A degradable rosin-based epoxy foam and a preparation method and application thereof

Abstract

The application discloses a degradable rosin-based epoxy foam and a preparation method and application thereof, and belongs to the technical field of shielding materials, and comprises the following steps: stirring and uniformly mixing propylenediamine-based latent foaming agent, propylenediamine, propylene abietic acid glycidyl ester and 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane, and obtaining the degradable rosin-based epoxy foam through reaction.The foaming agent used in the application is rapidly decomposed under heating conditions to release carbon dioxide and the curing agent propylenediamine, and the preparation is simple, environment-friendly and residue-free; the prepared epoxy foam is easy to degrade, excellent in electromagnetic shielding and joule heating performance, and has a wide application prospect in the fields of military equipment, aerospace and wearable electronic devices.

Description

TECHNICAL FIELD

[0001] The present application relates to a degradable rosin-based epoxy foam and its preparation method and application, belonging to the technical field of shielding materials. BACKGROUND

[0002] With the rapid development of portable electronic devices and communication technology, electromagnetic radiation pollution problems are increasingly prominent, which seriously affects human health and the normal operation of electronic devices; therefore, efficient electromagnetic shielding materials attract people's attention; in addition, the thermal regulation performance of the material can realize sensitive electro-thermal conversion to meet its practical application in cold regions. However, the traditional heating method usually has high energy consumption or requires a large area of insulating layer, which not only causes energy waste but also increases the weight of the equipment, and the temperature regulation driven by Joule heating shows great prospects due to its high efficiency, convenience and energy saving. Therefore, it is urgent to develop a material with high efficient electromagnetic shielding and excellent Joule heating performance to meet the use requirements of advanced electronic devices.

[0003] Currently, researchers have introduced conductive fillers or high-conductivity metal coatings into polymer foams to construct a conductive network, and the prepared conductive foam not only can effectively reduce the density of the material to meet the lightweight requirement, but also can enhance the attenuation of electromagnetic waves and improve the electromagnetic shielding performance through multiple reflections and scattering inside the porous structure. However, such materials are often prepared based on traditional petrochemical derivatives and cannot be degraded, which not only leads to the consumption of non-renewable petroleum resources but also causes serious environmental pollution, limiting their wide application in the field of electromagnetic shielding. Therefore, it is urgent to develop a biobased degradable material with high efficient electromagnetic shielding and Joule heating performance.

[0004] Epoxy foam has the properties of light weight, heat insulation and good stability, and is widely used in part weight reduction, thermal insulation and other fields. However, thermosetting epoxy foam is difficult to degrade and recycle, and the preparation of epoxy foam at present mostly uses sodium bicarbonate, supercritical CO2 and other foaming agents, which has complex production process and high cost. In view of the needs of sustainable development and environmental friendliness, degradable biobased epoxy foam materials have gradually attracted the attention of researchers. SUMMARY

[0005] In order to solve the defects of poor performance and non-degradability of electromagnetic shielding materials in the prior art, the present application provides a degradable rosin-based epoxy foam and its preparation method and application, which prepares a degradable rosin-based epoxy foam with high efficient electromagnetic shielding and Joule heating performance. The preparation method of the epoxy foam is simple, the foaming agent used has no residue, the cost is low, and the prepared epoxy foam material is easy to degrade and has excellent electromagnetic shielding and Joule heating performance.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of degradable rosin-based epoxy foam, comprising the following steps:

[0008] The propylenediamine-based latent blowing agent, propylenediamine, propylene pimaric acid glycidyl ester and 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane are stirred and uniformly mixed, and a reaction is performed to obtain the degradable rosin-based epoxy foam;

[0009] The preparation method of the propylenediamine-based latent blowing agent is that propylenediamine is dissolved in anhydrous ethanol, carbon dioxide gas is introduced, and a reaction is performed for 2-4 hours at room temperature to obtain the propylenediamine-based latent blowing agent;

[0010] The preparation method of the propylene pimaric acid glycidyl ester is that propylene pimaric acid, epichlorohydrin and benzyl triethyl ammonium chloride are reacted at 110-117 DEG C for 3-5 hours, then the temperature is lowered to 50-60 DEG C, sodium hydroxide is added, and a reaction is performed at 50-60 DEG C for 4-6 hours to obtain the propylene pimaric acid glycidyl ester.

