Novel modified oxadiazole polymer as well as preparation method and application thereof
The new modified oxadiazole polymer prepared through esterification, cyclization synthesis and polycondensation reaction solves the shortcomings of existing polyoxadiazole polymers in terms of mechanical strength, thermal stability and processability, and achieves more High mechanical strength and thermal stability, suitable for the preparation of a variety of high-performance materials.
Patent Information
- Application Number
- CN202411796374.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-02-14
AI Technical Summary
The existing polyoxadiazole polymers have shortcomings in terms of mechanical strength, thermal stability and processability, and are difficult to meet the needs of high-performance materials.
Through esterification, cyclization synthesis reaction and polycondensation reaction, a new modified oxadiazole polymer is prepared using hydrazine compounds and ester compounds to improve its mechanical strength and thermal stability.
The prepared new modified oxadiazole polymer has higher mechanical strength, thermal stability and processability, and is suitable for the preparation of high-strength, high toughness, friction-resistant foam plastics, fibers, films and coatings.
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Figure CN119431778A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of polymer compound synthesis, and in particular relates to a novel modified oxadiazole polymer and a preparation method and application thereof. Background Art
[0002] Polyoxadiazoles are chemically resistant and thermally stable heterocyclic polymers containing benzene and oxadiazole rings. They have no obvious glass transition temperature and melting point, are insoluble and infusible, have harsh processing conditions, and are difficult to control their molecular weight. They have many excellent properties, namely thermal stability and hydrolytic stability, strength, stiffness, fatigue resistance, and relatively low density, making them promising candidates for high temperature and flame retardant material applications. Due to their good stability, chemical resistance, and electrical insulation, aromatic polyoxadiazoles are used in various fields, such as high temperature resistance, electrical conductivity, luminescence, and lighting. By modifying the oxadiazole polymer through chemical synthesis and embedding flexible segments in the molecular chain, the polyoxadiazole polymer is endowed with some excellent properties while also making the polymer easier to process. This type of polymer not only has a melting point and a glass transition temperature, but also, from its molecular structure, it can be seen that this type of polymer has potential excellent properties in photochemical activity, thermal sensitivity, flame retardancy, mechanical properties, electronic conductivity, etc. Therefore, as a new polymer high-performance material, it will have great application prospects in optoelectronic materials, flame retardant materials, polymer modification and other fields. Summary of the invention
[0003] In view of the above-mentioned deficiencies of the prior art, the problem solved by the present invention is to provide a novel modified oxadiazole polymer having high mechanical strength, strong thermal stability and excellent performance in various aspects, as well as a preparation method and application thereof.
[0004] To solve the above problems, the technical solution adopted by the present invention is as follows:
[0005] A method for preparing a novel modified oxadiazole polymer comprises the following steps:
[0006] S1, esterification reaction: add hydrazine compound, ester compound, solvent and catalyst in a glass reaction container in sequence, fill with nitrogen, start continuous stirring and heat to raise the temperature, the reaction phase after the reaction is a slightly yellow solution, after the temperature is lowered to room temperature, a white solid precipitates; the solid-liquid mixture is solid-liquid separated to obtain a white powder; the white powder is washed several times to remove the residual solvent and then dried to obtain a product hydrazide ester compound;
[0007] S2, cyclization synthesis reaction: add the hydrazide ester compound in step S1 into a glass reaction container, add phosphorus oxychloride solvent, start continuous stirring and heat to raise the temperature, after a period of reaction, the reaction phase is a light yellow solution, and solid precipitates from the reaction; separate the solid and liquid to obtain a light yellow powder, wash the powder several times to remove the residual solvent and dry it to obtain a product which is an oxadiazole ester compound;
[0008] S3, polycondensation reaction: add the product of step S2 and the alcohol compound into a glass reaction container, add a catalyst and a stabilizer, and start stirring the reaction after the reactants melt under high temperature under vacuum. After a period of time, the reaction system is continuously evacuated. After a period of time, as the viscosity of the reaction liquid increases, the reaction system is evacuated again, and the reaction temperature is continuously raised. After a period of time, the reaction liquid becomes a brown-yellow viscous liquid. The reaction liquid is cooled, and solids precipitate. A solvent is added to dilute the reaction liquid, and the reaction liquid is subjected to solid-liquid separation. A solvent is added for ultrasonic washing, filtering, and drying to obtain a yellow powder novel modified oxadiazole polymer.
