Antibacterial cascade self-foaming vegetable oil-based foam material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of foam materials, and discloses an antibacterial cascade self-foaming plant oil-based foam material which is prepared from the following raw materials in parts by weight: 100-200 parts of castor oil, 100-200 parts of polyethyleneimine, 120-300 parts of diisocyanate and 1-5 parts of a catalyst, wherein the polyethyleneimine also needs to absorb CO2 before the reaction, and the obtained polyethyleneimine absorbing CO2 is used as a reactant. The raw materials of the foam material come from biological resources and conform to the concept of green sustainable development, and cascade self-foaming of the foam material is realized by utilizing the reaction activity difference of diisocyanate, castor oil and polyethyleneimine for absorbing CO2. The antibacterial cascaded self-foaming plant oil-based foam material has good compression strength and excellent antibacterial, heat-insulating and sound-absorbing properties. The invention further discloses a preparation method and application of the antibacterial cascade self-foaming plant oil-based foam material. The foam material can be used for preparing sound-insulation, heat-insulation and antibacterial materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of foam materials, and particularly relates to antibacterial, cascade self-foaming vegetable oil-based foam materials, their preparation methods and applications. Background Art

[0002] Foam materials can be divided into rigid foams, soft foams and semi-rigid foams. Since entering industrialization in the 1950s, with the rapid development of the logistics and packaging industries, the demand for foam materials with properties such as heat insulation, sound insulation, antibacterial properties or multiple properties has increased sharply.

[0003] The production of traditional foam materials requires catalysts, foaming agents, flame retardants, etc. However, traditional foaming agents such as HCFC foaming agents have the disadvantage of damaging the ozone layer, and the production of foam materials mainly relies on fossil raw materials, which have a high carbon footprint and are non-degradable, and no longer meet the requirements of today's green development. Therefore, there is an urgent need to develop foam materials based on bio-based materials and with multiple properties. Summary of the Invention

[0004] The purpose of the present invention is to provide antibacterial, cascade self-foaming vegetable oil-based foam materials, their preparation methods and applications, so as to solve the technical problem of developing foam materials based on bio-based materials and with multiple properties in the prior art.

[0005] According to the first aspect of the present invention, there is provided an antibacterial, cascade self-foaming vegetable oil-based foam material, which is prepared from the following raw materials in parts by weight: 100-200 parts of castor oil, 100-200 parts of polyethyleneimine, 120-300 parts of diisocyanate and 1-5 parts of catalyst; wherein, polyethyleneimine also needs to absorb CO 2 , and the polyethyleneimine obtained by absorbing CO 2 is used as a reactant, and the polyethyleneimine obtained by absorbing CO 2 is prepared by the reaction of the amino group of polyethyleneimine with CO 2 .

[0006] The raw materials of the antibacterial, cascade self-foaming vegetable oil-based foam material of the present invention include castor oil, diisocyanate and polyethyleneimine. Using castor oil as a polyol does not require fossil materials, which meets the requirements of green development; moreover, the addition of castor oil can achieve the purpose of regulating the foaming rate and curing rate. At the same time, polyethyleneimine also needs to absorb CO 2 to obtain polyethyleneimine that absorbs CO 2 as a reactive foaming agent, cross-linking agent and antibacterial agent, and the hydroxyl group on castor oil and the reaction activity difference of polyethyleneimine can be used to carry out a cascade reaction with diisocyanate.

[0007] Moreover, by using the reaction of diisocyanate with the amino group in polyethyleneimine to release the CO locked in the amino group2 For hole making, and regulating the CO 2 release rate through the nucleophilic exothermic reaction of isocyanate with active hydrogen (amino group and hydroxyl group), thereby regulating the pore size and quantity of the polyester foam, and thus developing a polyester foam material with adjustable hardness and softness properties to achieve the controllable regulation and functionalization of the polyester foam.

[0008] In addition, the un-released CO remaining in the polyethyleneimine 2 is tightly combined with the tertiary amine to form a quaternary ammonium salt ion, which can endow the foam material with excellent antibacterial properties. Experiments show that the antibacterial and cascade self-foaming vegetable oil-based foam material has good compressive strength and excellent antibacterial, heat insulation and sound absorption properties.

[0009] In some embodiments, the molar ratio of the total number of moles of the hydroxyl group of castor oil and the hydrogen atom on the amino group of polyethyleneimine to the isocyanate group of the diisocyanate is (0.8~1):(0.8~1).

