CN114230993B

CN114230993B - Biodegradable PHBH-based composite material and preparation method thereof

Info

Publication number: CN114230993B
Application number: CN202210109583.6A
Authority: CN
Inventors: 张青; 刘会媛; 陈伟; 舒世立
Original assignee: Tangshan Normal University
Current assignee: Tangshan Normal University
Priority date: 2022-01-28
Filing date: 2022-01-28
Publication date: 2023-06-16
Anticipated expiration: 2042-01-28
Also published as: CN114230993A

Abstract

The invention relates to a biodegradable PHBH-based composite material and a preparation method thereof. The composition is as follows: 100 parts of modified PHBH, 10-25 parts of PBAT, 3-8 parts of PMSt-GMA, 10-25 parts of thermoplastic sesbania gum, 1 part of 1,3:2, 4-di (p-methyl benzylidene) sorbitol, 2-15 parts of plasticizer and 0.2-0.5 part of lubricant. The preparation process comprises the following steps: under the catalysis of stannous octoate, a blocking agent maleic anhydride is adopted to modify PHBH. The thermoplastic sesbania gum is prepared by taking pentaerythritol as a plasticizer. After premixing the components, adding the components into a double-screw extrusion granulator for melt mixing, extruding and granulating. The invention discloses a method for preparing the same; three main components in the composite material belong to the following components; the environment-friendly polymer material can be completely biodegraded. The composite material has low cost, good mechanical property, thermal stability and degradation performance, and is suitable for manufacturing plastic products such as disposable tableware, packaging materials, plates and the like.

Description

Biodegradable PHBH-based composite material and preparation method thereof

Technical Field

The invention relates to the technical field of environment-friendly high polymer materials, in particular to a biodegradable PHBH-based composite material and a preparation method thereof.

Background

PHBH (fully called poly (3-hydroxybutyrate-co-3-hydroxycaproate)) is a thermoplastic aliphatic polyester synthesized by microorganisms as an energy source and a carbon source for storage when carbon and nitrogen are unbalanced, and has the advantages of no toxicity, high gas barrier property, excellent biocompatibility and biodegradability, and capability of being completely degraded into water and carbon dioxide under the action of microorganisms. But the mechanical property is poor, the thermal stability is low, the processing window is narrow, the thermoforming processing is difficult when the ceramic material is used alone, and the slow crystallization speed prolongs the processing and forming period. The thermal stability of PHBH can be improved by end-capping modification. And the polymer is blended with the polymer polybutylene adipate-co-polybutylene terephthalate which is biodegradable, so that the advantages of the respective characteristics are complemented.

PBAT (fully called polybutylene adipate-co-polybutylene terephthalate) is a fully biodegradable aromatic polyester, is a copolymer of polybutylene adipate (PBA) and polybutylene terephthalate (PBT), and has a structure comprising flexible aliphatic chains and rigid aromatic chains, so that the PBAT has both the ductility and the flexibility of the PBA chain segment and the heat resistance and the impact resistance of the PBT chain segment. PBAT can be used to prepare thin film type articles due to its excellent film forming properties and high melt strength. Chinese patent CN 104559087B and CN 103087484B respectively invent a high-barrier full-biodegradable mulch film and a biodegradable composite film material with controllable degradation rate, the related main raw materials are PBAT, PPC, PBS, PLA, PHBH and the like, wherein the flexible PBAT, PPC and PBS occupy larger proportion in the formula, and the prepared film has extremely high elongation at break, and the transverse elongation at break can be up to 764 percent. However, both the zippered degradation of PPC and the unmodified PHBH reduce the thermal stability of the film, and the presence of a large number of aromatic PBT chain segments results in a relatively slow degradation rate of only 23-73% after 30 days of soil burying.

SG (sesbania gum) is a natural polysaccharide polymer compound extracted from seed endosperm of sesbania of leguminous plant, and its main components are D-galactose and D-mannose. Sesbania is planted in large areas in the places such as Zhejiang and Henan in China, and has rich sources, no toxicity and low price. The SG can reduce the production cost of the composite material, provide necessary nutrient sources for microorganism metabolism, promote the growth and propagation of microorganisms to a certain extent, and further accelerate the degradation of the composite material. But SG molecules are mutually associated by hydrogen bonds, and the plasticity is poor. Thermoplastic SG can be prepared by melt plasticizing SG with pentaerythritol.

