Graphene / silane coupling agent grafted biomass material as well as preparation and application thereof

Abstract

The invention discloses a graphene / silane coupling agent grafted biomass material which is prepared by the following steps: mixing a biomass material with a solution containing graphene sol and a silane coupling agent, heating to 90-120 DEG C, and continuously stirring for 2-3 hours, so as to obtain the graphene / silane coupling agent grafted biomass material; the biomass material is bamboo powder, straw powder or starch; the particle size is 1500 to 2000 meshes; kH560 is adopted as the silane coupling agent; wherein the volume ratio of the graphene sol to the distilled water to the ethanol is (0.2-0.7): 1: (9-12), and the use amount of the KH560 is 10%-15% of the total volume of the mixed solution; the addition amount of the graphene / silane coupling agent grafted biomass material in the degradable mulching film is 10 to 25 weight percent; according to the invention, active sites are increased by grafting the graphene / silane coupling agent on the surface, so that combination with a reactive compatibilizer and a resin matrix is facilitated, and the performance of the biomass material / high polymer composite material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and specifically relates to a modified biomass material and a preparation and application thereof. Background Art

[0002] Degradable mulch is a new type of agricultural film produced to meet the needs of society for environmental protection. Degradable mulch has the characteristics of not needing to be recycled and can be partially or completely degraded by microorganisms in the soil. At present, synthetic polymer materials or natural polymer materials are the main raw materials for degradable mulch. Degradable polymers include polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT). However, the production cost of biodegradable polymers is usually high. For example, biodegradable PBAT is three times more expensive than traditional non-biodegradable low-density polyethylene. The high price hinders its widespread use in daily life.

[0003] Natural biomass materials, such as bamboo materials, straw and starch, are widely distributed in my country. Bamboo fiber and straw are renewable resources with a short growth cycle and good regeneration performance. The PLA or PBAT matrix filled with natural biomass materials has attracted the interest of researchers. Take bamboo materials as an example to illustrate. Bamboo materials contain a large number of hydrophilic hydroxyl groups, and the interfacial compatibility between them and the polymer matrix is ​​poor, resulting in reduced mechanical properties of the obtained composite materials. Improving interfacial compatibility is crucial for the preparation of bamboo material / polymer composites. Ultraviolet radiation, addition of plasticizers, plasma treatment and other technologies have been used to enhance interfacial compatibility. Although these methods can improve interfacial compatibility, they also have disadvantages such as severe fiber strength damage, high energy consumption, and toxic substances. Therefore, polymers filled with natural biomass materials still face great challenges in the preparation of degradable composites, and there are also great difficulties in the preparation of degradable mulch.

[0004] Silane coupling agents are widely used in composite materials to improve mechanical properties, and their dual-functional structure has aroused people's interest in reinforcing plant fibers / polymers. Silane coupling agents can form molecular bridges between high molecular polymers and inorganic substrates, increase bonding strength, and improve the performance of composite materials. However, studies have found that when silane coupling agents are used alone to graft and modify bamboo powder, the surface of bamboo powder has a limited number of grafting reaction active sites, resulting in less adsorption of silane coupling agents on the surface particles of bamboo powder. How to further increase the grafting sites of biomass materials and silane coupling agents has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present invention aims to provide a modified biomass material and a preparation method and application thereof, by grafting two substances, graphene / silane coupling agent, on the surface to increase active sites, facilitate combination with a reactive compatibilizer and a resin matrix, and improve the performance of a biomass material / polymer composite material.

[0006] In order to achieve the above purpose, the technical solutions adopted are as follows: A graphene / silane coupling agent grafted biomass material is prepared by the following method: The biomass material is mixed with a solution containing graphene sol and a silane coupling agent, and the temperature is raised to 90-120° C. and stirred for 2-3 h to obtain a graphene / silane coupling agent grafted biomass material.

[0007] According to the above scheme, the biomass material is bamboo powder, straw powder or starch; and the particle size is 1500-2000 mesh.

