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Plasma polymerization analysis of heat-sensitive polymer coating with low temperature plasma treatment technology

Plasma polymerization analysis of heat-sensitive polymer coating with low temperature plasma treatment technology

Plasma polymerization analysis of heat-sensitive polymer coating with low temperature plasma treatment technology: Plasma technology is more and more widely used in production, life and other fields. The surface modification of plasma materials is relatively convenient, clean, free from environmental interference, and has no restrictions on the types of materials. In plasma polymerization, N-isopropylacrylphthalamide monomer is carried, and enters into the reaction area to prepare N-isopropylacrylamide polymer on the surface of glass slide and polystyrene. Low temperature plasma mainly refers to a partially ionized gas generated by high temperature or gas discharge in industrial equipment or laboratories, which interacts with other substances. The plasma is mainly obtained by the gas discharge generated by the AC or DC power supply, and has a certain stability. The low temperature plasma is mostly generated in the form of gas discharge. In terms of the design of the plasma polymerization device, in order to promote the surface of the base material to obtain the N-isopropylacrylamide polymerized film, a solution bottle containing N-isopropylacrylamide was placed between the reaction chamber and the Ar gas cylinder. Monomer plasma polymerization can be achieved in a vacuum environment. At room temperature, N-isopropyl acrylphthalamide is white crystal, soluble in water, and the functional film produced has high temperature sensitivity, has a controlling effect on gel permeation chromatography and liquid chromatography packing, and can be used as temperature thickening agent, wound patch, resistive ink, anti-stain, etc. Poly-N-isopropylacrylophthalamide is a kind of heat-sensitive polymer material with good physiological compatibility and remarkable phase separation properties. It is widely used in substance separation and purification, drug controlled release and so on. Based on the atmospheric pressure environment, N-isopropyl acrylamide can be polymerized through dielectric barrier discharge, and the film is mainly obtained from the surface of the glass slide and polystyrene. During the polymerization process, a solution bottle containing N-isopropylpropene can be placed between the discharge area and the Ar gas bottle. When the gas in the Ar gas bottle is completely released, the solution is invaded through a long conduit (solution bottle), and then exported through a short conduit, and then N-isopropyl acrylic amine monomer is placed in the discharge area. The longer the polymerization time is, the thicker the film becomes, and the contact angle tends to increase, which is mostly due to the use of hydrophilic materials, which leads to an increase in the permeability of water droplets on its surface. In addition, nitrogen elements were introduced into the surface of the glass slide after polymerization treatment, and the components contained N-isopropylacrylamide monomer and polymer. The N-isopropyl acrylamide polymer film was obtained by plasma polymerization, and the thermal sensitivity of the polymer film was measured with the help of a temperature control device and a contact angle meter, which fully proved the spatial existence of poly-N-isopropyl acrylamide. The low-temperature plasma material processing technology has been fully applied in the fields of production and life, and it is believed that it will have a wider application space in other fields.

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The vacuum plasma surface treatment equipment will not produce a damaged layer on the surface of the material after treatment

The vacuum plasma surface treatment equipment will not produce a damaged layer on the surface of the material after treatment

The vacuum plasma surface treatment equipment will not produce a damaged layer on the surface of the material after treatment: Vacuum plasma surface treatment equipment uses plasma treatment to improve the adhesion and adhesion of the material surface. By removing organic pollutants, polar organic functional groups are introduced on the surface to improve the surface hydrophilicity and surface wetting performance, which is a thorough peeling. Dry cleaning, vacuum plasma surface treatment equipment will not produce a damaged layer on the surface of the material, and the surface quality of the material is guaranteed. Plasma surface treatment uses oxygen and argon gas to generate energy. When there is enough energy to open the carbon-fluorine bond of PTFE and fluorine atoms are replaced by active groups, PTFE will become Polar polymer with enhanced surface energy and improved hydrophilicity. According to the different shapes, processing purposes and requirements of the PTFE Teflon products to be processed, there will be differences. For example, film materials are suitable for use in roll-to-roll plasma equipment; plate materials are suitable for plasma cleaning machines with horizontal or vertical electrode structures. The control of the process parameters of the vacuum plasma surface treatment equipment has an important influence on the treatment of PTFE polytetrafluoroethylene materials. Plasma surface treatment equipment includes low-pressure vacuum plasma surface treatment equipment and atmospheric plasma surface treatment equipment. The former can be fed with different process gases and a number of process parameters can be deployed, which is relatively suitable for the treatment of PTFE polytetraoxide. Plasma surface treatment equipment, also known as plasma cleaning machine, or plasma surface treatment instrument, is a brand-new high-tech technology that uses plasma to achieve results that cannot be achieved by conventional cleaning methods. Plasma is a state of matter, also known as the fourth state of matter, and does not belong to the common solid-liquid-gas three-state. When enough energy is applied to a gas to ionize it, it becomes a plasma state. The "active" components of the plasma include: ions, electrons, atoms, reactive groups, excited nuclides (metastable states), photons, etc. If a reactive gas is introduced into the discharge gas of the vacuum plasma surface treatment equipment, a complex chemical reaction will occur on the surface of the activated material, and new functional groups, such as hydrocarbon groups, amino groups, carboxyl groups, etc., will be introduced. Significantly improve the surface activity of the material. Generally, materials such as NH3, O2, CO, Ar, N2, H2 and other gas plasma treatment will be exposed to air, and groups such as -COOH will be introduced on the surface to increase their hydrophilicity.

