CN115536993A - High-barrier bionic nano composite full-biodegradable film and preparation method thereof - Google Patents

Abstract

The invention relates to a high-barrier bionic nano composite full-biodegradable film and a preparation method thereof, wherein the film consists of PBAT master batches and nano mica sheets loaded with PBAT molecules, and the nano mica sheets loaded with the PBAT molecules are prepared by the following steps: the preparation method comprises the steps of mechanically crushing natural phlogopite into phlogopite powder, adding the phlogopite powder into a dichloromethane solution of PBAT, and sequentially carrying out high-speed shearing and ultrasonic treatment to obtain the PBAT molecule-loaded nano mica sheet. According to the invention, natural phlogopite powder is added into a PBAT solution, and then high-speed shearing and ultrasonic treatment are carried out, so that the phlogopite powder is decomposed into nanoscale mica, the stability and the dispersibility of the molecules on the surface of the nano mica in an organic solvent are greatly promoted, and the nano mica sheets are uniformly distributed in the PBAT substrate. The addition amount of the nano mica sheet in the PBAT is regulated and controlled, so that high barrier property and mechanical strength are achieved.

Description

High-barrier bionic nano composite full-biodegradable film and preparation method thereof

Technical Field

The invention belongs to the field of film manufacturing, and particularly relates to a high-barrier bionic nano composite full-biodegradable film and a preparation method thereof.

Background

The chemical properties of the traditional plastic products are relatively stable, and the traditional plastic products can cause serious white pollution to the ecological environment after being abandoned, and meanwhile, the traditional plastic products are mostly derived from petroleum, but petroleum resources are not renewable, so that a large amount of petroleum resources are consumed, and the energy crisis is caused. With the high-speed increase of economy in China and the huge population, the production and consumption of non-degradable plastics inevitably increase explosively, and the ecological environment will be under great pressure. In order to realize sustainable development and build healthy and friendly ecological and living environment, more and more people pay attention to environmental protection. Under the background, the degradable material is one of the important points of people's attention as a green substitute of plastics as a major factor for protecting ecological environment and reducing environmental pollution. Among them, polybutylene adipate terephthalate (PBAT) is a novel biodegradable resin polymer material, which is mainly formed by copolymerization of polybutylene terephthalate (PET) and polybutylene adipate (PBT), so that it has both excellent properties. The commercial PBAT was a white crystal with a melting point of 110-120 ℃. PBAT has received a great deal of attention in recent years as a degradable material due to its biodegradability and good tensile properties and flexibility, and has made great progress in the synthesis and modification of materials. However, the widespread use of PBAT or other environmentally friendly materials is still limited by problems such as insufficient performance or complex manufacturing processes, high costs, etc.

The patent with publication number CN114276691A discloses a fully biodegradable film bag material based on blending of greening garbage, vegetable oil, PBAT and other degradable plastics and silicate powder in a certain proportion, which meets the requirement of packaging functionality. However, the high barrier performance requirements based on food or fruit packaging are difficult to achieve. Biomimetic structural designs have been widely used in the manufacture of high performance artificial materials. The nacreous layer, having a "brick and mortar" microstructure, is built under mild conditions using common ingredients such as calcium carbonate and biopolymers. But exhibit excellent mechanical properties, which is the goal of better environmentally friendly material design. The choice of "brick" (i.e., two-dimensional building block) is of critical importance to construct high performance materials having a "brick and mortar" structure. Therefore, there is a need to develop high performance, low cost, fully biodegradable materials through an efficient and robust strategy.

Disclosure of Invention

Aiming at the problem that the full-biodegradable film made of degradable plastics in the prior art has low barrier property to water vapor and oxygen and cannot be applied to efficient fresh-keeping of food and fruits, the invention aims to provide the high-barrier bionic nano composite degradable film and the preparation method thereof.

