CN115558092A - Recycling method of waste PET and biodegradable copolyester prepared by adopting recycling method - Google Patents
Recycling method of waste PET and biodegradable copolyester prepared by adopting recycling method Download PDFInfo
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- CN115558092A CN115558092A CN202211224619.1A CN202211224619A CN115558092A CN 115558092 A CN115558092 A CN 115558092A CN 202211224619 A CN202211224619 A CN 202211224619A CN 115558092 A CN115558092 A CN 115558092A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/16—Dicarboxylic acids and dihydroxy compounds
- C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
- C08G63/181—Acids containing aromatic rings
- C08G63/183—Terephthalic acids
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
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- Y02W30/62—Plastics recycling; Rubber recycling
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Abstract
The application provides a recycling method of waste PET and biodegradable copolyester prepared by the method, and relates to the technical field of biodegradable polyester plastics. The recycling method of the waste PET directly mixes the PET with the aliphatic polyester or the aliphatic polyester precursor, under the catalysis condition, the repeating unit of the aliphatic polyester or the aliphatic polyester precursor is inserted into a PET molecular chain to form a prepolymer, then, the prepolymer is polymerized under the decompression condition, and micromolecular alcohol, acid or ester compounds are generated and removed, so that the biodegradable aliphatic-aromatic copolyester is finally generated. The reaction path provided by the application does not need to carry out alcoholysis on PET into monomers or oligomers and then react with other components, so that the chemical conversion step is greatly simplified, the chemical conversion process of the waste PET is greatly simplified, 100% utilization of the waste PET is realized, and the synthesis cost can be obviously reduced.
Description
Technical Field
The application relates to the technical field of biodegradable polyester plastics, in particular to a method for recycling waste PET and biodegradable copolyester prepared by the method.
Background
Polyethylene terephthalate (PET) is the linear thermoplastic polymer which is the earliest to realize industrialization, and has the advantages of low price, transparency, air tightness, good compressive strength, low production energy consumption and good processability, so that the PET is widely used in the fields of plastic packaging bottles, films, synthetic fibers and the like. To date, the global annual production of PET has exceeded 7000 million tons, and is second only to polyethylene and polypropylene, the third largest class of plastics. However, PET molecular chains have a rigid benzene ring structure and strong hydrophobicity, and are difficult to degrade in natural environments, and thus are classified into non-degradable plastics. Currently, most PET articles are disposable consumer products, one of the most difficult plastics to recycle, and are difficult to recycle through hot melting or solution treatment. Most of the products such as waste PET bottles, films, fibers, etc. are thrown into a refuse landfill or the sea, and become a public hazard of environmental pollution.
At present, three main types of recycling modes for waste PET exist: (1) A physical recycling method, which comprises the steps of crushing PET and then reprocessing the crushed PET into lower-quality plastic products, or modifying and granulating PET bottle materials with high molecular weight to directly produce fibers with lower molecular weight, wherein the products obtained by reprocessing by the physical recycling method still belong to non-degradable types; (2) The chemical conversion method is characterized in that waste PET is converted into monomer and other small molecular raw materials by chemical conversion (comprising an alcoholysis method, a hydrolysis method, an ammonolysis method and the like), wherein the alcoholysis method and the hydrolysis method depolymerize the waste PET polyester into a monomer state by using methanol, glycol and other alcohols or water, so that the recycling of the polyester waste is realized, but because polymers exist in products at the same time, the later separation difficulty is high, and the effective conversion rate is not high; the ammonolysis method cannot utilize the ethylene glycol units in the waste PET; (3) Biodegradation method which degrades waste PET plastic into initial raw material monomer (such as ethylene terephthalate, etc.) using active enzyme in microorganism, but it has low degradation efficiency and complicated operation process.
The existing chemical conversion of waste PET needs alcoholysis to a monomer or oligomer state, then the waste PET reacts with other components, the conversion process is complex, and a simple synthetic method for directly converting the waste PET into biodegradable polyester is lacked.
