Hydroquinone Di (2-Hydroxyethyl) Ether / Polylactic Acid Degradable Plastic and Its Preparation Method

Abstract

A hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic and its preparation method. The raw materials are made of hydroquinone dihydroxyethyl ether, succinic acid, stannous octoate, and lactide. The process of selecting hydroquinone dihydroxyethyl ether and succinic acid and then reacting with lactide is divided into the following two steps: Reaction stage I: Polymerization of hydroquinone dihydroxyethyl ether and succinic acid; Reaction stage II: Polymerization of lactic acid and the product of reaction stage I to form the final product. In this invention, first, flexible hydroquinone dihydroxyethyl ether reacts with succinic acid, and then ring-opening reaction occurs with lactide to form a triblock polyester. Hydroquinone dihydroxyethyl ether has good flexibility and good compatibility with polylactic acid. By copolymerizing with polylactic acid, the mechanical characteristics of large rigidity and easy brittleness of polylactic acid are improved, and the toughness and elongation at break of polylactic acid are increased, making its application fields wider. It is applied in the field of plastic technology.

Description

Technical Field

[0001] The present invention relates to a hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic in the field of plastic technology and a preparation method thereof. Background Art

[0002] Since the invention of plastics, they have been widely used due to their light weight, good performance and durability. Plastics have brought great convenience to people's lives and have become the fastest-growing major material in recent years. However, after a large number of plastic products are used and discarded, the environmental problems caused by improper disposal have become a hot topic of global concern. Strengthening garbage classification, recycling and reuse of waste plastics, and biochemical treatment of organic garbage have gradually become social consensus, and biodegradable plastic products have also been taken seriously because they contribute to compost biochemical treatment.

[0003] The raw material of polylactic acid (PLA) is lactic acid, which is mainly synthesized from biomass resources such as corn starch. It is one of the representatives of bio-based biodegradable plastics. Some recent studies have found more extensive synthetic methods for raw materials, such as preparing lactic acid from cassava, sugar beet, and even crop straws and cellulose, and then synthesizing polylactic acid (PLA). There are mainly three ways to synthesize polylactic acid: one is direct condensation of lactic acid; the second is to synthesize lactide from lactic acid and then catalytic ring-opening polymerization; the third is solid-phase polymerization. Most domestic synthetic routes of polylactic acid mainly follow the second way.

[0004] Polylactic acid (PLA) is a bio-based degradable polymer material, but polylactic acid is brittle, which limits its application range. Blending modification is an effective toughening method, but the improvement of toughness is often accompanied by a decrease in its strength. Therefore, preparing polylactic acid with good processing performance, high strength and high toughness is of great significance for its scientific research and engineering applications.

[0005] Hydroquinone dihydroxyethyl ether is an important intermediate of organic fine chemicals, which can be used to prepare high resilience elastomers and high-temperature resistant resins, and is mostly used to improve the mechanical properties of materials. Patent No. 202011544531.9 discloses a method for continuously synthesizing hydroquinone dihydroxyethyl ether, specifically a method for continuously synthesizing hydroquinone dihydroxyethyl ether in a microchannel reactor, and it is not applied to the optimization of subsequent material properties.

[0006] Therefore, developing a hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic and a preparation method thereof has always been a new topic to be urgently solved. Summary of the Invention

[0007] The object of the present invention is to provide a hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic and a preparation method thereof. In this invention, hydroquinone dihydroxyethyl ether is first reacted with succinic acid in a vacuum environment using stannous octoate, and the resulting intermediate segment is subjected to ring-opening polycondensation with lactide to generate a novel biodegradable plastic. This mainly improves the toughness of polylactic acid, and the flexible hydroquinone dihydroxyethyl ether changes the brittle characteristics of polylactic acid.