The invention is realized by the following technical scheme:

the high-barrier bionic nano composite full-biodegradable film comprises the following components in parts by weight:

100 portions of PBAT master batch

1-25 parts of nano mica plate loaded with PBAT molecules.

The nano mica sheet loaded with PBAT molecules is prepared by the following steps: the preparation method comprises the steps of mechanically crushing natural phlogopite into phlogopite powder, adding the phlogopite powder into a dichloromethane solution of PBAT, and sequentially carrying out high-speed shearing and ultrasonic treatment to obtain the PBAT molecule-loaded nano mica sheet.

Furthermore, the PBAT accounts for 5 to 25 weight percent of the methylene chloride solution of the PBAT, and the added phlogopite powder accounts for 5 to 50 weight percent of the PBAT.

Furthermore, the rotating speed of the high-speed shearing machine in the high-speed shearing treatment is 5000-20000rpm, and the time is 10-60min.

Further, the temperature of ultrasonic treatment is 25-60 deg.C, and the time is 10-100min.

The preparation method of the high-barrier bionic nano composite full-biodegradable film comprises the following steps:

1) PBAT is dispersed in dichloromethane and completely dissolved to 5wt% -25wt% to prepare PBAT solution;

2) Adding phlogopite powder into the PBAT solution to prepare slurry, wherein the adding amount of the phlogopite powder is 5-50 wt% of the PBAT;

3) Homogenizing the slurry of step 2) at 5000-20000rpm for 40min, and then ultrasonically dispersing at 25-60 deg.C for 10-100min to obtain mixed slurry with appropriate viscosity;

4) Drying the mixed slurry obtained in the step 3) to obtain nano mica powder coated with PBAT molecules;

5) Uniformly mixing the nano mica powder coated with the PBAT molecules with the PBAT master batches, and then granulating by a double-screw extruder to prepare mixed master batches;

6) And (3) carrying out basic film forming on the mixed master batch by a tape casting method or film forming by a film blowing machine.

According to the invention, natural phlogopite powder is added into a PBAT solution, and then high-speed shearing and ultrasonic treatment are carried out, so that the phlogopite powder is decomposed into nanoscale mica, the stability and the dispersibility of the molecules on the surface of the nano mica in an organic solvent are greatly promoted, and the nano mica sheets are uniformly distributed in the PBAT substrate. The addition amount of the nano mica sheet in the PBAT is regulated and controlled, so that high barrier property and mechanical strength are achieved.

Drawings

FIG. 1 is a schematic diagram of the preparation of a nano-mica sheet;

FIG. 2 is an electron microscope image of the nano-mica sheet;

FIG. 3 is a circuit diagram for preparing a high-barrier biomimetic nanocomposite PBAT film;

FIG. 4 is an electron microscope image of the nano mica sheet/PBAT composite film.

Detailed Description

The invention is described in further detail below with reference to the drawings and specific examples to better understand the technical solution.

Preparation and dispersion of the nano-scale mica sheet: in the design and manufacture of nano composite films inspired by the pearl layer, the selection of "bricks" plays a key role in the manufacture of materials having a "brick and mortar" structure. The natural phlogopite as the raw material of the brick has excellent ultraviolet shielding performance due to rich reserves. In order to extract the two-dimensional nanoscale member from phlogopite, natural phlogopite was mechanically pulverized into a phlogopite powder, which was then added to a dichloromethane solution of PBAT, and subjected to high-speed shearing and ultrasonic treatment in this order. Wherein, the PBAT in the PBAT solution accounts for 5 to 25 weight percent, and the added phlogopite powder accounts for 5 to 50 weight percent of the PBAT. The rotation speed of the high-speed shearing machine in the high-speed shearing treatment is 5000-20000rpm, and the time is 10-60min. The ultrasonic treatment temperature is 25-60 deg.C, and the treatment time is 10-100min. Through the two steps of treatment, the phlogopite is successfully stripped into two-dimensional inorganic mica nanosheets coated with PBAT molecules. The preparation route of the nano mica sheet is shown in figure 1, and the electron microscope of the nano mica sheet is shown in figure 2. Fig. 2 shows the successful preparation of nano-mica platelets.

