An environmentally controllable degradable agricultural mulch film and its application in weed control

Abstract

The invention discloses an environmentally controllable degradable agricultural mulch film and application thereof in weed control. The mulch film comprises the following raw materials in parts by weight: 40-60 parts of P3HT-g-polyketone, 40-60 parts of chitosan, 2-5 parts of nano hexagonal boron nitride, 0.5-1 part of phthalocyanine, and 1-2.5 parts of nano titanium dioxide. The P3HT-g-polyketone in the mulch film forms hydrogen bonds with the chitosan to form a cross-linked network, thereby forming a dense network structure on the surface of the mulch film. The barrier performance of oxygen and carbon dioxide can inhibit the growth of weeds covered by the environmentally controllable degradable agricultural mulch film, and the mulch film has a good heat preservation effect. The pores formed by the cross-linked network provide appropriate air permeability and water permeability to the planted citrus, and have no influence on the necessary oxygen content and later water supply of the soil, and can effectively retain water and fertilizer in the soil.

Description

Technical Field

[0001] The invention belongs to the technical field of environmentally degradable mulch films, and in particular relates to an environmentally controllable degradable agricultural mulch film and its application in weeding. Background Art

[0002] Citrus is a plant belonging to the Rutaceae family. It likes warm and humid climates and is slightly more cold-resistant than grapefruit, sour orange, and sweet orange. It is distributed between 16° and 37° north latitude. China is one of the important origins of citrus and the largest producer of citrus. It has rich citrus resources and a wide variety of excellent varieties. After long-term cultivation and selection, citrus has become a precious fruit for mankind.

[0003] The main weeds in citrus orchards are goosegrass, thatch, barnyard grass, etc. To remove weeds, the traditional method is manual weeding or spraying herbicides. Manual weeding has high labor costs and causes soil erosion, while spraying herbicides causes serious pollution to the soil and air. To solve the problems caused by manual weeding or spraying herbicides, the existing technology usually uses mulch film for weeding, but the existing mulch film either has low weeding efficiency or takes a long time to degrade, and it is increasingly difficult to meet the needs of weeding in citrus orchards. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention discloses an environmentally controllable degradable agricultural mulch film and its application in weed control. The P3HT-g-polyketone in the mulch film forms hydrogen bonds with chitosan to form a cross-linked network, forming a dense network structure on the surface of the mulch film. The barrier performance for oxygen and carbon dioxide can inhibit the growth of weeds under the cover of the environmentally controllable degradable agricultural mulch film, and has a good thermal insulation effect. The pores formed by the cross-linked network provide the planted citrus with appropriate air permeability and water permeability, have no effect on the necessary oxygen content and later water supply of the soil, and can effectively retain water and fertilizer in the soil.

[0005] The object of the present invention is to provide an environmentally controllable degradable agricultural mulch film, which comprises the following raw materials in parts by weight: 40 to 60 parts of P3HT-g-polyketone, 40 to 60 parts of chitosan, 2 to 5 parts of nano hexagonal boron nitride, 0.5 to 1 part of phthalocyanine, and 1 to 2.5 parts of nano titanium dioxide.

[0006] The P3HT-g-polyketone of the present invention forms hydrogen bonds with chitosan to form a cross-linked network, and there is a conjugation effect between the P3HT-g-polyketones, which further enhances the hydrogen bonding between the P3HT-g-polyketone and the chitosan, forming a dense network structure on the surface of the mulch film, and the barrier performance of oxygen and carbon dioxide can achieve the inhibition of weed growth under the environmentally controllable degradable agricultural mulch film, and has a good heat preservation effect. The cross-linked network forms pores to provide the planted citrus with appropriate air permeability and water permeability, does not affect the necessary oxygen content and later water supply of the soil, and can effectively retain water and fertilizer in the soil.

