Antibacterial, cascade self-foaming plant oil-based foam material and its preparation method and application

Abstract

The present invention belongs to the field of foam materials technology and discloses an antibacterial, cascading self-foaming plant oil-based foam material. The foam material is prepared from the following raw materials, in parts by weight: 100-200 parts castor oil, 100-200 parts polyethyleneimine, 120-300 parts diisocyanate, and 1-5 parts catalyst. The polyethyleneimine is further required to absorb CO₂ before the reaction, with the resulting CO₂-absorbing polyethyleneimine serving as a reactant. The raw materials for the foam material of the present invention are derived from biological resources, conforming to the concept of green and sustainable development. Furthermore, the foam material achieves cascading self-foaming by utilizing the difference in reactivity between the diisocyanate and castor oil and the CO₂-absorbing polyethyleneimine. The antibacterial, cascading self-foaming plant oil-based foam material exhibits good compressive strength and excellent antibacterial, heat-insulating, and sound-absorbing properties. The present invention also discloses a preparation method and application of the antibacterial, cascading self-foaming plant oil-based foam material. The foam material can be used to prepare sound-insulating, heat-insulating, and antibacterial materials.

Description

Technical Field

[0001] The invention belongs to the technical field of foam materials, and in particular relates to an antibacterial, cascade self-foaming plant oil-based foam material and a preparation method and application thereof. Background Art

[0002] Foam materials can be divided into rigid foam, flexible foam, and semi-rigid foam. Since the industrialization of the 1950s, with the rapid development of the logistics and packaging industries, the demand for foam materials with thermal insulation, sound insulation, antibacterial properties, or a combination of these properties has increased dramatically.

[0003] The production of traditional foam materials requires catalysts, blowing agents, flame retardants, etc. However, traditional blowing agents such as HCFC have the disadvantage of damaging the ozone layer. In addition, the production of foam materials mainly relies on fossil raw materials. Fossil raw materials have a high carbon footprint and are non-degradable. They have long been incompatible with the needs 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 an antibacterial, cascade self-foaming plant oil-based foam material and its preparation method and application, so as to solve the technical problem of developing a foam material based on bio-based materials and having multiple properties in the prior art.

[0005] According to a first aspect of the present invention, an antibacterial, cascade self-foaming plant oil-based foam material is provided, 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 the polyethyleneimine needs to absorb CO2 before the reaction, and the CO2-absorbing polyethyleneimine obtained is used as a reactant, and the CO2-absorbing polyethyleneimine is prepared by reacting the amino group of the polyethyleneimine with CO2.

[0006] The antibacterial, cascade self-foaming plant-oil-based foam material of the present invention comprises castor oil, diisocyanate, and polyethyleneimine. Using castor oil as the polyol eliminates the need for fossil fuels, meeting the needs of green development. Furthermore, the addition of castor oil can regulate both the foaming and curing rates. Furthermore, the polyethyleneimine absorbs CO₂ before the reaction to produce the CO₂-absorbing polyethyleneimine, which serves as a reactive blowing agent, crosslinker, and antibacterial agent. This allows for a cascade reaction with the diisocyanate, leveraging the differential reactivity between the hydroxyl groups on the castor oil and the polyethyleneimine.

[0007] Moreover, diisocyanate is used to react with the amine groups in polyethyleneimine to release CO2 locked in the amine groups for pore formation, and the CO2 release rate is regulated by the nucleophilic exothermic reaction of isocyanate with active hydrogen (amine and hydroxyl groups), thereby regulating the pore size and number of the polyester foam. In this way, polyester foam materials with adjustable soft and hard properties are developed to achieve controllable adjustment and functionalization of polyester foam.

[0008] In addition, the unreleased CO2 remaining in the polyethyleneimine binds tightly to the tertiary amine to form quaternary ammonium ions, which impart excellent antibacterial properties to the foam. Experiments have shown that the antibacterial, cascade self-foaming plant oil-based foam has good compressive strength and excellent antibacterial, thermal insulation, and sound absorption properties.