The nano-mica sheet can form a uniform dispersion in the PBAT solution, and the modification of PBAT molecules greatly improves the binding capacity between PBAT and the nano-mica sheet, so that the subsequent self-assembly process becomes possible.

Preparing a high-barrier bionic nano composite film: and drying the treated slurry to obtain the nano mica sheet powder. Uniformly mixing the nanometer mica sheet coated with the PBAT molecules with the PBAT master batches, granulating by a double-screw extruder, and extruding by a tape casting method to form a film or forming by a film blowing machine. The preparation route is shown in fig. 3, and the electron microscope image of the finally prepared nano mica sheet/PBAT composite film is shown in fig. 4. Fig. 4 shows the dispersion of nano-mica platelets in the composite film.

Example 1

PBAT was first dispersed in dichloromethane and completely dissolved to 15wt%. 30wt% phlogopite powder (relative to PBAT) was added. Homogenizing the slurry at 10000rpm for 40min, and ultrasonically dispersing at 25 deg.C for 60min to obtain mixed slurry with appropriate viscosity. And drying the well-dispersed slurry to obtain nano mica powder coated with PBAT molecules. And (3) uniformly mixing the nanometer mica sheet coated with the PBAT molecules with the PBAT master batch in a mixing ratio of 5. And finally, extruding the nano mica/PBAT full-biodegradable nano composite film inspired by the pearl layer into a film by a tape casting method or a film by a film blowing machine.

And (3) characterization: scanning electron microscope images were taken with a (JSM-5610, JEOL) field emission scanning electron microscope at an acceleration of 3 kV. Tensile testing was performed on an Instron 5943 universal tester. The samples were carefully cut into small pieces about 1cm wide. The test was performed at room temperature with a displacement rate of 5.0 mm/min. All samples were conditioned at 25 ℃ for 24 hours at 40% relative humidity prior to testing. Each material was tested at least five times. The toughness of the films inspired by the nacreous layer was evaluated by the area integral of the stress-strain curve obtained. The barrier performance test comprises that the oxygen transmission capacity is in accordance with GB/T19789-2005, and the water vapor transmission capacity is in accordance with the regulation of GB/T26253-2010 standard.

Example 2

PBAT was first dispersed in dichloromethane and completely dissolved to 25wt%. 50wt% phlogopite powder (relative to PBAT) was added. The slurry was homogenized at 18000rpm for 60min, and then ultrasonically dispersed at 60 deg.C for 100min to obtain a mixed slurry with appropriate viscosity. And drying the well-dispersed slurry to obtain nano mica powder coated with PBAT molecules. And (3) uniformly mixing the nanometer mica sheet coated with the PBAT molecules with the PBAT master batch in a mixing ratio of 10. And finally, extruding the nano mica/PBAT full-biodegradable nano composite film inspired by the pearl layer by a tape casting method to form a film or forming the film by a film blowing machine.

Example 3

The PBAT was first dispersed in dichloromethane and completely dissolved to 10wt%. 15wt% phlogopite powder (relative to PBAT) was added. Homogenizing the slurry at 20000rpm for 10min, and ultrasonically dispersing at 30 deg.C for 60min to obtain mixed slurry with appropriate viscosity. And drying the well-dispersed slurry to obtain nano mica powder coated with PBAT molecules. And (3) uniformly mixing the nano mica sheet coated with the PBAT molecules with the PBAT master batch in a mixing ratio of 25 to 100, and granulating by using a double-screw extruder. And finally, extruding the nano mica/PBAT full-biodegradable nano composite film inspired by the pearl layer by a tape casting method to form a film or forming the film by a film blowing machine.