[0010] In some embodiments, the molar ratio of the amino group of the polyethyleneimine that absorbs CO 2 to the hydroxyl group of castor oil is (0.7~0.3):(0.3~0.7).

[0011] In some embodiments, the molar ratio of the amino group of the polyethyleneimine that absorbs CO 2 to the hydroxyl group of castor oil is (0.5~0.3):(0.5~0.7).

[0012] In some embodiments, the polyethyleneimine that absorbs CO 2 is prepared by the following steps: putting the polyethyleneimine into a closed container and introducing CO 2 into the closed container, and then stirring the polyethyleneimine to obtain the polyethyleneimine that absorbs CO 2 .

[0013] In some embodiments, the polyethyleneimine that absorbs CO 2 is prepared by the following steps: putting the polyethyleneimine into a closed container and introducing CO 2 into the closed container until the pressure in the closed container is 1~5 MPa, and then stirring the polyethyleneimine at a stirring rate of 150~300 r·min -1 for 45~120 min to obtain it.

[0014] In some embodiments, the diisocyanate is selected from at least one of isophorone diisocyanate, hexamethylene-1,6-diisocyanate, dicyclohexylmethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, toluene diisocyanate.

[0015] In some embodiments, the catalyst is an organotin catalyst; preferably, the catalyst is selected from at least one of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, and dibutyltin dioctoate.

[0016] According to the second aspect of the present invention, there is provided a method for preparing an antibacterial, cascade self-foaming vegetable oil-based foam material, comprising the following steps: (1) Put polyethyleneimine into a reaction kettle and introduce CO 2 , to obtain polyethyleneimine that has absorbed CO 2 for subsequent preparation of the foam material; (2) Polymerize castor oil and diisocyanate for 0.5 - 1 h to obtain a reaction system; (3) Add a catalyst to the reaction system. When the content of NCO groups in the reaction system drops to 45% - 55%, add the polyethyleneimine that has absorbed CO 2 and continue the reaction. Promote the release of CO 2 through the reaction heat to achieve self-foaming. Stop stirring when bubbles are uniformly generated in the reaction system, and transfer the reaction system to a room temperature environment for self-foaming molding to obtain the product.

[0017] The method for preparing the antibacterial, cascade self-foaming vegetable oil-based foam material of the present invention adopts a one-pot method, and the preparation method is simple. First, pre-polymerize castor oil and diisocyanate through a polymerization reaction, then add a catalyst to increase the reaction rate of castor oil and diisocyanate, and then add the polyethyleneimine that has absorbed CO 2 . At this time, the NCO groups of diisocyanate react with the amino groups of polyethyleneimine to release the carbon dioxide locked in the amino groups for foaming and pore formation. At the same time, through the nucleophilic exothermic reaction of diisocyanate with active hydrogen (mainly the hydrogen atoms on the amino group and the hydrogen atoms on the hydroxyl group), the release rate of carbon dioxide is regulated to control the pore size and quantity of the foam material, thereby developing a foam material with adjustable hardness and softness. In addition, the antibacterial, cascade self-foaming vegetable oil-based foam material obtained by this preparation method has various properties, realizing the multi-functionalization of the foam material.

[0018] It should be noted that compared with the reaction activity of the amino groups of polyethyleneimine and the NCO groups of diisocyanate, the reaction activity of the hydroxyl groups of castor oil and the NCO groups of diisocyanate is lower. To avoid excessive cross-linking between the two, resulting in too much reaction resistance between polyethyleneimine and diisocyanate and insufficient pre-polymerization of castor oil and diisocyanate, the present invention selects to add the polyethyleneimine that has absorbed CO 2 when the content of NCO groups in the reaction system drops to 45% - 55%, ensuring sufficient pre-polymerization of the reaction system and an appropriate degree of cross-linking.

[0019] According to the third aspect of the present invention, there is provided an application of an antibacterial, cascade self-foaming vegetable oil-based foam material in the preparation of a material having at least one property of sound insulation, heat insulation, and antibacterial, which can be applied to multiple fields such as logistics, packaging, construction, furniture, household appliances, aerospace, etc.