[0009] In some embodiments, the molar ratio of the sum of the moles of the hydroxyl groups of castor oil and the hydrogen atoms on the amine groups of polyethyleneimine to the isocyanate groups of diisocyanate is (0.8-1):(0.8-1).

[0010] In some embodiments, the molar ratio of the amine groups of the CO2 absorbing polyethyleneimine to the hydroxyl groups of the castor oil is (0.7-0.3):(0.3-0.7).

[0011] In some embodiments, the molar ratio of the amine groups of the CO2 absorbing polyethyleneimine to the hydroxyl groups of the castor oil is (0.5-0.3):(0.5-0.7).

[0012] In some embodiments, the CO2-absorbing polyethyleneimine is prepared by the following steps: placing polyethyleneimine in a sealed container and introducing CO2 into the sealed container, and then stirring the polyethyleneimine to obtain the CO2-absorbing polyethyleneimine.

[0013] In some embodiments, 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 heating the polyethyleneimine at 150-300 r·min -1 The polyethyleneimine is stirred at a stirring rate of 45 to 120 min to obtain the product.

[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-xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and 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 a second aspect of the present invention, there is provided a method for preparing an antibacterial, cascade self-foaming plant oil-based foam material, comprising the following steps:

[0017] (1) placing polyethyleneimine in a reactor and introducing CO2 to obtain polyethyleneimine that absorbs CO2 for subsequent preparation of foam materials;

[0018] (2) polymerizing castor oil and diisocyanate for 0.5 to 1 h to obtain a reaction system;

[0019] (3) Adding a catalyst to the reaction system, reacting until the NCO group content in the reaction system drops to 45% to 55%, adding polyethyleneimine that absorbs CO2 to continue the reaction, and promoting the release of CO2 through the reaction heat to achieve self-foaming. When bubbles are uniformly generated in the reaction system, stirring is stopped, and the reaction system is transferred to room temperature for self-foaming molding.

[0020] The present invention employs a simple, one-pot method for preparing an antibacterial, cascading, self-foaming plant oil-based foam material. Castor oil and diisocyanate are first prepolymerized via a polymerization reaction. A catalyst is then added to increase the reaction rate between the castor oil and diisocyanate. A CO2-absorbing polyethyleneimine is then added. The NCO groups of the diisocyanate react with the amine groups of the polyethyleneimine to release carbon dioxide trapped within the amine groups for foaming and pore formation. Simultaneously, the diisocyanate undergoes an exothermic, nucleophilic reaction with active hydrogen atoms (primarily hydrogen atoms on amine and hydroxyl groups) to regulate the carbon dioxide release rate, enabling the pore size and number of the foam material to be controlled. This results in a foam material with adjustable softness and hardness. Furthermore, the antibacterial, cascading, self-foaming plant oil-based foam material obtained by this method exhibits multiple properties, achieving multifunctionality.

[0021] It should be noted that the reactivity of castor oil's hydroxyl groups with diisocyanate NCO groups is lower than the reactivity of polyethyleneimine's amine groups with diisocyanate NCO groups. To avoid excessive cross-linking between the two, which can lead to excessive resistance to the reaction between polyethyleneimine and diisocyanate and insufficient prepolymerization of castor oil and diisocyanate, the present invention adds CO₂-absorbing polyethyleneimine when the NCO group content in the reaction system drops to 45% to 55%, ensuring sufficient prepolymerization and an appropriate degree of cross-linking.

[0022] According to the third aspect of the present invention, there is provided an application of an antibacterial, cascade self-foaming plant oil-based foam material in the preparation of a material having at least one of the properties of sound insulation, heat preservation, and antibacterial, which can be applied to logistics, packaging, construction, furniture, home appliances, aerospace, and other fields.

[0023] Beneficial effects of the present invention:

[0024] (1) The raw materials of the present invention include castor oil, diisocyanate and polyethyleneimine that absorbs CO2. The polyethyleneimine that absorbs CO2 serves as a foaming agent and a cross-linking agent. There is no need to introduce other foaming agents that damage the environment. The raw materials are derived from biological resources, which is in line with the concept of green and sustainable development.