Disclosure of Invention
In order to solve the problems in the prior art, the present application mainly aims to provide a recycling method of waste PET and biodegradable copolyester prepared by the same.
In order to achieve the above object, in a first aspect, the present application provides a method for recycling waste PET, including:
(1) Mixing at least one of aliphatic polyester and an aliphatic polyester precursor with PET (polyethylene terephthalate), and reacting under the catalysis of a catalyst to form a prepolymer, wherein the PET comprises at least one of waste PET and a PET finished product, and the aliphatic polyester precursor comprises a mixed system of aliphatic dihydric alcohol and aliphatic dibasic acid;
(2) And carrying out polymerization reaction on the prepolymer under the reduced pressure condition, and removing volatile compounds in a reaction system to obtain the biodegradable aliphatic-aromatic copolyester, wherein the volatile compounds comprise at least one of volatile fatty alcohol, fatty acid and ester compounds.
According to the technical scheme, PET is directly mixed with aliphatic polyester or an aliphatic polyester precursor, the repeating unit of the aliphatic polyester or the aliphatic polyester precursor is inserted into a PET molecular chain to form a prepolymer under the catalysis condition, then the prepolymer is polymerized under the decompression condition to generate a small molecular alcohol, acid or ester compound, the small molecular alcohol, acid or ester compound is removed from a reaction system by utilizing the volatility of the small molecular alcohol, acid or ester compound, and finally the biodegradable aliphatic-aromatic copolyester is generated. The reaction route provided by the application does not need to carry out alcoholysis on PET into monomers or oligomers and then react with other components, so that the chemical conversion step is greatly simplified.
As a preferred embodiment of the recycling method described herein, at least one of the esterification reaction, the alcoholic hydroxyl-ester transesterification reaction, the ester-ester transesterification reaction, and the acid carboxyl-ester transesterification reaction occurs in the step (1) under the catalysis of the catalyst to form the prepolymer.
As shown in formula (I), alcohol hydroxyl-ester transesterification utilizes alcohol and ester as reactants to produce a new alcohol and ester. The polyester is degraded into oligomer by the micromolecular alcohol, and the oligomer can be polymerized into high molecular weight polyester by removing the liquid micromolecular alcohol through fractional distillation.
The ester-ester interchange reaction is also called a chain interchange reaction as shown in formula (II), i.e., an ester-ester interchange between two molecular polyester molecular chains occurs.
As shown in formula (III), the acid carboxyl-ester transesterification utilizes carboxylic acid and ester as reactants to generate a new carboxylic acid and a new ester, namely, polyester can be degraded into oligomer through micromolecular carboxylic acid, and the oligomer can be polymerized into high molecular weight polyester through sublimation and removal of micromolecular solid carboxylic acid.
It should be noted that, when the aliphatic polyester precursor is mixed with PET in step (1), the aliphatic diol and the aliphatic diacid contained in the aliphatic polyester precursor can also directly undergo esterification reaction under catalysis to form corresponding ester substances, and meanwhile, alcoholic hydroxyl-ester transesterification, ester-ester transesterification, and acid carboxyl-ester transesterification also proceed.
When the aliphatic polyester is mixed with the PET in the step (1), the aliphatic polyester and the PET undergo ester-ester interchange reaction under catalysis.
As a preferred embodiment of the recycling method described herein, the volatile compound is generated and removed in the step (2) by at least one of an alcoholic hydroxyl-ester transesterification reaction, an ester-ester transesterification reaction, and an acid carboxyl-ester transesterification reaction.
Since the alcoholic hydroxyl-ester interchange reaction, the ester-ester interchange reaction, and the acid carboxyl-ester interchange reaction are all reversible reactions, in the polymerization reaction process of step (2), small molecular alcohol, acid, or ester compounds can be generated through the reverse reactions of the three ester interchange reactions, and the small molecular alcohol, acid, or ester compounds can be removed from the reaction system by utilizing the volatility of the small molecular alcohol, acid, or ester compounds.