[0009] Furthermore, in step S1, the ester compound is any one of dimethyl terephthalate, dimethyl 1,4-naphthalene dicarboxylate, dimethyl 2,6-naphthalene dicarboxylate, dimethyl 2,7-naphthalene dicarboxylate, dimethyl 1,8-naphthalene dicarboxylate, and diethyl 5-(hydroxymethyl)isophthalate.
[0010] Further, in step S1, the structural formula of the hydrazine compound is: Wherein R1 can be -C2H4-, Either one.
[0011] Furthermore, in step S1, the solvent used is any one or any combination of trifluoromethanesulfonic acid, NMP, acetic acid, phosphoric acid, and dimethyl sulfoxide; the catalyst is any one or any combination of anhydrous magnesium sulfate, Al(i-Bu)3, Nd(naph)3, and CoCl; the molar ratio of the ester compound to the hydrazine compound is (2:1) to (10:1), and the amount of the catalyst accounts for 1% to 5% of the total material by mass.
[0012] Furthermore, in step S1, the reaction temperature is 80-150° C., and the reaction time is 12-18 hours.
[0013] Furthermore, in step S2, the reaction time is 8-14 hours, and the reaction temperature is 120-135° C.; the detergent for multiple washings is saturated sodium bicarbonate or sodium hydroxide, purified water, or ethanol.
[0014] Furthermore, in step S3, the alcohol compound is any one of ethylene glycol, propylene glycol, butylene glycol and hexylene glycol; the molar ratio of the alcohol compound to the oxadiazole ester compound in step S2 is 1.3:1-1.8:1; the catalyst is any one or more of antimony trioxide, titanium dioxide, germanium oxide, zirconium oxide and tungsten oxide, and the catalyst accounts for 10-15% of the total material mass ratio; the stabilizer is any one or more of phosphoric acid, acetic acid and nitric acid, and the stabilizer accounts for 10-15% of the total material mass ratio.
[0015] Furthermore, in step S3, the reaction temperature is 275-290 degrees and the reaction time is 6-10 hours.
[0016] A method for preparing a novel modified oxadiazole polymer is provided. The novel modified oxadiazole polymer is prepared.
[0017] The invention discloses an application of a novel modified oxadiazole polymer, wherein the polymer is melt-molded into dumbbell-shaped sheets by high-temperature injection, and is prepared into high-strength foam plastics.
[0018] The beneficial effects of the present invention are as follows:
[0019] The novel modified oxadiazole polymer prepared by the present invention has better flexibility and higher rigidity, stronger tensile strength and wear resistance than the conventional commonly used PET foam material, and is suitable for preparing high-strength, high-toughness, friction-resistant foam plastics, fibers, films, coatings, adhesives and other materials, and has high potential application value. The technology is expected to have important applications in various fields and promote the development of science and engineering.
[0020] The present invention provides a simple and low-cost synthesis preparation method, which uses hydrazine compounds and ester compounds to obtain a new high-performance new oxadiazole polymer through three-step esterification synthesis polymerization. This type of polymer has potential excellent properties such as photochemistry, thermal sensitivity, flame retardancy, mechanical properties, and electronic conductivity. The material made from this type of polymer has higher tensile strength and wear resistance. Therefore, as a new polymer high-performance material, it will have great application prospects in the fields of optoelectronic materials, flame retardant materials, etc. It is particularly suitable for preparing high-strength, high-toughness, friction-resistant foam plastics, fibers, emulsions and coatings. The high molecular polymer of the present invention has high potential application value in the fields of semiconductors and flame retardancy. This technology is expected to have important applications in various fields and promote the development of science and engineering. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 4 is a Fourier transform infrared spectrum of each embodiment of the present invention.
[0022] Figure 2The stress-strain comparison spectra of various embodiments of the present invention and PET material are shown in FIG.
[0023] Figure 3 The DSC comparison spectra of various embodiments of the present invention and PET material are shown in FIG.
[0024] Figure 4 The thermogravimetric comparison spectra of various embodiments of the present invention and PET material are shown in FIG. DETAILED DESCRIPTION
[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings.