[0025] (2) The present invention adopts a one-pot method to prepare an antibacterial, cascade self-foaming plant oil-based foam material. The preparation method is simple, and the soft and hard properties of the antibacterial, cascade self-foaming plant oil-based foam material prepared by the cascade self-foaming of the raw materials can be adjusted;

[0026] (3) The antibacterial, cascade self-foaming plant oil-based foam material of the present invention has good compressive strength and excellent antibacterial, heat-insulating, and sound-absorbing properties, thus achieving multifunctionality of the foam material. It has application prospects in the fields of packaging materials, building materials, furniture, and the like, and can also be used to prepare sound-insulating, heat-insulating, and antibacterial materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The invention provides a synthetic process for the antibacterial, cascade self-foaming plant oil-based foam material;

[0028] Figure 2 The polyethyleneimine of the present invention and the polyethyleneimine absorbing CO2 13 C NMR spectrum;

[0029] Figure 3 The polyethyleneimine of the present invention and the polyethyleneimine absorbing CO2 1 H NMR spectrum;

[0030] Figure 4 These are physical images and scanning electron microscope images of the antibacterial, cascade self-foaming plant oil-based foam materials of Examples 1 to 3 of the present invention and the self-foaming plant oil-based foam material of Comparative Example 1;

[0031] Figure 5 The mechanical properties test results of the antibacterial and cascade self-foaming plant oil-based foam materials of Examples 1 to 3 of the present invention and the self-foaming plant oil-based foam material of Comparative Example 1 are shown;

[0032] Figure 6 The thermal insulation performance test results of the antibacterial and cascade self-foaming plant oil-based foam materials of Examples 1 to 3 of the present invention and the self-foaming plant oil-based foam material of Comparative Example 1 are shown;

[0033] Figure 7 The sound absorption performance test results of the antibacterial and cascade self-foaming plant oil-based foam materials of Examples 1 to 3 of the present invention and the self-foaming plant oil-based foam material of Comparative Example 1 are shown;

[0034] Figure 8The growth of Staphylococcus aureus and Escherichia coli treated with the antibacterial, cascade self-foaming plant oil-based foam material of Example 1 of the present invention and the self-foaming plant oil-based foam material of Comparative Example 1 is shown. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings, but the embodiments 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.

[0036] The preparation process of the antibacterial, cascade self-foaming plant oil-based foam material of the present invention is as follows: Figure 1 As shown. The present invention utilizes the property of polyethyleneimine (PEI) to absorb and desorb CO2, places PEI in a closed reactor, and introduces CO2 into the closed reactor to obtain PEI@CO2. PEI@CO2 is used as a foaming agent and an in-situ cross-linking agent, and a reaction system consisting of castor oil and isophorone diisocyanate (IPDI) is added to carry out cascade self-foaming of the foam material. Specifically, castor oil and polyethyleneimine can undergo a cascade reaction with IPDI due to their different reactivity. The amine group of PEI has high reactivity with IPDI. The reaction between the two releases CO2 locked by the amine group for foaming and pore formation. The nucleophilic exothermic reaction between IPDI and active hydrogen (derived from the amine group of PEI and the hydrogen atoms on the hydroxyl group of castor oil) controls the CO2 release rate to achieve the control of the pore size and quantity of the foam material, thereby developing a foam material that meets the structure of soft foam and hard foam.

[0037] It should be noted that using isophorone diisocyanate as a raw material is only one embodiment of the present invention. Other diisocyanates can also be selected as raw materials, such as hexamethylene-1,6-diisocyanate, dicyclohexylmethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, p-xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and toluene diisocyanate.

