Preparation method of completely biodegradable dustproof net based on modified bamboo powder

Abstract

The invention discloses a preparation method of a completely biodegradable dustproof net based on modified bamboo powder, and belongs to the technical field of biodegradable new materials. The formula comprises the following components in parts by weight: 50-70 parts of poly (butylene adipate-co-terephthalate), 10-40 parts of bamboo powder, 0.1-2 parts of a silane coupling agent, 0.1-1 part of a surfactant, 0.1-1 part of an anti-blocking agent, 0.1-1 part of an antioxidant and 0.1-1 part of an ultraviolet light absorber. The dust screen prepared by the invention not only has biodegradability, but also has the characteristics of being green and environment-friendly by adopting the bio-based material bamboo powder. Meanwhile, in order to realize good combination of the bamboo powder and matrix plastic poly (butylene adipate-co-terephthalate), a silane coupling agent capable of combining the bamboo powder and the matrix plastic poly (butylene adipate-co-terephthalate) through a chemical reaction and a surfactant capable of combining the bamboo powder and the matrix plastic poly (butylene adipate-co-terephthalate) through a physical effect are sequentially adopted for composite modification of the bamboo powder; the dispersity of the bamboo powder and the compatibility of the bamboo powder and poly (butylene adipate-co-terephthalate) are effectively improved, and the prepared dustproof net has good mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of new biodegradable materials, and in particular relates to a preparation method of a completely biodegradable dustproof net based on modified bamboo powder. Background Art

[0002] Dust nets, also known as soil covering nets, are used to prevent dust pollution. Traditional dust nets are made of non-degradable polyethylene. Furthermore, they are typically disposable, meaning a large number of them are discarded each year.

[0003] A fully biodegradable, high-efficiency dust screen consists of more than 80% polylactic acid as its main component, with the remainder being modifiers, resulting in a relatively high cost. A fully biodegradable dust screen made from calcium powder-modified polybutylene adipate terephthalate (PBAT) uses calcium powder as a doping agent to reduce the use of PBAT. However, the mechanical properties of calcium powder-modified polybutylene adipate terephthalate (PBAT) are generally not strong enough. The mechanical properties of a biodegradable dust screen affect its service life, so greater strength is preferable.

[0004] Bamboo is widely cultivated in my country and is widely used for its rapid growth, high yield, high strength, and low cost. Bamboo powder, primarily composed of bamboo cellulose, exhibits excellent mechanical properties and can be used as a reinforcing material. Cellulose, a key component of bamboo powder, possesses a specific aspect ratio, significantly reinforcing the matrix material in the radial direction, offering advantages not possessed by calcium carbonate, talc, and other materials. Dust screens, on the other hand, are produced by blow-molding the raw material into a film, then cutting it into filaments for weaving. This requires the raw material to possess high tensile strength in at least one direction. However, the high number of hydroxyl groups on the surface of bamboo powder cellulose makes it highly hydrophilic and polar. Matrix plastics such as polybutylene adipate terephthalate (PBAT) and polylactic acid are mostly hydrophobic, making composites difficult to form, resulting in poor mechanical properties in the resulting blend. Previous studies have typically used silane coupling agents to modify bamboo powder, chemically linking the cellulose in the powder with the PBAT. However, bamboo powder cellulose itself contains a large number of hydroxyl groups. Adding a silane coupling agent can only react with a portion of these hydroxyl groups. The remaining hydroxyl groups still easily cause the cellulose to agglomerate, making it difficult to fully mix with the matrix material such as polybutylene adipate terephthalate (PBAT). There are also methods that use a very dilute polybutylene adipate terephthalate (PBAT) solution to coat bamboo powder fibers under the effect of high-speed shear, directly improving the compatibility of bamboo powder with the resin matrix polybutylene adipate terephthalate (PBAT). However, this process requires the use of the toxic organic solvent chloroform, and the simple physical coating effect is not sufficient to fully connect the two. Another method is to first coat the bamboo powder with polydopamine and then graft it with maleic anhydride to modify the bamboo powder. However, the polydopamine coating on the bamboo powder surface hinders the subsequent reaction between maleic anhydride and bamboo powder, thereby affecting the bonding of the modified bamboo powder with polylactic acid. In addition, the dark color of polydopamine will affect the color of the product to some extent. Summary of the Invention

[0005] In order to solve the compatibility problem between cellulose in bamboo powder and polybutylene adipate terephthalate (PBAT), the present invention provides a method for preparing a fully biodegradable dustproof net based on modified bamboo powder.