[0008] According to the above scheme, the silane coupling agent is KH560.

[0009] According to the above scheme, the solution containing graphene sol and silane coupling agent is a mixed solution of graphene sol, silane coupling agent, distilled water and ethanol; wherein the amount of graphene sol, distilled water and ethanol is in a volume ratio of (0.2~0.7):1:(9~12), and the amount of KH560 is 10%~15% of the total volume of the mixed solution.

[0010] According to the above scheme, the amount of biomass material added is 0.2-0.3 g / mL based on the solid-liquid ratio.

[0011] The method for preparing the above-mentioned graphene / silane coupling agent grafted biomass material comprises the following steps: The biomass material is added into a mixed solution, wherein the mixed solution is a mixture of graphene sol, distilled water, anhydrous ethanol and a silane coupling agent; the mixture is stirred at room temperature for 30-40 min, and the mixture is heated to 90-120° C. and stirred for 2-3 h to obtain a graphene / silane coupling agent grafted biomass material.

[0012] Application of the above-mentioned graphene / silane coupling agent grafted biomass material in degradable mulch.

[0013] According to the above scheme, the addition amount of the graphene / silane coupling agent grafted biomass material in the degradable mulch film is 10-15wt%.

[0014] Compared with the prior art, the present invention has the following beneficial effects: Graphene has two characteristics: (1) graphene has a large specific surface area; (2) there are a large number of active functional groups on the graphene surface, such as hydroxyl, carbonyl and carboxyl. When graphene is attached to the surface of bamboo powder, the surface of bamboo powder becomes rough, and the surface of bamboo powder has a large number of active sites for grafting reaction. Silane coupling agent can react with the hydroxyl groups on graphene to form -Si-O- bonds, and introduce silane coupling agent on the surface of graphene sheet. The successful grafting of graphene / silane coupling agent on bamboo powder can enhance the interfacial adhesion between bamboo powder and polymer, and at the same time increase the number of active sites on the surface of bamboo powder. The surface of bamboo powder is easy to bond with reactive compatibilizer and resin matrix, improves its reactivity, and increases the effective contact area with the matrix, thereby improving the compatibility of bamboo powder with PLA and PBAT, overcoming the poor compatibility problem of bamboo powder with PLA and PBAT. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 : Scanning electron micrograph of ungrafted ultrafine bamboo powder.

[0016] Figure 2 : Elemental analysis of ungrafted ultrafine bamboo powder.

[0017] Figure 3 : Elemental mapping of unmodified ultrafine bamboo powder.

[0018] Figure 4 : Scanning electron micrograph of ultrafine bamboo powder grafted with KH560 alone.

[0019] Figure 5 : Elemental analysis of ultrafine bamboo powder grafted with KH560 alone.

[0020] Figure 6 : Element mapping of ultrafine bamboo powder grafted with KH560 alone.

[0021] Figure 7 : Scanning electron micrograph of ultrafine bamboo powder grafted with graphene and KH560.

[0022] Figure 8 : Elemental analysis of ultrafine bamboo powder grafted with graphene and KH560.

[0023] Fig. 9 : Elemental mapping of ultrafine bamboo powder grafted with graphene and KH560.

[0024] Fig.10 : Scanning electron micrograph of ungrafted starch.

[0025] Fig.11 : Elemental analysis of ungrafted starch.

[0026] Fig.12: Elemental mapping of unmodified starch.

[0027] Fig.13 : Scanning electron micrograph of starch grafted with KH560 alone.

[0028] Fig.14 : Elemental analysis of starch grafted with KH560 alone.

[0029] Fig.15 : Elemental mapping of starch grafted with KH560 alone.

[0030] Fig.16 : Scanning electron microscopy images of starch grafted with graphene and KH560.

[0031] Fig.17 : Elemental analysis of starch grafted with graphene and KH560.