[0007] Nano-titanium dioxide has small particle size, large specific surface area and high surface energy, so it has strong redox ability. Under the action of ultraviolet light, the electrons in the valence band of nano-titanium dioxide (e - ) is easily excited to transition to the conduction band, generating corresponding holes (h + ), followed by + and e - It reacts with water and oxygen molecules adsorbed on the surface of nano-titanium dioxide to generate OH - , O 2- 、OOH - The highly active free radicals with extremely strong oxidizing effects can react with the C and H chains on the P3HT-g-polyketone molecular chain, thereby degrading the P3HT-g-polyketone in the ground film. However, the bandgap width of nano titanium dioxide is 3.2eV, so only ultraviolet rays with a wavelength less than 387nm can stimulate its oxidative activity. The present invention adds phthalocyanine and nano hexagonal boron nitride to the raw materials of the environmentally controllable degradable ground film. Under visible light irradiation, the electrons generated by phthalocyanine absorbing visible light can transition to the conduction band of titanium dioxide, effectively broadening the absorption range of the spectrum of titanium dioxide and increasing the utilization rate of sunlight. Nano hexagonal boron nitride reduces the recombination probability of photogenerated electrons and hole pairs of titanium dioxide, thereby improving the utilization rate of visible light. Phthalocyanine and nano hexagonal boron nitride synergistically improve the oxidative activity of titanium dioxide, thereby improving the degradability of the ground film.

[0008] Preferably, the number average molecular weight of the P3HT-g-polyketone is 50,000 to 100,000 g / mol, and the PDI is less than 1.3.

[0009] Preferably, the structure of the P3HT-g-polyketone is as shown in formula (I):

[0010]

[0011] The number average molecular weight of the P3HT-g-polyketone is 50,000 to 100,000 g / mol, and the PDI is less than 1.3.

[0012] More preferably, the number average molecular weight of the P3HT-g-polyketone is 70,000 to 90,000 g / mol, and the PDI is less than 1.3.

[0013] Preferably, the number average molecular weight of the chitosan is 20,000 to 80,000 g / mol.

[0014] More preferably, the number average molecular weight of the chitosan is 40,000 to 60,000 g / mol.

[0015] Preferably, the particle size of the nano hexagonal boron nitride is 30-50 nm.

[0016] Preferably, the particle size of the nano titanium dioxide is 1 to 100 nm.

[0017] More preferably, the particle size of the nano titanium dioxide is 20 to 90 nm.

[0018] More preferably, the particle size of the nano titanium dioxide is 25 to 50 nm.

[0019] Preferably, the environmentally controllable degradable agricultural mulch film further comprises 0.5 to 2.5 parts of a lubricant.

[0020] Preferably, the lubricant includes at least one of calcium stearate, oxidized polyethylene wax, paraffin, and glyceryl stearate.

[0021] Another object of the present invention is to provide a method for preparing the environmentally controllable degradable agricultural mulch film, comprising the following steps:

[0022] The environmentally controllable degradable agricultural mulch film is obtained by blending P3HT-g-polyketone, chitosan, nano hexagonal boron nitride, phthalocyanine and nano titanium dioxide, and then extruding, granulating, drying and blow molding.

[0023] Another object of the present invention is to provide a method for preparing the environmentally controllable degradable agricultural mulch film, comprising the following steps:

[0024] The environmentally controllable degradable agricultural mulch film is obtained by blending P3HT-g-polyketone, chitosan, nano hexagonal boron nitride, phthalocyanine, nano titanium dioxide and lubricant, and then extruding, granulating, drying and blow molding.

[0025] Another object of the present invention is to provide the application of the environmentally controllable degradable agricultural mulch film in weeding.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The environmentally controllable degradable agricultural mulch film of the present invention does not require the use of chemical herbicides, thereby solving the problems of high labor costs caused by manual weeding or spraying herbicides, and serious pollution of soil and air caused by herbicides. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] The raw materials involved in the present invention are all commercially available.

[0030] Example 1: Preparation of environmentally controllable degradable agricultural mulch film.

[0031] 40 parts of P3HT-g-polyketone, 60 parts of chitosan with a number average molecular weight of 20,000 to 80,000 g / mol, 5 parts of nano hexagonal boron nitride with a particle size of 30 to 50 nm, 1 part of phthalocyanine, 1 part of nano titanium dioxide with a particle size of 25 nm, and 0.5 parts of calcium stearate are mixed, extruded, granulated, dried, and blown to obtain an environmentally controllable degradable agricultural mulch film;

[0032] The structure of the P3HT-g-polyketone is shown in formula (I):

[0033]

[0034] The number average molecular weight of the P3HT-g-polyketone is 50,000 to 100,000 g / mol, and the PDI is less than 1.3.

[0035] Example 2: Preparation of environmentally controllable degradable agricultural mulch film.

