Degradable high-strength wear-resistant PBAT foaming material and preparation method thereof

Abstract

This invention discloses a biodegradable, high-strength, wear-resistant PBAT foam material and its preparation method. The composite material comprises the following components: 70 parts poly(butylene adipate / terephthalate) PBAT, 10 parts thermoplastic starch (TPS), 10 parts polylactic acid (PLA), 10 parts polybutylene succinate (PBS), 1-4 parts composite wear-resistant additives, 5 parts plasticizer, 0.5-1 parts AC foaming agent, 0.8 parts nucleating agent, 0.8 parts foaming accelerator, 5-8 parts crosslinking agent, and 0.2 parts lubricant. The preparation method includes the following steps: the above raw materials are thoroughly mixed and then fed into a flat vulcanizing apparatus to obtain the biodegradable, high-strength, wear-resistant PBAT foam material. The formulation of this invention, while retaining the product's foaming function, significantly increases the proportion of biodegradable components. The formulation is scientifically sound, the biodegradable components have good compatibility with the foam matrix, and the product has biodegradability, greatly improving economic and environmental benefits.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, specifically relating to a biodegradable, high-strength, wear-resistant PBAT foam material and its preparation method. Background Technology

[0002] PBAT is a compostable biopolyester, available from renewable resources, and possesses significant commercial value. Due to its low price, ease of processing, and particularly high flexibility, PBAT is likely to become a leading flexible bioplastic in the coming years. As a polyester primarily derived from fossil resources, its abundant market supply, relatively low price, high processability, and, most importantly, high flexibility (i.e., elongation at break exceeding 700%) have fueled interest in PBAT research, as it is particularly well-suited for producing flexible packaging, increasingly replacing and supporting fossil-based polyolefins and polyesters in a variety of applications, thereby reducing "white pollution." However, another characteristic of PBAT is its moderate stiffness (i.e., Young's modulus typically between 75 and 150 MPa), and its high production cost compared to non-degradable polymers limits its applications.

[0003] Polylactic acid (PLA) is the most widely produced biodegradable and bio-based polyester and a promising candidate to replace oil-based polymers in a variety of commercial and engineering applications. At room temperature, PLA's mechanical properties are comparable to petroleum-based polystyrene, while its overall thermal properties differ from other commercial plastics: PLA's melting temperature is similar to polypropylene, but its glass transition temperature is significantly higher, though lower than that of polyethylene terephthalate (PET) and polystyrene. PLA is biodegradable, produced from renewable resources, and non-toxic, making it an ideal polymer platform for designing and manufacturing food packaging, especially for high-volume, short-shelf-life foods. However, it also has some drawbacks, such as brittleness, low toughness, low heat distortion temperature, narrow processing temperature window, low melt strength, and low crystallization rate.

[0004] Polybutylene succinate (PBS) is an aliphatic polyester that can be contained in fossil-based biodegradable polymers. It is obtained from two monomers: succinic acid (SA) and 1,4-butanediol (BD). SA can be obtained by hydrogenation of fossil-derived maleic acid (anhydride) or 1,4-butanediol. BD is produced by hydrogenation of 1,4-butynediol, a substance previously obtained from acetylene and formaldehyde. BD can also be obtained by hydrogenation of maleic anhydride-derived methyl maleate. Compared to poly(lactic acid), PBS is more flexible, has a higher elongation at break, and exhibits similarly good barrier properties against oxygen and water vapor, and is therefore being investigated for use in the manufacture of flexible packaging.