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The effect of plasma plasma energy density on the conversion of reactants CH4 and CO2, C2 hydrocarbons, and CO yields

The effect of plasma plasma energy density on the conversion of reactants CH4 and CO2, C2 hydrocarbons, and CO yields

The effect of plasma plasma energy density on the conversion of reactants CH4 and CO2, C2 hydrocarbons, and CO yields: The effect of plasma energy density on the conversion rates of CH4 and CO2, the yields of C2 hydrocarbons and CO. It can be seen that the conversion rates of CH4 and CO2 both increase with the increase of energy density, which means increasing plasma plasma power and decreasing feed gas flow. That is, increasing the energy density is beneficial to improve the conversion rate of CH and CO2. When the energy density is 2200kJ/mol, the conversion rates of CH4 and CO2 are 43.6% and 58.4%, respectively. Although increasing the energy density is beneficial to improve the conversion rate of CH4 and CO2, it is beneficial to the cleavage of the C-H bond of methane (4.5eV) and the cleavage of the C-O bond of carbon dioxide (5.45eV), but the effects on the two are not the same. When the energy density is lower than 1500KJ/mol, the CH4 conversion rate is higher than the CO2 conversion rate under the same experimental conditions, which means that at a lower energy density, the average energy of the high-energy electrons in the system is lower, and the average energy of most electrons and the CH bond of methane is The bond energy is similar but lower than the cracking energy of carbon dioxide CO bond, so the CH4 conversion rate is higher than the CO2 conversion rate. When the energy density is higher than 1500 kJ/mol, the average energy of electrons in the system increases, and the energy of most electrons gradually approaches the cracking energy of carbon dioxide C-O bond, and the CO2 conversion rate increases rapidly. At the same time, the conversion rate of CH4 showed a logarithmic upward trend with the increase of energy density, and the conversion rate of CO2 showed a linear upward trend with the increase of energy density. This may be related to the cracking characteristics of methane and carbon dioxide under plasma plasma. Methane is cracked successively, that is, the conversion of one methane molecule often consumes multiple high-energy electrons. Methane. A lower energy density should be chosen for methane conversion. The influence of energy density on the yields of C2 hydrocarbons and CO both showed a linear upward trend with the increase of energy density, and the linear slope of CO yield was significantly higher than that of C2 hydrocarbon yield. For the C2 hydrocarbon yield, when the energy density was increased from 350 kJ/mol to 2200 k.J/mol, the C2 hydrocarbon yield increased from 5.7% to 20.6%, an increase of nearly 15 percentage points. For the CO yield, when the energy density increased from 350 kJ/mol to 2200 kJ/mol, the CO yield increased from 11.6% to 76.4%, an increase of nearly 65 percentage points. This shows that in the energy range investigated in the experiment, increasing the energy density is beneficial to improve the yield of C2 hydrocarbons and CO, but from the perspective of energy consumption, it is not comprehensive to measure the reaction efficiency only by the product yield, so it is necessary to introduce energy Efficiency This physical quantity evaluates the CO2 oxidation CH4 conversion reaction under the action of plasma plasma. Since no direct evidence for the conversion of CO2 to C2 hydrocarbons can be obtained under the experimental conditions, it can be considered that the C2 hydrocarbons originate from the coupling reaction of methane: CH4 → 0.5C2H6+0.5H2 ∆H11 =32.55kJ/mol (4-2) CH4 → 0.5C2H4+1H2 ∆H12=101.15kJ/mol (4-3) CH4 → 0.5C2H2+1.5H2 ∆H13=188.25kJ/mol (4-4) Coupling the above three reaction equations and considering the distribution of C2 hydrocarbon products, the overall reaction equation of methane coupling to form C2 hydrocarbons can be expressed as CH4 → 0.5n11C2H6+0.5n12C2H4+0.5n13C2H2+(2-1.5n11-n12-0.5n13)H2 ∆H1=(32.55n11+101.15n12+188.25n13)kJ/mol (4-5) n11, n2, n3 in formula (4-5) represent respectively: n11 is the mole fraction of C2H6 in the C2 hydrocarbon product, mol/%; n12 is the C2 hydrocarbon

