A tetra-chloro-phthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide tetrapolymer and a method for its preparation

Abstract

The application discloses a tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer and a preparation method thereof. A Lewis acid-base pair is used to initiate catalysis of ethylene oxide, propylene oxide, carbon dioxide and high-activity tetrachlorophthalic anhydride to obtain a polyester-polycarbonate copolymer with a diblock or triblock structure in a one-step method. The polyester segment formed by tetrachlorophthalic anhydride and an epoxide has a high glass transition temperature, and the polycarbonate segment formed by the epoxide and carbon dioxide has a relatively low glass transition temperature. The block copolymer has two glass transition temperatures, and the unique block structure ensures the heat resistance, mechanical strength and toughness of the copolymer, and widens the application field of the copolymer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, in particular to a tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer and a preparation method thereof. BACKGROUND

[0002] Biodegradable polypropylene carbonate (PPC) prepared by copolymerization of propylene oxide and carbon dioxide has high transparency and barrier properties, but its low glass transition temperature (38-42℃) limits its application in the packaging field. Recently, a ternary copolymer (PPC-P) prepared by copolymerization of propylene oxide, phthalic anhydride and carbon dioxide (CO2) maintains the high light transmission and high barrier properties of traditional PPC materials while showing improved glass transition temperature (47℃-53℃) and mechanical properties (~40 MPa), but the elongation at break is low (<10%) and the toughness is low (~3 MJ / m 3 )(CN 111378101A, J.CO2 Util.2021, 49, 101558). The synthesis methods disclosed in CN 111378101A and CN 114524930 A are one-step methods and the obtained copolymers are random structures. If block copolymers are desired, at least two-step synthesis is required, which is complicated and time-consuming. Therefore, it is necessary to find a new method to improve the toughness of PPC-P materials and further improve their glass transition temperature and gas barrier properties, and to obtain block copolymers with more excellent properties by a more simple method. SUMMARY

[0003] The present application aims to overcome the shortcomings of the prior art and provide a carbon dioxide-based polyester-polycarbonate material with high molecular weight, high glass transition temperature, excellent mechanical properties and high barrier properties, and a preparation method thereof, and a carbon dioxide-based polyester-polycarbonate material with multiple blocks can be obtained by only one-step reaction.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] A tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer, which is composed of polyester segments and polycarbonate segments, and its structure includes AB two blocks, BAB three blocks or ABA three blocks, and its structure is shown in formula I:

[0006]

[0007] As a preferred, in the above-mentioned tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer, the molar content of the polyester segment is 10%-50%, and the molar content of the polycarbonate segment is 90-50%.

[0008] The preparation method of the above-mentioned tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer structure comprises the following steps:

[0009] (1) For the preparation of AB type two-block copolymer and ABA type three-block copolymer, a one-pot one-step method is adopted: ethylene oxide, propylene oxide, tetrachlorophthalic anhydride, catalyst are added into a high-pressure reactor, carbon dioxide is introduced, and polymerization is carried out by heating, and after a period of reaction, the purified quaternary copolymer is obtained by precipitation and drying;

[0010] (2) For the preparation of BAB type three-block copolymer, a one-pot two-step method is adopted: ethylene oxide, propylene oxide, one quarter to one half of tetrachlorophthalic anhydride, catalyst are added into a high-pressure reactor, carbon dioxide is introduced, and polymerization is carried out by heating, and after a period of reaction, the remaining tetrachlorophthalic anhydride is added, and the reaction is continued for a period of time, and then the purified quaternary copolymer is obtained by precipitation and drying.

[0011] As a preferred, in the above-mentioned preparation method: the catalyst is a two-component catalyst of Lewis acid and organic amine or organic ammonium salt, and the Lewis acid is an organic boride.

[0012] As a preferred, in the above-mentioned preparation method: the organic boride is triethyl boron, and the organic amine or organic ammonium salt is triethylamine, tributylamine, bis(triphenylphosphine)ammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, tetra-n-butylammonium succinate, tetra-n-butylammonium isophthalate, tetra-n-butylammonium terephthalate or 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0013] As a preferred, in the above-mentioned preparation method: the molar ratio of ethylene oxide to tetrachlorophthalic anhydride is 10:1-30:1, the molar ratio of propylene oxide to tetrachlorophthalic anhydride is 30:1-10:1, the molar ratio of tetrachlorophthalic anhydride to organic amine or organic amine salt is 50:1-300:1, and the molar ratio of triethyl boron to organic amine or organic amine salt is 1.5:1-0.5:1.