[0006] The raw materials and amounts of the raw materials used in a fully biodegradable dust screen based on modified bamboo powder are as follows:

[0007] 50-70 parts by mass of polybutylene adipate terephthalate (PBAT), 10-40 parts by mass of bamboo powder, 0.1-2 parts by mass of a silane coupling agent, 0.1-1 parts by mass of a surfactant, 0.1-1 parts by mass of an anti-blocking agent, 0.1-1 parts by mass of an antioxidant, and 0.1-1 parts by mass of a UV absorber;

[0008] The preparation steps of the fully biodegradable dust screen based on modified bamboo powder are as follows:

[0009] (1) soaking 10-40 parts by weight of bamboo powder in a sodium hydroxide solution for 12 hours; washing with water until neutral, and drying to remove other impurities in the bamboo powder and retain the cellulose in the bamboo powder, thereby obtaining alkali-treated bamboo powder;

[0010] (2) in a high-speed mixer, stirring and mixing the alkali-treated bamboo powder and 0.1-2 parts by mass of a silane coupling agent for 10 minutes to obtain silane coupling agent-modified bamboo powder;

[0011] (3) In a high-speed mixer, the silane coupling agent-modified bamboo powder and 0.1-1 parts by mass of a surfactant were stirred and mixed for 10 minutes to obtain modified bamboo powder;

[0012] (4) In a high-speed mixer, the modified bamboo powder, 50-70 parts by weight of polybutylene adipate terephthalate (PBAT), 0.1-1 parts by weight of an anti-blocking agent, 0.1-1 parts by weight of an antioxidant, and 0.1-1 parts by weight of an ultraviolet absorber were stirred and mixed for 10 minutes to obtain a mixed dustproof net raw material;

[0013] (5) In a twin-screw extruder, the mixed dust-proof net raw material is extruded and pelletized to obtain resin particles for degradable dust-proof net;

[0014] (6) placing the resin particles for the degradable dust-proof net into a film blowing machine unit, extruding, blowing, pulling, drawing and winding to obtain flat wires of the degradable dust-proof net;

[0015] (7) The flat yarn is placed on a warp knitting machine, and the warp knitting machine is used to weave a completely biodegradable dustproof net.

[0016] The technical solutions are further defined as follows:

[0017] The fully biodegradable dustproof net has the following performances: longitudinal tensile strength of 25.49-29.79 / Mpa, longitudinal elongation at break of 406-453 / %, transverse tensile strength of 22.58-26.54 / Mpa, longitudinal elongation at break of 578-633 / %, longitudinal tearing force of 12.5-18.6 / N, and transverse tearing force of 10.8-13.1 / N.

[0018] In step (1), the mesh size of the bamboo powder is 200-2000 meshes, the mass concentration of the sodium hydroxide solution is 20-30%, and the mass of the 20-30% sodium hydroxide solution used is 10-20 times that of the bamboo powder.

[0019] In step (2), the silane coupling agent is preferably a silane coupling agent containing an amino group, with a general structural formula of NH3-R-Si(OR)3, preferably KH550.

[0020] In step (3), the surfactant is one of oleic acid, sodium stearate, calcium stearate, sodium lauryl sulfate, and sodium hexadecyl sulfate, preferably oleic acid.

[0021] In step (4), the opening agent is at least one of oleamide, erucamide, talc, and silicon dioxide; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant 264, and antioxidant 186; and the ultraviolet absorber is at least one of UV-234 and UV-326.