[0008] The object of the present invention is achieved as follows: A hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic, wherein the hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic is made from the following raw materials in parts by weight: 200 - 250 parts of hydroquinone dihydroxyethyl ether; 140 - 150 parts of succinic acid; 0.1 - 0.5 part of stannous octoate; 80 - 100 parts of lactide;

[0009] The process of the hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic selecting hydroquinone dihydroxyethyl ether and succinic acid and then reacting with lactide is divided into the following two steps: Reaction stage I: Polymerization of hydroquinone dihydroxyethyl ether and succinic acid; Reaction stage II: Polymerization of lactic acid and the product of reaction stage I to generate the final product; The reaction process is as follows:

[0010]

[0011] The preparation method of the hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic is as follows:

[0012] (1) Weigh hydroquinone dihydroxyethyl ether and succinic acid with a molar ratio of 1.1:1 and put them into a three-necked flask. Install the experimental device, seal it, and perform the inflation - evacuation operation with high-purity argon three times until the vacuum degree no longer changes; Gradually heat the oil bath to 180 °C, carry out the esterification reaction for 4 h, add stannous octoate, and then gradually heat to 220 °C. After that, evacuate the vacuum and carry out the polycondensation reaction with mechanical stirring for 6 h to obtain a middle segment with a certain molecular weight capped with dihydroxy groups; After standing at room temperature, dissolve it in chloroform and add it to methanol for precipitation. The resulting benzene-containing polyester is placed in a vacuum drying oven until it reaches a constant weight;

[0013] (2) After performing the evacuation - baking - argon filling operation with high-purity argon three times, weigh a certain molar ratio of benzene-containing polyester and lactide and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon as a protective gas; Gradually heat the oil bath to 120 °C, mechanically stir for 1 h to remove a small amount of water contained in the raw materials. Then add stannous octoate as a catalyst and raise the temperature of the oil bath to 150 °C. After the polymerization reaction for 12 h, let it stand at room temperature, dissolve it in chloroform, and add it to methanol for precipitation. The resulting product is placed in a vacuum drying oven until it reaches a constant weight to obtain a triblock polyester;

[0014] (3) Melt the triblock polyester through a hot press and mold it in a mold. After natural cooling, remove the mold;

[0015] The catalyst used is stannous octoate, and the addition amount is 0.1%-0.5% of the mass of lactide;

[0016] The ring-opening reaction temperature of the lactide is 150°C;

[0017] The temperature of the esterification reaction is 220°C, and the reaction time is 4 h.

[0018] The key point of the present invention lies in a hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic and its preparation method.

[0019] Compared with the prior art, a hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic and its preparation method have the advantages that first, flexible hydroquinone dihydroxyethyl ether reacts with succinic acid, and then undergoes ring-opening with lactide to generate a triblock polyester. Hydroquinone dihydroxyethyl ether has good flexibility and good compatibility with polylactic acid. By copolymerizing with polylactic acid, the mechanical characteristics of large rigidity and easy brittleness of polylactic acid are improved, and the toughness and elongation at break of polylactic acid are increased, making its application fields more extensive. It will be widely applied in the field of plastic technology. Specific embodiments

[0020] The present invention will be described in detail below in conjunction with specific embodiments.

[0021] A hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic is made from the following raw materials in parts by weight: 200-250 parts of hydroquinone dihydroxyethyl ether; 140-150 parts of succinic acid; 0.1-0.5 parts of stannous octoate; 80-100 parts of lactide.

[0022] The process of selecting hydroquinone dihydroxyethyl ether and succinic acid and then reacting with lactide for the hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic is divided into the following two steps: Reaction stage I: Polymerization of hydroquinone dihydroxyethyl ether and succinic acid; Reaction stage II: Polymerization of lactic acid and the product of reaction stage I to generate the final product; The reaction process is as follows:

[0023]

[0024] The preparation method of the hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic is as follows:

[0025] (1) Weigh hydroquinone dihydroxyethyl ether and succinic acid with a molar ratio of 1.1:1 and put them into a three-necked flask. Assemble the experimental device, seal it, and fill and evacuate it with high-purity argon three times until the vacuum degree no longer changes. Gradually heat the oil bath to 180 °C. After 4 hours of esterification reaction, add stannous octoate and gradually heat up to 220 °C. Then evacuate the air and carry out polycondensation reaction with mechanical stirring for 6 hours to obtain a middle segment with double hydroxyl ends of a certain molecular weight. After cooling to room temperature, dissolve it in chloroform and add it to methanol for precipitation. The obtained benzene-containing polyester is placed in a vacuum drying oven until it reaches a constant weight.