Disclosure of Invention

Aiming at the defects of poor mechanical property, low thermal stability, high price, slow degradation and the like of the existing PHBH and PBAT, the invention provides the PHBH/PBAT/SG composite material which is environment-friendly, low in cost and good in mechanical property, thermal stability and biodegradability.

In order to achieve the aim of the invention, the technical scheme adopted by the invention is as follows:

a biodegradable PHBH-based composite material comprises the following components: 100 parts of modified poly (3-hydroxybutyrate-co-3-hydroxycaproate), 10-25 parts of polybutylene adipate-co-polybutylene terephthalate, 3-8 parts of poly (alpha-methylstyrene-co-glycidyl methacrylate), 10-25 parts of thermoplastic sesbania gum, 1,3: 1 part of 2, 4-di (p-methyl benzylidene) sorbitol, 2-15 parts of plasticizer and 0.2-0.5 part of lubricant.

Compared with the prior art, the main components of the invention belong to biodegradable polymers, are nontoxic and environment-friendly, can be completely degraded into carbon dioxide and water under the action of microorganisms, and can not pollute the environment. The PHBH/PBAT/SG composite material is suitable for manufacturing plastic products such as disposable tableware, packaging materials, plates and the like through molding processes such as injection molding, blow molding, compression molding and the like.

The preferred scheme of the invention is as follows:

the preparation method of the modified poly (3-hydroxybutyrate-co-3-hydroxycaproate) comprises the following steps: premixing poly (3-hydroxybutyrate-co-3-hydroxycaproate), maleic anhydride and stannous octoate in a high-speed mixer for 10min, adding the mixture into a double-screw extrusion granulator for extrusion granulation, and setting the temperature of each area of the extruder to be 150-170 ℃; the mass ratio of the poly (3-hydroxybutyrate-co-3-hydroxycaproate) to the maleic anhydride is 100:0.5-5, and the mass ratio of the poly (3-hydroxybutyrate-co-3-hydroxycaproate) to the stannous octoate is 100:0.2-3.

The weight average molecular weight of the poly (3-hydroxybutyrate-co-3-hydroxycaproate) is 30 ten thousand to 80 ten thousand.

The weight average molecular weight of the polybutylene adipate-co-polybutylene terephthalate is 15 ten thousand to 35 ten thousand.

The epoxy value of the poly (alpha-methylstyrene-co-glycidyl methacrylate) is 0.05 to 0.1mol/100g.

The preparation method of the thermoplastic sesbania gum comprises the following steps: the sesbania gum and pentaerythritol with the mass ratio of 10:2-6 are premixed for 5-10 min by a high-speed mixer, the premix is added into a double-screw extrusion granulator for melt plasticization and extrusion granulation, and the temperature of each area of the extruder is set to 125-155 ℃.

The plasticizer is one of diisooctyl phthalate, epoxidized butyl oleate and propylene glycol sebacate polyester.

The lubricant is one or a mixture of zinc stearate and polyethylene wax.

The preparation method of the biodegradable PHBH-based composite material adopts the following technical scheme: the preparation method of the biodegradable PHBH-based composite material comprises the following steps: modified poly (3-hydroxybutyrate-co-3-hydroxycaproate), polybutylene adipate-co-polybutylene terephthalate, poly (alpha-methylstyrene-co-glycidyl methacrylate), thermoplastic sesbania gum, 1,3:2, 4-di (p-methyl benzylidene) sorbitol, a plasticizer and a lubricant are stirred in a high-speed mixer for 8-15 min, then are put into a hopper of a double-screw extrusion granulator, and are extruded and granulated after melt blending.

The modified PHBH, PBAT, poly (alpha-methylstyrene-co-glycidyl methacrylate) (PMSt-GMA) and thermoplastic SG are subjected to melt blending, and a series of composite materials with different degradation periods, high thermal stability and strength and toughness are obtained by controlling the component ratio.

In order to improve the thermal stability of PHBH, maleic anhydride is utilized to carry out end-capping modification on the PHBH under the catalysis of stannous octoate, the modified PHBH can carry out transesterification reaction with PBAT, and the generated copolymer can also play the role of an in-situ compatibilizer. In order to further improve the interfacial compatibility between the modified PHBH and the PBAT, PMSt-GMA with a certain epoxy value is added to carry out chain extension and capacity extension on the modified PHBH and the PBAT, and epoxy groups in the structure can react with terminal hydroxyl groups and carboxyl groups of the modified PHBH and the PBAT, so that the compatibility between components of a blending system is improved. Aiming at the problem of slow PHBH crystallization, nucleating agents 1 and 3 are added: 2, 4-bis (p-methylbenzylidene) sorbitol. In consideration of the problems of high production cost of the components of the composite material and slow degradation rate of the PBAT, the microbial nutrition source and the natural polysaccharide thermoplastic SG are added into the blend, so that the cost of the composite material can be reduced, and the biodegradation rate of the composite material can be improved.