[0022] In step (2), step (3) and step (4), the mixing speed of the high-speed mixer is 100-500 rpm.

[0023] In step (5), the temperature of each section of the twin-screw extruder is: 130-150°C for sections 1-2, 150-175°C for sections 3-8, 150-175°C for sections 9-11, and 155-170°C for the die.

[0024] The beneficial technical effects of the present invention are embodied in the following aspects:

[0025] 1. Bamboo powder, which is naturally grown, low-cost, biodegradable, and significantly enhances polybutylene adipate terephthalate (PBAT), is used to modify polybutylene adipate terephthalate (PBAT) material to prepare a dustproof net. The maximum bamboo powder filling amount can reach 40%. The prepared dustproof net not only has good mechanical properties but also has good biodegradability, is low-cost, non-toxic, pollution-free, and can be completely biodegraded.

[0026] 2. The present invention improves the compatibility between cellulose in bamboo powder and polybutylene adipate terephthalate (PBAT) by combining chemical and physical effects. First, a silane coupling agent is modified on the bamboo powder to connect the bamboo powder cellulose and polybutylene adipate terephthalate (PBAT) through a chemical reaction. Then, the bamboo powder cellulose modified with the silane coupling agent is coated with the hydrophilic end of the surfactant and the cellulose, thereby reducing the self-agglomeration effect of the cellulose. Then, the bamboo powder modified with the silane coupling agent and the surfactant is mixed with polybutylene adipate terephthalate (PBAT). The silane coupling agent and the surfactant are combined with the polybutylene adipate terephthalate (PBAT) through the chemical action and physical hydrophobic effect of the silane coupling agent and the surfactant, thereby significantly enhancing the compatibility between the bamboo powder cellulose and polybutylene adipate terephthalate (PBAT). By combining chemical and physical effects, the bamboo powder cellulose and PBAT are fully combined, effectively increasing the strength of the bamboo powder-modified polybutylene adipate terephthalate (PBAT) material. The resulting dust-proof net has good strength, reduces the use of polybutylene adipate terephthalate (PBAT), and has good biodegradability and environmental friendliness.

[0027] In the present invention, in step (2), alkali-treated bamboo powder and a silane coupling agent are first mixed, so that the silane coupling agent reacts with a portion of the hydroxyl groups on the bamboo powder, reducing the agglomeration and hydrophilicity of the bamboo powder, thereby obtaining silane coupling agent-modified bamboo powder. Then, in step (3), the silane coupling agent-modified bamboo powder is mixed with an amphiphilic surfactant. At this time, the hydrophilic end of the surfactant physically binds to the hydrophilic groups on the bamboo powder, while the hydrophobic end of the surfactant is exposed, further reducing the hydrophilicity of the bamboo powder, thereby obtaining modified bamboo powder. Next, through steps (4) and (5), the modified bamboo powder is mixed with polybutylene adipate terephthalate (PBAT) and subjected to twin-screw extrusion processing. At this time, the silane coupling agent can react with the PBAT to form a chemical bond, and the hydrophobic end of the surfactant can bind to the polybutylene adipate terephthalate (PBAT) through a physical hydrophobic effect. Both of these improve the compatibility of the bamboo powder and the polybutylene adipate terephthalate (PBAT). If the bamboo powder is modified with a surfactant alone, it only connects the bamboo powder and the polybutylene adipate terephthalate (PBAT) through a physical effect, and the effect is insufficient (see Example 1 and Comparative Example 1); and if the bamboo powder is modified with a silane coupling agent alone, there will be some hydroxyl groups that have not reacted with the silane coupling agent after modification, which increases the hydrophilicity and agglomeration of the bamboo powder, making it difficult to fully compatibility with the polybutylene adipate terephthalate (PBAT) (see Example 1 and Comparative Example 2). The reason for modifying the bamboo powder with the silane coupling agent first and then with the surfactant is that if the bamboo powder and the surfactant are mixed first, the surfactant will completely cover the bamboo powder through hydrophilic interaction, making it difficult for the hydroxyl groups of the bamboo powder to be exposed. As a result, the bamboo powder cannot react with the silane coupling agent in the next step, affecting the final combination with polybutylene adipate terephthalate (PBAT) (see Example 1 and Comparative Example 3). DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the embodiments.