For ease of understanding, the reaction mechanism involved in the recycling method of the present application will be explained below in conjunction with the reaction equation.
When the aliphatic polyester and the PET are mixed in the step (1), the corresponding reaction equation is shown as the formula (IV). It should be noted that the second step in formula (iv) utilizes the reverse reaction of the ester exchange reaction to generate the aliphatic dibasic acid, the aliphatic diol and the aliphatic ester compound, but the aliphatic ester compound has a relatively large molecular weight and cannot be volatilized and removed from the system, which is not favorable for the reverse reaction of the ester-base ester exchange reaction, and therefore, the second step in formula (iv) does not reflect the ester-base ester exchange reaction.
When mixing an aliphatic polyester precursor with PET in step (1), two situations may occur, including: the aliphatic dibasic alcohol is excessive, and the aliphatic dibasic acid is excessive.
When the aliphatic diol is excessive, the corresponding reaction equation is shown as the formula (V), when the aliphatic diol is excessive, the corresponding generated prepolymer is hydroxyl-terminated prepolymer, and the random copolymer with the end group being hydroxyl is generated after the prepolymer is polymerized.
When the aliphatic dibasic acid is in excess, the corresponding reaction equation is shown in formula (VI). When the aliphatic dibasic acid is excessive, the corresponding generated prepolymer is a carboxyl-terminated prepolymer, and a random copolymer with a carboxyl end group is generated after the prepolymer is polymerized.
In a preferred embodiment of the recycling method of the present application, the aliphatic polyester precursor is formed by esterification of the aliphatic diol and the aliphatic dibasic acid.
In the present application, the aliphatic diol may be at least one selected from the group consisting of ethylene glycol, 1, 3-malonic acid, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, diethylene glycol, polyethylene glycol, and polypropylene glycol. The aliphatic dibasic acid can be at least one of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and diglycolic acid. Accordingly, the aliphatic polyester may be selected from polyesters formed by copolymerizing the above-mentioned aliphatic diols with aliphatic dibasic acids.
In a preferred embodiment of the recycling method of the present invention, the molar ratio of the repeating unit of the aliphatic polyester to the repeating unit of the PET is 9 (1 to 81).
The inventors have found through extensive experiments that when the molar ratio of the repeating units of the aliphatic polyester to the repeating units of PET is within the above range, a copolyester having different properties and being biodegradable can be synthesized using the above reaction route proposed in the present application.
In a preferred embodiment of the recycling method of the present application, the molar ratio of the aliphatic diol to the aliphatic dibasic acid in the aliphatic polyester precursor is 6 (5 to 7.2).
As a preferred embodiment of the recycling method described herein, the catalyst includes at least one of calcium oxide, magnesium oxide, zinc oxide, tin oxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, calcium carbonate, magnesium carbonate, zinc carbonate, calcium bicarbonate, magnesium bicarbonate, calcium chloride, magnesium chloride, zinc chloride, stannous chloride, calcium acetate, magnesium acetate, zinc acetate, stannous acetate, antimony trioxide, antimony ethylene glycol, and tetrabutyl titanate.
As a preferred embodiment of the recycling method, the catalyst is used in an amount of 0.01 to 1% by mass based on the reactants.
As a preferred embodiment of the recycling method, the reaction temperature in the step (1) is 100-280 ℃, and the reaction time is 1-48 h; and
the temperature for carrying out the polymerization reaction in the step (2) is 150-300 ℃, the reaction time is 0.5-48 h, and the reaction pressure is 1-1000 Pa.
In a second aspect, the present application further provides a biodegradable aliphatic-aromatic copolyester prepared by the recycling method according to any one of the above methods.