[0038] Example 1

[0039] This embodiment provides an antibacterial, cascade self-foaming plant oil-based foam material, which is prepared by the following steps:

[0040] (1) Preparation of foaming agent: 30 g of polyethyleneimine was placed in a closed reactor, carbon dioxide was introduced into the closed reactor at room temperature (the pressure in the reactor was 3 MPa), and then the foaming agent was heated at 200 r·min. -1 The polyethyleneimine was stirred at a stirring rate of 60 min, and the product after absorbing carbon dioxide was used as a foaming agent, which was recorded as PEI@CO2;

[0041] (2) Preparation of antibacterial, cascade self-foaming plant oil-based foam materials: 10 g of castor oil and 18.23 g of isophorone diisocyanate were weighed, and the castor oil and isophorone diisocyanate were subjected to a bulk polymerization reaction in one pot for 1 h. Then, 0.5 g of dibutyltin dilaurate as a catalyst was added to the reaction system and stirred. When the NCO group content in the system dropped to about 50%, PEI@CO2 was added and the stirring reaction was continued (the molar ratio of the amino group of polyethyleneimine that absorbs CO2 to the hydroxyl group of castor oil is 0.5:0.5). The heat of reaction promoted the release of carbon dioxide in PEI@CO2, and the cascade self-foaming of the reaction system was realized. When bubbles were evenly generated, stirring was stopped and the foam was moved to room temperature for self-foaming molding.

[0042] Polyethyleneimine (PEI) and polyethyleneimine absorbing CO2 (PEI@CO2) were respectively 13 C NMR with 1 H NMR characterization, the results are shown in Figure 2 and Figure 3 .from Figure 2 It can be seen that compared with PEI, PEI@CO2 13 The obvious C=O signal peak appeared in the C NMR spectrum, indicating that PEI and CO2 were combined and new chemical bonds were generated. Figure 3 of 1 In the H NMR spectrum, the proton signals of PEI@CO2 relative to the primary and secondary amines of PEI are significantly weakened and shifted to the left, further indicating that carbon dioxide enters the polyethyleneimine and combines with the amine groups of polyethyleneimine. 13 The results of C NMR spectrum analysis show that PEI@CO2 1 The signal peak around 3.0 ppm in the H NMR spectrum is likely the peak of carbamate formed by the reaction of amine groups with CO2. These results indicate that the amine groups of polyethyleneimine can react with CO2 to successfully prepare CO2-absorbing polyethyleneimine.

[0043] Example 2

[0044] This embodiment provides an antibacterial, cascade self-foaming plant oil-based foam material, which is prepared by the following steps:

[0045] (1) Preparation of foaming agent: 30 g of polyethyleneimine was placed in a closed reactor, carbon dioxide was introduced into the closed reactor at room temperature (the pressure in the reactor was 3 MPa), and then the foaming agent was heated at 200 r·min. -1 The polyethyleneimine was stirred at a stirring rate of 60 min, and the product after absorbing carbon dioxide was used as a foaming agent, which was recorded as PEI@CO2;

[0046] (2) Preparation of antibacterial, cascade self-foaming plant oil-based foam materials: 10 g of castor oil and 15.34 g of isophorone diisocyanate were weighed, and the castor oil and isophorone diisocyanate were subjected to bulk polymerization in a one-pot method for 1 h. Then, 0.5 g of dibutyltin dilaurate as a catalyst was added to the reaction system. When the NCO group content in the system dropped to about 50%, PEI@CO2 was added and the reaction was continued with stirring (the molar ratio of the amino group of the polyethyleneimine that absorbs CO2 to the hydroxyl group of castor oil is 0.4:0.6). The heat of reaction promoted the release of carbon dioxide in PEI@CO2, and the cascade self-foaming of the reaction system was achieved. When bubbles were evenly generated, stirring was stopped, and the foam was moved to room temperature for self-foaming and molding.

[0047] Example 3

[0048] This embodiment provides an antibacterial, cascade self-foaming plant oil-based foam material, which is prepared by the following steps:

[0049] (1) Preparation of foaming agent: 30 g of polyethyleneimine was placed in a closed reactor, carbon dioxide was introduced into the closed reactor at room temperature (the pressure in the reactor was 3 MPa), and then the foaming agent was heated at 200 r·min. -1 The polyethyleneimine was stirred at a stirring rate of 60 min, and the product after absorbing carbon dioxide was used as a foaming agent, which was recorded as PEI@CO2;