Detailed Description

Example 1

3000g PHBH, 30g maleic anhydride and 20g stannous octoate are premixed in a high-speed mixer for 10min and then added into a double-screw extrusion granulator for extrusion granulation, so as to obtain the modified PHBH. The temperatures of each section from the feeding area to the die opening of the double-screw extruder are respectively as follows: 150 ℃,155 ℃,160 ℃,160 ℃,158 ℃,155 ℃, the rotation speed of a host machine is 85rpm, and the feeding rotation speed is 8.2rpm.

400g of sesbania gum and 180g of pentaerythritol are premixed for 8min under the action of a high-speed mixer, and the premixed materials are added into a double-screw extrusion granulator for melt plasticization and extrusion, so that the thermoplastic sesbania gum is obtained. The temperatures of each section from the feeding area to the die opening of the double-screw extruder are respectively as follows: 130 ℃,135 ℃,140 ℃,140 ℃,140 ℃,138 ℃, the rotation speed of the host machine is 85rpm, and the feeding rotation speed is 8.2rpm.

2500g of modified PHBH, 500g of PBAT, 120g of PMSt-GMA, 300g of thermoplastic sesbania gum, 25g of 1,3:2, 4-bis (p-methylbenzylidene) sorbitol, 250g of diisooctyl phthalate and 8g of zinc stearate were added to a high speed mixer and stirred for 10 minutes to form a premix. After the premixed material is cooled to room temperature, the premixed material is added into a hopper of a double-screw extruder, and extruded and granulated after melt blending. The temperatures of all sections fed to the die of the double-screw extruder are respectively as follows: 146 ℃,146 ℃,150 ℃,150 ℃,150 ℃,148 ℃, the rotation speed of a host machine is 105rpm, and the feeding rotation speed is 10rpm.

Example 2

3500g PHBH, 60g maleic anhydride and 50g stannous octoate are premixed in a high-speed mixer for 10min and then added into a double-screw extrusion granulator for extrusion granulation, thus obtaining the modified PHBH. The temperatures of each section from the feeding area to the die opening of the double-screw extruder are respectively as follows: 152 ℃,155 ℃,158 ℃,162 ℃,162 ℃,165 ℃,162 ℃, and the main machine rotating speed is 95rpm, and the feeding rotating speed is 9.3rpm.

600g sesbania gum and 250g pentaerythritol are premixed for 10min under the action of a high-speed mixer and oxidized soybean oil, and the premixed materials are added into a double-screw extrusion granulator for melt plasticization and extrusion, so that the thermoplastic sesbania gum is obtained. The temperatures of each section from the feeding area to the die opening of the double-screw extruder are respectively as follows: 135 ℃,138 ℃,140 ℃,140 ℃,142 ℃,142 ℃,140 ℃, the rotation speed of the host machine is 95rpm, and the feeding rotation speed is 9.3rpm.

3000g of modified PHBH, 620gPBAT, 180g of PMSt-GMA, 500g of thermoplastic sesbania gum, 30g of 1,3:2, 4-bis (p-methylbenzylidene) sorbitol, 260g of propylene glycol sebacate polyester, and 12g of zinc stearate were added to a high speed mixer and stirred for 10 minutes to form a premix. After the premixed material is cooled to room temperature, the premixed material is added into a hopper of a double-screw extruder, and extruded and granulated after melt blending. The temperatures of all sections fed to the die of the double-screw extruder are respectively as follows: 148 ℃,148 ℃,152 ℃,152 ℃,152 ℃,149 ℃, the rotation speed of the host machine is 98rpm, and the feeding rotation speed is 9.5rpm.

Example 3

3200g PHBH, 55g maleic anhydride and 35g stannous octoate are premixed in a high-speed mixer for 10min and then added into a double-screw extrusion granulator for extrusion granulation, so as to obtain the modified PHBH. The temperatures of each section from the feeding area to the die opening of the double-screw extruder are respectively as follows: 155 ℃,155 ℃,158 ℃,160 ℃,162 ℃,160 ℃,158 ℃, the rotation speed of a host machine is 110rpm, and the feeding rotation speed is 10.5rpm.