[0014] As a preferred, in the above-mentioned preparation method: the tetrachlorophthalic anhydride added in step (2) for the second time is pumped in by dissolving tetrachlorophthalic anhydride in 1,4-dioxane using a high-pressure pump.

[0015] As a preferred, in the above-mentioned preparation method: the temperature of the polymerization reaction is 40-50℃, the reaction pressure is 0.5-2 MPa, and the total reaction time is 4-10 hours.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] (1) The innovation of the present application is to introduce tetrachlorophthalic anhydride and ethylene oxide into the copolymerization system of epoxide and CO2, and to use a cheap, easily available, simple and efficient non-metallic Lewis acid and organic amine or organic ammonium salt two-component catalyst system to catalyze the four-component copolymerization of carbon dioxide, ethylene oxide, propylene oxide and tetrachlorophthalic anhydride to prepare a polyester-polycarbonate copolymer with a block structure. Since the reaction activity of tetrachlorophthalic anhydride in the catalyst system is very high, the synthesized polymer has a perfect block structure, and since the polyester formed by tetrachlorophthalic anhydride and the two epoxides has a very high glass transition temperature, the polyester segment formed by tetrachlorophthalic anhydride and epoxide has a glass transition temperature similar to that of polystyrene, and the main chain contains 10-50% of the polyester block, the thermal performance and strength of the material are significantly improved, and the polycarbonate copolymerized by CO2 and ethylene oxide has a lower glass transition temperature than that of CO2 and propylene oxide, and the block structure makes the polyester segment and the polycarbonate segment form a two-phase separation structure, so the polyester-polycarbonate block copolymer exhibits two glass transition temperatures, the polyester segment with a high glass transition temperature endows the polymer with excellent heat resistance and strength, and the polycarbonate segment with a low glass transition temperature endows the polymer with good flexibility. Therefore, compared with existing carbon dioxide copolymers, the tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide four-component copolymer of the present application has excellent heat resistance and mechanical properties.

[0018] (2) The tetrachlorophthalic anhydride used in the present application is a cheap and easily available raw material with very high reaction activity, and the copolymerization reaction of ethylene oxide, propylene oxide and carbon dioxide can be carried out by one-pot method and one-pot two-step method to obtain a polyester-polycarbonate copolymer with a block structure.

[0019] (3) Due to the introduction of chlorine atoms, the intermolecular forces are further enhanced, so that the tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide four-component copolymer has more excellent gas barrier property than other carbon dioxide copolymers. Since it is an amorphous structure and does not contain metal components in the catalyst system, the tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide four-component copolymer has extremely high light transmittance. Therefore, the present application provides a carbon dioxide-based polymer material with excellent heat resistance, mechanical properties, barrier properties and complete transparency, which expands the application range of carbon dioxide-based polymer materials.

[0020] The present application can be further explained and illustrated in combination with the following specific embodiments, but the specific embodiments do not limit the present application in any form. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings are used to further clearly illustrate and explain the technical solutions and embodiments of the present application, and do not constitute a limitation on the present application, in which:

[0022] Figure 1 NMR spectrum of the tetra-chloro-phthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary block copolymer obtained in Example 1 of the present application.

[0023] Figure 2 DSC spectrum of the tetra-chloro-phthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary block copolymer obtained in Example 1 of the present application.

[0024] Figure 3 DSC spectrum of the phthalic anhydride / epoxide / carbon dioxide ternary random copolymer obtained in the comparative example of the present application.

[0025] Figure 4 NMR spectrum of the phthalic anhydride / epoxide / carbon dioxide ternary random copolymer obtained in the comparative example of the present application. DETAILED DESCRIPTION

[0026] Example 1

[0027] In anhydrous and anaerobic environment, 2.85 g of tetra-chloro-phthalic anhydride, 16.6 g of ethylene oxide, 2.90 g of propylene oxide, 57.4 mg of bis(triphenylphosphine)amine chloride, 150 μL of triethyl boron solution were sequentially added into a 50 mL high-pressure reactor, 1.5 MPa of carbon dioxide was filled, and the reaction was carried out at 50°C for 5 h. After the reaction was completed, the carbon dioxide pressure was released, the product was dissolved in dichloromethane, and the AB block polymer was precipitated in ethanol. After the polymer was vacuum dried, molecular weight test, NMR, thermal performance and mechanical property analysis were carried out. Mn=54.9 kDa, PDI=1.37; polyester content 16.7%, polycarbonate content 75.2%, polyether content 8.1%; T g1 =12°C, T g2 =92°C; tensile strength 19 MPa, elongation at break 60%.