[0005] Starch is a sustainable, environmentally friendly, and inexpensive biopolymer, potentially a promising method for producing biocomposites. The low mechanical and tensile strength of starch-based films limits its application in the packaging industry. However, intermolecular forces and hydrogen bonds in starch hinder its processing as a thermoplastic material. To overcome this problem, various plasticizers have been used to create deformable thermoplastic materials known as thermoplastic starches. Most plasticizers are high-boiling-point liquids that do not readily evaporate, helping to maintain elasticity and starch stability below degradation temperatures. Thermoplastic starch (TPS), a starch derivative, is considered a suitable candidate to replace synthetic polymers used in packaging. However, TPS has drawbacks such as hygroscopicity, low permeability, and insufficient water resistance. To become a near-ideal food packaging material, TPS must be blended with synthetic or natural polymers to enhance its mechanical properties. Summary of the Invention

[0006] The present invention aims to provide a biodegradable, high-strength, wear-resistant PBAT foam material with excellent mechanical properties and wear resistance, and a method for preparing the same.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A biodegradable, high-strength, wear-resistant PBAT foam material is made from the following raw materials in parts by weight: 70 parts polybutylene adipate / terephthalate (PBAT), 10 parts thermoplastic starch (TPS), 10 parts polylactic acid (PLA), 10 parts polybutylene succinate (PBS), 1-4 parts composite wear-resistant additives, 5 parts plasticizer, 0.5-1 part AC foaming agent, 0.8 parts nucleating agent, 0.8 parts foaming accelerator, 5-8 parts crosslinking agent, and 0.2 parts lubricant;

[0009] Furthermore, the composite wear-resistant additive is a carbon fiber-zirconia composite.

[0010] Furthermore, the preparation steps of the composite wear-resistant additive (CF-ZrO2) are as follows:

[0011] (1) Take 3g ZrOCl 2· Dissolve 8H2O in 80 ml of deionized water, sonicate for 30 min, and then stir with a magnetic stirrer at 300 rpm for 2 h at room temperature to obtain a pink solution.

[0012] (2) Dissolve 1g of carbon fiber CF in the solution of step (1) and sonicate for 30min to make CF uniformly dispersed in the solution;

[0013] (3) 1 mL of 85 wt% hydrazine hydrate solution was added dropwise to the solution obtained in step (2), and then the mixed solution was transferred to a polytetrafluoroethylene-lined reactor and subjected to hydrothermal reaction at 180 °C for 18 hours. Afterwards, the mixed solution was separated by centrifugation, and the precipitate was washed several times with deionized water and anhydrous ethanol, and then dried at 60 °C for 12 hours to obtain CF-ZrO2.

[0014] Further, the nucleating agent is one or more of calcium carbonate and talc; the foaming accelerator is one or more of zinc oxide and zinc stearate; the crosslinking agent is dicumyl peroxide (DCP); and the lubricant is one or more of lead stearate (PbST), calcium stearate (CaST), and stearic acid; preferably, the lubricant is stearic acid.

[0015] Further, the preparation steps of the thermoplastic starch are as follows: corn starch is dried at 70°C for 12 hours, cooled to room temperature, and then 100 parts by weight of starch and 5 parts by weight of plasticizer glycerin are stirred at high speed in a high-speed mixer for 30 minutes. Then, it is sealed and allowed to stand for 72 hours to obtain thermoplastic starch, denoted as TPS.

[0016] Furthermore, the plasticizer is one or more combinations of glycerol and sorbitol.

[0017] Further, the preparation method of the biodegradable high-strength wear-resistant PBAT foam material is as follows: 70 parts of polybutylene adipate / terephthalate (PBAT), 10 parts of thermoplastic starch (TPS), 10 parts of polylactic acid (PLA), 10 parts of polybutylene succinate (PBS), 1-5 parts of wear-resistant reinforcing agent, 5 parts of plasticizer, 0.5-1 part of AC foaming agent, 0.8 parts of nucleating agent, 0.8 parts of foaming accelerator, 5-8 parts of crosslinking agent, and 0.2 parts of lubricant are mixed in an internal mixer, and then the blended product is subjected to cold and hot molding; specifically including the following steps:

[0018] 1) Place PBAT, PLA, PBS and TPS into a preheated internal mixer at 120℃ and mix for 10 minutes at a speed of 30 rpm.

