition current to ignite the dust cloud with an ignition delay time of 60ms, causing the flame to propagate upward.

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

[0048] When no explosion suppressant is added, the dust cloud dispersed in the pipeline spreads rapidly from the ignition center to the outside after being ignited. The flame shape is relatively regular, the outline is clear, the flame front is relatively continuous, and the flame propagation speed is fast. The flame brightness is strong, indicating that the aluminum dust combustion oxidation reaction is strong. When 20wt% of the mass of aluminum powder is added, the maximum height of the flame is significantly reduced and the flame brightness is significantly dimmed. The luminous area of ​​the flame is significantly smaller, the degree of fragmentation of the flame front increases, the flame becomes sparse and discrete, and the propagation speed decreases, indicating that PDMI effectively inhibits the explosive combustion and flame propagation of aluminum powder.

[0049] According to TGA (i.e. Figure 3 The TG curve in the graph, the DTG curve and the flame morphology change analysis show that the explosion suppression effect of PDMI particles (100-400 microns) comes from the following two aspects: First, the physical suppression effect. PDMI particles have a large specific surface area and a strong adsorption effect 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 aluminum powder explosion reaction occurs in a confined space, the energy generated by it can be blocked by PDMI particles between aluminum powders, 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 powders can absorb the heat released in the combustion reaction zone, reduce the combustion flame temperature of aluminum dust, weaken the thermal decomposition of unburned aluminum powder particles, and reduce the thermal decomposition oxidation rate of aluminum powder particles. In addition, the decomposition of PDMI particles will produce 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] In terms of chemical inhibition, the free radicals (hydrogen radicals, carbon radicals) generated during the pyrolysis of PDMI particles can also combine with the OH and H radicals in the explosion space of aluminum powder, seize the free radicals required for the explosion of aluminum powder, reduce the concentration of free radicals in the combustion reaction, and block the explosion chain reaction, thereby playing a role in chemical inhibition of the explosion.

[0051] Comparative Example 1

[0052] Poly(propylene) and poly(butyl)itaconate with monomer side chains greater than 3 carbon atoms are viscous liquids and cannot be formed into a sprayable explosion suppressant; poly(diethyl)itaconate is difficult to polymerize.

[0053] Comparative Example 2

[0054] Polydimethyl itaconate with a number average molecular weight lower than 20,000 g / mol is a viscous liquid and cannot be formed into a sprayable explosion suppressant.

[0055] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

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): Among them, n is 100~300.

2. The use according to claim 1, characterized in that: The number average molecular weight of the polydimethyl itaconate is 20000-40000 g / mol, the weight average molecular weight is 10000-41567 g / mol, and the polydispersity coefficient is 1.51-2.

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

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

5. The use according to claim 1, characterized in that: The application method specifically comprises: uniformly mixing the metal dust and the polymethyl itaconate to achieve explosion suppression.

6. An explosion suppression material, characterized in that: The main ingredients include dimethyl polyitaconate.

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