Compared with the prior art, the beneficial effects of the application are that:
(1) The technical scheme of the application includes that PET and aliphatic polyester or an aliphatic polyester precursor are directly mixed, a repeating unit of the aliphatic polyester or the aliphatic polyester precursor is inserted into a PET molecular chain to form a prepolymer under a catalytic condition, then the prepolymer is polymerized under a decompression condition to generate a micromolecular alcohol, acid or ester compound, the micromolecular alcohol, acid or ester compound is removed from a reaction system by utilizing the volatility of the micromolecular alcohol, acid or ester compound, and finally the biodegradable aliphatic-aromatic copolyester is generated. The reaction path provided by the application does not need to carry out alcoholysis on PET into monomers or oligomers and then react with other components, so that the chemical conversion step is greatly simplified, the chemical conversion process of the waste PET is greatly simplified, 100% utilization of the waste PET is realized, and the synthesis cost can be obviously reduced.
(2) The application adopts the plastic which is synthesized by waste PET and has thermoplasticity and complete biodegradation, realizes the conversion of non-degradable PET to biodegradable plastic, solves the recovery problem, and has great significance for solving the environmental pollution.
(3) In the recycling method, different types of aliphatic polyester precursors or aliphatic polyesters can be selected, so that the corresponding comprehensive properties of the obtained biodegradable plastic, such as mechanical property, heat resistance, degradation period and the like, can be conveniently regulated and controlled.
(4) The recycling method can be directly carried out by utilizing the existing polyester production equipment, has low equipment requirement and is beneficial to the rapid popularization of the process.
Drawings
FIG. 1 is a drawing of the PEST prepolymer and PEST product of example 1 1 H nuclear magnetic resonance spectrogram;
FIG. 2 shows PEST prepolymer and PEST product of example 8 1 H nuclear magnetic resonance spectrogram;
FIG. 3 shows PEST prepolymer and PEST product of example 15 1 H nuclear magnetic resonance spectrogram.
Detailed Description
To better illustrate the objects, aspects and advantages of the present application, the present application will be further described by the following specific examples.
In the embodiments and the comparative examples of the present application, waste PET is used as a recycled raw material, the waste PET can be derived from any PET product (such as PET bottle, etc.), and because waste PET is used as a recycled raw material, in the embodiments and the comparative examples of the present application, the waste PET material can be pretreated before a feeding reaction, and the pretreatment method includes: the waste PET material is cleaned, crushed and dried.
Other chemicals used in the examples and comparative examples of the present application were all commercially available products unless otherwise specified.
Examples 1 to 7
The method for recycling waste PET disclosed in examples 1 to 7 includes the steps of:
(1) Adding a certain mass of waste PET, ethylene glycol, succinic acid (wherein the molar weight of the ethylene glycol is greater than that of the succinic acid) and ethylene glycol antimony (the dosage of the ethylene glycol antimony is 0.025 percent of the total mass of reactants) into a 250mL reaction kettle, heating to 260 ℃ under a normal pressure condition for reaction, removing water generated by the reaction through nitrogen gas flow, wherein the reaction time is 2 hours, and obtaining poly (ethylene glycol succinate-co-ethylene terephthalate), namely PEST prepolymer after the reaction is completed;
(2) And vacuumizing the PEST prepolymer to reduce the pressure to 30Pa, keeping the temperature of a reaction system at 260 ℃, then carrying out polymerization reaction for 4 hours, and obtaining random poly (ethylene succinate-co-ethylene terephthalate) with the end group of hydroxyl, namely a PEST product, after the reaction is finished.
The molar ratios of the PET repeating unit, ethylene glycol and succinic acid among the reaction materials of examples 1 to 7 are shown in table 1 below, the number average molecular weights of the PEST prepolymers obtained in step (1) of each example are shown in table 1 below, and the number average molecular weights of the PEST products obtained in step (2) of each example are shown in table 1 below.