600g sesbania gum and 320g pentaerythritol are premixed for 8min under the action of a high-speed mixer, and the premixed materials are added into a double-screw extrusion granulator for melt plasticization and extrusion, so that the thermoplastic sesbania gum is obtained. The temperatures of each section from the feeding area to the die opening of the double-screw extruder are respectively as follows: 138 ℃,138 ℃,142 ℃,142 ℃,142 ℃,140 ℃, the host rotation speed is 102rpm, and the feeding rotation speed is 9.6rpm.

2800g of modified PHBH, 560gPBAT, 150g of PMSt-GMA, 500g of thermoplastic sesbania gum, 28g of 1,3 are weighed out: 2, 4-bis (p-methylbenzylidene) sorbitol, 270g propylene glycol sebacate polyester, and 10g zinc stearate were added to a high speed mixer and stirred for 10min to form a premix. After the premixed material is cooled to room temperature, the premixed material is added into a hopper of a double-screw extruder, and extruded and granulated after melt blending. The temperatures of all sections fed to the die of the double-screw extruder are respectively as follows: 149 ℃,150 ℃,153 ℃,153 ℃,152 ℃,151 ℃, the rotation speed of the host machine is 110rpm, and the feeding rotation speed is 10.8rpm.

Example 4

3800g PHBH, 100g maleic anhydride and 35g stannous octoate are premixed in a high-speed mixer for 10min and then added into a double-screw extrusion granulator for extrusion granulation, thus obtaining the modified PHBH. The temperatures of each section from the feeding area to the die opening of the double-screw extruder are respectively as follows: 155 ℃,155 ℃,160 ℃,160 ℃,162 ℃,160 ℃, the rotation speed of a host machine is 115rpm, and the feeding rotation speed is 11rpm.

750g sesbania gum and 400g epoxidized soybean oil are premixed for 9min under the action of a high-speed mixer, and the premixed materials are added into a double-screw extrusion granulator for melt plasticization and extrusion, so that the thermoplastic sesbania gum is obtained. The temperatures of each section from the feeding area to the die opening of the double-screw extruder are respectively as follows: 135 ℃,140 ℃,145 ℃,145 ℃,148 ℃,148 ℃,145 ℃, the host rotation speed is 98rpm, and the feeding rotation speed is 9.3rpm.

3500g of modified PHBH, 750g of PBAT, 200g of PMSt-GMA, 700g of thermoplastic sesbania gum and 35g of 1,3 are weighed out: 2, 4-bis (p-methylbenzylidene) sorbitol, 360g of diisooctyl phthalate and 12g of zinc stearate were added to a high speed mixer and stirred for 10 minutes to form a premix. After the premixed material is cooled to room temperature, the premixed material is added into a hopper of a double-screw extruder, and extruded and granulated after melt blending. The temperatures of all sections fed to the die of the double-screw extruder are respectively as follows: 147 ℃,147 ℃,150 ℃,150 ℃,150 ℃,149 ℃, the rotation speed of the host machine is 105rpm, and the feeding rotation speed is 9.8rpm.

Comparative example 1

600g of polylactic acid, 100g of PHBH, 300g of PBAT, 50g of ethylene-glycidyl methacrylate copolymer, 50g of talcum powder, 100g of tributyl citrate and 5g of oleamide are weighed and added to a high-speed mixer to be mixed for 20min. Adding the mixed raw materials into a double-screw extruder, and feeding the raw materials into the die at the following temperatures: 120 ℃,120 ℃,160 ℃,160 ℃,165 ℃,165 ℃,155 ℃, the rotation speed of a host machine is 100rpm, and the feeding rotation speed is 9.5rpm. Extruding and granulating by a double-screw extruder, and drying for later use.

Comparative example 2

450g PHBH, 350g polylactic acid, 150g mica, 2g1010 antioxidant, 5g calcium zinc stabilizer, 500mL white oil, 3g paraffin wax, 30g compatilizer (PHBH grafted fumaric anhydride polymer) and 10g ethylene bis stearamide are weighed, and added into a high-speed mixer for mixing for 3min. The mixed materials are added into a double-screw extruder, the feeding section is set to 125 ℃, the compression section is set to 140 ℃, the homogenization temperature is set to 130 ℃, the die temperature is set to 150 ℃, and the rotating speed of a host machine is 250rpm. Extruding and granulating by a double-screw extruder, and drying for later use.

The test process and test results of the modified PHBH/PBAT/thermoplastic sesbania gum composite material of the invention are described below.