[0029] The dust screens of Examples 1-3 and Comparative Examples 1-3 were tested for performance, and the results are shown in Table 1. The tensile strength and elongation at break tests were performed in accordance with GB / T 1040.1-2018 and GB / T 1040.3-2006, and the tear strength test was performed in accordance with GB / T 16578.1-2008.

[0030] Table 1 Dust screen performance test results

[0031]

[0032] Example 1

[0033] A formula for a fully biodegradable dust screen based on modified bamboo powder: 140 kg of polybutylene adipate terephthalate (PBAT), 60 kg of 1000 mesh bamboo powder, 1 kg of silane coupling agent KH550, 0.4 kg of surfactant oleic acid, 0.4 kg of opener oleic acid amide, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234.

[0034] The preparation steps are as follows:

[0035] S1: soaking 60 kg of bamboo powder in 900 kg of 20% sodium hydroxide solution for 12 hours; washing with water until neutral; and drying to remove other impurities in the bamboo powder and retain the cellulose in the bamboo powder to obtain alkali-treated bamboo powder.

[0036] S2: Add alkali-treated bamboo powder and 1 kg of silane coupling agent KH550 into a high-speed mixer at a speed of 200 rpm, and stir and mix for 10 minutes to obtain silane coupling agent-modified bamboo powder.

[0037] S3: Add the silane coupling agent modified bamboo powder and 0.4 kg of surfactant oleic acid into a high-speed mixer at a speed of 200 rpm and stir for 10 minutes to obtain modified bamboo powder.

[0038] S4: In a high-speed mixer, the modified bamboo powder, 140 kg of polybutylene adipate terephthalate (PBAT), 0.4 kg of oleamide, an anti-blocking agent, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234 were stirred and mixed for 10 minutes at a speed of 200 rpm to obtain a mixed dustproof net raw material.

[0039] S5: Add the above mixed dust-proof net raw materials into a twin-screw extruder, and set the temperature of each section in the twin-screw extruder to: 130 and 140°C for sections 1-2, 150, 155, 160, 165, 170, and 170°C for sections 3-8, and 170 and 165°C for sections 9-11. The die is 165°C, extruded, and pelletized to obtain resin particles specifically for degradable dust-proof nets.

[0040] S6: putting the above-mentioned resin particles for the degradable dust-proof net into a film blowing machine unit, extruding, blowing, pulling, drawing and winding to obtain the flat wire of the degradable dust-proof net.

[0041] S7: The flat yarn is placed on a warp knitting machine, and the warp knitting machine is used to weave the flat yarn into a completely biodegradable dust-proof net.

[0042] The dustproof net prepared in this embodiment 1 has the following performances: longitudinal tensile strength is 29.79 / Mpa, longitudinal elongation at break is 453 / %, transverse tensile strength is 26.54 / Mpa, longitudinal elongation at break is 633 / %, longitudinal tearing force is 18.6 / N, and transverse tearing force is 13.1 / N.

[0043] Example 2

[0044] A formula for a fully biodegradable dust screen based on modified bamboo powder: 140 kg of polybutylene adipate terephthalate (PBAT), 60 kg of 1000 mesh bamboo powder, 1 kg of silane coupling agent KH550, 0.2 kg of surfactant oleic acid, 0.4 kg of opener oleic acid amide, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234.

[0045] The preparation steps are:

[0046] S1: Soak 60 kg of bamboo powder in 900 kg of 20% sodium hydroxide solution for 12 hours, then wash with water until neutral, and dry to remove other impurities in the bamboo powder while retaining the cellulose in the bamboo powder, thereby obtaining alkali-treated bamboo powder.

[0047] S2: Add the alkali-treated bamboo powder and 1 kg of silane coupling agent KH550 into a high-speed mixer at a speed of 200 rpm and stir for 10 minutes to obtain bamboo powder modified with the silane coupling agent.