[0032] Fig.18 : Elemental mapping of starch grafted with graphene and KH560. DETAILED DESCRIPTION

[0033] The following examples further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0034] The specific embodiment provides a kind of ultrafine bamboo powder, the scanning electron microscope picture is shown in the attached Figure 1 See the attached elemental analysis diagram Figure 2 See the attached element mapping diagram Figure 3 shown.

[0035] The specific embodiment also provides a superfine bamboo powder grafted with KH560 alone, which is prepared in the following manner: The biomass material is added to a mixed solution, which is a mixture of distilled water, anhydrous ethanol, and a silane coupling agent; the mixture is stirred at room temperature for 35 minutes, heated to 105°C and stirred for 2.5 hours to obtain a biomass material grafted with a silane coupling agent. The solution containing the silane coupling agent is a mixed solution of a silane coupling agent, distilled water, and ethanol; the amount of distilled water and ethanol is 1:10 in a volume ratio, and the amount of KH560 is 12wt% of the total volume of the mixed solution.

[0036] The obtained ultrafine bamboo powder grafted with KH560 alone, the scanning electron microscope image is shown in the attached Figure 4 See the attached elemental analysis diagram Figure 5 See the attached element mapping diagram Figure 6 shown.

[0037] Example 1 A superfine bamboo powder grafted with graphene and KH560: Ultrafine bamboo powder is added to a mixed solution, which is a mixture of graphene sol, distilled water, anhydrous ethanol, and a silane coupling agent; the mixture is stirred at room temperature for 35 minutes, heated to 105°C and stirred for 2.5 hours to obtain a graphene / silane coupling agent grafted biomass material. The solution containing graphene sol and silane coupling agent is a mixed solution of graphene sol, silane coupling agent, distilled water, and ethanol; wherein the amount of graphene sol, distilled water, and ethanol is in a volume ratio of 0.4:1:10, and the amount of KH560 is 12wt% of the total volume of the mixed solution.

[0038] The obtained ultrafine bamboo powder grafted with graphene and KH560, the scanning electron microscope image is attached Figure 7 See the attached elemental analysis diagram Figure 8 See the attached element mapping diagram Fig. 9 shown.

[0039] Figure 1-3 The scanning electron microscope image, element analysis image, and element mapping image of the ungrafted ultrafine bamboo powder are shown in the figure. It can be seen from the figure that the surface of the ungrafted ultrafine bamboo powder is smooth, and the main elements are C and O. Figure 4-6 The following are the scanning electron microscope images, element analysis images, and element mapping images of the ultrafine bamboo powder grafted with KH560 alone. As can be seen from the images, some stripes appear on the surface of the ultrafine bamboo powder grafted with KH560 alone, indicating that the surface is rough. The main elements are C and O, and there is already Si on the surface. Figure 6 The Si element is evenly distributed, indicating that KH560 grafting is successful. Figure 7-9 The scanning electron microscope images, element analysis images, and element mapping images of the ultrafine bamboo powder grafted with graphene and KH560 are shown in the figure. As can be seen from the figure, the surface protrusions of the ultrafine bamboo powder grafted with KH560 alone increase, the surface is rougher, and the surface graphene increases the active sites, which helps to promote the grafting of KH560. The main elements are C and O, and there is Si on the surface. Fig. 9 The Si element is evenly distributed, indicating that KH560 grafting is successful.

[0040] Example 2 A starch grafted with KH560 alone: Starch is added to a mixed solution, which is a mixture of distilled water, anhydrous ethanol, and a silane coupling agent; the mixture is stirred at room temperature for 30 minutes, heated to 110°C and stirred for 2 hours to obtain a biomass material grafted with a silane coupling agent. The solution containing graphene sol and a silane coupling agent is a mixed solution of a silane coupling agent, distilled water, and ethanol; the amount of distilled water and ethanol is 1:11 by volume, and the amount of KH560 is 13wt% of the total volume of the mixed solution.