TABLE 1 raw material composition and product condition of examples 1 to 7
Of these, the PEST prepolymer and PEST product of example 1 1 As shown in fig. 1, it can be seen from fig. 1 that the total molar ratio of alkyd units in both the prepolymer and the product is greater than 1, and thus, it can be confirmed that the end groups in the PEST prepolymer and the PEST product of example 1 are hydroxyl groups.
Examples 8 to 14
The method for recycling waste PET disclosed in examples 8 to 14 includes the steps of:
(1) Adding a certain mass of waste PET, glycol, succinic acid (wherein the molar weight of the glycol is less than that of the succinic acid) and ethylene glycol antimony (the dosage of the ethylene glycol antimony is 0.025 percent of the total mass of reactants) into a 250mL reaction kettle, heating to 260 ℃ under normal pressure to perform reaction, removing water generated by the reaction through nitrogen gas flow, wherein the reaction time is 2 hours, and obtaining poly (ethylene glycol succinate-co-ethylene terephthalate), namely PEST prepolymer, after the reaction is completed;
(2) And vacuumizing the PEST prepolymer to reduce the pressure to 30Pa, keeping the temperature of a reaction system at 260 ℃, then carrying out polymerization reaction for 4 hours, and obtaining random poly (ethylene succinate-co-ethylene terephthalate) with carboxyl as a terminal group, namely a PEST product after the reaction is finished.
The molar ratios of the PET repeating unit, ethylene glycol and succinic acid among the reaction materials of examples 8 to 14 are shown in table 2 below, the number average molecular weights of the PEST prepolymers obtained in step (1) of each example are shown in table 2 below, and the number average molecular weights of the PEST products obtained in step (2) of each example are shown in table 2 below.
TABLE 2 raw material composition and product condition of examples 8-14
Of these, the PEST prepolymer and PEST product corresponding to example 8 1 As shown in fig. 2, it can be seen from fig. 2 that the total molar ratio of alkyd units in both the prepolymer and the product is less than 1, and thus, it can be confirmed that the end groups in the PEST prepolymer and the PEST product of example 1 are carboxyl groups.
Examples 15 to 21
The method for recycling waste PET disclosed in examples 15 to 21 includes the steps of:
(1) Adding a certain mass of waste PET and polyethylene glycol succinate (PES) into a 250mL reaction kettle, heating to 260 ℃ under normal pressure, reacting, removing water generated by the reaction through nitrogen gas flow, wherein the reaction time is 2h, and obtaining poly (ethylene succinate-co-ethylene terephthalate), namely PEST prepolymer, after the reaction is finished;
(2) And vacuumizing the PEST prepolymer to reduce the pressure to 30Pa, keeping the temperature of a reaction system at 260 ℃, then carrying out ester exchange reaction for 4 hours, and obtaining poly (ethylene succinate-co-ethylene terephthalate) with a hydroxyl end group, namely a PEST product after the reaction is finished.
The molar ratios of the PET repeating units and PES in the reaction materials of examples 15 to 21 are shown in table 3 below, the number average molecular weights of the PEST prepolymers obtained in step (1) of each example are shown in table 3 below, and the number average molecular weights of the PEST products obtained in step (2) of each example are shown in table 3 below.
TABLE 3 feed composition and product conditions for examples 15-21
Of these, the PEST prepolymer and PEST product of example 15 1 The H NMR spectrum is shown in FIG. 3, since the PET block is insoluble and the PES block is soluble in chloroform, the ratio of terephthalic acid units in the spectrum is much smaller than that in the product and the prepolymer in FIG. 1, confirming that the structure of the PEST obtained is block type.
Example 22
The recycling method of the waste PET disclosed in this example is basically the same as that of example 1, except that: this example uses adipic acid instead of succinic acid as in example 1.
Example 23
The method for recycling waste PET disclosed in this example is substantially the same as that of example 1, except that: this example uses butanediol instead of ethylene glycol in example 1.