[0050] (2) Preparation of antibacterial, cascade self-foaming plant oil-based foam materials: 10 g of castor oil and 12.58 g of isophorone diisocyanate were weighed, and the castor oil and isophorone diisocyanate were subjected to bulk polymerization in a one-pot method for 1 h. Then, 0.5 g of dibutyltin dilaurate as a catalyst was added to the reaction system. When the NCO group content in the system dropped to about 50%, PEI@CO2 was added and the reaction was continued with stirring (the molar ratio of the amino group of the polyethyleneimine that absorbs CO2 to the hydroxyl group of castor oil is 0.3:0.7). The heat of reaction promoted the release of carbon dioxide in PEI@CO2, and the cascade self-foaming of the reaction system was achieved. When bubbles were evenly generated, stirring was stopped, and the foam was moved to room temperature for self-foaming and molding.

[0051] Comparative Example 1

[0052] This comparative example provides a self-foaming vegetable oil-based foam material, which is prepared by the following steps:

[0053] (1) Preparation of foaming agent: 30 g of polyethyleneimine was placed in a closed reactor, carbon dioxide was introduced into the closed reactor at room temperature (the pressure in the reactor was 3 MPa), and then the foaming agent was heated at 200 r·min. -1 The polyethyleneimine was stirred at a stirring rate of 60 min, and the product after absorbing carbon dioxide was used as a foaming agent, which was recorded as PEI@CO2;

[0054] (2) Preparation of antibacterial, cascade self-foaming plant oil-based foam materials: 16.32 g of isophorone diisocyanate was reacted with 0.5 g of catalyst dibutyltin dilaurate for 1 h, and then PEI@CO2 was added and the reaction was continued with stirring. The heat of reaction promoted the release of carbon dioxide in PEI@CO2, thereby achieving self-foaming of the reaction system. When bubbles were uniformly generated, stirring was stopped and the material was moved to room temperature for self-foaming molding.

[0055] Experimental Example 1

[0056] In this experimental example, the antibacterial, cascade self-foaming plant oil-based foam materials prepared in Examples 1 to 3 and the self-foaming plant oil-based foam material prepared in Comparative Example 1 were photographed and characterized by scanning electron microscopy (SEM). The results are as follows: Figure 4 As shown. Figure 4 It can be seen that the pore structure of the self-foaming plant oil-based foam material of Comparative Example 1 collapses, while the pore structure of the antibacterial and cascade self-foaming plant oil-based foam materials of Examples 1 to 3 does not collapse, and the holes have both open and closed pores, and their pore size and distribution are uneven. This difference is due to the addition of castor oil, which 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 amine group of polyethyleneimine to the hydroxyl group of castor oil decreases, the porosity of the foam material increases. In addition, the pore structure of the antibacterial and cascade self-foaming plant oil-based foam material of Example 1 is mainly closed-cell, which conforms to the pore structure of hard foam. The pore structure of the antibacterial and cascade self-foaming plant oil-based foam material of Example 3 is mainly open-cell, which conforms to the pore structure of soft foam. In other words, the pore structure can be adjusted from closed-cell to open-cell by regulating castor oil and PEI@CO2 ratio, and then the transition from hard foam to soft foam is realized from the pore structure.

[0057] Table 1 Porosity of foam materials

[0058]

[0059] Experimental Example 2

[0060] In this experimental example, mechanical properties tests were performed on the antibacterial and cascade self-foaming plant oil-based foam materials of Examples 1 to 3 and the self-foaming plant oil-based foam material of Comparative Example 1 to study the mechanical properties of each foam material.

[0061] Test method: Tests were performed at room temperature using an MTS universal testing machine at a compression rate of 5 mm / min. Both the experimental and comparative samples were tested three times in parallel, and the average values ​​were plotted.