[0041] A starch grafted with graphene and KH560 at the same time: Starch is added to a mixed solution, which is a mixture of graphene sol, distilled water, anhydrous ethanol, and a silane coupling agent; the mixture is stirred at room temperature for 30 minutes, heated to 110°C and stirred for 2 hours to obtain a graphene / silane coupling agent grafted biomass material. The solution containing graphene sol and silane coupling agent is a mixed solution of graphene sol, silane coupling agent, distilled water, and ethanol; wherein the amount of graphene sol, distilled water, and ethanol is in a volume ratio of 0.5:1:11, and the amount of KH560 is 13wt% of the total volume of the mixed solution.

[0042] Figure 10-12 The scanning electron microscope image, element analysis image, and element mapping image of the ungrafted starch are shown in Figure 1. As can be seen from the figure, the surface of the ungrafted starch is smooth with only tiny cracks, and the main elements are C and O. Figure 13-15 The following are the scanning electron microscope images, element analysis images, and element mapping images of starch grafted with KH560 alone. As can be seen from the images, the surface of starch grafted with KH560 alone has obvious cracks, indicating that the surface is rough. The main elements are C and O, and there is already Si on the surface. Fig.14 The Si element is evenly distributed, indicating that KH560 grafting is successful. Figure 16-18 The following are the scanning electron microscope images, elemental analysis images, and elemental mapping images of starch grafted with graphene and KH560. As can be seen from the images, the cracks of starch grafted with KH560 alone are significantly deepened, and the surface is rougher. The graphene on the surface increases the active sites, which helps to promote the grafting of KH560. The main elements are C and O, and there is Si on the surface. Fig.17 The Si element is evenly distributed, indicating that KH560 grafting is successful.

[0043] Application Comparative Example 1 The degradable mulch was prepared by blow molding process, and the raw material ratio was 40:15:10:15:1.2. The degradable mulch was prepared by bamboo powder, bamboo powder grafted with graphene and KH560, starch, and starch grafted with graphene and KH560 as biomass materials. The performance characterization parameters are shown in Table 1. In the tensile performance test, the degradable mulch adopted the "5-type specimen specification" with a width of 6 mm and a thickness of 0.1 mm.

[0044] Table 1

Claims

1. A graphene / silane coupling agent grafted biomass material, characterized in that Prepared in the following way: The biomass material is mixed with a solution containing graphene sol and a silane coupling agent, and the temperature is raised to 90-120° C. and stirred for 2-3 h to obtain a graphene / silane coupling agent grafted biomass material.

2. The graphene / silane coupling agent grafted biomass material according to claim 1, characterized in that The biomass material is bamboo powder, straw powder or starch; and the particle size is 1500-2000 meshes.

3. The graphene / silane coupling agent grafted biomass material according to claim 1, characterized in that The silane coupling agent is KH560.

4. The graphene / silane coupling agent grafted biomass material according to claim 1, characterized in that The solution containing graphene sol and silane coupling agent is a mixed solution of graphene sol, silane coupling agent, distilled water and ethanol; wherein the amount of graphene sol, distilled water and ethanol is in a volume ratio of (0.2-0.7):1:(9-12), and the amount of KH560 is 10%-15% of the total volume of the mixed solution.

5. The graphene / silane coupling agent grafted biomass material according to claim 1, characterized in that The amount of the biomass material added is 0.2-0.3 g / mL based on the solid-liquid ratio.

6. The method for preparing the graphene / silane coupling agent grafted biomass material according to any one of claims 1 to 5, characterized in that The following steps are involved: The biomass material is added into a mixed solution, wherein the mixed solution is a mixture of graphene sol, distilled water, anhydrous ethanol and a silane coupling agent; the mixture is stirred at room temperature for 30-40 min, and the mixture is heated to 90-120° C. and stirred for 2-3 h to obtain a graphene / silane coupling agent grafted biomass material.

7. Use of the graphene / silane coupling agent grafted biomass material according to any one of claims 1 to 5 in degradable mulch.

8. The use of the graphene / silane coupling agent grafted biomass material in the degradable mulch as claimed in claim 7, wherein the addition amount of the graphene / silane coupling agent grafted biomass material in the degradable mulch is 10-25wt%.

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