[0026] (2) After evacuating, baking, and filling with argon three times with high-purity argon, weigh a certain molar ratio of benzene-containing polyester and lactide and put them into a three-necked flask. Assemble the experimental device, seal it, and fill it with high-purity argon as a protective gas. Gradually heat the oil bath to 120 °C and stir mechanically for 1 hour to remove a small amount of water contained in the raw materials. Then add stannous octoate as a catalyst and raise the temperature of the oil bath to 150 °C. After 12 hours of polymerization reaction, cool it to room temperature, dissolve it in chloroform and add it to methanol for precipitation. The obtained product is placed in a vacuum drying oven until it reaches a constant weight to obtain a triblock polyester.

[0027] (3) Melt the triblock polyester by a hot press and mold it in a mold. After natural cooling, remove the mold.

[0028] The catalyst described above is stannous octoate, and the addition amount is 0.1%-0.5% of the mass of lactide.

[0029] The ring-opening reaction temperature of the lactide is 150 °C.

[0030] The temperature of the esterification reaction is 220 °C, and the reaction time is 4 hours.

[0031] Example 1:

[0032] The preparation method of hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic: Weigh 250 parts of hydroquinone dihydroxyethyl ether and 140 parts of succinic acid respectively and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon gas and evacuate it repeatedly three times until the vacuum degree no longer changes. Gradually heat the oil bath to 180 °C. After 4 hours of esterification reaction, add 1 part of stannous octoate and gradually heat up to 220 °C. Then evacuate the vacuum and carry out polycondensation reaction for 6 hours with mechanical stirring to obtain a middle segment with a certain molecular weight and double hydroxyl end groups. After standing at room temperature, dissolve it in chloroform and add it to methanol for precipitation. Put the obtained triblock polyester into a vacuum drying oven until it reaches a constant weight. After performing the operations of evacuating with high-purity argon, baking, and filling with argon three times, take 130 parts of the prepared polyester and 100 parts of lactide and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon gas as the protective gas. Gradually heat the oil bath to 120 °C, stir mechanically for 1 hour to remove a small amount of water contained in the raw materials. Then add 0.5 part of stannous octoate as a catalyst and raise the temperature of the oil bath to 150 °C. After 12 hours of polymerization reaction, let it stand at room temperature, dissolve it in chloroform and add it to methanol for precipitation. Put the obtained triblock polyester into a vacuum drying oven until it reaches a constant weight to obtain the triblock polyester.

[0033] Example 2:

[0034] The preparation method of hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic: Weigh 250 parts of hydroquinone dihydroxyethyl ether and 140 parts of succinic acid respectively and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon gas and evacuate it repeatedly three times until the vacuum degree no longer changes. Gradually heat the oil bath to 180 °C. After 4 hours of esterification reaction, add 1 part of stannous octoate and gradually heat up to 220 °C. Then evacuate the vacuum and carry out polycondensation reaction for 6 hours with mechanical stirring to obtain a middle segment with a certain molecular weight and double hydroxyl end groups. After standing at room temperature, dissolve it in chloroform and add it to methanol for precipitation. Put the obtained triblock polyester into a vacuum drying oven until it reaches a constant weight. After performing the operations of evacuating with high-purity argon, baking, and filling with argon three times, take 140 parts of the prepared polyester and 100 parts of lactide and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon gas as the protective gas. Gradually heat the oil bath to 120 °C, stir mechanically for 1 hour to remove a small amount of water contained in the raw materials. Then add 0.5 part of stannous octoate as a catalyst and raise the temperature of the oil bath to 150 °C. After 12 hours of polymerization reaction, let it stand at room temperature, dissolve it in chloroform and add it to methanol for precipitation. Put the obtained triblock polyester into a vacuum drying oven until it reaches a constant weight to obtain the triblock polyester.