[0019] 2) Add the composite wear-resistant additive, plasticizer, AC foaming agent, nucleating agent, foaming accelerator, lubricant, and crosslinking agent to the blend obtained in step 1), and continue to mix in a mixer at 120°C for 5 minutes;

[0020] 3) After the blend obtained in step 2) is shredded by a shredder, it is transferred to a flat vulcanizing machine for molding. The temperature of the upper and lower molds is 170℃, the pressure is 10-12MPa, the molding time is 300s, and after cooling for 360s, the mold is opened and the product is taken out, which is the biodegradable high-strength wear-resistant PBAT foam material.

[0021] The beneficial effects of this invention are:

[0022] (1) Zirconia (ZrO2) nanoparticles have the advantages of low cost, easy preparation, high strength, good toughness, heat resistance, wear resistance and good chemical stability. Carbon fiber can improve creep resistance and hardness. Introducing ZrO2 nanoparticles into the CF surface can make the carbon fiber surface rough. The zirconium dioxide particles are tightly attached to the carbon fiber, making its surface uneven. During the friction process, the carbon fiber is not easy to be pulled out or broken, thereby improving the adhesion between the carbon fiber and the matrix interface, effectively realizing the synergistic effect of CF and ZrO2, and finally obtaining a polymer composite material with excellent wear resistance.

[0023] (2) The addition of CF can play a role in bearing part of the load, further preventing the wear of the polymer matrix, and reducing the frictional heat in the contact area with the matrix. The presence of ZrO2 nanoparticles has good mechanical strength, which can increase the load-bearing capacity, form good stress transmission, and prevent CF from being exposed and damaged.

[0024] (3) Fixing zirconium dioxide onto a rod structure by loading it with carbon fiber can effectively improve the problem of poor interfacial bonding between CF and polymer matrix, which easily leads to stress concentration and further causes crack generation and propagation during sliding. Attached Figure Description

[0025] Figure 1 The infrared spectrum of the composite wear-resistant additive (CF-ZrO2) in Example 1 is shown below.

[0026] Figure 2 This is a scanning electron microscope image of the composite wear-resistant additive (CF-ZrO2) from Example 1. Detailed Implementation

[0027] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0028] The present invention will be further illustrated by the following embodiments.

[0029] Example 1

[0030] (1) Preparation of thermoplastic starch: Corn starch was dried at 70°C for 12 hours, cooled to room temperature, and 100 parts of starch and 5 parts of plasticizer glycerin were stirred at high speed in a high-speed mixer for 30 minutes. Then it was sealed and allowed to stand for 72 hours to obtain thermoplastic starch, denoted as TPS.

[0031] (2) Preparation steps of composite wear-resistant additive (CF-ZrO2):

[0032] (2-1) Preparation of ZrO2: 3 grams of ZrOCl 2· Dissolve 8H2O in 80 ml of deionized water, sonicate for 30 min, and then stir with a magnetic stirrer at 300 rpm for 2 h at room temperature to obtain a pink solution.

[0033] (2-2) Preparation of CF-ZrO2: Dissolve 1g of CF in the solution of step (1) and sonicate for 30min to make CF uniformly dispersed in the solution;

[0034] (2-3) 1 mL of 85 wt% hydrazine hydrate solution was added dropwise to the above solution. The mixed solution was then transferred to a polytetrafluoroethylene-lined reactor and subjected to a hydrothermal reaction at 180 °C for 18 hours. Afterward, the mixed solution was separated by centrifugation, and the precipitate was washed several times with deionized water and anhydrous ethanol. Then, it was dried at 60 °C for 12 hours to obtain CF-ZrO2.

[0035] (3) Preparation of biodegradable high-strength wear-resistant PBAT foam material:

[0036] (3-1): 70 parts of poly(butylene adipate / terephthalate) PBAT, 10 parts of thermoplastic starch TPS, 10 parts of polylactic acid PLA, and 10 parts of polybutylene succinate PBS were placed in a preheated internal mixer at 120℃ and mixed for 10 min at a speed of 30 rpm.