[0062] Mechanical properties test results are shown in Figure 5The results show that as the proportion of castor oil in the raw materials increases, the compressive strength of the antibacterial and cascade self-foaming plant oil-based foam materials gradually increases. Specifically, the self-foaming plant oil-based foam material of Comparative Example 1, which does not contain castor oil, has poor compressive strength. The compressive strength of the antibacterial and cascade self-foaming plant oil-based foam materials of Examples 1-3 is higher than that of the self-foaming plant oil-based foam material of Comparative Example 1. This is because castor oil increases the soft segment content of the polymer chain and the hydrogen bonding content within the foam material (due to the urethane bonds formed between castor oil and diisocyanate in the reaction system, the internal hydrogen bonding between PEI@CO2 and diisocyanate polyurea, and the external hydrogen bonding formed between amino groups, hydroxyl groups, and other groups in the reaction system), resulting in the plant oil-based foam materials exhibiting better compression properties. As the castor oil content in the raw material increases, the compressive strength of the antibacterial, cascade self-foaming plant oil-based foam material first increases and then decreases. The compressive strength of the antibacterial, cascade self-foaming plant oil-based foam material of Example 2 can reach 1.6 MPa. The emergence of this trend may be because as the castor oil content increases, the hydrogen bond content increases and the internal entanglement of the molecules increases the strength. At this time, the compressive strength and strain of the foam material increase. However, when the castor oil content exceeds a certain amount, the soft segment content is too large, the crosslinking density of the foam material is weakened, and the compressive strength of the material decreases.

[0063] Experimental Example 3

[0064] In this experimental example, the thermal insulation performance of the antibacterial and cascade self-foaming plant oil-based foam materials of Examples 1 to 3 and the self-foaming plant oil-based foam material of Comparative Example 1 was tested to study the thermal insulation performance of each foam material.

[0065] The thermal conductivity of each foam material was characterized by a room temperature thermal conductivity meter. The results are as follows: Figure 6 As shown. Among them, the thermal conductivity of the self-foaming plant oil-based foam material in Comparative Example 1 is 0.07352 W / (m·K), while the thermal conductivity of the antibacterial and cascade self-foaming plant oil-based foam materials in Examples 1 to 3 is lower than that of Comparative Example 1 under the same test conditions, indicating that the antibacterial and cascade self-foaming plant oil-based foam materials in the present invention have more excellent thermal insulation performance. The thermal conductivity of the antibacterial and cascade self-foaming plant oil-based foam material in 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 thermal insulation performance under the same environmental conditions and have the potential to become thermal insulation materials.

[0066] Experimental Example 4

[0067] In this experimental example, the sound absorption performance of the antibacterial and cascade self-foaming plant oil-based foam materials of Examples 1 to 3 and the self-foaming plant oil-based foam material of Comparative Example 1 was tested to study the sound absorption performance of each foam material.

[0068] The thermal conductivity of each foam material is characterized by a measuring instrument. The results are as follows: Figure 7 As shown. Figure 7 It can be seen that under the noise environment of 200~1600Hz, the sound absorption performance of the self-foaming plant 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 plant oil-based foam materials of Examples 1~3 have more excellent sound absorption performance, which is manifested in that the sound absorption coefficient of the foam materials of each embodiment is greater than that of the foam material of Comparative Example 1 under the noise environment of 200~1600Hz. Among them, the sound absorption coefficient of the foam materials of each embodiment can reach the highest under the noise environment of 900~1200Hz. In addition, the maximum sound absorption coefficient of the foam material increases with the increase of the castor oil content in the raw material. Among them, the sound absorption coefficient of the antibacterial and cascade self-foaming plant oil-based foam material of Example 3 can reach a maximum of 0.83, which shows that the plant oil-based foam material obtained by regulating the porosity and size by castor oil has obvious sound absorption performance advantages and has the potential to become a sound insulation material.

[0069] Experimental Example 5

[0070] Based on the fact that the tertiary amine groups in polyethyleneimine absorb CO2 to form quaternary ammonium salt ions with antibacterial effect, this experimental example conducted antibacterial experiments on the antibacterial, cascade self-foaming plant oil-based foam material of Example 1 and the self-foaming plant oil-based foam material of Comparative Example 1 to compare the antibacterial properties of the foam materials.