[0020] Advantages of the present invention: (1) The raw materials of the present invention include castor oil, diisocyanate, and polyethyleneimine that absorbs CO 2 The polyethyleneimine that absorbs CO 2 is used as a foaming agent and a cross-linking agent, and there is no need to additionally introduce other environmentally damaging foaming agents. The raw materials are derived from biological resources, which conforms to the concept of green and sustainable development; (2) The present invention uses a one-pot method to prepare an antibacterial, cascade self-foaming vegetable oil-based foam material. The preparation method is simple, and the hardness and softness properties of the antibacterial, cascade self-foaming vegetable oil-based foam material prepared by using the cascade self-foaming of the raw materials can be adjusted; (3) The antibacterial, cascade self-foaming vegetable oil-based foam material of the present invention has good compressive strength and excellent antibacterial, heat insulation, and sound absorption properties, realizing the multifunctionalization of the foam material. It has application prospects in the fields of packaging materials, building materials, furniture, etc., and can also be used to prepare sound insulation, heat insulation, and antibacterial materials. Description of the drawings

[0021] Figure 1 is the synthesis process of the antibacterial, cascade self-foaming vegetable oil-based foam material of the present invention; Figure 2 is the 2 C NMR diagram of polyethyleneimine and polyethyleneimine that absorbs CO 13 ; Figure 3 is the 2 H NMR diagram of polyethyleneimine and polyethyleneimine that absorbs CO 1 ; Figure 4 is the physical diagram and scanning electron microscope diagram of the antibacterial, cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 of the present invention and the self-foaming vegetable oil-based foam material of Comparative Example 1; Figure 5 is the mechanical property test results of the antibacterial, cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 of the present invention and the self-foaming vegetable oil-based foam material of Comparative Example 1; Figure 6 is the heat insulation property test results of the antibacterial, cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 of the present invention and the self-foaming vegetable oil-based foam material of Comparative Example 1; Figure 7Acoustic performance test results of the antibacterial, cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 of the present invention and the self-foaming vegetable oil-based foam material of Comparative Example 1; Figure 8 Growth conditions of Staphylococcus aureus and Escherichia coli treated with the antibacterial, cascade self-foaming vegetable oil-based foam material of Example 1 of the present invention and the self-foaming vegetable oil-based foam material of Comparative Example 1. Detailed implementation manners

[0022] The present invention will be further described in detail below with reference to the accompanying drawings, but the implementation manners of the present invention are not limited thereto. The raw materials and reagents involved in the following examples can all be obtained from commercial channels.

[0023] The preparation process of the antibacterial, cascade self-foaming vegetable oil-based foam material of the present invention is as Figure 1 shown. The present invention utilizes the characteristics of polyethyleneimine (PEI) to absorb and desorb CO 2 . Put PEI into a closed reaction kettle, and introduce CO 2 into the closed reaction kettle to obtain PEI@CO 2 . PEI@CO 2 is used as a foaming agent and an in-situ cross-linking agent, and is added to a reaction system composed of castor oil and isophorone diisocyanate (IPDI) for cascade self-foaming of the foam material. Specifically, due to the difference in reaction activity between castor oil and polyethyleneimine, they can carry out cascade reactions with IPDI. The amino group of PEI has a high reaction activity with IPDI, and the reaction between the two releases CO 2 locked by the amino group for foaming and pore formation, and the release rate of CO 2 is regulated by the nucleophilic exothermic reaction between IPDI and active hydrogen (hydrogen atoms on the amino group of PEI and the hydroxyl group of castor oil) to control the pore size and quantity of the foam material, thereby developing a foam material that meets the structures of soft foam and hard foam.

[0024] It should be noted that using isophorone diisocyanate as a raw material is only one implementation manner of the present invention, and other diisocyanates can also be selected as raw materials, such as hexamethylene-1,6-diisocyanate, dicyclohexylmethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, toluene diisocyanate.