[0037] (3-2) Add 1 part of composite wear-resistant additive, 5 parts of plasticizer, 0.5 parts of AC foaming agent, 0.8 parts of talc, 0.8 parts of foaming accelerator, 0.8 parts of zinc stearate, 8 parts of DCP, and 0.2 parts of stearic acid to the internal mixer and continue to mix them together with the melt blend described in step (3-1) in the internal mixer at 120°C for 5 minutes;

[0038] (3-3) After the blend described in step (3-2) is shredded by a shredder, it is transferred into a flat vulcanizing machine for molding. The temperature of the upper and lower molds is 170℃, the pressure is 12MPa, the molding time is 300s, and the product is taken out after cooling for 360s.

[0039] Example 2

[0040] (1) Preparation of thermoplastic starch: Same as in Example 1;

[0041] (2) Preparation of CF-ZrO2: Same as in Example 1;

[0042] (3) Preparation of biodegradable high-strength wear-resistant PBAT foam material:

[0043] (3-1): 70 parts of poly(butylene adipate / terephthalate) PBAT, 10 parts of thermoplastic starch TPS, 10 parts of polylactic acid PLA, and 10 parts of polybutylene succinate PBS were placed in a preheated internal mixer at 120℃ and mixed for 10 min at a speed of 30 rpm.

[0044] (3-2) Add 3 parts of composite wear-resistant additive, 5 parts of plasticizer, 0.5 parts of AC foaming agent, 0.8 parts of talc, 0.8 parts of foaming accelerator, 0.8 parts of zinc stearate, 8 parts of DCP, and 0.2 parts of stearic acid to the internal mixer and continue to mix them together with the melt blend described in step (3-1) in the internal mixer at 120°C for 5 minutes;

[0045] (3-3) After the blend described in step (3-2) is shredded by a shredder, it is transferred into a flat vulcanizing machine for molding. The temperature of the upper and lower molds is 170℃, the pressure is 12MPa, the molding time is 300s, and the product is taken out after cooling for 360s.

[0046] Example 3

[0047] (1) Preparation of thermoplastic starch; same as in Example 1

[0048] (2) The preparation of CF-ZrO2 is the same as in Example 1;

[0049] (3) Preparation of biodegradable high-strength wear-resistant PBAT foam material:

[0050] (3-1): 70 parts of poly(butylene adipate / terephthalate) PBAT, 10 parts of thermoplastic starch TPS, 10 parts of polylactic acid PLA, and 10 parts of polybutylene succinate PBS were placed in a preheated internal mixer at 120℃ and mixed for 10 min at a speed of 30 rpm.

[0051] (3-2) Add 5 parts of composite wear-resistant additive, 5 parts of plasticizer, 0.5 parts of AC foaming agent, 0.8 parts of talc, 0.8 parts of foaming accelerator, 0.8 parts of zinc stearate, 8 parts of DCP, and 0.2 parts of stearic acid to the internal mixer and continue to mix them together with the melt blend described in step (3-1) in the internal mixer at 120°C for 5 minutes;

[0052] (3-3) After the blend described in step (3-2) is shredded by a shredder, it is transferred into a flat vulcanizing machine for molding. The temperature of the upper and lower molds is 170℃, the pressure is 12MPa, the molding time is 300s, and the product is taken out after cooling for 360s.

[0053] Comparative Example 1 (without CF-ZrO2 reinforcing agent)

[0054] (1) Preparation of thermoplastic starch; same as in Example 1

[0055] (2) Preparation of biodegradable PBAT foam material:

[0056] (2-1): 70 parts of poly(butylene adipate / terephthalate) PBAT, 10 parts of thermoplastic starch TPS, 10 parts of polylactic acid PLA, and 10 parts of polybutylene succinate PBS were placed in a preheated internal mixer at 120℃ and mixed for 10 min at a speed of 30 rpm.

