Degradable environment-friendly tableware and preparation method thereof

Abstract

The invention relates to the technical field of degradable tableware, in particular to degradable environment-friendly tableware and a preparation method thereof. The degradable environment-friendly tableware is prepared from the following components in parts by weight: 30 to 40 parts of polylactic acid, 20 to 30 parts of polyhydroxyalkanoate, 10 to 15 parts of modified copolyester, 20 to 30 parts of modified starch and 10 to 15 parts of deionized water. The invention further provides a preparation method of the degradable environment-friendly tableware. The prepared tableware is good in biodegradation effect, beneficial to environmental protection, good in mechanical property and flame retardance, capable of effectively inhibiting bacteria and high in water resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of degradable tableware, and specifically to degradable and environmentally friendly tableware and a preparation method thereof. Background Art

[0002] At present, the main materials of disposable tableware are polypropylene and polyethylene, which have the advantages of good thermal insulation, good pressure resistance, light weight and low price. However, traditional plastic tableware made of polypropylene and polyethylene is non-degradable tableware, which will cause environmental pollution problems. Therefore, the promotion of degradable tableware has increased. Chinese patent CN1367196A discloses a formula and production method of degradable and environmentally friendly tableware, which has the advantages of waterproof and oil-proof and high degradation rate, but the products produced are fragile and have poor mechanical strength; Chinese patent 201811224083.7 discloses a degradable tableware and a preparation method thereof, which uses plant fiber pulp as the main material and easily degradable polylactic acid, stearic acid and acrylate as auxiliary materials. It is easy to degrade as a whole and can be used as organic fertilizer after degradation. It has good waterproof and oil-proof properties, but the mechanical properties of the degradable tableware are poor and its service life is shortened. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a degradable and environmentally friendly tableware and a preparation method thereof.

[0004] The present invention is achieved through the following technical solutions: A degradable and environment-friendly tableware. The raw materials for preparing the tableware include the following components in parts by weight: 30-40 parts of polylactic acid, 20-30 parts of polyhydroxyalkanoate, 10-15 parts of modified copolyester, 20-30 parts of modified starch and 10-15 parts of deionized water.

[0005] Further, the polyhydroxyalkanoate (PHA) includes but is not limited to at least one of poly-β-hydroxybutyric acid (PHB), a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV), a copolyester of 3-hydroxybutyric acid and 3-hydroxyhexanoic acid (PHBHHx), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)).

[0006] Furthermore, the raw materials for preparing the modified copolyester include the following components in parts by weight: 7-11 parts of nano zinc oxide, 8-12 parts of 3-(triethoxysilyl)propyl succinic anhydride, 15-20 parts of lactic acid, 17-23 parts of 3-hydroxybutyric acid, 6-9 parts of N-Boc-serinol, and 5-7 parts of hexachlorocyclotriphosphazene.

[0007] Furthermore, the preparation method of the modified copolyester comprises the following steps: (1) Add nano zinc oxide with a particle size of 40-50 nm to deionized water, and ultrasonicate at 300-400 W for 25-30 min to obtain dispersion A; add 3-(triethoxysilyl)propyl succinic anhydride to deionized water, and ultrasonicate at 500 W for 5-7 min to obtain dispersion B; add the dispersion B to dispersion A, stir at 25° C. for 20-30 min, stir at 120° C. for 1-1.5 h, and stir at a speed of 500-600 rpm; cool to room temperature, filter, wash the filter cake with deionized water, and vacuum dry at 60-70° C. to obtain modified zinc oxide; (2) Under nitrogen protection, the modified zinc oxide obtained in step (1), lactic acid, 3-hydroxybutyric acid and N-Boc-serinol were mixed, tetrabutyl titanate was added, and the mixture was stirred at 130-150° C. and 150-200 rpm for 5-6 h, and then the mixture was heated to 170-180° C. and 10 -3 MPa to remove water, add 10 times the weight of trifluoroacetic acid, stir at 300-400 rpm for 5-6 h, add ether twice the volume of trifluoroacetic acid, centrifuge at 5000 rpm for 20-30 min, wash the precipitate with deionized water, freeze-dry at -40 °C to obtain amino side chain copolyester; (3) The amino side chain copolyester obtained in step (2) and triethylamine are added to tetrahydrofuran and mixed evenly, and a tetrahydrofuran solution of hexachlorocyclotriphosphazene is added dropwise at a rate of 2 mL / min, and the mixture is stirred at 150-200 rpm and 70-80° C. for 4-5 h. The mixture is cooled to room temperature and filtered. The filter cake is washed with anhydrous ethanol and deionized water, and vacuum dried at 40-50° C. to obtain a modified copolyester.