[0071] The antibacterial, cascade self-foaming plant oil-based foam material of Example 1 and the self-foaming plant oil-based foam material of Comparative Example 1 (hereinafter referred to as "samples") were irradiated under ultraviolet light for 30 minutes, then soaked in a PBS solution for 30 minutes and set aside. The samples were co-cultured with 1 mL of Staphylococcus aureus or Escherichia coli bacterial liquid for 3.5 hours, the bacterial liquid was filtered and retained, and 30 μL of the bacterial liquid was evenly spread on the agar surface. The cells were cultured in a 37°C incubator for 16 hours, and the growth of Staphylococcus aureus and Escherichia coli was observed.

[0072] After 16 hours of incubation, the agar was photographed and the growth of Staphylococcus aureus and Escherichia coli was recorded. Figure 8As shown. The results show that, in the antibacterial experiment, the self-foaming vegetable oil-based foam material of Comparative Example 1 exhibits non-antibacterial properties, and a large number of strains appear on the surface of its corresponding agar after cultivation. Compared to Comparative Example 1, the antibacterial and cascade self-foaming vegetable oil-based foam material of Example 1 exhibits a more excellent antibacterial effect, and it can be observed that agar indicates that no strain appears. This may be related to the material structure of Example 1 and Comparative Example 1. Although the component structures of the foam materials of Example 1 and Comparative Example 1 both contain quaternary ammonium salts, the self-foaming vegetable oil-based foam material of Comparative Example 1 has a collapsed material structure, and the molecular chain segments are tightly entangled and embedded in the material, which is not conducive to the exposure of the quaternary ammonium salt therein to contact with bacteria, and therefore its antibacterial property cannot be achieved. Example 1 Antibacterial, cascade self-foaming plant oil-based foam material: The unreleased carbon dioxide remaining in the polyethyleneimine is tightly combined with the tertiary amine of the polyethyleneimine to form quaternary ammonium salt ions, which can give the foam material excellent antibacterial properties. At the same time, the branched structure of castor oil has a supporting effect on the foam skeleton, creating a good pore structure for the foam material. These interconnected pores are conducive to the exposure of the quaternary ammonium salt, thereby playing an anti-killing effect on Staphylococcus aureus and Escherichia coli.

[0073] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. Cascade self-foaming vegetable oil-based foam material, characterized in that, The invention 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 CO2-absorbing polyethyleneimine is used as a reactant. The CO2-absorbing polyethyleneimine is prepared by reacting the amine groups of the polyethyleneimine with CO2; the molar ratio of the amine groups of the CO2-absorbing polyethyleneimine to the hydroxyl groups of the castor oil is (0.7-0.3):(0.3-0.7); The preparation method of the cascade self-foaming vegetable oil-based foam material comprises the following steps: (1) placing polyethyleneimine in a reactor and introducing CO2 to obtain polyethyleneimine that absorbs 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) Adding a catalyst to the reaction system, reacting until the NCO group content in the reaction system drops to 45% to 55%, adding polyethyleneimine that absorbs CO2 to continue the reaction, and transferring the reaction system to room temperature for self-foaming molding until bubbles are uniformly generated in the reaction system.

2. The cascade self-foaming vegetable oil-based foam material according to claim 1, 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).

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

4. The cascade self-foaming vegetable 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.

5. The cascade self-foaming vegetable 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, introducing CO2 into the sealed container, and then stirring the polyethyleneimine.

6. The cascade self-foaming vegetable 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 reaches 1-5 MPa, and then -1 The polyethyleneimine is stirred at a stirring rate of 45 to 120 min to obtain the product.

7. The method for preparing the cascade self-foaming vegetable oil-based foam material according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) placing polyethyleneimine in a reactor and introducing CO2 to obtain polyethyleneimine that absorbs 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) Adding a catalyst to the reaction system, reacting until the NCO group content in the reaction system drops to 45% to 55%, adding polyethyleneimine that absorbs CO2 to continue the reaction, and transferring the reaction system to room temperature for self-foaming molding until bubbles are uniformly generated in the reaction system.

8. Use of the cascade self-foaming vegetable oil-based foam material according to any one of claims 1 to 6 in packaging materials, building materials, furniture materials, household appliance materials or aerospace materials.

9. Use of the cascade self-foaming vegetable oil-based foam material according to any one of claims 1 to 6 in preparing a material having at least one of the properties of sound insulation and heat preservation.

Images