CN116333460A

CN116333460A - Degradable PBAT blend solid foaming material and preparation method and application thereof

Info

Publication number: CN116333460A
Application number: CN202310212431.3A
Authority: CN
Inventors: 汪龙; 高鹏; 吴明辉; 任倩; 李继张; 郑文革
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS
Priority date: 2023-02-27
Filing date: 2023-02-27
Publication date: 2023-06-27

Abstract

The application discloses a degradable PBAT blend solid foaming material, a preparation method and application thereof. The degradable PBAT blend solid foaming material comprises the following components in parts by weight: 60-95 parts of PBAT; 5-40 parts of modified filler; an antioxidant; 0.1-2 parts; 0.1-1.5 parts of chain extender; the modified filler is selected from at least one of PET, PTT, PBT. The PBAT is melt-blended and modified by externally introducing a polymer with a BT structure or a similar BT structure, so that the melt strength and the matrix modulus of the blend are improved, and the PBAT microporous foam with high expansion multiplying power and shrinkage resistance is prepared. Has good industrial application prospect.

Description

Degradable PBAT blend solid foaming material and preparation method and application thereof

Technical Field

The application relates to a degradable PBAT blend solid foaming material, a preparation method and application thereof, and belongs to the field of degradable foaming materials.

Background

With the rapid development of petrochemical industry, plastic products are gradually applied to various fields in our daily life, which brings convenience to us and also causes serious plastic abandoned pollution, namely 'white pollution'. At present, the treatment means of waste plastics are mostly limited to simple incineration, landfill, concentrated stacking and the like, are difficult to recycle, cause huge economic loss and seriously influence our living environment. Therefore, popularization of application of biodegradable plastics will make a certain contribution to environmental protection.

Polybutylene terephthalate (PBAT) is a novel biodegradable copolyester synthesized from adipic acid, terephthalic acid and butanediol through direct esterification or transesterification, has the characteristics of PBT and PBA, has better ductility and toughness, and has degradability mainly from aliphatic units (BA units) in a molecular chain, and mechanical properties and thermal stability mainly from main chain benzene ring structural units (BT units) in the molecular chain. Increasing the content of BT units in the PBAT molecular chain will significantly increase the mechanical and thermal properties of PBAT, but the presence of the benzene ring structure will decrease the degradability of PBAT.

The production cost of the PBAT raw material is high, so that the application and industrialization of the PBAT are difficult to popularize, and therefore, the preparation of the foam material with high foaming multiplying power can realize cost reduction by a weight reduction means and possibly become a trend of the application and development of the PBAT material.

Since PBAT is a linear molecular chain, its low viscosity and relatively low molecular weight limit its foaming behavior. On the one hand, cell walls are easily broken or combined during foaming, so that a mutually connected cell structure is formed; on the other hand, the PBAT matrix modulus is low, the formed high-rate foam is difficult to stabilize, and shrinkage is easy to occur. Many methods such as blending, filling, crosslinking, chain extension, etc. are currently used to improve the hair of PBATsBubble properties. The Chinese patent No. CN101565509B is prepared by modifying PBAT with glyceryl stearate, and passing through supercritical CO at foaming temperature of 20-80deg.C ₂ Rapid pressure relief foaming to obtain a cell size of 2.5-80.3 μm and a cell density of 2.28X10 ⁶ -8.73×10 ⁹ cell/cm ³ Is prepared from the modified PBAT foaming material. The foaming process needs to use chloroform as a solvent for solution blending, so that the cost is high, the foaming process has certain toxicity, and the foaming process is not suitable for industrial production. The Chinese patent No. CN 112694636A adopts a sulfuric acid hydrolysis method to prepare cellulose nanocrystals, and the cellulose nanocrystals are melt-blended with PBAT, a chain extender and a foaming agent to obtain a melt, and the melt is subjected to pressure reduction, temperature reduction, extrusion and foaming to prepare the soft PBAT-based biodegradable foaming material. The physical crosslinking point is initiated by the action between polyhydroxy CNC and PBAT ester groups, so that the acting force between molecules is increased, and the prepared soft foaming material has better creep resistance, but the treatment process of cellulose nanocrystalline is complex and is difficult to obtain in a large scale.