The molar ratios of the PET repeating unit, the aliphatic diol, and the aliphatic dibasic acid among the reaction materials of examples 22 to 23 are shown in table 4 below, the number average molecular weights of the PEST prepolymers obtained in step (1) of each example are shown in table 4 below, and the number average molecular weights of the PEST products obtained in step (2) of each example are shown in table 4 below.
TABLE 4 raw material composition and product condition of examples 22 to 23
Comparative examples 1 to 7
The recycling method of waste PET disclosed in comparative examples 1 to 7 includes the steps of:
waste PET and polyethylene glycol succinate (PES) with certain mass are added into an extruder, heated to 260 ℃ under the normal pressure condition, and extruded to obtain poly (ethylene succinate-co-ethylene terephthalate), namely PEST product.
The molar ratios of the PET repeating unit and PES in the reaction raw materials of comparative examples 1 to 7 are shown in table 5 below, and the number average molecular weights of the PEST products prepared in the respective examples are shown in table 5 below.
TABLE 5 raw material composition and product conditions of comparative examples 1 to 7
Experimental example 1
And (3) testing mechanical properties: the PEST products prepared in examples 1 to 23 and comparative examples 1 to 7 were injection-molded into corresponding test strips according to a unified procedure, and the tensile strength and elongation at break of the samples were measured according to the measuring method (tensile rate of 50 mm/min) specified in the ISO 527-2 plastic tensile property testing method, and the test results are shown in Table 6 below.
TABLE 6 mechanical property test results of examples 1 to 23 and comparative examples 1 to 7
As can be seen from Table 6, the mechanical properties of the biodegradable plastic can be conveniently controlled by adjusting the formula proportion and polymerization mode of each raw material (excessive aliphatic dibasic acid, excessive aliphatic dihydric alcohol and direct addition of PES). And the molecular weight and the mechanical property of the product obtained in the polymerization mode of excessive aliphatic dibasic acid, excessive aliphatic dihydric alcohol or directly adding PES are obviously superior to those of the product obtained in the blending extrusion under the same condition.
Experimental example 2
And (3) testing the degradation performance: some of the PEST products prepared in the examples and comparative examples were injection molded into corresponding test strips according to a uniform procedure, and the test specimens were molded into disks having a diameter of about 10mm and a thickness of about 0.5mm. Preparing 1U/ml sodium phosphate (0.01M, pH = 7.2-7.4) buffer solution of cholesterol esterase, filtering by a sterile filter before use, and performing degradation test at the constant temperature of 35 +/-2 ℃; the round samples prepared above were filled in 100ml vials, 50m1 enzyme solution was added, samples were taken at intervals, and the molecular weight of the samples after degradation was measured after lyophilization, the results of which are shown in table 7 below.
TABLE 7 results of biodegradability tests
As can be seen from Table 7, the present application can conveniently control the degradation period of the biodegradable plastic by adjusting the formula ratio and the polymerization mode (excessive aliphatic dibasic acid, excessive aliphatic dihydric alcohol, and direct PES addition). Meanwhile, the degradation rate of the product with excessive aliphatic dibasic acid is larger than that of the product with excessive aliphatic dibasic alcohol in the same proportion.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present application and not for limiting the protection scope of the present application, and although the present application is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present application without departing from the spirit and scope of the technical solutions of the present application.
Claims (10)
1. A method for recycling waste PET is characterized by comprising the following steps:
(1) Mixing at least one of aliphatic polyester and an aliphatic polyester precursor with PET (polyethylene terephthalate), and reacting under the catalysis of a catalyst to form a prepolymer, wherein the PET comprises at least one of waste PET and a PET finished product, and the aliphatic polyester precursor comprises a mixed system of aliphatic dihydric alcohol and aliphatic dibasic acid;
(2) And carrying out polymerization reaction on the prepolymer under the reduced pressure condition, and removing volatile compounds in a reaction system to obtain the biodegradable aliphatic-aromatic copolyester, wherein the volatile compounds comprise at least one of volatile aliphatic alcohol, fatty acid and ester compounds.