[0008] Furthermore, in step (1), the mass concentration of nano zinc oxide in the dispersion A in deionized water is 1-2 mg / mL.

[0009] Furthermore, in step (1), the mass concentration of 3-(triethoxysilyl)propyl succinic anhydride in deionized water in the dispersion B is 1.6-2 mg / mL.

[0010] Furthermore, in step (2), the amount of tetrabutyl titanate used is 10-15wt% of the lactic acid.

[0011] Furthermore, in step (3), the mass concentration of the hexachlorocyclotriphosphazene in tetrahydrofuran is 50-80 mg / mL.

[0012] Furthermore, in step (3), the mass ratio of hexachlorocyclotriphosphazene to triethylamine is 4:1.

[0013] Furthermore, in step (3), the mass concentration of triethylamine in tetrahydrofuran is 20 mg / mL.

[0014] Furthermore, the raw materials for preparing the modified starch include the following components in parts by weight: 10-15 parts of corn starch, 20-30 parts of phytic acid, and 18-27 parts of cardanol.

[0015] Furthermore, the preparation method of the modified starch comprises the following steps: (a) adding phytic acid and cardanol to N,N-dimethylformamide solvent and mixing, adding 4-dimethylaminopyridine and dicyclohexylcarbodiimide, stirring at 90-100° C. and 200-300 rpm for 3-4 h, removing the solvent under reduced pressure, washing with acetone and deionized water, and drying under vacuum at 50-60° C. to obtain modified cardanol; (b) Add corn starch to deionized water, ultrasonicate at 300W for 10-15 min, stir at 200-300 rpm for 1-1.5 h, add the modified cardanol obtained in step (a), stir at 80-90°C and 500-600 rpm for 3-4 h, cool to room temperature, centrifuge at 5000 rpm for 30 min, wash the precipitate with deionized water, and freeze-dry at -40°C to obtain modified starch.

[0016] Furthermore, in step (a), the mass concentration of phytic acid in N,N-dimethylformamide is 20-30 mg / mL.

[0017] Furthermore, in step (a), the mass concentration of 4-dimethylaminopyridine in N,N-dimethylformamide is 2-3 g / L.

[0018] Furthermore, in step (a), the mass ratio of 4-dimethylaminopyridine to dicyclohexylcarbodiimide is 4-6:1.

[0019] Furthermore, in step (b), the mass fraction of the corn starch in deionized water is 10 wt %.