[0025] Example 1 This example provides an antibacterial, cascade self-foaming vegetable oil-based foam material, which is prepared through the following steps: (1) Preparation of the foaming agent: Put 30 g of polyethyleneimine into a closed reaction kettle, introduce carbon dioxide into the closed reaction kettle at room temperature (the pressure in the reaction kettle is 3 MPa), and then rotate at 200 r·min -1Stir polyethyleneimine at a stirring rate for 60 min, and then use the product after absorbing carbon dioxide as a foaming agent, denoted as PEI@CO 2 ; (2) Preparation of antibacterial and cascade self-foaming vegetable oil-based foam materials: Weigh 10 g of castor oil and 18.23 g of isophorone diisocyanate. Polymerize castor oil and isophorone diisocyanate by bulk polymerization in one-pot for 1 h, then add 0.5 g of catalyst dibutyltin dilaurate to the reaction system, stir, and when the content of NCO groups in the reaction system drops to about 50%, add PEI@CO 2 Continue to stir and react (the molar ratio of the amino group of polyethyleneimine absorbing CO 2 to the hydroxyl group of castor oil is 0.5:0.5). Promote the release of carbon dioxide in PEI@CO 2 through the reaction heat to achieve the cascade self-foaming of the reaction system. Stop stirring after uniform bubbles are generated, and transfer it to room temperature for self-foaming molding to obtain the product. Perform 2 C NMR and 2 H NMR characterizations on polyethyleneimine (PEI) and polyethyleneimine absorbing CO 13 respectively. The results are shown in 1 and Figure 2 and Figure 3 . It can be seen from Figure 2 that compared with PEI, an obvious C=O signal peak appears in the 2 C NMR spectrum of PEI@CO 13 , indicating that PEI combines with CO 2 and new chemical bonds are formed. Figure 3 In the 1 H NMR spectrum of PEI@CO 2 , the proton signals of primary and secondary amines of PEI@CO 13 relative to PEI are significantly weakened and shifted to the left, further indicating that carbon dioxide enters polyethyleneimine and combines with the amino group of polyethyleneimine. Combining the analysis results of the 2 C NMR spectrum, the signal peak at about 3.0 ppm in the 1 H NMR spectrum of PEI@CO 2 may be the peak of amino formate formed by the reaction of the amino group with CO 2 . The above results show that the amino group of polyethyleneimine can react with CO 2 to successfully prepare polyethyleneimine absorbing CO

[0026] Example 2 This example provides antibacterial and cascade self-foaming vegetable oil-based foam materials, which are prepared through the following steps: (1) Preparation of blowing agent: Put 30 g of polyethyleneimine into a closed reaction kettle, and introduce carbon dioxide into the closed reaction kettle at room temperature (the pressure in the reaction kettle is 3 MPa), and then stir the polyethyleneimine at a stirring rate of 200 r·min -1 for 60 min, and then use the product after absorbing carbon dioxide as the blowing agent, denoted as PEI@CO 2 ; (2) Preparation of antibacterial and cascade self-foaming vegetable oil-based foam materials: Weigh 10 g of castor oil and 15.34 g of isophorone diisocyanate, and carry out bulk polymerization reaction of castor oil and isophorone diisocyanate by one-pot method for 1 h, and then add 0.5 g of catalyst dibutyltin dilaurate to the reaction system. When the content of NCO groups in the reaction system drops to about 50%, add PEI@CO 2 and continue stirring the reaction (the molar ratio of the amino group of polyethyleneimine absorbing CO 2 to the hydroxyl group of castor oil is 0.4:0.6). Promote the release of carbon dioxide in PEI@CO 2 through the reaction heat to achieve the cascade self-foaming of the reaction system. Stop stirring after uniform bubbles are generated, and transfer it to room temperature for self-foaming molding to obtain. Example 3 This example provides antibacterial and cascade self-foaming vegetable oil-based foam materials, which are prepared through the following steps: (1) Preparation of blowing agent: Put 30 g of polyethyleneimine into a closed reaction kettle, and introduce carbon dioxide into the closed reaction kettle at room temperature (the pressure in the reaction kettle is 3 MPa), and then stir the polyethyleneimine at a stirring rate of 200 r·min -1 for 60 min, and then use the product after absorbing carbon dioxide as the blowing agent, denoted as PEI@CO 2 ; (2) Preparation of antibacterial and cascade self-foaming vegetable oil-based foam materials: Weigh 10 g of castor oil and 12.58 g of isophorone diisocyanate, and carry out bulk polymerization reaction of castor oil and isophorone diisocyanate by one-pot method for 1 h, and then add 0.5 g of catalyst dibutyltin dilaurate to the reaction system. When the content of NCO groups in the reaction system drops to about 50%, add PEI@CO 2 and continue stirring the reaction (the molar ratio of the amino group of polyethyleneimine absorbing CO 2 to the hydroxyl group of castor oil is 0.3:0.7). Promote the release of carbon dioxide in PEI@CO 2 through the reaction heat to achieve the cascade self-foaming of the reaction system. Stop stirring after uniform bubbles are generated, and transfer it to room temperature for self-foaming molding to obtain. Comparative Example 1 This comparative example provides self-foaming vegetable oil-based foam materials, which are prepared through the following steps: (1) Preparation of foaming agent: Put 30 g of polyethyleneimine into a closed reaction kettle, and introduce carbon dioxide into the closed reaction kettle at room temperature (the pressure in the reaction kettle is 3 MPa), and then stir the polyethyleneimine at a stirring rate of 200 r·min -1 for 60 min. Subsequently, the product after absorbing carbon dioxide is used as a foaming agent, denoted as PEI@CO 2 ; (2) Preparation of antibacterial and cascade self-foaming vegetable oil-based foam materials: React 16.32 g of isophorone diisocyanate with 0.5 g of catalyst dibutyltin dilaurate for 1 h, and then add PEI@CO 2 and continue to stir and react. Promote the release of carbon dioxide in PEI@CO 2 through the reaction heat to achieve the self-foaming of the reaction system. Stop stirring after uniform bubbles are generated, and transfer it to room temperature for self-foaming and molding to obtain the product. Experimental Example 1 In this experimental example, the antibacterial and cascade self-foaming vegetable oil-based foam materials prepared in Examples 1 to 3, and the self-foaming vegetable oil-based foam materials prepared in Comparative Example 1 were photographed and characterized by scanning electron microscopy (SEM). The results are as follows Figure 4 shown. It can be seen from Figure 4 that the pore structure of the self-foaming vegetable oil-based foam material in Comparative Example 1 collapsed, while the pore structures of the antibacterial and cascade self-foaming vegetable oil-based foam materials in Examples 1 to 3 did not collapse, and the holes were both open and closed, and their pore sizes and distributions were non-uniform. This difference is due to the addition of castor oil can regulate the foaming rate and curing rate of the foam material. The porosity of each foam material is shown in Table 1. It can be seen that as the molar ratio of the amino group of polyethyleneimine to the hydroxyl group of castor oil decreases, the porosity of the foam material increases. In addition, the cell structure of the antibacterial and cascade self-foaming vegetable oil-based foam material in Example 1 is mainly closed cells, which conforms to the cell structure of rigid foam. The cell structure of the antibacterial and cascade self-foaming vegetable oil-based foam material in Example 3 is mainly open cells, which conforms to the cell structure of soft foam. That is to say, the cell structure can be adjusted from closed cells to open cells by regulating the ratio of castor oil and PEI@CO 2 proportion, and further realize the transformation from rigid foam to soft foam from the pore structure.