In summary, the foaming technology of the PBAT foaming material in the prior art needs to be improved, and a foaming technology suitable for the industrial development needs is developed to produce a microporous foaming material with high quality, low cost and high foaming ratio, so as to meet the requirements of packaging and other industries on green environment-friendly foaming materials.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a simple preparation method of a modified PBAT foaming material, wherein a polymer with a BT structure or a similar BT structure is externally introduced to carry out melt blending modification on PBAT, so that the melt strength and matrix modulus of the blend are improved, and the PBAT microporous foam with high expansion rate and shrinkage resistance is prepared. The high melt strength is beneficial to resisting the biaxial stretching action of the cells in the growth process, and the breakage and coalescence of the cells are reduced; the high matrix modulus is beneficial to maintain the cell structure of the foam and to resist shrinkage behavior caused by outdiffusion of the blowing agent.

According to a first aspect of the present application, a degradable PBAT blend solid state foam material is provided.

A degradable PBAT blend solid state foam material, comprising the following components in parts by weight:

the modified filler is selected from at least one of PET, PTT, PBT.

Preferably, the modified filler is selected from PTT.

In the application, the modified filler is selected from PET, PTT or PBT, is a polymer with a BT structure or a similar BT structure, can introduce BT units, and can improve the foaming behavior of PBAT while improving the matrix modulus.

Alternatively, the PBAT is independently selected from any of 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, or a range of values therebetween.

Alternatively, the parts by weight of the modified filler are independently selected from any of 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, or a range of values between any two.

Alternatively, the parts by weight of the antioxidant are independently selected from any of 0.1 part, 0.2 part, 0.5 part, 0.7 part, 1 part, 1.2 part, 1.5 part, 1.7 part, 2 part, or a range of values between any two.

Alternatively, the parts by weight of the chain extender are independently selected from any of 0.1 parts, 0.2 parts, 0.5 parts, 0.7 parts, 1 part, 1.2 parts, 1.5 parts, or a range of values between any two.

Optionally, the chain extender is an epoxy-functional chain extender containing a plurality of epoxy functional groups.

Preferably, the chain extender is selected from at least one of ADR-4368, ADR-4370, ADR-4400, and ADR-4468.

Optionally, the antioxidant is at least one selected from hindered phenol antioxidants, aromatic amine antioxidants and auxiliary antioxidants.

Preferably, the antioxidant is selected from hindered phenol antioxidants and/or auxiliary antioxidants.

Preferably, the antioxidant is selected from antioxidant 1010 and/or antioxidant 168.

Optionally, the expansion ratio of the degradable PBAT blend solid-state foaming material is 8-30 times.

Optionally, the expansion ratio of the solid foaming material of the degradation PBAT blend is 8.75-27.21 times.

Optionally, the cell size of the degraded PBAT blend solid state foam material is from 35 to 65 μm.

Alternatively, the cell size of the degraded PBAT blend solid state foam material is from 35.8 to 61.32 μm.

According to a second aspect of the present application, there is provided a method for preparing the degradable PBAT blend solid state foam material described above.

A preparation method of a degradable PBAT blend solid foaming material comprises the following steps:

(S1) drying the PBAT and the modified filler;

(S2) mixing the dried PBAT, modified filler, antioxidant and chain extender according to the weight part ratio, and extruding and granulating by a double-screw extruder to obtain blend particles;

(S3) carrying out hot press molding on the blend particles by a flat vulcanizing machine to obtain a blend sheet;

and (S4) placing the blend sheet into a high-pressure reaction kettle, filling supercritical gas, foaming, releasing pressure, and cooling to obtain the degradable PBAT blend solid foaming material.

Optionally, in step (S1), the drying conditions are: the temperature is 60-80 ℃ and the time is 8-24 h.

Optionally, in step (S2), the conditions of extrusion are: the temperature is 130-240 ℃, and the rotating speed of the rotor is 60-150 rpm.

Optionally, in step (S3), the thickness of the thermoformed blend sheet is from 0.4 to 5.1mm.

Optionally, in step (S3), the thickness of the thermoformed blend sheet is from 0.5 to 5mm.

Optionally, in step (S4), the supercritical gas is selected from supercritical CO ₂ And/orN ₂ 。

Optionally, in step (S4), the foaming conditions are: the pressure is 10-25 MPa, the temperature is 60-120 ℃ and the time is 30-240 min.