[0020] Furthermore, the present invention also provides a method for preparing the degradable and environmentally friendly tableware, comprising the following steps: S1: polylactic acid, polyhydroxyalkanoate, modified copolyester, modified starch and deionized water are mixed, and stirred at 50-60°C and 400-500 rpm for 15-20 min to obtain a mixed slurry; S2: injecting the mixed slurry obtained in step S1 into a mold, hot pressing at 160-180° C. and 110-140 MPa for 10-20 min, demolding after molding, and drying at 80-90° C. to obtain biodegradable and environmentally friendly tableware.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a degradable and environmentally friendly tableware and a preparation method thereof. Degradable materials are used, which are biodegradable and can reduce environmental pollution. Modified copolyester and modified starch are prepared, which are blended with polylactic acid and polyhydroxyalkanoate and cross-linked with each other to improve the mechanical properties of the tableware, make it heat-resistant and water-resistant, and can effectively resist bacteria. The invention prepares a modified copolyester. A silane coupling agent [3-(trimethoxysilyl)propyl] succinic anhydride is combined with a hydroxyl group on the surface of nano zinc oxide to graft anhydride bonds on the surface of the nano zinc oxide, which can participate in the polymerization of the copolyester, introduce the nano zinc oxide into the molecular chain of the copolyester, enhance the dispersibility of the nano zinc oxide, reduce agglomeration, and enhance the mechanical properties. Lactic acid and 3-hydroxybutyric acid are used as monomers for synthesizing the copolyester, which can improve the interface compatibility with substrates polylactic acid and polyhydroxyalkanoate, enhance the crosslinking degree, and improve the mechanical properties of tableware. When preparing the copolyester, the invention adds N-Boc-serinol containing an amino protective group, which can participate in the polymerization of the copolyester. After the polymerization, the protective group is removed to obtain a copolyester containing an amino side chain. The amino group can be combined with a chlorine atom in hexachlorocyclotriphosphazene, and the hexachlorocyclotriphosphazene is grafted on the amino copolyester to enhance the flame retardant properties. The present invention prepares modified starch, introduces phytic acid, contains phosphorus atoms, and can improve flame retardancy. The phosphate group of phytic acid can undergo esterification reaction with the phenolic hydroxyl group of cardanol. The phosphate group of phytic acid can also undergo esterification reaction with the hydroxyl group of corn starch. Cardanol can be connected to corn starch through phytic acid. Cardanol contains a long-chain hydrocarbon group, which can enhance hydrophobicity, enhance the interfacial compatibility of starch with a polylactic acid substrate and a modified copolyester, and improve mechanical properties. Phytic acid contains 6 phosphate groups, which can enhance the degree of crosslinking and improve mechanical properties. Cardanol contains double bonds, and olefinic unsaturated bonds are introduced. In a humid and oxygen-containing environment, the double bonds are more easily broken and easily decomposed by microorganisms, thereby improving degradation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 The degradation performance of the tableware described in Example 1 and Comparative Examples 1-3 of the present invention; Figure 2 The antibacterial properties of the tableware described in Example 1 and Comparative Examples 1-3 of the present invention; Figure 3 The water resistance of the tableware described in Examples 1-3 and Comparative Examples 1-3 of the present invention; Figure 4 The flame retardant properties of the tableware described in Examples 1-3 of the present invention and Comparative Examples 1-3. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention are purchased through commercial channels.

[0025] Example 1: A biodegradable and environmentally friendly tableware, prepared by raw materials including the following components in parts by weight: 40 parts of polylactic acid, 30 parts of poly-β-hydroxybutyric acid, 15 parts of modified copolyester, 30 parts of modified starch, and 15 parts of deionized water.

[0026] The raw materials for preparing the modified copolyester include the following components in parts by weight: 11 parts of nano zinc oxide, 12 parts of 3-(triethoxysilyl)propyl succinic anhydride, 20 parts of lactic acid, 23 parts of 3-hydroxybutyric acid, 9 parts of N-Boc-serinol and 7 parts of hexachlorocyclotriphosphazene.

[0027] The preparation method of the modified copolyester comprises the following steps: (1) 11 g of nano zinc oxide with a particle size of 50 nm was added to 5.5 L of deionized water and ultrasonicated at 400 W for 30 min to obtain dispersion A. 12 g of 3-(triethoxysilyl)propyl succinic anhydride was added to 6 L of deionized water and ultrasonicated at 500 W for 7 min to obtain dispersion B, which was added to dispersion A and stirred at 25 ° C for 30 min and 120 ° C for 1.5 h at a stirring speed of 600 rpm. The mixture was cooled to room temperature and filtered. The filter cake was washed with deionized water and dried in a vacuum at 70 ° C to obtain modified zinc oxide. (2) Under nitrogen protection, the modified zinc oxide obtained in step (1), 20 g of lactic acid, 23 g of 3-hydroxybutyric acid and 9 g of N-Boc-serinol were mixed, 3 g of tetrabutyl titanate was added, and the mixture was stirred at 150°C and 200 rpm for 6 h. The mixture was heated to 180°C and 10 -3 MPa to remove water, add 10 times the weight of trifluoroacetic acid, stir at 400 rpm for 6 h, add ether twice the volume of trifluoroacetic acid, centrifuge at 5000 rpm for 30 min, wash the precipitate with deionized water, freeze-dry at -40 °C to obtain amino side chain copolyester; (3) The amino side chain copolyester obtained in step (2) and 1.75 g of triethylamine were added to 87.5 mL of tetrahydrofuran and mixed evenly. 7 g of hexachlorocyclotriphosphazene and 87.5 mL of tetrahydrofuran solution were added dropwise at a rate of 2 mL / min. The mixture was stirred at 200 rpm and 80°C for 5 h. The mixture was cooled to room temperature and filtered. The filter cake was washed with anhydrous ethanol and deionized water and dried in vacuo at 50°C to obtain a modified copolyester.