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The reaction mechanism of O2 oxidation of CH4 under the action of plasma cold plasma to prepare C2 hydrocarbon reaction

The reaction mechanism of O2 oxidation of CH4 under the action of plasma cold plasma to prepare C2 hydrocarbon reaction

The reaction mechanism of O2 oxidation of CH4 under the action of plasma cold plasma to prepare C2 hydrocarbon reaction: The free radical reaction induced by plasma plasma is very similar to the heterogeneous catalytic reaction, but plasma plasma is a very effective free radical initiation method. The current consensus on the reaction mechanism of CO2 oxidation of CH4 to prepare C2 hydrocarbons in one step is that CO2 decomposes under the action of plasma to generate CO and excited and metastable reactive oxygen species. These oxygen species react in the oxidative coupling reaction of methane. is very active, according to the main products of the reaction are C2H6, C2H4, C2H2, CO and H2, the possible reaction mechanism is as follows: (1) generate oxygen species CO2 + e → CO + 0- (4-9) CO2 + e → CO + 0 + e (4-10) (2) generate methyl radical CH4 + 0- → CH3∙ + 0H- (4-11) CH4 + O → CH3∙ + OH (4-12) (3) generate C2 hydrocarbons CH3 + CH3 → C2H6 (4-13) C2H6 + e → C2H5 + H + e (4-14) C2H6 + O → C2H5 +OH (4-15) 2C2H5 → C2H4 + C2H6 (4-16) C2H5 + CH3 → C2H4 + CH4 (4-17) (4) Generate CO CHX + O → HCHO + H (4-18) HCHO + O → OH +CHO (4-19) CHO + O → OH + CO (4-20) As an effective free radical initiation method, plasma cold plasma has been successfully used in CO2 oxidation of CH4 to produce C2 hydrocarbons in one step, and has achieved better experimental results than chemical catalysis. However, the selectivity of C2 hydrocarbon products is low, and the reaction mechanism is still unclear. Therefore, it is necessary to conduct in-depth research on the one-step preparation of C2 hydrocarbons from CO2 oxidation of CH4 under the action of plasma. Using the emission spectroscopy method, many kinds of excited state species in the plasma plasma can be effectively detected in the ultraviolet-visible band, without disturbing the plasma reaction system, and in-situ analysis can be realized. Therefore, in recent years, research reports on the application of emission spectroscopy in-situ diagnostic technology to plasma systems have been increasing, but they mainly focus on the research on the deposition system of CH4-H2 diamond thin film under plasma conditions. The in situ diagnostic technique of emission spectrometry was used to analyze the reactive species of CH4 in the CO2 oxidation CH reaction system under plasma conditions with different CO2 addition amounts.

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CH4 and CO2 reforming reaction under the combined action of DBD plasma and catalyst

CH4 and CO2 reforming reaction under the combined action of DBD plasma and catalyst

CH4 and CO2 reforming reaction under the combined action of DBD plasma and catalyst: The conversion reaction of CO2 oxidation to CH4 under the action of plasma is mainly initiated by free radicals, and the target product C2 hydrocarbon has poor selectivity. The CO2 oxidation CH4 conversion reaction under chemical catalysis has higher selectivity of the target product. For example, the target product given by the supported nickel catalyst is syngas (CO+H2); the target product using lanthanide oxides as the catalyst is a C2 hydrocarbon. In the catalytic reaction, due to the high energy required to break the C-H bond of methane and the C-O bond of CO2, the synthetic route using C2 hydrocarbons as the target product has disadvantages such as high reaction temperature and low conversion rate of CH4. Wang et al. investigated the CH4 and CO2 reforming reaction under the combined action of DBD plasma and catalyst. The results show that the synergistic effect of the two can effectively improve the conversion rate of reactants and the selectivity of target products. Some research groups have also investigated the reforming reaction of CH4 and CO2 under the conditions of sliding arc discharge combined with catalyst, and the experimental results all show that the synergistic effect of the two is obvious.  The plasma-catalytic co-activation method is used to promote the conversion of methane into the target product C2 hydrocarbons. Although the heterogeneous catalysis of plasma may occur in the plasma area, plasma afterglow area and product collection area, because the pulsed corona plasma works under normal pressure, the particle density in the system is high and the collision probability is high, so The active particles such as free radicals have extremely short lifetimes, and the heterogeneous catalysis that occurs in the plasma region is mainly studied.

