阅读说明：本技术 一种水热炭改性可生物降解塑料的方法与应用 (Method for modifying biodegradable plastic by hydrothermal carbon and application ) 是由 张士成 叶诚 冯嘉春 于 2021-09-13 设计创作，主要内容包括：本发明涉及可降解塑料领域,具体为一种水热炭改性可生物降解塑料的方法与应用,本发明以可生物降解高分子化合物为基体,以生物质为原料,利用水热转化技术制备水热炭,再将基体与水热炭均匀混合,制备水热炭可生物降解复合材料。本发明工艺简单,水热炭与可生物降解塑料结合稳定,制备出的水热炭可生物降解复合材料具有良好的热稳定性能、疏水性能和结晶性能,且力学性能达到一般泛用塑料的规格。可广泛应用于农业、包装材料、一次性用品和层压材料中。为改善生物降解塑料性能、降低可生物降解塑料成本,促进生物质资源化利用,拓展了水热炭应用领域,为实现水热炭的高级循环提供了一种新型可持续的方法。(The invention relates to the field of degradable plastics, in particular to a method for modifying biodegradable plastics by hydrothermal carbon and application. The invention has simple process, the hydrothermal carbon and the biodegradable plastic are combined stably, the prepared hydrothermal carbon biodegradable composite material has good thermal stability, hydrophobic property and crystallization property, and the mechanical property reaches the specification of common general plastic. Can be widely applied to agriculture, packaging materials, disposable products and laminated materials. The method is a novel sustainable method for improving the performance of the biodegradable plastic, reducing the cost of the biodegradable plastic, promoting the resource utilization of biomass, expanding the application field of hydrothermal carbon and realizing the high-grade circulation of the hydrothermal carbon.)

1. A method for modifying biodegradable plastic by hydrothermal carbon is characterized by comprising the following specific steps: the biodegradable high molecular compound is modified by the hydrothermal carbon by taking the biodegradable high molecular compound as a matrix and the hydrothermal carbon as a modifier and uniformly mixing the matrix and the hydrothermal carbon at a high temperature through mixing equipment.

2. The method for modifying biodegradable plastic through hydrothermal carbon as claimed in claim 1, wherein the hydrothermal carbon is obtained by using water as a reaction matrix, setting corresponding hydrothermal temperature according to the mass ratio of biomass powder to water, and performing hydrothermal carbonization treatment on biomass in a hydrothermal reaction kettle.

3. The method for modifying biodegradable plastic through hydrothermal carbon as claimed in claim 1, wherein the biodegradable polymer compound is PBAT, PLA, PCL, PHA, PVA, PBS, PBSA, PPC, PBAT + PLA or any one of the above biodegradable plastic blends.

4. The method for modifying biodegradable plastic through hydrothermal carbon as claimed in claim 1, wherein the mixing device of the substrate and the hydrothermal carbon is any one of an internal mixer, a single screw extruder, a twin screw extruder, an open mill, a mixing roll or a kneader.

5. The method for modifying biodegradable plastic through hydrothermal carbon as claimed in claim 1, wherein the temperature of the mixing device is higher than the melting temperature of the biodegradable polymer compound and lower than the preparation temperature of the hydrothermal carbon.

6. The method for modifying biodegradable plastic through hydrothermal carbon as claimed in claim 1, wherein the mass ratio of the biodegradable high molecular compound to the hydrothermal carbon is 100 (1-60).

7. The method of claim 2, wherein the biomass is any one of corn stover, rice stover, wheat straw, rice hulls, corn cobs, canola straw, bagasse, sunflower straw, sorghum straw, switchgrass, alfalfa, bermuda grass, wood chips, pine branches, sand willow branches, poplar wood, birch, sycamore, cedar wood, camphorwood biomass, sludge, or kitchen waste.

8. The method for modifying biodegradable plastic through hydrothermal carbon as claimed in claim 2, wherein the mass ratio of the biomass powder to water is 1 (5-30), and the hydrothermal temperature is 150-350 ℃.

9. A method for modifying biodegradable plastic with hydrothermal carbon as claimed in claim 1, to obtain the hydrothermal carbon biodegradable composite material.

10. A hydrothermal carbon biodegradable composite obtained by the method of claim 9 for use in agriculture, packaging materials, disposables or laminates.

Technical Field

The invention relates to the technical field of biodegradable plastics, in particular to a method for modifying biodegradable plastics by hydrothermal carbon and application thereof.

Background

Currently, the problem of "white pollution" caused by waste plastics poses a great threat to human health and ecological environmental systems. In the face of the "white pollution" problem, conventional solutions include: incinerating, burying and recycling. However, the plastic products for packaging and agriculture have the characteristics of disposability, difficult recycling and low recycling value, and the traditional method for the plastic products has the problems of high recycling cost and difficult recycling, so that only biodegradable plastics can fundamentally solve the problem of white pollution caused by the plastic products.