[0028] The raw materials for preparing the modified starch include the following components in parts by weight: 15 parts of corn starch, 30 parts of phytic acid, and 27 parts of cardanol.

[0029] The preparation method of modified starch comprises the following steps: (a) 30 g of phytic acid and 27 g of cardanol were added to 1000 mL of N,N-dimethylformamide solvent and mixed, 3 g of 4-dimethylaminopyridine and 0.5 g of dicyclohexylcarbodiimide were added, and the mixture was stirred at 100 °C and 300 rpm for 4 h. The solvent was removed under reduced pressure, and the mixture was washed with acetone and deionized water, and dried in a vacuum at 60 °C to obtain modified cardanol; (b) 15 g corn starch was added to 135 g deionized water, ultrasonicated at 300 W for 15 min, stirred at 300 rpm for 1.5 h, the modified cardanol obtained in step (a) was added, stirred at 90 ° C and 600 rpm for 4 h, cooled to room temperature, centrifuged at 5000 rpm for 30 min, the precipitate was washed with deionized water, and freeze-dried at -40 ° C to obtain modified starch.

[0030] This embodiment also provides a method for preparing the degradable and environmentally friendly tableware, comprising the following steps: S1: 40 g of polylactic acid, 30 g of poly-β-hydroxybutyric acid, 15 g of modified copolyester, 30 g of modified starch and 15 g of deionized water were mixed, and stirred at 60°C and 500 rpm for 20 min to obtain a mixed slurry; S2: inject the mixed slurry obtained in step S1 into a mold, hot press at 180°C and 140 MPa for 10 min, demould after molding, and dry at 90°C to obtain biodegradable and environmentally friendly tableware.

[0031] Example 2: A biodegradable and environmentally friendly tableware, prepared by raw materials including the following components in parts by weight: 30 parts of polylactic acid, 20 parts of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate, 10 parts of a modified copolyester, 20 parts of modified starch, and 10 parts of deionized water.

[0032] The raw materials for preparing the modified copolyester include the following components in parts by weight: 7 parts of nano zinc oxide, 8 parts of 3-(triethoxysilyl)propyl succinic anhydride, 15 parts of lactic acid, 17 parts of 3-hydroxybutyric acid, 6 parts of N-Boc-serinol and 5 parts of hexachlorocyclotriphosphazene.