[0026] Example 1
[0027] A method for preparing a novel oxadiazole polymer comprises the following steps:
[0028] S1: Esterification reaction: 4.02g terephthalic acid dihydrazide, 11.90g dimethyl terephthalate, 100ml trifluoromethanesulfonic acid and 0.1600g Al(i-Bu)3 were added to a 500ml four-necked glass reaction container, nitrogen was introduced (flow rate was 10mL / min), stirring was started (stirring speed was 400r / min), and the temperature was raised to 100 degrees. After reacting for 12h, the reaction phase was a slightly yellow solution. After the temperature was lowered to room temperature, a white solid precipitated. The solid-liquid mixture was subjected to solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper) to obtain a white powder; the white powder was washed with anhydrous ethanol for 3 times (50ml*3), and then washed with pure water for 3 times (100ml*3) to remove the residual solvent, and finally the powder was placed in a vacuum oven and dried at 100°C for 10h to obtain 9.050g of the product hydrazide ester compound.
[0029] S2: Cyclization synthesis reaction: Add 9.05g of the white solid in step S1 into a 500ml four-necked glass reaction vessel, add 30ml of phosphorus oxychloride solvent, start stirring (stirring speed is 400r / min), and heat to 125 degrees. The reaction time is 9h. The reaction phase is a light yellow solution, and solid precipitates from the reaction. The reaction solution is cooled to room temperature, and the solid-liquid mixture is filtered under reduced pressure at -0.08MPa for solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper) to obtain a light yellow powder, wash the powder with saturated sodium bicarbonate for 3 times, then wash it with purified water for 3 times (100ml*3), and finally wash it with anhydrous ethanol for 3 times (100ml*3) to remove the residual solvent, and finally dry the powder in a vacuum oven at 100°C for 24h to obtain 24.88g of the product oxadiazole ester compound.
[0030] S3: Polycondensation reaction: 24.88g of the product of step S2 and 3.50g of ethylene glycol were added to a 500ml four-necked glass reaction container, 2.88g of a catalyst solution of 28.238g of antimony trioxide dissolved in 100ml of ethylene glycol at a high temperature of 160 degrees, and 2.88g of a phosphoric acid solution stabilizer diluted with 100ml of ethylene glycol were added, and the air in the reaction system was extracted with an oil pump to make the reaction system in a vacuum state. After the reactants were melted at a high temperature of 280 degrees, stirring was started (the stirring speed was 4 00r / min), after 2h of reaction, the reaction system was further vacuumed. After 4h of reaction, the viscosity of the reaction solution increased and the color became darker. The reaction system was vacuumed again and the reaction temperature was continued to be raised to 290 degrees. After 6h of reaction, the reaction solution became a brown-yellow viscous liquid. The reaction solution was cooled to room temperature and solid precipitated. Methanol was added to dilute the reaction solution and the reaction solution was separated from the solid. The solid was added to methanol and ultrasonically washed 3 times, and the solid-liquid mixture was filtered under reduced pressure at -0.08MPa for solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper), the powder was placed in a vacuum oven at 100°C and dried for 24 hours to obtain 25.68g of yellow powder product.
[0031] The reaction yield of the novel oxadiazole polymer of Example 1 is 78%, and its number average molecular weight is determined to be about 15,000.
[0032] The polymer of Example 1 was melt-molded into dumbbell-shaped sheets at high temperature to obtain the modified material POP1, and its mechanical properties were measured by single-arm tensile tester CZ-8000A106 (Guangdong Zhongzhi Testing Instrument Co., Ltd., China) using the tensile test method of GB2651-1989. Figure 2 As shown, the stress and strain values are 85 MPa and 5.5% respectively.
[0033] Example 2
[0034] A method for preparing a novel oxadiazole polymer comprises the following steps:
[0035] S1: Esterification reaction: 4.02g terephthalic acid dihydrazide, 15.17g 1,4-naphthalene dicarboxylic acid dimethyl ester, 100ml acetic acid and 0.1490g CoCl3 were added to a 500ml four-necked glass reaction container, nitrogen was introduced (flow rate was 10mL / min), stirring was started (stirring speed was 400r / min), and the temperature was raised to 105 degrees. After 14h of reaction, the reaction phase was a slightly yellow solution. After the temperature was lowered to room temperature, a white solid precipitated. The solid-liquid mixture was separated into solid and liquid (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper) to obtain a white powder; the white powder was washed with anhydrous ethanol for 3 times (50ml*3), and then washed with pure water for 3 times (100ml*3) to remove the residual solvent, and finally the powder was placed in a vacuum oven and dried at 100°C for 10h to obtain 15.48g of the product hydrazide ester compound.