[0048] S3: The bamboo powder modified with the silane coupling agent and 0.2 kg of surfactant oleic acid were added into a high-speed mixer at a speed of 200 rpm and stirred for 10 minutes to obtain the modified bamboo powder.

[0049] S4: In a high-speed mixer, the modified bamboo powder, 140 kg of polybutylene adipate terephthalate (PBAT), 0.4 kg of oleamide, an anti-blocking agent, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234 were stirred and mixed for 10 minutes at a speed of 200 rpm to obtain a mixed dustproof net raw material.

[0050] S5: Add the mixed dust-proof net raw materials mentioned above into a twin-screw extruder. The temperature of each section in the twin-screw extruder is set to: 130 and 140°C for sections 1-2, 150, 155, 160, 165, 170, and 170°C for sections 3-8, and 170 and 165°C for sections 9-11. The die is 165°C, and the extruder is extruded and pelletized to obtain resin particles specifically for degradable dust-proof nets.

[0051] S6: putting the above-mentioned resin particles for the degradable dust-proof net into a film blowing machine unit, extruding, blowing, pulling, drawing and winding to obtain the flat wire of the degradable dust-proof net.

[0052] S7: The flat yarn is placed on a warp knitting machine, and the warp knitting machine is used to weave the flat yarn into a dustproof net.

[0053] The dustproof net prepared in this embodiment 2 has the following performances: longitudinal tensile strength is 26.66 / Mpa, longitudinal elongation at break is 426 / %, transverse tensile strength is 23.36 / Mpa, longitudinal elongation at break is 607 / %, longitudinal tearing force is 14.6 / N, and transverse tearing force is 11.4 / N.

[0054] Example 3

[0055] A formula for a fully biodegradable dust screen based on modified bamboo powder: 120 kg of polybutylene adipate terephthalate (PBAT), 80 kg of 1000 mesh bamboo powder, 1 kg of silane coupling agent KH550, 0.4 kg of surfactant oleic acid, 0.4 kg of opener oleic acid amide, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234.

[0056] The preparation steps are:

[0057] S1: 80 kg of bamboo powder is soaked in 1200 kg of 20% sodium hydroxide solution for 12 hours, then washed with water until neutralized, and dried to remove other impurities in the bamboo powder while retaining the cellulose in the bamboo powder, thereby obtaining alkali-treated bamboo powder.

[0058] S2: Add the alkali-treated bamboo powder and 1 kg of silane coupling agent KH550 into a high-speed mixer at a speed of 200 rpm and stir for 10 minutes to obtain bamboo powder modified with the silane coupling agent.

[0059] S3: The bamboo powder modified with the silane coupling agent and 0.4 kg of surfactant oleic acid were added into a high-speed mixer at a speed of 200 rpm and stirred for 10 minutes to obtain the modified bamboo powder.

[0060] S4: In a high-speed mixer, the modified bamboo powder, 120 kg of polybutylene adipate terephthalate (PBAT), 0.4 kg of an opener oleic acid amide, 0.4 kg of an antioxidant 1010, and 0.4 kg of an ultraviolet absorber UV-234 were stirred and mixed for 10 minutes at a speed of 200 rpm to obtain a mixed dustproof net raw material.

[0061] S5: Add the mixed dust-proof net raw materials mentioned above into a twin-screw extruder. The temperature of each section in the twin-screw extruder is set to: 130 and 140°C for sections 1-2, 150, 155, 160, 165, 170, and 170°C for sections 3-8, and 170 and 165°C for sections 9-11. The die is 165°C, and the extruder is extruded and pelletized to obtain resin particles specifically for degradable dust-proof nets.

[0062] S6: putting the above-mentioned resin particles for the degradable dust-proof net into a film blowing machine unit, extruding, blowing, pulling, drawing and winding to obtain the flat wire of the degradable dust-proof net.