Optionally, in step (S4), the pressure relief time is 1-10S.

Specifically, the preparation method comprises the following steps:

(1) Drying PBAT and PTT in a vacuum drying oven at 60-80 ℃ for 6-24h;

(2) Mixing PBAT, PTT and processing aid according to the formula proportion, extruding and granulating by a double-screw extruder at 130-240 ℃ and rotor speed of 60-150 rpm;

(3) Hot-press molding the blend at 240 ℃ by a flat vulcanizing machine;

(4) And (3) putting the PBAT/PTT blend into a foaming kettle, filling supercritical gas with a certain pressure, heating the foaming kettle to a set temperature, quickly releasing pressure after saturation for a certain time, taking out a foaming sample, and cooling to obtain the PBAT blend foaming material.

In this application, "PBAT" refers to polybutylene terephthalate-adipate.

"PET" refers to polyethylene terephthalate.

"PTT" refers to polytrimethylene terephthalate.

"PBT" refers to polybutylene terephthalate.

According to a further aspect of the application, the degradable PBAT blend solid-state foaming material and the application of the degradable PBAT blend solid-state foaming material prepared by the preparation method in the packaging field are provided.

The beneficial effects that this application can produce include:

1) According to the preparation method of the degradable PBAT blend solid-state foaming material, provided by the application, the PBAT is subjected to melt blending modification by externally introducing the polymer with the BT structure similar to the BT structure, so that the matrix modulus is improved, and meanwhile, under the action of the chain extender, the branching degree of molecular chains and the entanglement degree among the molecular chains are increased by utilizing the reaction between the functional groups at the tail ends of the molecular chains, so that the melt strength of the blend is improved, and the foaming behavior of the blend is remarkably improved. Besides the polymer, only a small amount of chain extender is added for melt blending modification, so that the cost is low and the process is simple.

2) The degradable PBAT blend solid foaming material provided by the application meets the requirements of packaging and other industries on green environment-friendly foaming materials, and has outstanding advantages in the packaging field. Has good industrial application prospect.

Drawings

FIG. 1 is a scanning electron micrograph of a quenched section of the sample of example 2, on a scale of 20. Mu.m.

FIG. 2 is a scanning electron micrograph of a quenched section of the sample of comparative example 1 on a scale of 20. Mu.m.

Detailed Description

The present application is described in detail below with reference to examples, but the present application is not limited to these examples.

Unless otherwise indicated, all starting materials in the examples of the present application were purchased commercially.

Unless otherwise specified, the test methods all use conventional methods, and the instrument settings all use manufacturer recommended settings.

The cell size test method in the examples of the present application is as follows:

and quenching the microporous foaming material by liquid nitrogen, spraying metal on the section, and observing the cell structure inside the foaming material by adopting a Scanning Electron Microscope (SEM). Cell size was measured using Image J software.

The scanning electron microscope has the instrument model of Zeiss EVO18 and the test condition of 20KV.

In the embodiment, the antioxidants are divided into a main antioxidant and an auxiliary antioxidant which are mixed according to the mass ratio of 1:1, wherein the main antioxidant selects antioxidant 1010 and the auxiliary antioxidant selects antioxidant 168; the chain extender is selected from the group consisting of epoxy-functionalized ADR-4468.

Example 1

The preparation method of the degradable PBAT blend solid foaming material comprises the following steps:

(1) Drying PBAT and PTT in a vacuum drying oven at60 ℃ and 80 ℃ for 8 hours respectively;

(2) Weighing 90 parts (900 g) of PBAT, 10 parts of PTT, 0.5 part of antioxidant and 0.1 part of chain extender according to mass percent, uniformly mixing the weighed raw materials, and extruding and granulating by a double-screw extruder, wherein the temperature from a feed opening to a machine head is 130 ℃, 150 ℃, 170 ℃, 190 ℃, 210 ℃, 230 ℃, 240 ℃ and the screw rotation speed is 80 revolutions per minute;

(3) Hot-pressing the dried PBAT/PTT blend particles into a sheet with the thickness of 2+/-0.2 mm by using a flat vulcanizing machine at 240 ℃;

(4) Placing a PBAT/PTT blend sample in a high-pressure reaction kettle for foaming, wherein the volume of the sample is not more than 1/20 of that of the kettle body so as to prevent the sample from being limited in the expansion process, the foaming temperature is set to 115 ℃, the pressure is 20MPa, the saturation time is 180min, the pressure release time is 2s, and taking out the foaming sample, thereby obtaining the PBAT/PTT foaming material. The expansion ratio of the PBAT/PTT foam prepared in this example was 8.75 times and the cell size was 35.8. Mu.m.