[0036] S2: Cyclization synthesis reaction: Add 15.48g of the white solid in step S1 into a 500ml four-necked glass reaction vessel, add 30ml of phosphorus oxychloride solvent, start stirring (stirring speed is 400r / min), and heat to 125 degrees. The reaction time is 10h. The reaction phase is a light yellow solution, and solid precipitates from the reaction. The reaction solution is cooled to room temperature, and the solid-liquid mixture is filtered under reduced pressure at -0.08MPa for solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper) to obtain a light yellow powder, the powder was washed 3 times with saturated sodium bicarbonate, then washed 3 times with purified water (100ml*3), and finally washed 3 times with anhydrous ethanol (100ml*3) to remove residual solvent, and finally the powder was placed in a vacuum oven at 100°C and dried for 24h to obtain 28.65g of product oxadiazole ester compound.
[0037] S3: Polycondensation reaction: 28.65 g of the product of step S2 and 4.50 g of propylene glycol were added to a 500 ml four-necked glass reaction container, 2.88 g of a catalyst solution of 28.238 g of antimony trioxide dissolved in 100 ml of ethylene glycol at a high temperature of 160 degrees, and 2.88 g of a phosphoric acid solution stabilizer diluted with 100 ml of ethylene glycol were added, the air in the reaction system was extracted with an oil pump, the reaction system was placed in a vacuum state, and after the reactants were melted at a high temperature of 280 degrees, stirring was started (the stirring speed was 4 00r / min), after 2h of reaction, the reaction system was further vacuumed. After 4h of reaction, the viscosity of the reaction solution increased and the color became darker. The reaction system was vacuumed again and the reaction temperature was continued to be raised to 290 degrees. After 6h of reaction, the reaction solution became a brown-yellow viscous liquid. The reaction solution was cooled to room temperature and solid precipitated. Methanol was added to dilute the reaction solution and the reaction solution was separated from the solid. The solid was added to methanol and ultrasonically washed 3 times, and the solid-liquid mixture was filtered under reduced pressure at -0.08MPa for solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper), the powder was placed in a vacuum oven at 100°C and dried for 24 hours to obtain 35.68g of yellow powder product.
[0038] The reaction yield of the novel oxadiazole polymer of Example 2 is 79%, and its number average molecular weight is determined to be about 15,000.
[0039] The polymer of Example 2 was melt-molded into dumbbell-shaped sheets at high temperature to obtain the modified material POP2, and its mechanical properties were measured using a single-arm tensile tester CZ-8000A106 (Guangdong Zhongzhi Testing Instrument Co., Ltd., China) using the tensile test method of GB2651-1989. Figure 2 As shown, the stress and strain values are 95 MPa and 8.0% respectively.
[0040] Example 3
[0041] A method for preparing a novel oxadiazole polymer comprises the following steps:
[0042] S1: Esterification reaction: 5.05g of isophthalic acid dihydrazide, 15.10g of 2,6-naphthalene dicarboxylic acid dimethyl ester, 100ml of phosphoric acid and 0.1600g of Nd(naph)3 were added to a 500ml four-necked glass reaction container in sequence, nitrogen was introduced (flow rate was 10mL / min), stirring was started (stirring speed was 400r / min), and the temperature was raised to 100 degrees. After reacting for 14h, the reaction phase was a slightly yellow solution. After the temperature was lowered to room temperature, a white solid precipitated. The solid-liquid mixture was subjected to solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper) to obtain a white powder; the white powder was washed with anhydrous ethanol for 3 times (50ml*3), and then washed with pure water for 3 times (100ml*3) to remove the residual solvent, and finally the powder was placed in a vacuum oven and dried at 100°C for 10h to obtain 16.52g of the product hydrazide ester compound.
[0043] S2: Cyclization synthesis reaction: Add 16.52g of the white solid in step S1 into a 500ml four-necked glass reaction vessel, add 40ml of phosphorus oxychloride solvent, start stirring (stirring speed is 400r / min), and heat to 130 degrees. The reaction time is 8h. The reaction phase is a light yellow solution, and solid precipitates from the reaction. The reaction solution is cooled to room temperature, and the solid-liquid mixture is filtered under reduced pressure at -0.08MPa for solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper) to obtain a light yellow powder, wash the powder with saturated sodium bicarbonate for 3 times, then wash it with purified water for 3 times (100ml*3), and finally wash it with anhydrous ethanol for 3 times (100ml*3) to remove the residual solvent, and finally dry the powder in a vacuum oven at 100°C for 24h to obtain 25.22g of the product oxadiazole ester compound.
