阅读说明：本技术 一种与垒土基质相融的生物降解复合材料 (Biodegradable composite material fused with soil-base matrix ) 是由 曾智 于 2020-05-29 设计创作，主要内容包括：本发明公开一种与垒土基质相融的生物降解复合材料,涉及生物降解材料技术领域。本发明公开的与垒土基质相融的生物降解复合材料由生物降解聚合物、聚己内酯、淀粉和纤维素组成,经接枝淀粉的制备、接枝淀粉/聚己内酯交联、接枝淀粉/聚己内酯/生物降解聚合物复合材料的共混以及多孔处理等步骤而制成。本发明提供的与垒土基质相融的生物降解复合材料,通过加入少量的生物降解材料使垒土能够有效固化并具有可塑性,成本较低,具有优良的保水性和透气性能,可以与塑料一样加工成不同形状,也可以使培养土种植各种不同的植物,以适应立体绿化行业的可重复使用需求,也可以适应旱土机械化插种技术的可降解使用需求。(The invention discloses a biodegradable composite material fused with a soil-base matrix, and relates to the technical field of biodegradable materials. The biodegradable composite material fused with the earth-building matrix consists of biodegradable polymer, polycaprolactone, starch and cellulose, and is prepared by the steps of preparation of grafted starch, crosslinking of the grafted starch/polycaprolactone, blending of the grafted starch/polycaprolactone/biodegradable polymer composite material, porous treatment and the like. The biodegradable composite material which is provided by the invention and is combined with the soil-building matrix enables the soil-building matrix to be effectively solidified and have plasticity by adding a small amount of biodegradable material, has low cost and excellent water retention and air permeability, can be processed into different shapes like plastic, and enables the culture soil to plant various plants, so as to meet the reusable requirements of the three-dimensional greening industry and the degradable use requirements of the mechanical dry soil planting technology.)

1. A biodegradable composite material which is fused with a soil-base matrix is characterized by consisting of a biodegradable polymer, polycaprolactone, starch and cellulose, and the preparation method comprises the following steps:

(1) preparation of grafted starch: adding starch into water, stirring and heating to 70-90 ℃, carrying out gelatinization reaction for 30-50min, then cooling to 50-60 ℃, adding an initiator, stirring for 30min, then adding an acrylic acid solution and a cross-linking agent, reacting for 1-3h, filtering, washing for 3 times by using deionized water, drying for 2-3h at 100 ℃, and crushing to obtain the required grafted starch with a three-dimensional network structure;

(2) mixing the grafted starch/polycaprolactone, namely adding the grafted starch and the polycaprolactone into a high-efficiency drum mixer, mixing at the rotating speed of 120-;

(3) the preparation of the composite material comprises the steps of adding the grafted starch/PC L mixture into a high-efficiency drum mixer, adding the biodegradable polymer and the cellulose, mixing at the temperature of 60-80 ℃ and the rotating speed of 180rpm for 10-20min, and extruding and granulating to obtain the composite material;

(4) adding the composite material into a mixed solution of 90% DMSO and 10% water, keeping the temperature for 2h at 40-60 ℃, filtering, washing with deionized water for 3 times, drying at 60-80 ℃ for 1-2h, and pulverizing to obtain the porous reticular biodegradable composite material.

2. The biodegradable composite material compatible with subsoil matrix as claimed in claim 1, characterized in that said biodegradable polymer is one or more of polybutylene succinate and its copolymer, polylactic acid, polyhydroxyalkanoate, polyvinyl alcohol biodegradable plastic.

3. The biodegradable composite material fused with subsoil matrix according to claim 1, characterized in that said acrylic acid solution treatment in step (1) is: adding NaOH solution into acrylic acid, and adjusting the pH value to 6-8 to obtain acrylic acid solution.

4. The biodegradable composite material blended with the clay matrix according to claim 3, wherein in the step (1), the initiator is ammonium persulfate/sodium bisulfite, and the cross-linking agent is N, N' -methylene bisacrylamide, wherein the mass ratio of the starch to the acrylic acid is 1 (7-9), the mass of the initiator is 2.5-3.5% of the mass of the starch, and the mass of the cross-linking agent is 0.25-0.35% of the mass of the starch.

5. The biodegradable composite material compatible with subsoil matrix, according to claim 4, characterized in that the mass ratio of said ammonium persulphate to said sodium bisulphite is (2-5): 6.

6. The biodegradable composite material blended with a subsoil matrix according to claim 1, characterized in that the mass ratio of grafted starch to polycaprolactone in step (2) is 10: (1-3).