[0033] The preparation method of the modified copolyester comprises the following steps: (1) 7 g of nano zinc oxide with a particle size of 40 nm was added to 7 L of deionized water and ultrasonicated at 300 W for 25 min to obtain dispersion A. 8 g of 3-(triethoxysilyl)propyl succinic anhydride was added to 5 L of deionized water and ultrasonicated at 500 W for 5 min to obtain dispersion B, which was added to dispersion A and stirred at 25 ° C for 20 min and 120 ° C for 1 h at a stirring speed of 500 rpm. The mixture was cooled to room temperature and filtered. The filter cake was washed with deionized water and dried in a vacuum at 60 ° C to obtain modified zinc oxide. (2) Under nitrogen protection, the modified zinc oxide obtained in step (1), 15 g of lactic acid, 17 g of 3-hydroxybutyric acid and 6 g of N-Boc-serinol were mixed, 1.5 g of tetrabutyl titanate was added, and the mixture was stirred at 130°C and 150 rpm for 5 h, and then heated to 170°C and 10 -3 MPa to remove water, add 10 times the weight of trifluoroacetic acid, stir at 300 rpm for 5 h, add ether twice the volume of trifluoroacetic acid, centrifuge at 5000 rpm for 20 min, wash the precipitate with deionized water, freeze-dry at -40 °C to obtain amino side chain copolyester; (3) The amino side chain copolyester obtained in step (2) and 1.25 g of triethylamine were added to 62.5 mL of tetrahydrofuran and mixed evenly. A solution of 5 g of hexachlorocyclotriphosphazene and 100 mL of tetrahydrofuran was added dropwise at a rate of 2 mL / min. The mixture was stirred at 150 rpm and 70°C for 4 h. The mixture was cooled to room temperature and filtered. The filter cake was washed with anhydrous ethanol and deionized water and dried in vacuo at 40°C to obtain a modified copolyester.

[0034] The raw materials for preparing the modified starch include the following components in parts by weight: 10 parts of corn starch, 20 parts of phytic acid, and 18 parts of cardanol.

[0035] The preparation method of modified starch comprises the following steps: (a) 20 g of phytic acid and 18 g of cardanol were added to 1000 mL of N,N-dimethylformamide solvent, 2 g of 4-dimethylaminopyridine and 0.5 g of dicyclohexylcarbodiimide were added, and the mixture was stirred at 90 °C and 200 rpm for 3 h. The solvent was removed under reduced pressure, and the mixture was washed with acetone and deionized water, and dried under vacuum at 50 °C to obtain modified cardanol. (b) 10 g corn starch was added to 90 g deionized water, ultrasonicated at 300 W for 10 min, stirred at 200 rpm for 1 h, the modified cardanol obtained in step (a) was added, stirred at 80 ° C and 500 rpm for 3 h, cooled to room temperature, centrifuged at 5000 rpm for 30 min, the precipitate was washed with deionized water, and freeze-dried at -40 ° C to obtain modified starch.

[0036] This embodiment also provides a method for preparing the degradable and environmentally friendly tableware, comprising the following steps: S1: 30 g of polylactic acid, 20 g of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate, 10 g of a modified copolyester, 20 g of a modified starch and 8 g of deionized water were mixed, and stirred at 50°C and 400 rpm for 15 min to obtain a mixed slurry; S2: inject the mixed slurry obtained in step S1 into a mold, hot press at 160°C and 110 MPa for 20 min, demould after molding, and dry at 80°C to obtain biodegradable and environmentally friendly tableware.

[0037] Example 3: A biodegradable and environmentally friendly tableware, prepared by raw materials including the following components in parts by weight: 35 parts of polylactic acid, 25 parts of copolyester of 3-hydroxybutyric acid and 3-hydroxyhexanoic acid, 12 parts of modified copolyester, 25 parts of modified starch, and 12 parts of deionized water.

[0038] The raw materials for preparing the modified copolyester include the following components in parts by weight: 10 parts of nano zinc oxide, 10 parts of 3-(triethoxysilyl)propyl succinic anhydride, 18 parts of lactic acid, 20 parts of 3-hydroxybutyric acid, 8 parts of N-Boc-serinol and 6 parts of hexachlorocyclotriphosphazene.