[0028] Example 2

[0029] In anhydrous and anaerobic environment, 16.6 g of ethylene oxide, 2.90 g of propylene oxide, 10.0 mg of triethylamine, 150 μL of triethyl boron solution were sequentially added into a 50 mL high-pressure reactor, 1.0 MPa of carbon dioxide was filled, and the reaction was carried out at 45°C for 4 h. 2.85 g of tetra-chloro-phthalic anhydride in 1,4-dioxane was pumped into the reaction system by a high-pressure pump, and the reaction was continued for 3 h. After the reaction was completed, the carbon dioxide pressure was released, the product was dissolved in dichloromethane, and the BAB block polymer was precipitated in ethanol. After the polymer was vacuum dried, molecular weight test, NMR, thermal performance and mechanical property analysis were carried out. Mn=56.2 kDa, PDI=1.31; polyester content 22.2%, polycarbonate content 72.5%, polyether content 5.3%; T g1 =14°C, Tg2 = 91 °C; tensile strength 24 MPa, elongation at break 55%.

[0030] Example 3

[0031] In anhydrous and anaerobic environment, 2.85 g of pyromellitic anhydride, 13.7 g of ethylene oxide, 5.80 g of propylene oxide, 57.4 mg of bis(triphenylphosphine)amine chloride, 112 μL of triethylboron solution, were sequentially added into a 50 mL high-pressure reactor, 2.0 MPa of carbon dioxide was filled, and the reaction was carried out at 40 °C for 9 h. After the reaction was completed, the carbon dioxide pressure was released, the product was dissolved with dichloromethane, and the AB block polymer was precipitated in ethanol. After the polymer was vacuum dried, molecular weight test, nuclear magnetic resonance, thermal performance and mechanical property analysis were carried out. Mn= 59.8 kDa, PDI = 1.28; polyester content 26%, polycarbonate content 71.9%, polyether content 2.1%; T g1 = 13 °C, T g2 = 93 °C; tensile strength 22 MPa, elongation at break 52%.

[0032] Example 4

[0033] In anhydrous and anaerobic environment, 2.85 g of pyromellitic anhydride, 10.8 g of ethylene oxide, 11.6 g of propylene oxide, 30 mg of bis(triphenylphosphine)amine chloride, 100 μL of triethylboron solution, were sequentially added into a 50 mL high-pressure reactor, 1.5 MPa of carbon dioxide was filled, and the reaction was carried out at 45 °C for 6 h. After the reaction was completed, the carbon dioxide pressure was released, the product was dissolved with dichloromethane, and the AB block polymer was precipitated in ethanol. After the polymer was vacuum dried, molecular weight test, nuclear magnetic resonance, thermal performance and mechanical property analysis were carried out. Mn= 62.5 kDa, PDI = 1.28; polyester content 36%, polycarbonate content 62.8%, polyether content 1.2%; T g1 = 15 °C, T g2 = 92 °C; tensile strength 30 MPa, elongation at break 27%.

[0034] Example 5

[0035] In anhydrous and anaerobic environment, 2.85 g of chloranil, 4.40 g of ethylene oxide, 17.4 g of propylene oxide, 33 mg of tetrabutylphthalic acid ammonium, 150 μL of triethyl boron solution, were sequentially added into a 50 mL high-pressure reactor, 1.5 MPa of carbon dioxide was filled, and the reaction was carried out at 50°C for 6 h. After the reaction was completed, the carbon dioxide pressure was released, the product was dissolved in dichloromethane, and the ABA block polymer was precipitated in ethanol. After the polymer was vacuum dried, molecular weight test, nuclear magnetic resonance, thermal performance and mechanical property analysis were carried out. Mn = 67.3 kDa, PDI = 1.28; polyester content 27%, polycarbonate content 70.4%, polyether content 2.6%; T g1 = 32°C, T g2 = 100°C; tensile strength 24 MPa, elongation at break 22%.

[0036] Comparative Example 1

[0037] In anhydrous and anaerobic environment, 8.2 g of phthalic anhydride (PA), 16 g of propylene oxide, 80 mg of bis(triphenylphosphine)amine chloride, 200 μL of triethyl boron solution, were sequentially added into a 50 mL high-pressure reactor, 1.0 MPa of carbon dioxide was filled, and the reaction was carried out at 65°C for 8 h. After the reaction was completed, the carbon dioxide pressure was released, the product was dissolved in dichloromethane, and the random polymer was precipitated in ethanol. After the polymer was vacuum dried, molecular weight test, nuclear magnetic resonance, thermal performance and mechanical property analysis were carried out. Mn = 62.1 kDa, PDI = 1.31; polyester content 33.1%, polycarbonate content 61.0%, polyether content 5.9%; T g = 45.6°C; tensile strength 36 MPa, elongation at break 8%.