[0063] S7: The flat yarn is placed on a warp knitting machine, and the warp knitting machine is used to weave the flat yarn into a dustproof net.

[0064] The dustproof net prepared in this embodiment 1 has the following performances: longitudinal tensile strength is 25.49 / Mpa, longitudinal elongation at break is 406 / %, transverse tensile strength is 22.58 / Mpa, longitudinal elongation at break is 578 / %, longitudinal tearing force is 12.5 / N, and transverse tearing force is 10.8 / N.

[0065] Comparative Example 1

[0066] A formula for a fully biodegradable dust screen based on modified bamboo powder: 140 kg of polybutylene adipate terephthalate (PBAT), 60 kg of 1000 mesh bamboo powder, 0.4 kg of surfactant oleic acid, 0.4 kg of opener oleic acid amide, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234.

[0067] The formula of Comparative Example 1 does not contain silane coupling agent KH550.

[0068] The preparation steps are:

[0069] S1: Soak 60 kg of bamboo powder in 900 kg of 20% sodium hydroxide solution for 12 hours, then wash with water until neutral, and dry to remove other impurities in the bamboo powder while retaining the cellulose in the bamboo powder, thereby obtaining alkali-treated bamboo powder.

[0070] S2: The alkali-treated bamboo powder and 0.4 kg of surfactant oleic acid were added to a high-speed mixer at a speed of 200 rpm and stirred for 10 minutes to obtain modified bamboo powder.

[0071] S3: In a high-speed mixer, the modified bamboo powder, 140 kg of polybutylene adipate terephthalate (PBAT), 0.4 kg of oleamide, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234 were stirred and mixed for 10 minutes at a speed of 200 rpm to obtain a mixed dustproof net raw material.

[0072] S4: Add the mixed dust-proof net raw materials mentioned above into a twin-screw extruder. The temperature of each section in the twin-screw extruder is set to: 130 and 140°C for sections 1-2, 150, 155, 160, 165, 170, and 170°C for sections 3-8, and 170 and 165°C for sections 9-11. The die is set at 165°C, and the extruder is extruded and pelletized to obtain resin particles specifically for degradable dust-proof nets.

[0073] S5: putting the above-mentioned resin particles for the degradable dust-proof net into a film blowing machine unit, and extruding, blowing, pulling, drawing and winding to obtain the flat wire of the degradable dust-proof net.

[0074] S6: Put the flat yarn onto a warp knitting machine, and weave it into a dustproof net.

[0075] The dustproof net prepared in this comparative example 1 has the following performances: longitudinal tensile strength is 15.78 / Mpa, longitudinal elongation at break is 387 / %, transverse tensile strength is 14.25 / Mpa, longitudinal elongation at break is 512 / %, longitudinal tearing force is 9.5 / N, and transverse tearing force is 7.9 / N.

[0076] Comparative Example 2

[0077] A formula of a fully biodegradable dust screen based on modified bamboo powder: 140 kg of polybutylene adipate terephthalate (PBAT), 60 kg of 1000 mesh bamboo powder, 1 kg of silane coupling agent KH550, 0.4 kg of opener oleic acid amide, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234.

[0078] The formulation of Comparative Example 2 does not contain the surfactant oleic acid.

[0079] The preparation steps are:

[0080] S1: Soak 60 kg of bamboo powder in 900 kg of 20% sodium hydroxide solution for 12 hours, then wash with water until neutral, and dry to remove other impurities in the bamboo powder while retaining the cellulose in the bamboo powder, thereby obtaining alkali-treated bamboo powder.

[0081] S2: Add the alkali-treated bamboo powder and 1 kg of silane coupling agent into a high-speed mixer at a speed of 200 rpm and stir for 10 minutes to obtain modified bamboo powder.

[0082] S3: In a high-speed mixer, the modified bamboo powder, 140 kg of polybutylene adipate terephthalate (PBAT), 0.4 kg of oleamide, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234 were stirred and mixed for 10 minutes at a speed of 200 rpm to obtain a mixed dustproof net raw material.