[0011] Preferably, the mass ratio of the propylenediamine-based latent blowing agent, propylenediamine, propylene pimaric acid glycidyl ester and 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane is (0.1-0.3):1:(5-11):(3-7).

[0012] Preferably, the reaction condition in step (1) is that the temperature is kept at 50-70 DEG C for 20-40 minutes, and then the temperature is kept at 120-160 DEG C for 1-4 hours.

[0013] Preferably, the mass ratio of the propylene pimaric acid, epichlorohydrin, benzyl triethyl ammonium chloride and sodium hydroxide is (80-90):(400-410):1:(15-20).

[0014] The application further provides a degradable rosin-based epoxy foam prepared by any one of the preparation methods.

[0015] Meanwhile, the application provides application of the degradable rosin-based epoxy foam in electromagnetic materials.

[0016] Preferably, the application method of the application of the degradable rosin-based epoxy foam in electromagnetic materials comprises the following steps:

[0017] (1) the degradable rosin-based epoxy foam is immersed in an acidic stannous chloride solution, sensitized at room temperature, and then washed with deionized water for 10-30 minutes to obtain the sensitized degradable rosin-based epoxy foam;

[0018] (2) the sensitized degradable rosin-based epoxy foam is reacted in Tollens A solution for 0.5-1.5 h to obtain a chemically modified degradable rosin-based epoxy foam;

[0019] (3) the modified degradable rosin-based epoxy foam is placed in a mixture of a reducing solution and a silver salt solution for electroless plating for 1-2 h, and after drying, the process is repeated for 1-3 times to obtain a degradable rosin-based epoxy foam with conductive properties.

[0020] Preferably, the acid stannous chloride solution is prepared by dissolving stannous chloride dihydrate in a dilute hydrochloric acid solution to obtain an acid stannous chloride solution.

[0021] The silver salt solution is prepared by adding sodium hydroxide to Tollens B solution and stirring, and then continuously adding an ammonia solution until the solution becomes clear, and the obtained transparent solution is a silver salt solution.

[0022] Preferably, the Tollens A and Tollens B solutions are prepared by adding an ammonia solution to 3-5 g / L silver nitrate solution A and 10-20 g / L silver nitrate solution B, respectively, until the solution changes from turbid to clear, and Tollens A and Tollens B solutions are obtained, respectively.

[0023] The reducing solution is prepared by dissolving tartaric acid, glucose, ethylenediamine, ethanol and polyethylene glycol in deionized water to obtain a reducing solution.

[0024] Preferably, the mass ratio of tartaric acid, glucose, ethylenediamine, ethanol and polyethylene glycol is 1:(8-10):(3-5):(45-50):(0.2-0.5).

[0025] The techniques not mentioned in the present application refer to the prior art.

[0026] (1) The preparation method of the degradable rosin-based epoxy foam of the present application is simple, and the use of natural product derivatives to prepare the degradable rosin-based epoxy foam conforms to the green development concept. The foaming agent used has no residue, low cost, and the foaming agent used rapidly decomposes to release carbon dioxide and the curing agent propylene diamine under heating conditions.

[0027] (2) The prepared rosin-based epoxy foam has excellent degradability, electromagnetic shielding and joule heating performance, and the electromagnetic shielding effectiveness can reach 76.37 dB. The surface temperature of the degradable rosin-based epoxy foam reaches a steady state temperature within 90 s under the driving of a voltage of 0.4-1.0 V, and has wide application prospects in the fields of military equipment, aerospace and wearable electronic devices. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1A thermogravimetric analysis graph of the propylenediamine-based latent blowing agent prepared for Example 1; 13 A C NMR graph;

[0029] Figure 2 A thermogravimetric analysis graph of the propylenediamine-based latent blowing agent prepared for Example 1;

[0030] Figure 3 A DSC graph of the glycidyl acrylpimarate prepared for Example 1; 1 A H NMR graph;