Example 2

The preparation method of the degradable PBAT blend solid foaming material comprises the following steps: 1) Drying PBAT and PTT in a vacuum drying oven at60 ℃ and 80 ℃ for 8 hours respectively;

(2) Weighing 80 parts (800 g) of PBAT, 20 parts of PTT, 0.5 part of antioxidant and 0.1 part of chain extender according to mass percent, uniformly mixing the weighed raw materials, and extruding and granulating by a double-screw extruder, wherein the temperature from a feed opening to a machine head is 130 ℃, 150 ℃, 170 ℃, 190 ℃, 210 ℃, 230 ℃, 240 ℃ and the screw rotation speed is 80 revolutions per minute;

(4) Placing a PBAT/PTT blend sample in a high-pressure reaction kettle for foaming, wherein the volume of the sample is not more than 1/20 of that of the kettle body so as to prevent the sample from being limited in the expansion process, the foaming temperature is set to 115 ℃, the pressure is 20MPa, the saturation time is 180min, the pressure release time is 2s, and taking out the foaming sample, thereby obtaining the PBAT/PTT foaming material. The expansion ratio of the PBAT/PTT foam prepared in this example was 12.23 times and the cell size was 44.9. Mu.m.

Example 3

(2) Weighing 70 parts (700 g) of PBAT, 30 parts of PTT, 0.5 part of antioxidant and 0.1 part of chain extender according to mass percent, uniformly mixing the weighed raw materials, and extruding and granulating by a double-screw extruder, wherein the temperature from a feed opening to a machine head is 130 ℃, 150 ℃, 170 ℃, 190 ℃, 210 ℃, 230 ℃, 240 ℃ and the screw rotation speed is 80 revolutions per minute;

(4) Placing a PBAT/PTT blend sample in a high-pressure reaction kettle for foaming, wherein the volume of the sample is not more than 1/20 of that of the kettle body so as to prevent the sample from being limited in the expansion process, the foaming temperature is set to 115 ℃, the pressure is 20MPa, the saturation time is 180min, the pressure release time is 2s, and taking out the foaming sample, thereby obtaining the PBAT/PTT foaming material. The expansion ratio of the PBAT/PTT foam prepared in this example was 20.32 times and the cell size was 53.7. Mu.m.

Example 4

(2) Weighing 70 parts (700 g) of PBAT, 30 parts of PTT, 0.5 part of antioxidant and 1 part of chain extender according to mass percent, uniformly mixing the weighed raw materials, and extruding and granulating by a double-screw extruder, wherein the temperature from a feed opening to a machine head is 130 ℃, 150 ℃, 170 ℃, 190 ℃, 210 ℃, 230 ℃, 240 ℃ and the screw rotating speed is 80 revolutions per minute;

(4) Placing a PBAT/PTT blend sample in a high-pressure reaction kettle for foaming, wherein the volume of the sample is not more than 1/20 of that of the kettle body so as to prevent the sample from being limited in the expansion process, the foaming temperature is set to 115 ℃, the pressure is 20MPa, the saturation time is 180min, the pressure release time is 2s, and taking out the foaming sample, thereby obtaining the PBAT/PTT foaming material. The expansion ratio of the PBAT/PTT foam prepared in this example was 27.21 times and the cell size was 61.3. Mu.m.

Example 5

The procedure was as in example 4 except that PTT was replaced with PBT to give a PBAT/PBT foam. The expansion ratio of the PBAT/PBT foam prepared in this example was 26.75 times and the cell size was 59.7. Mu.m.