[0038] From Figures 1-3 It can be seen from the above data that the carbon dioxide-based polyester-polycarbonate quaternary copolymer prepared by the present application has two obvious glass transition temperatures compared with other carbon dioxide copolymers. The polyester segment glass transition temperature is as high as 80-106°C, and the polycarbonate segment glass transition temperature is between 10-30°C. The block structure of the phase separation gives the carbon dioxide copolymer more excellent heat resistance and mechanical properties. Comparative Example 1 has only one glass transition temperature at 45.6°C, which is a brittle material at room temperature and loses mechanical strength above 50°C. Although the difference between Comparative Example 1 and Example 1 is only that chloranil is replaced by phthalic anhydride, the products obtained are very different. Figure 4 and Figure 1 Comparing the nuclear magnetic resonance spectra of the two products can find that there is almost no connection peak (4.9 ppm and 5.3 ppm) between polyester and polycarbonate in Figure 1 , indicating that Example 1 obtains a block structure copolymer, whileFigure 4 The presence of numerous peaks representing alternating structures (around 5.0 ppm and 5.3 ppm) indicates that Comparative Example 1 yielded a copolymer with a random structure. Therefore, Example 1 can easily obtain a block polymer using a one-step method, while the Comparative Example, using a one-step method, can only obtain a polymer with a random structure, requiring additional synthesis steps and changes in synthesis conditions to obtain the corresponding block structure. This phase-separated block structure endows the carbon dioxide copolymer with superior heat resistance and mechanical properties, expanding the application areas of carbon dioxide copolymers.

Claims

1. A tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer, characterized in that... Composed of polyester segment B and polycarbonate segment A, its structure includes AB diblock, BAB triblock, or ABA triblock; the preparation method includes the following steps: (1) The preparation of AB type diblock copolymers and ABA type triblock copolymers adopts a one-pot one-step method: ethylene oxide, propylene oxide, tetrachlorophthalic anhydride and catalyst are added to a high-pressure reactor, carbon dioxide is introduced, and the polymerization reaction is carried out by heating. After a period of reaction, the purified quaternary copolymer is obtained by precipitation and drying. (2) The preparation of BAB type triblock copolymer adopts a one-pot two-step method: ethylene oxide, propylene oxide, one-quarter to one-half of tetrachlorophthalic anhydride and catalyst are added to a high-pressure reactor, carbon dioxide is introduced, and the polymerization reaction is carried out by heating. After a period of reaction, the remaining tetrachlorophthalic anhydride is added, and the reaction is continued for a period of time. Then, the purified quaternary copolymer is obtained by precipitation and drying. The catalyst is a two-component catalyst consisting of a Lewis acid and an organic amine or an organic ammonium salt, wherein the Lewis acid is an organoboride.

2. The tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer according to claim 1, characterized in that... The molar content of the polyester segment is 10%-50%, and the molar content of the polycarbonate segment is 90-50%.

3. The tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer according to claim 1, characterized in that: The organoboronide is triethylboron, and the organic amine or organic ammonium salt is triethylamine, tributylamine, bis(triphenylphosphino)ammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium succinate, tetrabutylammonium isophthalate, tetrabutylammonium terephthalate, or 1,8-diazabicyclo[5.4.0]undec-7-ene.

4. The tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer according to claim 3, characterized in that: The molar ratio of ethylene oxide to tetrachlorophthalic anhydride is 10:1 to 30:1, the molar ratio of propylene oxide to tetrachlorophthalic anhydride is 30:1 to 10:1, the molar ratio of tetrachlorophthalic anhydride to organic amine or organic ammonium salt is 50:1 to 300:1, and the molar ratio of triethylboron to organic amine or organic ammonium salt is 1.5:1 to 0.5:

1.

5. The tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer according to claim 1, characterized in that: The tetrachlorophthalic anhydride added in step (2) is injected by dissolving tetrachlorophthalic anhydride in 1,4-dioxane using a high-pressure pump.

6. The tetrachlorophthalic anhydride / ethylene oxide / propylene oxide / carbon dioxide quaternary copolymer according to claim 1, characterized in that: The polymerization reaction is carried out at a temperature of 40-50℃, a reaction pressure of 0.5-2 MPa, and a total reaction time of 4-10 hours.

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