7. The biodegradable composite material compatible with subsoil matrix as claimed in claim 1, characterized in that in said step (3) said cellulose is one of ethyl cellulose and hydroxymethyl cellulose, wherein the mass ratio of grafted starch/PC L mixture, biodegradable polymer and cellulose is 10 (2-4) to (0.2-0.4).

8. The biodegradable composite material fused with clay matrix as claimed in claim 7, wherein the processing temperature of the extrusion granulation in step (3) is 160-180 ℃.

Technical Field

The invention belongs to the technical field of biodegradable materials, and particularly relates to a biodegradable material capable of being fused with a culture soil matrix.

Background

With the enhancement of the environmental protection consciousness of modern people, the rapid development of garden greening and flower seedling industries is driven. In order to meet the requirements of flower nursery stock on growth and development, according to different requirements of various varieties on soil, the culture soil which is specially and manually prepared and contains abundant nutrients, has good drainage and air permeability, can preserve moisture and fertilizer, does not crack when being dry, does not stick when being wet and does not crust after being watered is used. With global warming, pollution aggravation, and comprehensive rising of three-dimensional greening and indoor greening, how to ensure that culture soil is not lost and scattered and can be solidified, and the research and development directions of people are provided for enhancing the water retention capacity of soil and simultaneously keeping the ventilation property of the culture soil.

Disclosure of Invention

The invention provides a biodegradable composite material which is compatible with a soil-building matrix, and mainly aims to enable soil-building to be effectively solidified and have plasticity by adding a small amount of biodegradable material, have low cost and excellent water retention and air permeability, can be processed into different shapes like plastic, and can also enable culture soil to plant various plants so as to meet the reusable requirements of the three-dimensional greening industry and the degradable use requirements of the mechanical dry soil planting technology.

In order to realize the aim of the invention, the invention provides a biodegradable composite material fused with a soil-barrier matrix, which consists of a biodegradable polymer, polycaprolactone, starch and cellulose, and the preparation method comprises the following steps:

(1) preparation of grafted starch: adding starch into water, stirring and heating to 70-90 ℃, carrying out gelatinization reaction for 30-50min, then cooling to 50-60 ℃, adding an initiator, stirring for 30min, then adding an acrylic acid solution and a cross-linking agent, reacting for 1-3h, filtering, washing for 3 times by using deionized water, drying for 2-3h at 100 ℃, and crushing to obtain the required grafted starch with a three-dimensional network structure;

(2) mixing the grafted starch/polycaprolactone, namely adding the grafted starch and the polycaprolactone into a high-efficiency drum mixer, mixing at the rotating speed of 120-;

(3) the preparation of the composite material comprises the steps of adding the grafted starch/PC L mixture into a high-efficiency drum mixer, adding the biodegradable polymer and the cellulose, mixing at the temperature of 60-80 ℃ and the rotating speed of 180rpm for 10-20min, and extruding and granulating to obtain the composite material;

(4) adding the composite material into a mixed solution of 90% DMSO and 10% water, keeping the temperature for 2h at 40-60 ℃, filtering, washing with deionized water for 3 times, drying at 60-80 ℃ for 1-2h, and pulverizing to obtain the porous reticular biodegradable composite material.

Further, the biodegradable polymer is one or more of polybutylene succinate and a copolymer thereof, polylactic acid, polyhydroxyalkanoate and polyvinyl alcohol biodegradable plastic.

Further, the treatment method of the acrylic acid solution in the step (1) comprises the following steps: adding NaOH solution into acrylic acid, and adjusting the pH value to 6-8 to obtain acrylic acid solution.

Further, in the step (1), the initiator is ammonium persulfate/sodium bisulfite, and the cross-linking agent is N, N' -methylene bisacrylamide, wherein the mass ratio of the starch to the acrylic acid is 1 (7-9), the mass of the initiator is 2.5-3.5% of the mass of the starch, and the mass of the cross-linking agent is 0.25-0.35% of the mass of the starch.

Further, the mass ratio of the ammonium persulfate to the sodium bisulfite is (2-5) to 6.

Further, the mass ratio of the grafted starch to the polycaprolactone in the step (2) is 10: (1-3).

Further, in the step (3), the cellulose is one of ethyl cellulose and hydroxymethyl cellulose, wherein the mass ratio of the grafted starch/PC L mixture to the biodegradable polymer to the cellulose is 10 (2-4) to (0.2-0.4).

Further, the processing temperature of the extrusion granulation in the step (3) is 160-180 ℃.