[0083] S4: Add the mixed dust-proof net raw materials mentioned above into a twin-screw extruder. The temperature of each section in the twin-screw extruder is set to: 130 and 140°C for sections 1-2, 150, 155, 160, 165, 170, and 170°C for sections 3-8, and 170 and 165°C for sections 9-11. The die is set at 165°C, and the extruder is extruded and pelletized to obtain resin particles specifically for degradable dust-proof nets.

[0084] S5: putting the above-mentioned resin particles for the degradable dust-proof net into a film blowing machine unit, and extruding, blowing, pulling, drawing and winding to obtain the flat wire of the degradable dust-proof net.

[0085] S6: Put the flat yarn onto a warp knitting machine, and weave it into a dustproof net.

[0086] The dustproof net prepared in this comparative example 2 has the following performances: longitudinal tensile strength is 20.21 / Mpa, longitudinal elongation at break is 420 / %, transverse tensile strength is 17.38 / Mpa, longitudinal elongation at break is 582 / %, longitudinal tearing force is 11.24 / N, and transverse tearing force is 8.71 / N.

[0087] Comparative Example 3

[0088] A formula for a fully biodegradable dust screen based on modified bamboo powder: 140 kg of polybutylene adipate terephthalate (PBAT), 60 kg of 1000 mesh bamboo powder, 1 kg of silane coupling agent KH550, 0.4 kg of surfactant oleic acid, 0.4 kg of opener oleic acid amide, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234.

[0089] The preparation steps are:

[0090] S1: Soak 60 kg of bamboo powder in 900 kg of 20% sodium hydroxide solution for 12 hours, then wash with water until neutral, and dry to remove other impurities in the bamboo powder while retaining the cellulose in the bamboo powder, thereby obtaining alkali-treated bamboo powder.

[0091] S2: The alkali-treated bamboo powder and 0.4 kg of surfactant oleic acid were added to a high-speed mixer at a speed of 200 rpm and stirred for 10 minutes to obtain surfactant-modified bamboo powder.

[0092] S3: Add the surfactant-modified bamboo powder and 1 kg of silane coupling agent into a high-speed mixer at a speed of 200 rpm and stir for 10 minutes to obtain modified bamboo powder.

[0093] S4: In a high-speed mixer, the modified bamboo powder, 140 kg of polybutylene adipate terephthalate (PBAT), 0.4 kg of oleamide, an anti-blocking agent, 0.4 kg of antioxidant 1010, and 0.4 kg of ultraviolet absorber UV-234 were stirred and mixed for 10 minutes at a speed of 200 rpm to obtain a mixed dustproof net raw material.

[0094] S5: Add the mixed dust-proof net raw materials mentioned above into a twin-screw extruder. The temperature of each section in the twin-screw extruder is set to: 130 and 140°C for sections 1-2, 150, 155, 160, 165, 170, and 170°C for sections 3-8, and 170 and 165°C for sections 9-11. The die is 165°C, and the extruder is extruded and pelletized to obtain resin particles specifically for degradable dust-proof nets.

[0095] S6: putting the above-mentioned resin particles for the degradable dust-proof net into a film blowing machine unit, extruding, blowing, pulling, drawing and winding to obtain the flat wire of the degradable dust-proof net.

[0096] S7: The flat yarn is placed on a warp knitting machine, and the warp knitting machine is used to weave the flat yarn into a dustproof net.

[0097] The dustproof net prepared in this comparative example 3 has the following performances: longitudinal tensile strength is 16.25 / Mpa, longitudinal elongation at break is 409 / %, transverse tensile strength is 16.87 / Mpa, longitudinal elongation at break is 557 / %, longitudinal tearing force is 10.28 / N, and transverse tearing force is 8.27 / N.

[0098] A comprehensive comparison of Examples 1-3 and Comparative Examples 1-3 shows that the simultaneous use of a chemically coupled silane coupling agent and a physically coupled surfactant further improves the mechanical properties of the dustproof net, demonstrating a synergistic effect. The dustproof net prepared using the method of the present invention not only exhibits biodegradability but also exhibits excellent mechanical properties, effectively preventing wind and dust.