[0031] Figure 4 An infrared spectrum graph of the degradable rosin-based epoxy foam prepared for Example 3;

[0032] Figure 5 A stress-strain curve graph of the degradable rosin-based epoxy foam prepared for Examples 1 to 4;

[0033] Figure 6 A reversible compression performance graph of the degradable rosin-based epoxy foam prepared for Example 3;

[0034] Figure 7 A degradation graph of the rosin-based epoxy foam prepared for Example 3;

[0035] Figure 8 An infrared comparison graph of the rosin-based epoxy foam prepared for Example 3 before and after degradation;

[0036] Figure 9 An electromagnetic shielding efficiency graph of the silver-modified degradable rosin-based epoxy foam prepared;

[0037] Figure 10 A Joule heating temperature change curve graph of the silver-modified degradable rosin-based epoxy foam prepared under a voltage of 0.4 to 1.0 V. DETAILED DESCRIPTION

[0038] In order to better understand the present application, the content of the present application will be further illustrated below in conjunction with examples, but the content of the present application is not limited only to the following examples.

[0039] Example 1

[0040] A method of preparing a degradable rosin-based epoxy foam, comprising the steps of:

[0041] Into a 250 mL three-necked flask equipped with a mechanical stirrer, 10.0 g of propylene diamine (DP) and 50 mL of anhydrous ethanol were added and stirred to form a homogeneous solution. Then, CO2 gas was bubbled into the solution at a flow rate of 80 mL / min through a gas inlet tube. After the solution started to bubble, it was stirred at a speed of 500 rpm for 3 h. Then, the stirring was stopped and a white precipitate was filtered and dried to obtain a white powder, propylene diamine-based latent blowing agent (DPC, 12.05 g).

[0042] 23.5 g of acrylpimaric acid, 116.0 g of epichlorohydrin and 0.286 g of benzyl triethyl ammonium chloride were reacted at 117 °C for 3 h. The temperature of the system was lowered to 60 °C and 5.0 g of sodium hydroxide was added. The reaction was continued at 60 °C for another 3 h. After the reaction was completed, the system was cooled to room temperature. The precipitate was removed by filtration. The filtrate was distilled under reduced pressure to remove epichlorohydrin. A light yellow liquid, acrylpimaric acid-based glycidyl ester (EAPA, 27.92 g) was obtained. The yield was 91.42% and the epoxy value was 0.339 mol / 100 g.

[0043] Into a disposable plastic cup, 23.34 g of acrylpimaric acid-based glycidyl ester (EAPA), 7.47 g of 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane (TMSEP), 0.6 g of propylene diamine-based latent blowing agent (DPC) and 2.2 g of propylene diamine (DP) were added. The mixture was stirred at a speed of 1200 rpm for 3 min using a mechanical stirrer to obtain a light yellow emulsion. The emulsion was transferred into a paper cup coated with a release agent. The paper cup was placed in an oven at room temperature and heated to 70 °C for 30 min and then to 120 °C for 2 h to obtain a degradable pimaric acid-based epoxy foam F1.

[0044] Figure 1 The thermal gravimetric analysis of the propylene diamine-based latent blowing agent prepared in Example 1 showed that it was stable at room temperature with an initial decomposition temperature of 84.1 °C (1% weight loss). 13 The C NMR chart showed a carbon peak of the ionic carbamate at 165.9 ppm, indicating that the propylene diamine chemically absorbed CO2 to form a carbamate structure. Figure 2 The thermal gravimetric analysis of the propylene diamine-based latent blowing agent prepared in Example 1 showed that it was stable at room temperature with an initial decomposition temperature of 84.1 °C (1% weight loss). Figure 3 The H NMR chart of the acrylpimaric acid-based glycidyl ester prepared in Example 1 showed a proton peak of the methylene group on the structure of epichlorohydrin at 4.50-3.80 ppm, indicating that the acrylpimaric acid-based glycidyl ester was successfully prepared. 1 The H NMR chart of the acrylpimaric acid-based glycidyl ester prepared in Example 1 showed a proton peak of the methylene group on the structure of epichlorohydrin at 4.50-3.80 ppm, indicating that the acrylpimaric acid-based glycidyl ester was successfully prepared.