The invention achieves the following beneficial effects:

1. the biodegradable composite material adopts acrylic acid grafted starch, hydrogen bonds can be formed between acrylic acid and starch molecules in the grafted starch, and chains of glucose form a net with each other, so that the grafted starch with a three-dimensional net structure is formed. The three-dimensional network structure is distributed with a plurality of ion groups, and water molecules enter the network structure and then are bonded with the ions to be adsorbed and fixed in the network. The network has elasticity, so that a large amount of water molecules can be accommodated, the biodegradable composite material has excellent water absorbability and water retentivity when being applied to the base soil, and the base soil has good air permeability due to the three-dimensional network structure.

2. The biodegradable composite material of the invention is a blend with a network structure obtained by crosslinking and mixing polycaprolactone and grafted starch at high temperature and high pressure. Polycaprolactone has good mechanical property and thermal stability, and also has excellent toughness and compatibility, can improve the thermal stability of the grafted starch and the biodegradable polymer, improve the toughness of the starch, reduce the hydrophilicity of the grafted starch, and strengthen the compatibility with the biodegradable polymer and the soil-base matrix.

3. The biodegradable composite material is prepared by blending a biodegradable polymer and a grafted starch/polycaprolactone mixture, and the biodegradable polymer and the grafted starch/polycaprolactone are crosslinked and blended, so that the thermoplasticity of the biodegradable composite material is further improved, and the biodegradable composite material is processed into finished products in various shapes; the grafted starch with strong cohesiveness and the polycaprolactone with good compatibility ensure that the components of the biodegradable composite material have good compatibility, and the biodegradable composite material and the soil-covering matrix have good compatibility, thereby being beneficial to the plastic stability of the biodegradable composite material and effectively realizing various service performances in the soil.

4. The biodegradable composite material is dissolved by adopting a solution of 90 percent DMSO and 10 percent water at a high temperature, and is used for dissolving starch which is not grafted in the starch grafting reaction process to prepare the porous biodegradable composite material. Because starch is easy to form gel with water, the biodegradable composite material containing starch is easy to be mixed with the soil-blocking matrix to form balls, and the balls cannot be smoothly and uniformly stirred and cannot be uniformly combined with the soil-blocking matrix, so that the porosity and the structural strength of a final product are influenced.

5. When the biodegradable composite material is used, the biodegradable composite material needs to be subjected to heating treatment and is fused with the subsoil matrix to form plastic solidified subsoil. Because the difference between the melting temperature and the decomposition temperature of the components in the biodegradable composite material is not large, the processing temperature is strict during heating treatment and is generally controlled to be between 140 ℃ and 160 ℃, so that the biodegradable composite material and the soil-blocking matrix are favorable for better bonding effect, and the biodegradable composite material cannot generate thermal decomposition.

6. When the biodegradable composite material is used, a proper heating method needs to be selected according to the composition of main components of the base soil, otherwise, the processed product cannot achieve the required curing effect, and finished products with various shapes cannot be processed.

7. The biodegradable composite material can be fused with a soil-covering matrix, and is prepared by blending the biodegradable polymer and the grafted starch by mainly utilizing the processability and the forming characteristics of the biodegradable polymer. The composite material has less addition of biodegradable polymer and low cost because the main component is starch; and due to the existence of the grafted starch, the grafted starch has excellent water retention; the porous three-dimensional network structure can be uniformly combined with the soil-base matrix, is not easy to nodulate and forms good plant growth pores.

8. The invention can be fused with the base organic phase of the base soil, thereby changing the physical property of the base soil, and leading the base soil to be solidified and molded, thereby solving the problems of soil scattering and water washing loss, and ensuring the basic nutrient substances in the base soil required by plants; after being fused with a soil-building matrix, the dry soil is mechanically inserted into soil without recovery, can be degraded by microorganisms in the soil, does not pollute the environment, and is green and environment-friendly.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The following embodiments are combined to mix the biodegradable composite material with different components of the present invention with the base soil to obtain different biodegradable base soil, and then the relevant physical and chemical properties of the biodegradable base soil, such as comprehensive strength, texture, porosity, water retention (water holding capacity), pH (pH), conductivity (EC), Cation Exchange Capacity (CEC), biodegradability, etc., are observed and calculated.

1. Measurement of comprehensive strength: the rampart blocks formed in examples and comparative examples were freely dropped from a height of 1.5m, and recorded as 1 if the crushed pieces were scattered more than 10 pieces, as 2 if the crushed pieces were divided into 5 to 8 pieces, as 3 if the crushed pieces were divided into 2 to 4 pieces, and as 4 if there was no crushed piece.