Currently, the common biodegradable plastics on the market are: polylactic acid (PLA), polybutylene terephthalate adipate (PBAT), Polycaprolactone (PCL) and the like, although biodegradable plastics have unique degradation performance, the biodegradable plastics cannot be compared with traditional plastics in mechanical performance, application and cost, and thus the application of the biodegradable plastics is limited.

In order to solve the problems of the biodegradable plastics, research specialists at home and abroad also make related modification researches. Such as: functional polymers are added, such as: starch, chitosan and protein, but have the problems of low thermal stability and low mechanical strength; or with the addition of biopolymers such as: PBAT, PCL and PBS, but the problems of low mechanical strength and high cost still exist; or a composite material to which natural fibers are added, but has problems of low thermal stability and high viscosity.

As is well known, the biomass resources in China are rich, and the biomass can be recycled. Among them, the hydrothermal technique is an environment-friendly thermochemical conversion technique. Biomass produces hydrothermal char during hydrothermal conversion. The hydrothermal carbon is a carbon-rich solid with high thermal stability and low cost, and can be used as a soil conditioner to improve the soil property.

The invention combines two aspects of biodegradable plastics and resource utilization, and mixes and modifies hydrothermal carbon generated by hydrothermal conversion of biomass and biodegradable plastics to prepare the hydrothermal carbon biodegradable composite material, thereby expanding the application field of the hydrothermal carbon, realizing high-grade circulation of the hydrothermal carbon, improving the performance of the biodegradable plastics and reducing the cost of the biodegradable plastics.

Disclosure of Invention

In order to overcome the problems of poor performance and cost of the existing biodegradable plastic, the invention aims to provide a method for modifying the biodegradable plastic by hydrothermal carbon and application thereof.

The invention provides a method for modifying biodegradable plastic by hydrothermal carbon, which comprises the following specific steps: the biodegradable plastic modified by the hydrothermal carbon is realized by taking a biodegradable high molecular compound as a matrix and the hydrothermal carbon as a modifier and uniformly mixing the matrix and the hydrothermal carbon at a high temperature through mixing equipment.

According to the invention, the hydrothermal carbon is obtained by using water as a reaction matrix, controlling the mass ratio of biomass powder to water, setting corresponding hydrothermal temperature, and carrying out hydrothermal carbonization treatment on biomass in a hydrothermal reaction kettle.

In the invention, the biodegradable high molecular compound is any one of PBAT, PLA, PCL, PHA, PVA, PBS, PBSA, PPC, PBAT + PLA or biodegradable plastic blends of the PBAT, the PLA and the PCL.

In the invention, the mixing device of the matrix and the hydrothermal carbon is any one of an internal mixer, a single-screw extruder, a double-screw extruder, an open mill, a mixing roll or a kneading machine.

In the invention, the high temperature is that the temperature of the mixing equipment is higher than the melting temperature of the biodegradable plastic and lower than the preparation temperature of the hydrothermal carbon.

In the method for modifying the biodegradable plastic by using the hydrothermal carbon, the mass ratio of the biodegradable high molecular compound to the hydrothermal carbon is 100 (1-60).

In the invention, the biomass is any one of corn stalks, rice stalks, wheat stalks, rice hulls, corn cobs, rape stalks, bagasse, sunflower stalks, sorghum stalks, switchgrass, alfalfa, bermuda grass, wood chips, pine branches, sand willow branches, poplar, birch, sycamore, cedar, camphorwood biomass, sludge or kitchen waste.

In the invention, the mass ratio of the biomass powder to water is 1 (5-30), and the preparation temperature of the hydrothermal carbon is 150-350 ℃.

The hydrothermal carbon modification method of the biodegradable plastic provided by the invention can be used for obtaining the hydrothermal carbon biodegradable composite material.

The hydrothermal carbon biodegradable composite material obtained by the method is applied to agriculture, packaging materials, disposable articles or laminated materials.

Compared with the prior art, the invention has the following advantages:

1. the hydrothermal carbon biodegradable plastic developed by the invention is a green and environment-friendly biodegradable composite material.

2. The invention has simple preparation process and stable combination.

3. The invention can effectively improve the thermal stability, hydrophobic property and crystallization property of the biodegradable plastic and reduce the production cost.

4. The mechanical property of the hydrothermal carbon biodegradable composite material developed by the invention can reach the specification of common general-purpose plastics.

Drawings

FIG. 1 is a basic flow chart of a method for modifying biodegradable plastic by hydrothermal carbon and an application thereof.

Detailed Description

The present technology is further described below in conjunction with examples, the described implementations being only some of the examples of the present invention. Based on the embodiments of the present invention, those skilled in the art can make equivalent substitutions and modifications without making creative efforts and fall within the protection scope of the present invention.

Example 1:

adding the biodegradable plastic PBAT into an internal mixer with the temperature of 150 ℃ and the rotor speed of 60r/min for internal mixing for 10min, and uniformly mixing to obtain a white cured product, namely pure PBAT, which is called PBAT for short.