[0035] Example 3:

[0036] The preparation method of hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic is as follows: Weigh 250 parts of hydroquinone dihydroxyethyl ether and 140 parts of succinic acid and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon gas and evacuate it repeatedly three times until the vacuum degree no longer changes. Gradually heat the oil bath to 180°C. After 4 hours of esterification reaction, add 1 part of stannous octoate and gradually heat up to 220°C. Then evacuate the vacuum and carry out polycondensation reaction with mechanical stirring for 6 hours to obtain a middle segment with a certain molecular weight and double hydroxyl end groups. After cooling to room temperature, dissolve it in chloroform and add it to methanol for precipitation. Put the obtained triblock polyester into a vacuum drying oven until it reaches a constant weight. After performing the operations of evacuating with high-purity argon, baking, and filling with argon three times, take 150 parts of the prepared polyester and 100 parts of lactide and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon as a protective gas. Gradually heat the oil bath to 120°C and stir mechanically for 1 hour to remove a small amount of water contained in the raw materials. Then add 0.5 part of stannous octoate as a catalyst and raise the temperature of the oil bath to 150°C. After 12 hours of polymerization reaction, cool it to room temperature, dissolve it in chloroform and add it to methanol for precipitation. Put the obtained triblock polyester into a vacuum drying oven until it reaches a constant weight to obtain a triblock polyester.

[0037] Basic comparison:

[0038] Take pure polylactic acid as a control group for performance comparison.

[0039] The performance comparison between the polylactic acid prepared in Examples 1 to 3 of the present invention and ordinary polylactic acid is as shown in the following table:

[0040] Tensile strength MPa Elongation at break % Example 1 16.32 43.66 Example 2 18.82 51.28 Example 3 27.85 83.36 Basic comparison 60.23 11.28

[0041] From the obtained experimental data, it can be seen that the elongation at break of hydroquinone dihydroxyethyl ether / polylactic acid is greater than that of different polylactic acids. Thus, it can be seen that the toughness of hydroquinone dihydroxyethyl ether / polylactic acid has been greatly improved compared with ordinary polylactic acid.

Claims

1. A hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic, characterized in that: The described hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic is made from the following raw materials with the weight ratio of each component: 250 parts of hydroquinone dihydroxyethyl ether; 140 parts of succinic acid; 1.5 parts of stannous octoate; 100 parts of lactide; For the described hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic, the process of selecting hydroquinone dihydroxyethyl ether and succinic acid and then reacting with lactide is divided into the following two steps: Reaction stage I: Polymerization of hydroquinone dihydroxyethyl ether and succinic acid; Reaction stage II: Polymerization of lactic acid and the product of reaction stage I to form the final product; The reaction process is as follows: The preparation method of the described hydroquinone dihydroxyethyl ether / polylactic acid degradable plastic is as follows: (1) Weigh 250 parts of hydroquinone dihydroxyethyl ether and 140 parts of succinic acid respectively and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon gas and evacuate it repeatedly three times until the vacuum degree no longer changes; Gradually heat the oil bath to 180 °C, carry out esterification reaction for 4 h, add 1 part of stannous octoate, and gradually heat up to 220 °C. Then evacuate the vacuum and carry out polycondensation reaction with mechanical stirring for 6 h to obtain a middle segment with double hydroxyl ends of a certain molecular weight; After standing at room temperature, dissolve it in chloroform and add it to methanol for precipitation. The obtained polyester containing benzene is placed in a vacuum drying oven until it reaches a constant weight; (2) After evacuating, baking, and filling with argon with high-purity argon three times, take 150 parts of the prepared polyester and 100 parts of lactide and put them into a three-necked flask. Install the experimental device, seal it, and fill it with high-purity argon as a protective gas; Gradually heat the oil bath to 120 °C, stir mechanically for 1 h to remove a small amount of water contained in the raw materials. Then add 0.5 part of stannous octoate as a catalyst and raise the temperature of the oil bath to 150 °C. After polymerization reaction for 12 h, let it stand at room temperature, dissolve it in chloroform and add it to methanol for precipitation. The obtained product is placed in a vacuum drying oven until it reaches a constant weight to obtain a triblock polyester; (3) Melt the triblock polyester through a hot press and mold it in a mold. After natural cooling, remove the mold.

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