2. And (3) measuring the soil texture: soil texture types were estimated based on the different plasticity and cohesiveness of the individual size fractions. A small amount (about 2g) of soil sample is taken in the hand, water is added for wetting, and simultaneously the soil is fully kneaded, so that the soil absorbs water uniformly (namely, the water is added into the soil sample just before the soil sample is not sticky to the hand). The texture type was then determined by pressing the gauge.

TABLE 1 general soil texture identification Specification Table

3. Determination of soil porosity:

firstly, the volume of the steel soil sampling container is measured, and the weight of the container is weighed. Then a steel soil sampling container is used for filling soil building blocks with the same inner diameter as the soil sampling container, the soil building blocks are leveled with the opening of the cylinder, soil particles adhered to the outer wall of the soil sampling container are removed, then two ends of the soil sampling container are immediately covered, and the soil sampling container is placed into an oven to be continuously baked for 24 hours at the temperature of 105 ℃ until the weight is constant. The sample was then removed from the oven and weighed as W₁Removing soil sample in the cutting ring, wiping the cutting ring, weighing the cutting ring with weight of W₂。

(1) The volume of the soil sampling container is calculated according to the formula: where V is pi r²h, wherein V is the volume (cm) of the soil sampling container³) R is the inner radius (cm) of the soil sampling container, h is the height (cm) of the cutting ring, and pi is the circumferential rate.

(2) The soil volume weight is calculated according to the following formula:

(3) the total porosity of the soil is calculated by an empirical formula, wherein the empirical formula is as follows:

Pt(％)＝93.947-32.995D

4. measurement of water holding capacity: the subsoil blocks formed in examples and comparative examples were soaked in water for 30min to allow them to absorb sufficient water, taken out until no free water flowed out, and weighed again after waiting for 5 hours. And (3) putting the soil sample in an oven at 105 +/-2 ℃ and drying to constant weight, so that the contained water (including hygroscopic water) is completely evaporated, and the water content of the soil is calculated. The concrete steps refer to the operation of the soil moisture determination method according to GB 7172-.

5. And (3) measuring the pH value of the soil: a mixed indicator colorimetric method is adopted. Firstly, preparing a mixed indicator, accurately weighing equal amounts (0.2500 g) of bromocresol green, bromocresol purple and cresol red by a balance, putting the materials into an agate mortar, adding about 15 ml of 0.1N sodium hydroxide and 5 ml of distilled water for grinding together, then diluting the materials to 1000 ml by using the distilled water, and storing the materials in a brown bottle for later use.

Then, the soil blocks with the size of the soybeans are taken and placed into the holes of the wiped colorimetric porcelain plates, 2-3 drops of mixed indicator are added until a little liquid flows out, the mixture is slightly oscillated for about half a minute, the porcelain plates or the spoon are inclined, the liquid flows out, the color comparison is carried out with the standard colorimetric card shown in the following table, and the teaching characters of the pH value of the soil are accurately read.

TABLE 2 color change range of mixed indicator after dropping into soil

pH value	4.0	4.5	5.0	5.5	6.0	6.5	7.0	7.5	8.0
										Card color	Yellow colour	Green yellow	Yellow green	Grass green	Green	Lime green	Grey blue	Blue purple	Purple pigment

6. Measurement of conductivity: the conductivity (EC) of the water immersion liquid is measured by an electric conduction method. In general, soluble salts in soil are leached out by a balance method according to a certain water-soil ratio, the soluble salts are strong electrolytes, the water solubility of the soluble salts has a conductive effect, and the strength of the conductive capability can be expressed by the conductivity. In a certain concentration range, the content of soluble salt is in positive correlation with the conductivity, and the higher the salt content is, the higher the osmotic pressure of the solution is, the higher the conductivity is.

7. Measurement of cation exchange amount: according to the national standard (GB) for measuring the cation exchange capacity of the forest soil of GB 7863-1987.

8. Biodegradability: 10g of each of examples and comparative examples was weighed, pulverized, embedded in compost in a plastic container, the compost container was left in a test environment of 50. + -. 2 ℃ in air circulation for 6 months, periodically watered, the moisture of the compost container was maintained, and then the amount of mass reduction was measured. If the mass reduction rate is more than 80%, marking as 1; if the mass reduction rate is 50-80%, marking as 2; if the mass reduction rate is 10-50%, marking as 3; when the mass reduction rate is 10% or less, it is recorded as 4. In order to ensure the diversity of microorganisms, compost generated by organic matters in municipal solid waste in a composting device is used, and the compost age is 4 months.