Claims

1. A method for preparing a fully biodegradable dust-proof net based on modified bamboo powder, characterized in that: The raw materials used and the amounts of raw materials used are as follows: 50-70 parts by mass of polybutylene adipate terephthalate (PBAT), 10-40 parts by mass of bamboo powder, 0.1-2 parts by mass of a silane coupling agent, 0.1-1 parts by mass of a surfactant, 0.1-1 parts by mass of an anti-blocking agent, 0.1-1 parts by mass of an antioxidant, and 0.1-1 parts by mass of a UV absorber; The preparation steps are as follows: (1) soaking 10-40 parts by weight of bamboo powder in a sodium hydroxide solution for 12 hours; washing with water until neutral, and drying to remove other impurities in the bamboo powder and retain the cellulose in the bamboo powder, thereby obtaining alkali-treated bamboo powder; (2) in a high-speed mixer, stirring and mixing the alkali-treated bamboo powder and 0.1-2 parts by mass of a silane coupling agent for 10 minutes to obtain silane coupling agent-modified bamboo powder; (3) In a high-speed mixer, the silane coupling agent-modified bamboo powder and 0.1-1 parts by mass of a surfactant were stirred and mixed for 10 minutes to obtain modified bamboo powder; (4) In a high-speed mixer, the modified bamboo powder, 50-70 parts by weight of polybutylene adipate terephthalate (PBAT), 0.1-1 parts by weight of an anti-blocking agent, 0.1-1 parts by weight of an antioxidant, and 0.1-1 parts by weight of an ultraviolet absorber were stirred and mixed for 10 minutes to obtain a mixed dustproof net raw material; (5) In a twin-screw extruder, the mixed dust-proof net raw material is extruded and pelletized to obtain resin particles for degradable dust-proof net; (6) placing the resin pellets for the degradable dust-proof net into a film blowing machine unit, extruding, blowing, pulling, drawing and winding to obtain flat filaments of the bamboo powder-modified PBAT degradable dust-proof net; (7) The flat yarn is placed on a warp knitting machine, and the warp knitting machine is used to weave a completely biodegradable dustproof net.

2. The preparation method according to claim 1, wherein: The fully biodegradable dustproof net has the following performances: longitudinal tensile strength of 25.49-29.79 / Mpa, longitudinal elongation at break of 406-453 / %, transverse tensile strength of 22.58-26.54 / Mpa, longitudinal elongation at break of 578-633 / %, longitudinal tearing force of 12.5-18.6 / N, and transverse tearing force of 10.8-13.1 / N.

3. The preparation method according to claim 1, wherein: In step (1), the mesh size of the bamboo powder is 200-2000 mesh; the mass concentration of the sodium hydroxide solution is 20-30%, and the mass of the 20-30% sodium hydroxide solution used is 10-20 times the mass of the bamboo powder.

4. The preparation method according to claim 1, wherein: In step (2), the silane coupling agent is preferably a silane coupling agent containing an amino group, with a general structural formula of NH3-R-Si(OR)3, preferably KH550.

5. The preparation method according to claim 1, wherein: In step (3), the surfactant is one of oleic acid, sodium stearate, calcium stearate, sodium lauryl sulfate, and sodium hexadecyl sulfate, preferably oleic acid.

6. The preparation method according to claim 1, wherein: In step (4), the opening agent is at least one of oleamide, erucamide, talc, and silicon dioxide; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant 264, and antioxidant 186; and the ultraviolet absorber is at least one of UV-234 and UV-326.

7. The preparation method according to claim 1, wherein: In step (2), step (3) and step (4), the mixing speed of the high-speed mixer is 100-500 rpm.

8. The preparation method according to claim 1, wherein: In step (5), the temperature of each section of the twin-screw extruder is: 130-150°C for sections 1-2, 150-175°C for sections 3-8, 150-175°C for sections 9-11, and 155-170°C for the die.

Images