[0036] 60 parts of P3HT-g-polyketone, 40 parts of chitosan with a number average molecular weight of 20,000 to 80,000 g / mol, 2 parts of nano hexagonal boron nitride with a particle size of 30 to 50 nm, 0.5 parts of phthalocyanine, 2.5 parts of nano titanium dioxide with a particle size of 50 nm, and 2.5 parts of calcium stearate are mixed, extruded, granulated, dried, and blown to obtain an environmentally controllable degradable agricultural mulch film;

[0037] The structure of the P3HT-g-polyketone is shown in formula (I):

[0038]

[0039] The number average molecular weight of the P3HT-g-polyketone is 50,000 to 100,000 g / mol, and the PDI is less than 1.3.

[0040] Example 3: Preparation of environmentally controllable degradable agricultural mulch film.

[0041] 50 parts of P3HT-g-polyketone, 50 parts of chitosan with a number average molecular weight of 20,000 to 80,000 g / mol, 4 parts of nano hexagonal boron nitride with a particle size of 30 to 50 nm, 0.8 parts of phthalocyanine, 1.7 parts of nano titanium dioxide with a particle size of 25 nm, and 1 part of calcium stearate are mixed, extruded, granulated, dried, and blown to obtain an environmentally controllable degradable agricultural mulch film;

[0042] The structure of the P3HT-g-polyketone is shown in formula (I):

[0043]

[0044] The number average molecular weight of the P3HT-g-polyketone is 50,000 to 100,000 g / mol, and the PDI is less than 1.3.

[0045] Comparative Example 1: Preparation of environmentally controllable degradable agricultural mulch film.

[0046] 100 parts of P3HT-g-polyketone, 4 parts of nano hexagonal boron nitride with a particle size of 30 to 50 nm, 0.8 parts of phthalocyanine, 1.7 parts of nano titanium dioxide with a particle size of 25 nm, and 1 part of calcium stearate are mixed, extruded, granulated, dried, and blown to obtain an environmentally controllable degradable agricultural mulch film;

[0047] The structure of the P3HT-g-polyketone is shown in formula (I):

[0048]

[0049] The number average molecular weight of the P3HT-g-polyketone is 50,000 to 100,000 g / mol, and the PDI is less than 1.3.

[0050] Comparative Example 2: Preparation of environmentally controllable degradable agricultural mulch film.

[0051] 50 parts of polyketone, 50 parts of chitosan with a number average molecular weight of 20,000 to 80,000 g / mol, 4 parts of nano hexagonal boron nitride with a particle size of 30 to 50 nm, 0.8 parts of phthalocyanine, 1.7 parts of nano titanium dioxide with a particle size of 25 nm, and 1 part of calcium stearate are mixed, extruded, granulated, dried, and blown to obtain an environmentally controllable degradable agricultural mulch film;

[0052] The structure of the polyketone is shown below:

[0053]

[0054] Wherein, the number average molecular weight is not less than 20000 g / mol.

[0055] Comparative Example 3: Preparation of environmentally controllable degradable agricultural mulch film.

[0056] 50 parts of P3HT-g-polyketone, 50 parts of chitosan with a number average molecular weight of 20,000 to 80,000 g / mol, 4.8 parts of nano hexagonal boron nitride with a particle size of 30 to 50 nm, 1.7 parts of nano titanium dioxide with a particle size of 25 nm, and 1 part of calcium stearate are mixed, extruded, granulated, dried, and blow-molded to obtain an environmentally controllable degradable agricultural mulch film;

[0057] The structure of the P3HT-g-polyketone is shown in formula (I):

[0058]

[0059] The number average molecular weight of the P3HT-g-polyketone is 50,000 to 100,000 g / mol, and the PDI is less than 1.3.

[0060] Comparative Example 4: Preparation of environmentally controllable degradable agricultural mulch film.

[0061] 50 parts of P3HT-g-polyketone, 50 parts of chitosan with a number average molecular weight of 20,000 to 80,000 g / mol, 4.8 parts of phthalocyanine, 1.7 parts of nano titanium dioxide with a particle size of 25 nm, and 1 part of calcium stearate are mixed, extruded, granulated, dried, and blown to obtain an environmentally controllable degradable agricultural mulch film;

[0062] The structure of the P3HT-g-polyketone is shown in formula (I):

[0063]

[0064] The number average molecular weight of the P3HT-g-polyketone is 50,000 to 100,000 g / mol, and the PDI is less than 1.3.