[0039] The preparation method of the modified copolyester comprises the following steps: (1) 10 g of nano zinc oxide with a particle size of 45 nm was added to 6 L of deionized water and ultrasonicated at 350 W for 28 min to obtain dispersion A. 10 g of 3-(triethoxysilyl)propyl succinic anhydride was added to 6 L of deionized water and ultrasonicated at 500 W for 6 min to obtain dispersion B, which was added to dispersion A and stirred at 25 ° C for 25 min and 120 ° C for 1.2 h at a stirring speed of 550 rpm. The mixture was cooled to room temperature and filtered. The filter cake was washed with deionized water and dried in a vacuum at 65 ° C to obtain modified zinc oxide. (2) Under nitrogen protection, the modified zinc oxide obtained in step (1), 18 g of lactic acid, 20 g of 3-hydroxybutyric acid and 8 g of N-Boc-serinol were mixed, 2.16 g of tetrabutyl titanate was added, and the mixture was stirred at 140°C and 180 rpm for 5.5 h, and then heated to 175°C and 10 - 3 MPa to remove water, add 10 times the weight of trifluoroacetic acid, stir at 350 rpm for 5.5 h, add ether twice the volume of trifluoroacetic acid, centrifuge at 5000 rpm for 25 min, wash the precipitate with deionized water, freeze-dry at -40 °C to obtain amino side chain copolyester; (3) The amino side chain copolyester obtained in step (2) and 1.5 g of triethylamine were added to 75 mL of tetrahydrofuran and mixed evenly. A solution of 6 g of hexachlorocyclotriphosphazene and 100 mL of tetrahydrofuran was added dropwise at a rate of 2 mL / min. The mixture was stirred at 180 rpm and 75°C for 4.5 h. The mixture was cooled to room temperature and filtered. The filter cake was washed with anhydrous ethanol and deionized water and dried in vacuo at 45°C to obtain a modified copolyester.

[0040] The raw materials for preparing the modified starch include the following components in parts by weight: 12 parts of corn starch, 25 parts of phytic acid, and 23 parts of cardanol.

[0041] The preparation method of modified starch comprises the following steps: (a) 25 g of phytic acid and 23 g of cardanol were added to 1000 mL of N,N-dimethylformamide solvent and mixed, 2.5 g of 4-dimethylaminopyridine and 0.5 g of dicyclohexylcarbodiimide were added, and the mixture was stirred at 95 °C and 250 rpm for 3.5 h. The solvent was removed under reduced pressure, and the mixture was washed with acetone and deionized water, and dried under vacuum at 55 °C to obtain modified cardanol; (b) 12 g corn starch was added to 108 g deionized water, ultrasonicated at 300 W for 12 min, stirred at 250 rpm for 1.2 h, the modified cardanol obtained in step (a) was added, stirred at 85 ° C and 550 rpm for 3.5 h, cooled to room temperature, centrifuged at 5000 rpm for 30 min, the precipitate was washed with deionized water, and freeze-dried at -40 ° C to obtain modified starch.

[0042] This embodiment also provides a method for preparing the degradable and environmentally friendly tableware, comprising the following steps: S1: 35 g of polylactic acid, 25 g of copolyester of 3-hydroxybutyric acid and 3-hydroxyhexanoic acid, 12 g of modified copolyester, 25 g of modified starch and 10 g of deionized water were mixed, and stirred at 55°C and 450 rpm for 18 min to obtain a mixed slurry; S2: inject the mixed slurry obtained in step S1 into a mold, hot press at 170°C and 120 MPa for 15 min, demould after molding, and dry at 85°C to obtain biodegradable and environmentally friendly tableware.

[0043] The only difference between Comparative Example 1 and Example 1 is that no modified nano zinc oxide is added.

[0044] The difference between Comparative Example 2 and Example 1 is that step (3) is not performed and the amino side chain copolyester is used instead of the modified copolyester.

[0045] The only difference between Comparative Example 3 and Example 1 is that corn starch is used instead of modified corn starch.

[0046] Experimental Example 1: Referring to the method of national standard GB / T19277.1-2011 "Determination of the final aerobic biodegradability of materials under controlled composting conditions using the method of measuring the released carbon dioxide Part 1: General method", the biodegradation rate of the material is expressed by the ratio of the actual carbon dioxide release to its theoretical maximum release. The test was carried out at 58°C, and the dry weight ratio of the compost and the test material in each compost container was about 6:1; the degradation performance of the degradable and environmentally friendly tableware prepared in Example 1 and Comparative Examples 1-3 was tested, and the carbon dioxide release of the material was measured after 0, 3, 7, 15, 30, and 45 days, and the biodegradation rate was calculated. The results are as follows: Figure 1 shown.