Example 2:

adding biodegradable plastic PBAT and hydrothermal carbon of 180 ℃ into an internal mixer at the temperature of 150 ℃ and the rotor speed of 60r/min according to the adding amount (shown in table 1) for internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

The specific mass between PBAT and hydrothermal charcoal is shown in table 1.

TABLE 1 Mass ratio of biodegradable plastic PBAT to hydrothermal charcoal

Adding amount of	PBAT/g	Hydrothermal charcoal/g
			①	54	6
②	48	12

Example 3:

adding biodegradable plastic PBAT and hydrothermal carbon at 210 ℃ into an internal mixer at the temperature of 150 ℃ and the rotor speed of 60r/min according to the adding amount (shown in table 1) for internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 4:

adding the biodegradable plastic PBAT and the hydrothermal carbon at 240 ℃ into an internal mixer at the temperature of 150 ℃ and the rotor speed of 60r/min according to the adding amount (shown in table 1) for internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 5:

adding the biodegradable plastic PBAT and the hydrothermal carbon at 270 ℃ into an internal mixer at the temperature of 150 ℃ and the rotor speed of 60r/min according to the adding amount (shown in table 1) for internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 6:

adding biodegradable plastic PBAT and hydrothermal carbon of 300 ℃ into an internal mixer at the temperature of 150 ℃ and the rotor speed of 60r/min according to the adding amount (shown in table 1) for internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 7:

adding the biodegradable plastic PBAT and the hydrothermal carbon with the temperature of 180 ℃ into an internal mixer with the temperature of 150 ℃ and the rotating speed of a rotor of 60r/min according to the addition amount of the second component (shown in table 1) to carry out internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 8:

adding the biodegradable plastic PBAT and the hydrothermal carbon with the temperature of 210 ℃ into an internal mixer with the temperature of 150 ℃ and the rotating speed of a rotor of 60r/min according to the addition amount of the second component (shown in table 1) to carry out internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 9:

adding the biodegradable plastic PBAT and the hydrothermal carbon at 240 ℃ into an internal mixer at the temperature of 150 ℃ and the rotating speed of a rotor of 60r/min according to the addition amount of the second component (shown in table 1) to carry out internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 10:

adding the biodegradable plastic PBAT and the hydrothermal carbon at 270 ℃ into an internal mixer at the temperature of 150 ℃ and the rotor speed of 60r/min according to the addition amount of the second component (shown in table 1) to carry out internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 11:

adding the biodegradable plastic PBAT and the hydrothermal carbon with the temperature of 300 ℃ into an internal mixer with the temperature of 150 ℃ and the rotating speed of a rotor of 60r/min according to the addition amount of the second component (shown in table 1) to carry out internal mixing for 10min, and uniformly mixing to obtain a black cured product, namely the hydrothermal carbon biodegradable composite material.

Example 12:

in order to further examine the performance of the hydrothermal carbon biodegradable composite material prepared by the invention, in this example, PBAT was selected as a matrix, and the thermal stability, hydrophobic property and crystallization property of the composite material prepared in examples 1 to 11 were tested.

The initial decomposition temperature, the maximum weight loss rate temperature, the termination temperature, the contact angle and the crystallization temperature of examples 1 to 11 were measured, and the test results are shown in table 2.

TABLE 2 analysis tables of thermal stability, hydrophobicity and crystallinity of examples 1 to 11

As can be seen from Table 2, the initial decomposition temperature, the maximum weight loss rate temperature, the end temperature, the contact angle and the crystallization temperature of examples 2 to 11 were all enhanced as compared with those of example 1. Therefore, the hydrothermal carbon is used as a modifier to improve the thermal stability and the hydrophobic property of the biodegradable plastic, promote the crystallization of the biodegradable plastic, shorten the molding period of the biodegradable plastic and improve the production efficiency.

Comparative example 1:

carrying out melt mixing on common seedling raising cups in the market, uniformly mixing the mixture by using an internal mixer, and taking out the mixture.

The mechanical properties of the above examples 2 to 11 and comparative example 1 were respectively tested, and the specific test method was as follows: examples 2 to 11 and comparative example 1 were each tabletted by a press vulcanizer compression method, and then cut into dumbbell-shaped sheets having a uniform thickness on a slicer. The tensile properties of the plastics were tested using GB/T1040-92.

The tensile strength and elongation at break of examples 2 to 11 and comparative example 1 were measured, respectively, and the results are shown in Table 3.

Table 3 tensile Strength and elongation at Break test results for examples 2-11 and comparative example 1

As can be seen from Table 3, the mechanical properties of the present invention are significantly better than those of comparative example 1, therefore, the mechanical properties of the hydrothermal carbon biodegradable plastic developed by the present invention can reach the specifications of general-purpose plastics, and can be further processed to prepare biodegradable plastic finished products, which can be applied in various fields such as agriculture, packaging materials, disposable products, laminating materials, etc.