[0027] Table 1 Porosity of foam materials

[0028] Experimental Example 2 In this experimental example, the antibacterial and cascade self-foaming vegetable oil-based foam materials in Examples 1 to 3, and the self-foaming vegetable oil-based foam materials in Comparative Example 1 were tested for mechanical properties to study the mechanical properties of each foam material.

[0029] Testing method: At room temperature, tests were carried out using an MTS universal testing machine at a compression rate of 5 mm / min. The samples of experimental examples and comparative examples were all tested in parallel 3 times, and the average values were taken for plotting.

[0030] The test results of mechanical properties are shown in Figure 5 , and it can be seen from the results that as the proportion of castor oil in the raw materials increases, the compressive strength of the antibacterial and cascade self-foaming vegetable oil-based foam materials shows a gradually increasing trend. Specifically, the self-foaming vegetable oil-based foam material of Comparative Example 1 does not contain castor oil and has poor compressive strength. The compressive strengths of the antibacterial and cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 are all higher than that of the self-foaming vegetable oil-based foam material of Comparative Example 1. This is because castor oil increases the content of soft chain segments in the polymer chain and the content of hydrogen bonds inside the foam material (resulting from the urethane bonds formed by castor oil and diisocyanate in the reaction system, the internal hydrogen bond interaction of PEI@CO 2 and the polyurea of diisocyanate, as well as the external hydrogen bonds formed by amino groups, hydroxyl groups and other groups in the reaction system), making the vegetable oil-based foam material exhibit better compressive properties. As the content of castor oil in the raw materials increases, the compressive strength of the antibacterial and cascade self-foaming vegetable oil-based foam materials first increases and then decreases. The compressive strength of the antibacterial and cascade self-foaming vegetable oil-based foam material of Example 2 can reach 1.6 MPa. The appearance of this trend may be because as the content of castor oil increases, the content of hydrogen bonds increases and the entanglement inside the molecules enhances the strength. At this time, the compressive strength and strain of the foam material increase. However, when the content of castor oil exceeds a certain amount, the content of soft chain segments is too large, and the crosslinking density of the foam material weakens, resulting in a decrease in the compressive strength of the material.