[0044] S3: Polycondensation reaction: 25.22 g of the product of step S2 and 3.50 g of propylene glycol were added to a 500 ml four-necked glass reaction vessel, 3.05 g of a catalyst solution of 28.238 g of antimony trioxide dissolved in 100 ml of ethylene glycol at 160 degrees was added, and 3.00 g of a phosphoric acid solution stabilizer diluted with 100 ml of ethylene glycol was added. The air in the reaction system was extracted with an oil pump to place the reaction system in a vacuum state. After the reactants were melted at 280 degrees, stirring was started (the stirring speed was 4 00r / min), after 2h of reaction, the reaction system was further vacuumed. After 4h of reaction, the viscosity of the reaction solution increased and the color became darker. The reaction system was vacuumed again and the reaction temperature was continued to be raised to 290 degrees. After 6h of reaction, the reaction solution became a brown-yellow viscous liquid. The reaction solution was cooled to room temperature and solid precipitated. Methanol was added to dilute the reaction solution and the reaction solution was separated from the solid. The solid was added to methanol and ultrasonically washed 3 times, and the solid-liquid mixture was filtered under reduced pressure at -0.08MPa for solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper), the powder was placed in a vacuum oven at 100°C and dried for 24h to obtain 27.05g of yellow powder product.
[0045] The reaction yield of the novel oxadiazole polymer of Example 3 was 80.5%, and its number average molecular weight was determined to be about 13,500.
[0046] The polymer of Example 3 was melt-molded into dumbbell-shaped sheets at high temperature to obtain the modified material POP3, and its mechanical properties were measured by single-arm tensile tester CZ-8000A106 (Guangdong Zhongzhi Testing Instrument Co., Ltd., China) using the tensile test method of GB2651-1989. Figure 2 As shown, the stress and strain values are 93 MPa and 7.5% respectively.
[0047] Example 4
[0048] A method for preparing a novel oxadiazole polymer comprises the following steps:
[0049] S1: Esterification reaction: 5.50g of isophthalic acid dihydrazide, 16.90g of 5-(hydroxymethyl)isophthalic acid diethyl ester, 100ml of acetic acid and 0.1600g of CoCl were added to a 500ml four-necked glass reaction container, nitrogen was introduced (flow rate was 10mL / min), stirring was started (stirring speed was 400r / min), and the temperature was raised to 100 degrees. After reacting for 12h, the reaction phase was a slightly yellow solution. After the temperature was lowered to room temperature, a white solid precipitated. The solid-liquid mixture was subjected to solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper) to obtain a white powder; the white powder was washed with anhydrous ethanol for 3 times (50ml*3), and then washed with pure water for 3 times (100ml*3) to remove the residual solvent, and finally the powder was placed in a vacuum oven and dried at 100°C for 10h to obtain 16.54g of the product hydrazide ester compound.
[0050] S2: Cyclization synthesis reaction: Add 16.54g of the white solid in step S1 into a 500ml four-necked glass reaction vessel, add 50ml of phosphorus oxychloride solvent, start stirring (stirring speed is 400r / min), and heat to 125 degrees. The reaction time is 9h. The reaction phase is a slightly yellow solution, and solid precipitates from the reaction. The reaction solution is cooled to room temperature, and the solid-liquid mixture is filtered under reduced pressure at -0.08MPa for solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper) to obtain a light yellow powder, wash the powder with saturated sodium bicarbonate for 3 times, then wash it with purified water for 3 times (100ml*3), and finally wash it with anhydrous ethanol for 3 times (100ml*3) to remove the residual solvent, and finally dry the powder in a vacuum oven at 100°C for 24h to obtain 23.26g of the product oxadiazole ester compound.