[0045] Example 2

[0046] The preparation method of EAPA and DPC was the same as that in Example 1.

[0047] Take 17.51 g of propenyl abietate glycidyl ester (EAPA), 11.20 g of 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane (TMSEP), 0.6 g of propylenediamine latent blowing agent (DPC) and 2.2 g of propylenediamine (DP) into a disposable plastic cup, stir with a mechanical stirrer at a speed of 1200 rpm for 3 min to obtain a light yellow emulsion, transfer the emulsion into a paper cup coated with release agent, heat to 70°C in an oven at room temperature and keep for 30 min, finally heat to 120°C and cure for 2 h to obtain degradable rosin-based epoxy foam F2.

[0048] Example 3

[0049] The preparation method of EAPA and DPC is the same as that in Example 1.

[0050] Take 17.51 g of propenyl abietate glycidyl ester (EAPA), 11.20 g of 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane (TMSEP), 0.6 g of propylenediamine latent blowing agent (DPC) and 2.2 g of propylenediamine (DP) into a disposable plastic cup, stir with a mechanical stirrer at a speed of 1200 rpm for 3 min to obtain a light yellow emulsion, transfer the emulsion into a paper cup coated with release agent, heat to 70°C in an oven at room temperature and keep for 30 min, finally heat to 120°C and cure for 2 h to obtain degradable rosin-based epoxy foam F2.

[0051] Example 4

[0052] The preparation method of EAPA and DPC is the same as that in Example 1.

[0053] Take 17.51 g of propenyl abietate glycidyl ester (EAPA), 11.20 g of 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane (TMSEP), 0.6 g of propylenediamine latent blowing agent (DPC) and 2.2 g of propylenediamine (DP) into a disposable plastic cup, stir with a mechanical stirrer at a speed of 1200 rpm for 3 min to obtain a light yellow emulsion, transfer the emulsion into a paper cup coated with release agent, heat to 70°C in an oven at room temperature and keep for 30 min, finally heat to 120°C and cure for 2 h to obtain degradable rosin-based epoxy foam F2.

[0054] Application Example

[0055] An acidic stannous chloride solution was prepared by dissolving 1.2 g of stannous chloride dihydrate in 100 mL of 1.5 vol% dilute hydrochloric acid solution. Subsequently, Tollens reagent A and B were prepared by adding aqueous ammonia solution to 100 mL of silver nitrate solution A (3 g / L) and 100 mL of silver nitrate solution B (20 g / L), respectively, until the solution changed from turbid to clear. The clear solution obtained by further adding aqueous ammonia solution to Tollens reagent B until the solution became clear was referred to as silver salt solution. A reducing solution was prepared by dissolving 0.1 g of tartaric acid, 0.8 g of glucose, 0.5 mL of ethylenediamine, 6 mL of ethanol, and 0.036 g of polyethylene glycol 1000 in 100 mL of deionized water.

[0056] The application method of the application includes the following steps:

[0057] (1) The epoxy foam F3 in Example 3 was immersed in the acidic stannous chloride solution, sensitized at room temperature, and then washed with distilled water for 10 min to obtain the sensitized degradable rosin-based epoxy foam;

[0058] (2) The sensitized degradable rosin-based epoxy foam was reacted in Tollens A solution at 35°C for 30 min to obtain the chemically modified degradable rosin-based epoxy foam;

[0059] (3) 80 mL of the reducing solution and 20 mL of the silver salt solution were poured into a paper cup and stirred, and the modified degradable rosin-based epoxy foam was silver-plated in the paper cup for 1 h. Subsequently, the foam was taken out of the plating solution, washed with water, and vacuum dried to obtain the silver-modified degradable rosin-based epoxy foam F3A. The chemical plating process was repeated 1-3 times to obtain the degradable rosin-based epoxy foam with conductive properties, i.e., the silver-modified degradable rosin-based epoxy foams F3A1, F3A2, and F3A3.