[0031] Experimental Example 3 In this experimental example, the antibacterial and cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 and the self-foaming vegetable oil-based foam material of Comparative Example 1 were tested for heat insulation performance to study the heat insulation performance of each foam material.

[0032] The thermal conductivity of each foam material was characterized by a room temperature thermal conductivity meter, and the results are as Figure 6 shown. Among them, the thermal conductivity of the self-foaming vegetable oil-based foam material of Comparative Example 1 is 0.07352 W / (m·K), while the thermal conductivities of the antibacterial and cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 are all smaller than that of Comparative Example 1 under the same test conditions, indicating that the antibacterial and cascade self-foaming vegetable oil-based foam materials in the present invention have more excellent heat insulation performance. The thermal conductivity of the antibacterial and cascade self-foaming vegetable oil-based foam material of Example 3 can reach 0.03116 W / (m·K) at room temperature, which is 0.5 times the thermal conductivity of Comparative Example 1. This shows that Example 3 and Comparative Example 1 have significantly improved heat insulation performance under the same environmental conditions and have the potential to become thermal insulation materials.

[0033] Experimental Example 4 In this experimental example, the sound absorption performance of the antibacterial and cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 and the self-foaming vegetable oil-based foam material of Comparative Example 1 was tested to study the sound absorption performance of each foam material.

[0034] The thermal conductivity of each foam material was characterized by a measuring instrument, and the results are as Figure 7 shown. From Figure 7 It can be seen that in a noise environment of 200 - 1600 Hz, the sound absorption performance of the self-foaming vegetable oil-based foam material of Comparative Example 1 is relatively poor, and its maximum sound absorption coefficient is only 0.23. The antibacterial and cascade self-foaming vegetable oil-based foam materials of Examples 1 to 3 have more excellent sound absorption performance, which is manifested in that the sound absorption coefficients of the foam materials of each example are greater than those of the foam material of Comparative Example 1 in a noise environment of 200 - 1600 Hz. Among them, in a noise environment of 900 - 1200 Hz, the sound absorption coefficients of the foam materials of each example can reach the maximum. In addition, the maximum sound absorption coefficient of the foam material increases with the increase in the content of castor oil in the raw materials. Among them, the sound absorption coefficient of the antibacterial and cascade self-foaming vegetable oil-based foam material of Example 3 can reach a maximum of 0.83, which indicates that the vegetable oil-based foam material obtained by regulating the porosity and size through castor oil has obvious advantages in sound absorption performance and has the potential to become a sound insulation material.

[0035] Experimental Example 5 Based on the antibacterial effect of the quaternary ammonium salt ions formed after the absorption of CO 2 by the tertiary amine groups in polyethyleneimine, in this experimental example, the antibacterial experiments of the antibacterial and cascade self-foaming vegetable oil-based foam material of Example 1 and the self-foaming vegetable oil-based foam material of Comparative Example 1 were carried out to compare the antibacterial performance of the foam materials.

[0036] The antibacterial and cascade self-foaming vegetable oil-based foam material of Example 1 and the self-foaming vegetable oil-based foam material of Comparative Example 1 (hereinafter referred to as "samples") were irradiated under ultraviolet light for 30 minutes, and then soaked in PBS solution for 30 minutes for standby; after the samples and 1 mL of Staphylococcus aureus or Escherichia coli bacterial solution were co-cultured for 3.5 hours respectively, the bacterial solution was filtered and retained, 30 μL of the bacterial solution was evenly spread on the surface of agar, and the growth of Staphylococcus aureus and Escherichia coli was observed after culturing in a 37°C incubator for 16 hours.