[0065] A potted weeding experiment was carried out on the mulch films of Examples 1 to 3 and Comparative Examples 1 to 4: barnyard grass seeds were evenly sprinkled in each potted plant. After the grass seeds germinated, 35 potted plants with similar germination numbers were taken for the weeding experiment. The 35 potted plants were divided into 7 groups, with 5 potted plants in each group; the mulch films of Examples 1 to 3 and Comparative Examples 1 to 4 were respectively covered on the newly germinated grass in each group of potted plants, and the surrounding area was lightly compacted with soil; after 30 days, the mulch films were uncovered, the growth of the grass in the mulch films was observed, and the survival rate of the young grass was determined. The results are shown in Table 1.

[0066] The environmentally controllable degradable agricultural mulch films prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were applied to citrus cultivation: the citrus orchard was divided into 7 areas on average, and the ground of the 7 areas was covered with the environmentally controllable degradable agricultural mulch films of Examples 1 to 3 or Comparative Examples 1 to 4, respectively. The complete degradation time of the mulch films was observed, and the results are shown in Table 1.

[0067] Table 1. Weed control and controlled degradation performance of the environmentally controllable degradable agricultural mulch films of Examples 1 to 3 or Comparative Examples 1 to 4.

[0068]

[0069]

[0070] It can be seen from Table 1 that the environmentally controllable degradable agricultural mulch films prepared in Examples 1 to 3 of the present invention have good weed control and degradation properties. Comparative Example 1 does not contain chitosan and cannot form a cross-linked network, so the weed control rate decreases. The polyketone molecular chain of Comparative Example 2 does not contain a conjugated structure, the cross-linking effect decreases, and the weed control rate decreases.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the specification of this application, the technicians can still modify or replace the specific implementation mode of the present invention with equivalents, but these modifications or changes do not deviate from the scope of protection of the pending claims of the present application.

Claims

1. An environmentally controllable degradable agricultural mulch film, characterized in that: The ground film comprises the following raw materials by weight: 40-60 parts of P3HT-g-polyketone, 40-60 parts of chitosan, 2-5 parts of nano hexagonal boron nitride, 0.5-1 part of phthalocyanine, and 1-2.5 parts of nano titanium dioxide; The structure of the P3HT-g-polyketone is shown in formula (I): Formula (I); The P3HT-g-polyketone has a number average molecular weight of 50,000 to 100,000 g / mol and a PDI of less than 1.3; The number average molecular weight of the chitosan is 20,000 to 80,000 g / mol; The particle size of the nano hexagonal boron nitride is 30-50 nm.

2. The environmentally controllable degradable agricultural mulch film according to claim 1, characterized in that: The particle size of the nano titanium dioxide is 1-100 nm.

3. The environmentally controllable degradable agricultural mulch film according to claim 2, characterized in that: The environmentally controllable degradable agricultural mulch film also includes 0.5 to 2.5 parts of lubricant.

4. The environmentally controllable degradable agricultural mulch film according to claim 3, characterized in that: The lubricant includes at least one of calcium stearate, oxidized polyethylene wax, paraffin, and glyceryl stearate.

5. The method for preparing the environmentally controllable degradable agricultural mulch film according to claim 1, characterized in that: The steps include: The environmentally controllable degradable agricultural mulch film is obtained by blending P3HT-g-polyketone, chitosan, nano hexagonal boron nitride, phthalocyanine and nano titanium dioxide, and then extruding, granulating, drying and blow molding.

6. The method for preparing the environmentally controllable degradable agricultural mulch film according to claim 3, characterized in that: The steps include: The environmentally controllable degradable agricultural mulch film is obtained by blending P3HT-g-polyketone, chitosan, nano hexagonal boron nitride, phthalocyanine, nano titanium dioxide and lubricant, and then extruding, granulating, drying and blow molding.

7. Use of the environmentally controlled degradable agricultural mulch film according to any one of claims 1 to 4 or the environmentally controlled degradable agricultural mulch film prepared by the preparation method of the environmentally controlled degradable agricultural mulch film according to any one of claims 5 to 6 in weeding.

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