[0057] (2-2) Add 5 parts plasticizer, 0.5 parts AC foaming agent, 0.8 parts talc, 0.8 parts foaming accelerator, 0.8 parts zinc stearate, 8 parts DCP, and 0.2 parts stearic acid to the internal mixer and continue to mix them together with the melt blend described in step (2-2) in the internal mixer at 120°C for 5 minutes;

[0058] (2-3) After the blend described in step (2-2) is shredded by a shredder, it is transferred into a flat vulcanizing machine for molding. The temperature of the upper and lower molds is 170℃, the pressure is 12MPa, the molding time is 300s, and the product is taken out after cooling for 360s.

[0059] Comparative Example 2 (CF added separately to the system)

[0060] (1) Preparation of thermoplastic starch; same as in Example 1;

[0061] (2) Preparation of biodegradable high-strength wear-resistant PBAT foam material:

[0062] (2-1): 70 parts of poly(butylene adipate / terephthalate) PBAT, 10 parts of thermoplastic starch TPS, 10 parts of polylactic acid PLA, and 10 parts of polybutylene succinate PBS were placed in a preheated internal mixer at 120℃ and mixed for 10 min at a speed of 30 rpm.

[0063] (2-2) Add 5 parts CF, 5 parts plasticizer, 0.5 parts AC foaming agent, 0.8 parts talc, 0.8 parts foaming accelerator, 0.8 parts zinc stearate, 8 parts DCP, and 0.2 parts stearic acid to the internal mixer and continue mixing with the melt blend described in step (2-1) in the internal mixer at 120°C for 5 minutes;

[0064] (2-3) After the blend described in step (2-2) is shredded by a shredder, it is transferred into a flat vulcanizing machine for molding. The temperature of the upper and lower molds is 170℃, the pressure is 12MPa, the molding time is 300s, and the product is taken out after cooling for 360s.

[0065] Comparative Example 3 (CF and ZrO2 were added to the system separately)

[0066] (1) Preparation of thermoplastic starch; same as in Example 1;

[0067] (2) Preparation of biodegradable high-strength wear-resistant PBAT foam material:

[0068] (2-1): 70 parts of poly(butylene adipate / terephthalate) PBAT, 10 parts of thermoplastic starch TPS, 10 parts of polylactic acid PLA, and 10 parts of polybutylene succinate PBS were placed in a preheated internal mixer at 120℃ and mixed for 10 min at a speed of 30 rpm.

[0069] (2-2) Add 3.2 parts CF, 1.8 parts ZrO2, 5 parts plasticizer, 0.5 parts AC foaming agent, 0.8 parts talc, 0.8 parts foaming accelerator, 0.8 parts zinc stearate, 8 parts DCP, and 0.2 parts stearic acid to the internal mixer and continue mixing with the melt blend described in step (2-1) in the internal mixer at 120°C for 5 minutes;

[0070] (2-3) After the blend described in step (2-2) is shredded by a shredder, it is transferred into a flat vulcanizing machine for molding. The temperature of the upper and lower molds is 170℃, the pressure is 12MPa, the molding time is 300s, and the product is taken out after cooling for 360s.

[0071] Performance testing

[0072] Table 1: Sample Performance Testing

[0073]

[0074] As shown in Table 1, compared to Comparative Examples 1, 2, and 3, which did not contain any wear-resistant reinforcing agents but only added CF or ZrO2, the mechanical properties of the samples increased to varying degrees from Example 1 to Example 3 with the increase of CF-ZrO2 content. This indicates that the addition of CF-ZrO2 improves the wear resistance of the matrix, and the filler has good compatibility with the matrix. Observing the data of Comparative Example 2, when CF was added to the matrix alone, due to poor compatibility, agglomeration easily occurred during the melting process, and therefore the mechanical properties were far less ideal than those of the composite material.