[0060] Figure 4 The infrared spectrum of the degradable rosin-based epoxy foam prepared in Example 3 showed that the characteristic absorption peak of the epoxy group at 909 cm -1 disappeared, the absorption peak representing the amine group at 3353 cm -1 in the propylenediamine-based latent blowing agent disappeared, and a hydroxyl peak at 3431 cm -1 appeared in the infrared spectrum of the foam. In summary, the propylenediamine-based latent blowing agent decomposed, and the amine group and the epoxy group reacted.

[0061] Figure 5The stress-strain curves of the degradable epoxy foams prepared in Examples 1-4 show that the compressive strength (10% strain) of the foams increases from 0.05 MPa to 1.51 MPa as the EAPA content increases, and the maximum compressive strength of the F1 foam reaches 1.75 MPa; the hardness of the foams can be changed by adjusting the molar ratio of EAPA to TMSEP.

[0062] Figure 6 The reversible compression performance graph of the degradable rosin-based epoxy foam F3 prepared in Example 3 shows that the hysteresis loops almost coincide after 60 cycles during the loading-unloading process, indicating that the epoxy foam F3 has excellent reversible compression performance.

[0063] Figure 7 The degradation schematic of the rosin-based epoxy foam prepared in Example 3 shows that after 1.8 g of the epoxy foam is mixed with 10 wt% aluminum nitrate nonahydrate and 12 g of N,N-dimethylacetamide and heated to 120-140°C and magnetically stirred for 2 h, no obvious solid is observed in the mixed solution, indicating that the epoxy foam has been degraded.

[0064] Figure 8 The infrared comparison graph of the rosin-based epoxy foam prepared in Example 3 before and after degradation shows that the relative peak intensity of the C-N stretching vibration peak at 1107 cm -1 in the degradation product is significantly reduced, and the peak at 3415 cm -1 moves to lower wavenumbers, proving that the C-N bond is cleaved during the degradation reaction and that there is an N-H bond in the degradation product.

[0065] Figure 9 The electromagnetic shielding efficiency graph of the silver-modified degradable rosin-based epoxy foam prepared shows that the electromagnetic shielding efficiency of the silver-modified degradable rosin-based epoxy foam prepared is 39.27-76.37 dB, i.e., the silver-modified degradable rosin-based epoxy foam prepared has excellent electromagnetic shielding performance; among them, the electromagnetic shielding efficiency of the silver-modified degradable rosin-based epoxy foam prepared by repeating the chemical plating three times in Example 5 reaches 76.37 dB; after calculation, it can attenuate 99.99999% of electromagnetic waves, meeting the requirements of electronic devices for electromagnetic shielding materials.

[0066] Figure 10 The Joule heating temperature change curve graph of the silver-modified degradable rosin-based epoxy foam F3A3 prepared at a voltage drive of 0.4-1.0 V shows that the temperature of the silver-modified degradable rosin-based epoxy foam F3A3 prepared increases from 20°C to 60°C as the voltage increases from 0.4 V to 1.0 V, and the temperature of the silver-modified degradable rosin-based epoxy foam F3A3 prepared reaches 60°C at a voltage of 1.0 V. Figure 10As can be seen, the degradable rosin-based epoxy foam with electromagnetic shielding performance and Joule heating performance reaches a steady temperature within 90s under the driving of 0.4-1.0V voltage; wherein, the steady temperature of the silver-modified degradable rosin-based epoxy foam can reach 104.0 DEG C under the driving of 1.0V voltage; after the power is cut off, the surface temperature thereof will rapidly decrease to the ambient temperature; thus, it can be seen that the silver-modified degradable rosin-based epoxy foam has excellent Joule heating performance, and the restriction of cold environment on electronic equipment can be relieved.