The foam material prepared in the above example was observed for the cell structure inside the foam material by using a Scanning Electron Microscope (SEM), and by taking the PBAT/PTT foam material prepared in example 2 as a typical example, fig. 1 is a scanning electron microscope drawing of a quenched section thereof, and the scale is 20 μm, it can be seen that the cells of the foam have a closed cell structure, no obvious cell coalescence and rupture, uniform cell distribution, and no rupture and wrinkles are found on the cell walls.

Comparative example 1

The comparative example is a preparation method of a pure PBAT foaming material, comprising the following steps:

(1) Drying PBAT in a vacuum drying oven at60 ℃ for 8 hours;

(2) Weighing 100 parts (1000 g) of PBAT, 0.5 part of antioxidant and 0.1 part of chain extender according to mass percent, uniformly mixing the weighed raw materials, and extruding and granulating by a double-screw extruder, wherein the temperature from a feed opening to a machine head is 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃ and 180 ℃ respectively, and the screw rotating speed is 80 revolutions per minute;

(3) Hot-pressing the dried PBAT particles into a sheet with the thickness of 2+/-0.2 mm by using a flat vulcanizing machine at 180 ℃;

(4) And (3) placing the pure PBAT sample in a high-pressure reaction kettle for foaming, wherein the volume of the sample is not more than 1/20 of that of the kettle body so as to prevent the sample from being limited in the expansion process, the foaming temperature is set to 115 ℃, the pressure is 20MPa, the saturation time is 180min, the pressure release time is 2s, and taking out the foaming sample to obtain the pure PBAT foaming material. The PBAT foam prepared in this comparative example had an initial magnification of 36.75 times, a final magnification of 5.91 times and a cell size of 58.9. Mu.m. FIG. 2 is a scanning electron micrograph of a quenched section with a 20 μm scale, which shows that the PBAT foam has a poor overall cell morphology and a thinner cell wall. Because of the low PBAT modulus, it is difficult to maintain the cell structure at higher foaming rates, creating significant shrinkage phenomena, leading to cracking and wrinkling of the cell walls.

The foregoing description is only a few examples of the present application and is not intended to limit the present application in any way, and although the present application is disclosed in the preferred examples, it is not intended to limit the present application, and any person skilled in the art may make some changes or modifications to the disclosed technology without departing from the scope of the technical solution of the present application, and the technical solution is equivalent to the equivalent embodiments.

Claims

1. The degradable PBAT blend solid-state foaming material is characterized by comprising the following components in parts by weight:

the modified filler is selected from at least one of PET, PTT, PBT.

2. The degradable PBAT blend solid state foam material of claim 1, wherein the chain extender is an epoxy functionalized chain extender containing a plurality of epoxy functional groups;

preferably, the chain extender is selected from at least one of ADR-4368, ADR-4370, ADR-4400 and ADR-4468.

3. The degradable PBAT blend solid state foam material of claim 1, wherein the antioxidant is selected from at least one of hindered phenolic antioxidants, aromatic amine antioxidants, auxiliary antioxidants;

preferably, the antioxidant is selected from the group consisting of antioxidant 1010 and/or antioxidant 168.

4. The degradable PBAT blend solid state foam material of claim 1, wherein the expansion ratio of the degradable PBAT blend solid state foam material is 8-30 times;

the cell size of the solid foaming material of the degradation PBAT blend is 35-65 mu m.

5. The method for preparing the degradable PBAT blend solid state foaming material as claimed in any one of claims 1 to 4, which is characterized by comprising the following steps:

(S1) drying the PBAT and the modified filler;

6. The method according to claim 5, wherein in the step (S2), the conditions of extrusion are: the temperature is 130-240 ℃, and the rotating speed of the rotor is 60-150 rpm.

7. The method according to claim 5, wherein in the step (S3), the thickness of the hot-press-molded blend sheet is 0.4 to 5.1mm.

8. According to claimThe process according to 5, wherein in the step (S4), the supercritical gas is selected from the group consisting of supercritical CO ₂ And/or N ₂ 。

9. The method according to claim 5, wherein in the step (S4), the foaming conditions are as follows: the pressure is 10-25 MPa, the temperature is 60-120 ℃ and the time is 30-240 min.

10. Use of the degradable PBAT blend solid-state foaming material according to any one of claims 1 to 4 and the degradable PBAT blend solid-state foaming material prepared by the preparation method according to any one of claims 5 to 9 in the packaging field.