[0047] Figure 1 The results show that the biodegradable and environmentally friendly tableware obtained in Example 1 has a biodegradation rate of more than 75% after 45 days, which is better than Comparative Examples 1-3. Comparative Example 1 does not introduce nano zinc oxide, and the degradation rate decreases. Comparative Examples 2 and 3 do not introduce hexachlorocyclotriphosphazene and cardanol, and the biodegradation rates decrease. The degradable and environmentally friendly tableware of the present invention has good biodegradability, can reduce pollution, and is beneficial to environmental protection.

[0048] Experimental Example 2: Referring to the method of GB / T1843-2008, the impact strength of the biodegradable and environmentally friendly tableware samples of Example 1 and Comparative Examples 1-3 was measured; referring to the method of GB / T1040-2006, the tensile strength was tested, and the results are shown in Table 1.

[0049] Table 1:

[0050] The results in Table 1 show that the tensile strength and impact strength of Example 1 are higher than those of Comparative Examples 1-3. Example 1 has higher mechanical properties than Comparative Examples 1-3. Comparative Example 1 does not add nano zinc oxide, lacks filler, and has reduced mechanical properties. Comparative Example 2 does not introduce hexachlorocyclotriphosphazene, and Comparative Example 3 does not introduce phytic acid and cardanol, so the interface compatibility is reduced, the degree of crosslinking is reduced, and the mechanical properties are reduced.

[0051] Experimental Example 3: Referring to the method of GB / T31402-2015, the antibacterial rates of the biodegradable and environmentally friendly tableware samples of Example 1 and Comparative Examples 1-3 were determined. The experimental bacteria were Staphylococcus aureus and Escherichia coli. The results are as follows: Figure 2 shown.

[0052] Figure 2 The results show that the antibacterial properties of Examples 1-3 are better than those of Comparative Examples 1-3. Comparative Example 1 does not add nano zinc oxide with antibacterial properties, and the antibacterial properties are reduced. Comparative Example 2 does not introduce hexachlorocyclotriphosphazene, which has little effect on the antibacterial properties. Comparative Example 3 does not introduce cardanol, and the antibacterial properties are reduced.

[0053] Experimental Example 4: Weigh the mass of the biodegradable and environmentally friendly tableware samples of Examples 1-3 and Comparative Examples 1-3, and record it as G1. Then add 100 mL of 95°C water to the tableware samples, let them stand for 30 minutes, pour them out, absorb the excess water with filter paper, and weigh the samples again, and record it as G2. The weight difference between G2 and G1 is the water absorption. The results are as follows: Figure 3 shown.

[0054] Figure 3 The results show that Examples 1-3 have better water resistance than Comparative Examples 1-3. Comparative Example 1 does not add nano zinc oxide, the degree of crosslinking decreases, and the hydrophobicity decreases. Comparative Example 2 does not introduce hexachlorocyclotriphosphazene, the hydrophobicity decreases, and the water resistance decreases. Comparative Example 3 uses corn starch instead of modified corn starch, does not introduce cardanol, the hydrophobicity decreases, the interfacial compatibility decreases, and the water resistance decreases.

[0055] Experimental Example 5: Flame retardant properties Using ASTM D2863-2017a as the experimental standard, the limiting oxygen index of the sample was measured. The results are as follows Figure 4 shown.

[0056] Figure 4 The results show that the flame retardant properties of Examples 1-3 are better than those of Comparative Examples 1-3. Comparative Example 1 does not add nano zinc oxide, Comparative Example 2 does not introduce hexachlorocyclotriphosphazene, and Comparative Example 3 does not introduce phytic acid. The crosslinking strength decreases, the mechanical properties decrease, and the flame retardancy decreases.