2. The method of claim 1, wherein at least one of esterification, alcoholic hydroxyl-transesterification, ester-transesterification, and acid carboxyl-ester transesterification occurs in step (1) catalyzed by the catalyst to form the prepolymer.
3. The method of claim 1, wherein said volatile compounds are generated and removed in step (2) by at least one of an alcoholic hydroxyl-ester transesterification reaction, an ester-ester transesterification reaction, and an acid carboxyl-ester transesterification reaction.
4. The method of claim 1, wherein the aliphatic diol in the aliphatic polyester precursor is esterified with the aliphatic diacid to form the aliphatic polyester.
5. The method according to claim 4, wherein the molar ratio of the repeating unit of the aliphatic polyester to the repeating unit of the PET is 9 (1-81).
6. The method according to claim 5, wherein the molar ratio of the aliphatic diol to the aliphatic dibasic acid in the aliphatic polyester precursor is 6 (5-7.2).
7. The method of claim 1, wherein the catalyst comprises at least one of calcium oxide, magnesium oxide, zinc oxide, tin oxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, calcium carbonate, magnesium carbonate, zinc carbonate, calcium bicarbonate, magnesium bicarbonate, calcium chloride, magnesium chloride, zinc chloride, stannous chloride, calcium acetate, magnesium acetate, zinc acetate, stannous acetate, antimony trioxide, antimony ethylene glycol, and tetrabutyl titanate.
8. The method of claim 1, wherein the catalyst is used in an amount of 0.01 to 1% by mass of the reactants.
9. The method of claim 1, wherein the reaction temperature in step (1) is 100 to 280 ℃ and the reaction time is 1 to 48 hours; and
the temperature for carrying out the polymerization reaction in the step (2) is 150-300 ℃, the reaction time is 0.5-48 h, and the reaction pressure is 1-1000 Pa.
10. Biodegradable aliphatic-aromatic copolyester prepared according to the method of any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211224619.1A CN115558092A (en) | 2022-10-09 | 2022-10-09 | Recycling method of waste PET and biodegradable copolyester prepared by adopting recycling method |
| PCT/CN2023/089763 WO2024077921A1 (en) | 2022-10-09 | 2023-04-21 | Recycling method for waste pet and biodegradable copolyester prepared by using same |
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| CN202211224619.1A CN115558092A (en) | 2022-10-09 | 2022-10-09 | Recycling method of waste PET and biodegradable copolyester prepared by adopting recycling method |
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| WO2024077921A1 (en) * | 2022-10-09 | 2024-04-18 | 化学与精细化工广东省实验室 | Recycling method for waste pet and biodegradable copolyester prepared by using same |
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| JP2002053652A (en) * | 2000-05-30 | 2002-02-19 | Nippon Shokubai Co Ltd | Biodegradable and recycled polyester resin and production method thereof |
| CN102477149A (en) * | 2010-11-29 | 2012-05-30 | 上海杰事杰新材料(集团)股份有限公司 | Preparation method of biodegradable aliphatic-aromatic copolyester |
| CN114805779A (en) * | 2022-05-05 | 2022-07-29 | 浙江大学 | Method for synthesizing aromatic-aliphatic copolyester from aromatic polyester and product thereof |
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| CN104558549A (en) * | 2013-10-11 | 2015-04-29 | 中国石油化工股份有限公司 | A preparing method of aliphatic/aromatic copolyester |
| CN115558092A (en) * | 2022-10-09 | 2023-01-03 | 化学与精细化工广东省实验室 | Recycling method of waste PET and biodegradable copolyester prepared by adopting recycling method |
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| WO2024077921A1 (en) * | 2022-10-09 | 2024-04-18 | 化学与精细化工广东省实验室 | Recycling method for waste pet and biodegradable copolyester prepared by using same |
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