Example 4

PBAT was first dispersed in dichloromethane and completely dissolved to 5wt%. 5wt% phlogopite powder (relative to PBAT) was added. Homogenizing the slurry at 5000rpm for 20min, and ultrasonically dispersing at 45 deg.C for 10min to obtain mixed slurry with appropriate viscosity. And drying the well-dispersed slurry to obtain nano mica powder coated with PBAT molecules. And (3) uniformly mixing the nano mica sheet coated with the PBAT molecules with the PBAT master batch in a mixing ratio of 1. And finally, extruding the nano mica/PBAT full-biodegradable nano composite film inspired by the pearl layer into a film by a tape casting method or a film by a film blowing machine.

Comparative example 1

Extruding the PBAT master batch into a film by a tape casting method or forming the film by a film blowing machine.

The final properties of the films obtained in the examples and comparative examples are shown in Table 1.

TABLE 1

	PBAT(wt%)	Nano mica plate (wt% in PBAT)	Water vapor transmission g/(m) 2 ·24h)0.1MPa	Oxygen transmission L/(m) 2 ·24h)	Tensile Strength (MPa)
						Example one	15	30	1120	0.92	49
Example two	25	50	1092	0.81	45
						EXAMPLE III	10	20	1157	1.2	48
Example four	5	5	1529	3.5	58
						Comparative example 1	100	0	1908	9.4	41

As shown in Table 1, the barrier property and tensile strength of the composite film are significantly improved after the nano mica sheet is added. And along with the increase of the addition of the nano mica sheets, the barrier property of the composite film is gradually improved. The advantages of the bionic nano composite structure are shown, and the preparation of the high-barrier full-biodegradable film material is also shown.

Claims (5)

1. The high-barrier bionic nano composite full-biodegradable film is characterized by comprising the following components in parts by weight:

PBAT master batch 100 parts

1-25 parts of PBAT molecule-loaded nano mica sheet

The nano mica sheet loaded with PBAT molecules is prepared by the following steps: the preparation method comprises the steps of mechanically crushing natural phlogopite into phlogopite powder, adding the phlogopite powder into a dichloromethane solution of PBAT, and sequentially carrying out high-speed shearing and ultrasonic treatment to obtain the PBAT molecule-loaded nano mica sheet.

2. The high-barrier biomimetic nanocomposite full biodegradable film according to claim 1, wherein the proportion of PBAT in the methylene chloride solution of PBAT is 5wt% to 25wt%, and the proportion of phlogopite powder added is 5wt% to 50wt% of PBAT.

3. The high-barrier bionic nano-composite full-biodegradable film according to claim 1, wherein the rotation speed of the high-speed shearing machine in the high-speed shearing treatment is 5000-20000rpm, and the time is 10-60min.

4. The high-barrier biomimetic nanocomposite full biodegradable film according to claim 1, wherein the temperature of the ultrasonic treatment is 25-60 ℃ and the time is 10-100min.

5. The preparation method of the high-barrier bionic nano composite full-biodegradable film is characterized by comprising the following steps of:

1) PBAT is dispersed in methylene dichloride and is completely dissolved to 5 to 25 weight percent to prepare PBAT solution;

2) Adding phlogopite powder into the PBAT solution to prepare slurry, wherein the adding amount of the phlogopite powder is 5-50 wt% of the PBAT;

3) Homogenizing the slurry of step 2) at 5000-20000rpm for 40min, and then ultrasonically dispersing at 25-60 deg.C for 10-100min to obtain mixed slurry with appropriate viscosity;

4) Drying the mixed slurry obtained in the step 3) to obtain nano mica powder coated with PBAT molecules;

5) Uniformly mixing the nano mica powder coated with the PBAT molecules with the PBAT master batches, and then granulating by a double-screw extruder to prepare mixed master batches;

6) And extruding the mixed master batch into a film by a tape casting method or forming the film by a film blowing machine.

Images