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Catalytic activity of plasma supported alkaline earth metal oxide catalysts

Catalytic activity of plasma supported alkaline earth metal oxide catalysts

Catalytic activity of plasma supported alkaline earth metal oxide catalysts: The research on the reaction of CO2 oxidation of CH4 to C2 hydrocarbons under the combined action of plasma plasma and carrier shows that the acidic carrier Y-Al2O3 has a high methane conversion rate (43.4%), but the C2 hydrocarbon selectivity is low (30.6%): basic carrier MgO has a low methane conversion (17.8%), but a high C2 hydrocarbon selectivity (57.4%). If MgO is loaded on Y-Al2O3, can a higher C2 hydrocarbon selectivity be obtained on the basis of maintaining a certain methane conversion rate? Wang and Ohtsuka used the catalytic activation method to study the reaction of CO2 oxidation of CH to C2 hydrocarbons. The results show that some alkaline earth metal oxides such as CaO have high catalytic activity, which can improve the C2 hydrocarbon selectivity to a certain extent. The reaction of CO2 oxidation of CH4 to C2 hydrocarbons under the action of MgO/Y-Al2O3, CaO/Y-Al2O3, SrO/Y-Al2O3 and BaO/Y-Al2O3 was investigated under plasma conditions (Table 4-2). Compared with the result of Y-Al2O3 on the carrier, the CH conversion rate was decreased, but the C2 hydrocarbon selectivity was increased by more than 40 percentage points, indicating that the catalytic activity can be improved by loading basic active components on the acidic carrier. Under certain plasma conditions, the CH4 conversion and C2 hydrocarbon yield have a certain relationship with the basicity of MgO, CaO, SrO and BaO, that is, the basicity helps to improve the CH4 conversion and C2 hydrocarbon yield. For alkaline earth metal oxides, the basicity increases with increasing atomic number, so BaO/Y-Al2O3 and plasma can work together to obtain higher C2 hydrocarbon yields. Therefore, the catalytic activity sequence of the supported alkaline earth metal oxide catalysts under plasma ion conditions is BaO/Y-Al2O3 > SrO/Y-Al2O3 > CaO/Y-Al2O3 > MgO/Y-Al2O3. The effect of alkaline earth metal oxides on the distribution of C2 hydrocarbon products shows that they have little effect on the distribution of C2 hydrocarbon products. Acetylene is the major C2 hydrocarbon product. Table 4-2 Effects of alkaline earth metal oxide catalysts on the reaction (unit: %) Catalyst Xat Xco, sc. Yc Yco Y-Al2O3 43.4 16.7 30.6 13.4 37.1 MgO/Y-Al2O3 24.0 20.2 62.9 15.1 33.9 CaO/Y-Al2O3 24.4 19.3 64.3 15.7 34.4 SrO/Y-Al2O3 24.6 19.3 66.2 16.3 34.2 BaOr/Y-Al2O3 26.4 19.4 63.3 16.7 35.6 BaO loading and catalyst calcination temperature have a certain influence on the catalytic activity of supported alkali metal oxide catalysts. When the loading varies from 5% to 20%, with the increase of BaO loading, the conversion rates of CH4 and CO2 show the same trend. Peak-to-peak variation, peak high at 10% load. The yields of C2 hydrocarbons and CO basically changed in peak shape. This shows that the increase of BaO loading within a certain range is beneficial to improve the catalytic activity, but too high loading will lead to the accumulation of BaO on the surface of Y-Al2O3, which reduces the catalytic activity of the catalyst. The calcination temperature of the catalyst has an effect on the size and surface morphology of the active particles of the catalyst, and affects the reactivity of the catalyst to a certain extent. Generally speaking, at lower calcination temperature, it is easy to obtain highly dispersed small particles, and the lattice structure is often defective; at higher calcination temperature, larger particles are obtained. In the calcination temperature range of 400～800℃, the research on the effect of calcination temperature on the catalytic activity of 10%-BaO/Y-Al2O3 shows that when the calcination temperature is 400℃, the conversion rates of CH4 and CO2 are slightly higher than other calcination temperatures, but C2 hydrocarbons The low selectivity of C2 resulted in a decrease in the yield of C2 hydrocarbons. This is because at this temperature, the Ba(NO3)2 supported on the surface of Y-Al203 is not completely decomposed, which can be confirmed by the X-ray diffraction (XRD) spectrum of the sample; when the calcination temperature is between When the temperature is between 500 and 800 °C, the catalytic activity has little effect; when the reaction temperature is higher than 800 °C, Y-Al2O3 is transformed into δ-A12O3, and the reaction activity decreases.

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