[0067] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A process for the preparation of a degradable rosin-based epoxy foam, characterized in that, The method comprises the following steps: The propylene glycol amine latent blowing agent, propylene glycol amine, propylene glycerol glycidyl ester and 1,3-bis(3-glycidyl propyl)-1,1,3,3-tetramethyl disiloxane are stirred and mixed uniformly, and a degradable rosin-based epoxy foam is obtained by reaction; The preparation method of the propylene glycol amine latent blowing agent is that propylene glycol amine is dissolved in anhydrous ethanol, carbon dioxide gas is introduced, and reaction is carried out for 2-4 hours at room temperature to obtain the propylene glycol amine latent blowing agent; The preparation method of the propylene glycerol glycidyl ester is that propylene glycerol glycidyl ester is obtained by reacting propylene glycerol glycidyl ester, epichlorohydrin and benzyl triethyl ammonium chloride at 110-117 ℃ for 3-5 hours, then the temperature is lowered to 50-60 ℃, and sodium hydroxide is added, and the reaction is continued at 50-60 ℃ for 4-6 hours.

2. The method for preparing biodegradable rosin-based epoxy foam according to claim 1, characterized in that, The mass ratio of the propylene glycol amine latent blowing agent, propylene glycol amine, propylene glycerol glycidyl ester and 1,3-bis(3-glycidyl propyl)-1,1,3,3-tetramethyl disiloxane is (0.1-0.3):1:(5-11):(3-7).

3. The method for preparing biodegradable rosin-based epoxy foam according to claim 1 or 2, characterized in that, The reaction conditions for obtaining the degradable rosin-based epoxy foam by reaction are that the temperature is kept at 50-70 ℃ for 20-40 minutes, and then the temperature is kept at 120-160 ℃ for 1-4 hours.

4. The method for preparing biodegradable rosin-based epoxy foam according to claim 1, characterized in that, The mass ratio of the propylene glycerol glycidyl ester, epichlorohydrin, benzyl triethyl ammonium chloride and sodium hydroxide is (80-90):(400-410):1:(15-20).

5. A degradable rosin-based epoxy foam prepared by the preparation method of any one of claims 1-4.

6. The application of the degradable rosin-based epoxy foam prepared by the preparation method of any one of claims 1-4 or the degradable rosin-based epoxy foam of claim 5 in electromagnetic materials.

7. Use of the degradable rosin-based epoxy foam according to claim 6 in electromagnetic materials, characterized in that, The application method comprises the following steps: (1) The degradable rosin-based epoxy foam is immersed in an acidic stannous chloride solution, sensitized at room temperature, and then washed with deionized water for 10-30 minutes to obtain sensitized degradable rosin-based epoxy foam; (2) The sensitized degradable rosin-based epoxy foam is reacted in Tollens A solution for 0.5-1.5 hours to obtain chemically modified degradable rosin-based epoxy foam; (3) The modified degradable rosin-based epoxy foam is placed in a mixture of a reducing solution and a silver salt solution for electroless plating for 1-2 hours, dried, and the process is repeated 1-3 times to obtain degradable rosin-based epoxy foam with conductive properties; The preparation method of the silver salt solution is that sodium hydroxide is added to Tollens B solution and stirred, and then ammonia solution is continuously added until the solution becomes clear, and the transparent solution obtained is the silver salt solution; The preparation method of the Tollens A and Tollens B solutions is that ammonia solution is added to 3-5 g / L silver nitrate solution A and 10-20 g / L silver nitrate solution B, respectively, until the solution changes from turbid to clear, and Tollens A and Tollens B solutions are obtained, respectively.

8. The method for preparing biodegradable rosin-based epoxy foam according to claim 7, characterized in that, The preparation method of the acidic stannous chloride solution is to dissolve stannous chloride dihydrate in a dilute hydrochloric acid solution to obtain the acidic stannous chloride solution.

9. The method for preparing biodegradable rosin-based epoxy foam according to claim 8, characterized in that, The preparation method of the reducing solution is to dissolve tartaric acid, glucose, ethylenediamine, ethanol and polyethylene glycol in deionized water to obtain the reducing solution.

10. The method for preparing biodegradable rosin-based epoxy foam according to claim 9, characterized in that, The mass ratio of the tartaric acid, glucose, ethylenediamine, ethanol and polyethylene glycol is 1:(8-10):(3-5):(45-50):(0.2-0.5).

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