[0057] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A degradable and environmentally friendly tableware, characterized in that: The raw materials for preparation include the following components in parts by weight: 30-40 parts of polylactic acid, 20-30 parts of polyhydroxyalkanoate, 10-15 parts of modified copolyester, 20-30 parts of modified starch, and 10-15 parts of deionized water; The raw materials for preparing the modified copolyester include the following components in parts by weight: 7-11 parts of nano zinc oxide, 8-12 parts of 3-(triethoxysilyl)propyl succinic anhydride, 15-20 parts of lactic acid, 17-23 parts of 3-hydroxybutyric acid, 6-9 parts of N-Boc-serinol, and 5-7 parts of hexachlorocyclotriphosphazene; The preparation method of the modified copolyester comprises the following steps: (1) adding nano zinc oxide to deionized water, ultrasonicating, to obtain dispersion A, adding 3-(triethoxysilyl)propyl succinic anhydride to deionized water, ultrasonicating, to obtain dispersion B, adding the dispersion B to dispersion A, stirring, cooling, filtering, washing the filter cake with deionized water, and drying to obtain modified zinc oxide; (2) under nitrogen protection, the modified zinc oxide obtained in step (1), lactic acid, 3-hydroxybutyric acid and N-Boc-serinol are mixed, tetrabutyl titanate is added, stirred, the temperature is increased to remove water, the mixture is added to trifluoroacetic acid, stirred, ether is added, centrifuged, the precipitate is washed with deionized water, and freeze-dried to obtain an amino side chain copolyester; (3) adding the amino side chain copolyester obtained in step (2) and triethylamine to tetrahydrofuran and mixing evenly, adding dropwise a tetrahydrofuran solution of hexachlorocyclotriphosphazene, stirring to react, cooling, filtering with suction, washing the filter cake with anhydrous ethanol and deionized water, and drying to obtain a modified copolyester; The raw materials for preparing the modified starch include the following components in parts by weight: 10-15 parts of corn starch, 20-30 parts of phytic acid, and 18-27 parts of cardanol; Furthermore, the preparation method of the modified starch comprises the following steps: (a) adding phytic acid and cardanol to a solvent N,N-dimethylformamide and mixing them evenly, adding 4-dimethylaminopyridine and dicyclohexylcarbodiimide, stirring, removing the solvent under reduced pressure, washing, and drying to obtain modified cardanol; (b) adding corn starch to deionized water, ultrasonicating, stirring, adding the modified cardanol obtained in step (a), stirring, cooling, centrifuging, washing the precipitate, and freeze-drying to obtain modified starch.

2. The degradable and environmentally friendly tableware according to claim 1, characterized in that: In step (1), the mass concentration of nano zinc oxide in deionized water in the dispersion A is 1-2 mg / mL; the mass concentration of 3-(triethoxysilyl)propyl succinic anhydride in deionized water in the dispersion B is 1.6-2 mg / mL.

3. The degradable and environmentally friendly tableware according to claim 2, characterized in that: In step (2), the amount of tetrabutyl titanate used is 10-15wt% of lactic acid.

4. The degradable and environmentally friendly tableware according to claim 3, characterized in that: In step (3), the mass concentration of hexachlorocyclotriphosphazene in tetrahydrofuran is 50-80 mg / mL; the mass ratio of hexachlorocyclotriphosphazene to triethylamine is 4:1; and the mass concentration of triethylamine in tetrahydrofuran is 20 mg / mL.

5. The degradable and environmentally friendly tableware according to claim 4, characterized in that: In step (a), the mass concentration of phytic acid in N,N-dimethylformamide is 20-30 mg / mL; the mass concentration of 4-dimethylaminopyridine in N,N-dimethylformamide is 2-3 g / L; and the mass ratio of 4-dimethylaminopyridine to dicyclohexylcarbodiimide is 4-6:

1.

6. The degradable and environmentally friendly tableware according to claim 5, characterized in that: In step (b), the mass fraction of the corn starch in deionized water is 10wt%.

7. A method for preparing the degradable and environmentally friendly tableware according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: mixing polylactic acid, polyhydroxyalkanoate, modified copolyester, modified starch and deionized water, stirring to obtain a mixed slurry; S2: injecting the mixed slurry obtained in step S1 into a mold, demoulding after hot pressing, and drying to obtain biodegradable and environmentally friendly tableware.

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