[0037] After culturing for 16 hours, the agar was photographed and recorded, and the growth of Staphylococcus aureus and Escherichia coli was as Figure 8As shown. The results show that in the antibacterial experiment, the self-foaming vegetable oil-based foam material of Comparative Example 1 showed non-antibacterial properties, and a large number of strains appeared on the surface of the corresponding agar after cultivation. Compared with Comparative Example 1, the antibacterial and cascade self-foaming vegetable oil-based foam material of Example 1 showed more excellent antibacterial effects, and no strains were observed on the surface of the agar. This may be related to the material structures of Example 1 and Comparative Example 1. Although both the component structures of the foam materials in Example 1 and Comparative Example 1 contain quaternary ammonium salts, due to the collapsed material structure of the self-foaming vegetable oil-based foam material of Comparative Example 1, the molecular chain segments are tightly entangled and embedded inside the material, which is not conducive to the exposure of the quaternary ammonium salts therein to contact with bacteria, so its antibacterial property cannot be achieved. In the antibacterial and cascade self-foaming vegetable oil-based foam material of Example 1, the carbon dioxide remaining in polyethyleneimine and not released tightly combines with the tertiary amine of polyethyleneimine to form quaternary ammonium ions, which can endow the foam material with excellent antibacterial properties. At the same time, the branched structure of castor oil plays a supporting role for the foam skeleton, creating a good pore structure for the foam material. These interconnected pores are conducive to the exposure of quaternary ammonium salts, thereby playing an antibacterial role against Staphylococcus aureus and Escherichia coli.

[0038] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. Antibacterial, cascade self-foaming plant oil-based foam material, characterized in that: The method is prepared from the following raw materials in parts by weight: 100-200 parts of castor oil, 100-200 parts of polyethyleneimine, 120-300 parts of diisocyanate and 1-5 parts of catalyst; the polyethyleneimine needs to absorb CO2 before the reaction, and the obtained polyethyleneimine absorbing CO2 is used as a reactant, and the polyethyleneimine absorbing CO2 is prepared by reacting the amine group of polyethyleneimine with CO2.

2. The antibacterial, cascade self-foaming plant oil-based foam material according to claim 1, characterized in that: The molar ratio of the amine group of the CO2 absorbing polyethyleneimine to the hydroxyl group of the castor oil is (0.7-0.3):(0.3-0.7).

3. The antibacterial, cascade self-foaming plant oil-based foam material according to claim 1 or 2, characterized in that: The ratio of the sum of the molar numbers of the hydroxyl groups of the castor oil and the hydrogen atoms on the amine groups of the polyethyleneimine to the molar number of the isocyanate groups of the diisocyanate is (0.8-1):(0.8-1).

4. The antibacterial, cascade self-foaming plant oil-based foam material according to claim 3, characterized in that: The diisocyanate is selected from at least one of isophorone diisocyanate, hexamethylene-1,6-diisocyanate, dicyclohexylmethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, p-xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate and toluene diisocyanate.

5. The antibacterial, cascade self-foaming plant oil-based foam material according to claim 1, characterized in that: The catalyst is selected from at least one of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate and dibutyltin dioctoate.

6. The antibacterial, cascade self-foaming plant oil-based foam material according to claim 1, characterized in that: The polyethyleneimine for absorbing CO2 is prepared by the following steps: placing polyethyleneimine in a sealed container and introducing CO2 into the sealed container, and then stirring the polyethyleneimine.

7. The antibacterial, cascade self-foaming plant oil-based foam material according to claim 1, characterized in that: The polyethyleneimine for absorbing CO2 is prepared by the following steps: placing polyethyleneimine in a sealed container and introducing CO2 into the sealed container until the pressure in the sealed container is 1-5 MPa, and then -1 The polyethyleneimine is stirred at a stirring rate of 45 to 120 min to obtain the product.

8. The method for preparing the antibacterial, cascade self-foaming plant oil-based foam material according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) placing polyethyleneimine in a reactor and introducing CO2 to obtain polyethyleneimine absorbing CO2 for subsequent preparation of foam materials; (2) polymerizing castor oil and diisocyanate for 0.5 to 1 h to obtain a reaction system; (3) Add a catalyst to the reaction system, and react until the NCO group content in the reaction system drops to 45% to 55%, then add polyethyleneimine that absorbs CO2 to continue the reaction until bubbles are uniformly generated in the reaction system, and then transfer the reaction system to room temperature for self-foaming molding to obtain the product.

9. Use of the antibacterial, cascade self-foaming vegetable oil-based foam material according to any one of claims 1 to 7 in packaging materials, building materials, furniture materials, home appliance materials or aerospace materials.

10. Use of the antibacterial, cascade self-foaming plant oil-based foam material according to any one of claims 1 to 7 in the preparation of a material having at least one of the properties of sound insulation, heat preservation and antibacterial.

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