[0075] Figure 1 501 cm −1 The spectral band at 3443 cm⁻¹ is attributed to Zr-O vibration. −1 The absorption bands centered at 1632 cm⁻¹ are attributed to the tensile vibration of -OH, and the weak peak at 1632 cm⁻¹ is attributed to the bending vibration of -OH. CF-ZrO₂ possesses characteristic peaks of both CF and ZrO₂, indicating that the surface composite wear-resistant additive has been successfully prepared.

[0076] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A degradable high-strength wear-resistant PBAT foamed material, characterized by: It is composed of the following raw materials in parts by weight: 70 parts poly(butylene adipate / terephthalate) PBAT, 10 parts thermoplastic starch TPS, 10 parts polylactic acid PLA, 10 parts polybutylene succinate PBS, 1-4 parts composite wear-resistant agent, 5 parts plasticizer, 0.5-1 part AC foaming agent, 0.8 parts nucleating agent, 0.8 parts foaming accelerator, 8 parts crosslinking agent, and 0.2 parts lubricant; The composite wear-resistant additive is a carbon fiber-zirconia composite, and the preparation method of the composite wear-resistant additive includes the following steps: (1) Disperse zirconium oxychloride octahydrate in deionized water and stir with a magnetic stirrer at 300 rpm for 2 h at room temperature to obtain a pink solution; (2) Disperse the carbon fiber in deionized water by ultrasonication for 1 hour to ensure uniform dispersion of the carbon fiber, and then mix it with zirconium oxychloride solution; (3) Add hydrazine hydrate solution dropwise to the solution obtained in step (2) to obtain a white slurry; (4) Transfer all the white slurry obtained in step (3) to a high-pressure reactor and hydrothermally react at 180°C for 18 hours. Then wash with deionized water and anhydrous ethanol, and dry overnight to obtain a composite wear-resistant additive.

2. The degradable high-strength wear-resistant PBAT foamed material according to claim 1, characterized in that: The plasticizer is one or more of glycerol, dibutyl phthalate, and dioctyl phthalate.

3. The degradable high-strength wear-resistant PBAT foamed material according to claim 1, characterized in that: The nucleating agent is one or more combinations of calcium carbonate and talc.

4. The degradable high-strength wear-resistant PBAT foamed material according to claim 1, characterized in that: The bridging agent is dicumyl peroxide.

5. The degradable high-strength wear-resistant PBAT foamed material according to claim 1, characterized in that: The lubricant is one or more of lead stearate, calcium stearate, and stearic acid.

6. The degradable high-strength wear-resistant PBAT foamed material according to claim 1, characterized in that: The preparation method of the thermoplastic starch includes the following steps: first, drying corn starch at 70°C for 12 hours, cooling it to room temperature, then mixing the starch and plasticizer glycerin at high speed in a high-speed mixer for 30 minutes, and then sealing and letting it stand for 72 hours to obtain thermoplastic starch.

7. A process for the preparation of a degradable high-strength wear-resistant PBAT foamed material as claimed in any one of claims 1-6, characterized by: Includes the following steps: 1) Place PBAT, TPS, PBS, and PLA into a preheated internal mixer at 120℃ and mix for 10 minutes at a speed of 30 rpm. 2) Add the composite wear-resistant additive, plasticizer, AC foaming agent, nucleating agent, foaming accelerator, lubricant, and crosslinking agent to the blend obtained in step 1), and continue to mix in a mixer at 120°C for 5 minutes; 3) The blend obtained in step 2) is shredded by a shredder and then transferred to a flat vulcanizing machine for molding. The temperature of the upper and lower molds is 170℃, the pressure is 10-12MPa, the molding time is 300s, and after cooling for 360s, the mold is opened and the material is removed to obtain the biodegradable high-strength wear-resistant PBAT foam material.

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