Mechanical property test: preparing the samples into dumbbell-shaped sample bars, testing the tensile properties of the dumbbell-shaped sample bars by adopting an electronic universal tester according to the requirements of GB/T1040.1-2006, and taking an average value of 5 samples measured in each group, wherein the tensile speed is 10mm/min. Samples were prepared as rectangular bars and subjected to the unnotched impact test according to GB/T1843-2008 with an impact energy of 5J, and the average value was taken for each group of 5 samples.

Thermal stability test: taking the temperature at which the sample is decomposed by 5% as the thermal decomposition temperature, weighing 5-10 mg of the sample by adopting a thermogravimetric analyzer (TGA), carrying out under a nitrogen atmosphere, heating to 800 ℃ at the heating rate of 20 ℃/min, wherein the flow rate of the nitrogen is 10 mL/min. The softening point of the sample is tested by using a Vicat tester, the test weight is 10N according to the ASTM D1525-07 test standard, and the temperature rising rate is 120 ℃/h.

Degradation performance test: the sample is rolled and molded into a membrane with the thickness of about 0.2mm at the temperature of 150-160 ℃ and a soil suspension culture degradation test method is adopted. After 175h the sample membrane was removed and treated with 75% aqueous ethanol. Repeatedly cleaning with distilled water, and vacuum drying to constant weight. The weight change of the film was detected.

TABLE 1 results of Performance test of examples 1-4 and comparative examples 1-2

Claims

1. A biodegradable PHBH-based composite material is characterized in that the composite material comprises the following components: 100 parts of modified poly (3-hydroxybutyrate-co-3-hydroxycaproate), 10-25 parts of polybutylene adipate-co-polybutylene terephthalate, 3-8 parts of poly (alpha-methylstyrene-co-glycidyl methacrylate), 10-25 parts of thermoplastic sesbania gum, 1 part of 1,3:2, 4-di (p-methylbenzylidene) sorbitol, 2-15 parts of plasticizer and 0.2-0.5 part of lubricant; the preparation method of the modified poly (3-hydroxybutyrate-co-3-hydroxycaproate) comprises the following steps: premixing poly (3-hydroxybutyrate-co-3-hydroxycaproate), maleic anhydride and stannous octoate in a high-speed mixer for 10min, adding the mixture into a double-screw extrusion granulator for extrusion granulation, and setting the temperature of each area of the extruder to be 150-170 ℃; the mass ratio of the poly (3-hydroxybutyrate-co-3-hydroxycaproate) to the maleic anhydride is 100:0.5-5, and the mass ratio of the poly (3-hydroxybutyrate-co-3-hydroxycaproate) to the stannous octoate is 100:0.2-3; the preparation method of the thermoplastic sesbania gum comprises the following steps: the mass ratio is 10: 2-6 sesbania gum and pentaerythritol are premixed for 5-10 min by a high-speed mixer, and then the premix is added into a double-screw extrusion granulator for melting plasticization and extrusion granulation, and the temperature of each area of the extruder is set to be 125-155 ℃.

2. The biodegradable PHBH-based composite of claim 1, wherein the poly (3-hydroxybutyrate-co-3-hydroxycaproate) has a weight average molecular weight of 30-80 tens of thousands.

3. The biodegradable PHBH-based composite material according to claim 2, characterized in that the weight average molecular weight of polybutylene adipate-co-polybutylene terephthalate is 15-35 ten thousand.

4. The biodegradable PHBH-based composite according to claim 1, characterized in that: the epoxy value of the poly (alpha-methylstyrene-co-glycidyl methacrylate) is 0.05-0.1 mol/100g.

5. The biodegradable PHBH-based composite according to claim 1, wherein the plasticizer is one of diisooctyl phthalate, epoxidized butyl oleate, propylene glycol sebacate polyester.

6. The biodegradable PHBH-based composite according to claim 1, characterized in that said lubricant is one or a mixture of both zinc stearate, polyethylene wax.

7. A method for preparing the biodegradable PHBH-based composite material according to any one of claims 1 to 6, comprising the steps of: modified poly (3-hydroxybutyrate-co-3-hydroxycaproate), polybutylene adipate-co-polybutylene terephthalate, poly (alpha-methylstyrene-co-glycidyl methacrylate), thermoplastic sesbania gum, 1,3:2, 4-di (p-methylbenzylidene) sorbitol, plasticizer and lubricant are stirred in a high-speed mixer for 8-15 min, and then are put into a hopper of a double-screw extrusion granulator, and extruded and granulated after melt blending.