[0051] S3: Polycondensation reaction: 23.26g of the product of step S2 and 3.50g of ethylene glycol were added to a 500ml four-necked glass reaction vessel, 3.00g of a catalyst solution of 28.238g of antimony trioxide dissolved in 100ml of ethylene glycol at a high temperature of 160 degrees, and 3.00g of a phosphoric acid solution stabilizer diluted with 100ml of ethylene glycol were added, and the air in the reaction system was extracted with an oil pump to make the reaction system in a vacuum state. After the reactants were melted at a high temperature of 280 degrees, stirring was started (the stirring speed was 4 00r / min), after 2h of reaction, the reaction system was further vacuumed. After 4h of reaction, the viscosity of the reaction solution increased and the color became darker. The reaction system was vacuumed again and the reaction temperature was continued to be raised to 295 degrees. After 6h of reaction, the reaction solution became a brown-yellow viscous liquid. The reaction solution was cooled to room temperature and solid precipitated. Methanol was added to dilute the reaction solution and the reaction solution was separated from the solid. The solid was added to methanol and ultrasonically washed 3 times, and the solid-liquid mixture was filtered under reduced pressure at -0.08MPa for solid-liquid separation (using Buchner funnel, 500mL suction filtration bottle, medium-speed qualitative filter paper), the powder was placed in a vacuum oven at 100°C and dried for 24h to obtain 28.05g of yellow powder product.
[0052] The reaction yield of the novel oxadiazole polymer of Example 4 was 73.5%, and its number average molecular weight was determined to be about 14,000.
[0053] The polymer of Example 4 was melt-molded into dumbbell-shaped sheets at high temperature to obtain the modified material POP4, and its mechanical properties were measured by single-arm tensile tester CZ-8000A106 (Guangdong Zhongzhi Testing Instrument Co., Ltd., China) using the tensile test method of GB2651-1989. Figure 2 As shown, the stress and strain values are 75 MPa and 6.3% respectively.
[0054] Figure 1 The infrared spectra of PET and four oxadiazole polymers. It can be seen from the figure that the corresponding wavelengths correspond to the relevant groups of the structure: 871cm-1 is benzene ring substitution, 1238cm-1, 1340cm-1 is CN bond, 1370cm-1, 1306cm-1 is C=NN=C bond, 2964cm-1 is saturated CH bond, 970cm-1, 1016cm-1 is -COC- bond, 1712cm-1 is C=O bond, and 1091cm-1 is -CO- ester bond.
[0055] Depend on Figure 2 It can be seen from the above figure that the stress of PET is about 30MPa, and the stress values of the four oxadiazole polymers are 85MPa, 95MPa, 93MPa, and 75MPa, respectively. This shows that the mechanical strength of the four oxadiazole polymers is higher than that of PET material.
[0056] Depend on Figure 3 It can be seen from the above figure that the melting point of PET is around 230 degrees, and the melting points of the four oxadiazole polymers are all higher, and the melting points are not obvious, all around 300 degrees. This shows that compared with traditional thermoplastic PET materials, the four oxadiazole polymer materials are more inclined to thermosetting materials.
[0057] Depend on Figure 4 It can be seen from the above figure that the thermal decomposition temperature of PET is about 230 degrees, and the thermal decomposition temperatures of the four oxadiazole polymers are all improved, with temperature values between 380-450 degrees. Therefore, compared with traditional PET materials, oxadiazole polymers have higher thermal stability.
[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a novel modified oxadiazole polymer, characterized in that: Here are the steps: S1, esterification reaction: add hydrazine compound, ester compound, solvent and catalyst in a glass reaction container in sequence, fill with nitrogen, start continuous stirring and heat to raise the temperature, the reaction phase after the reaction is a slightly yellow solution, after the temperature is lowered to room temperature, a white solid precipitates; the solid-liquid mixture is solid-liquid separated to obtain a white powder; the white powder is washed several times to remove the residual solvent and then dried to obtain a product hydrazide ester compound; S2, cyclization synthesis reaction: add the hydrazide ester compound in step S1 into a glass reaction container, add phosphorus oxychloride solvent, start continuous stirring and heat to raise the temperature, after a period of reaction, the reaction phase is a light yellow solution, and solid precipitates from the reaction; separate the solid and liquid to obtain a light yellow powder, wash the powder several times to remove the residual solvent and dry it to obtain a product which is an oxadiazole ester compound; S3, polycondensation reaction: add the product of step S2 and the alcohol compound into a glass reaction container, add a catalyst and a stabilizer, and start stirring the reaction after the reactants melt under high temperature under vacuum. After a period of time, the reaction system is continuously evacuated. After a period of time, as the viscosity of the reaction liquid increases, the reaction system is evacuated again, and the reaction temperature is continuously raised. After a period of time, the reaction liquid becomes a brown-yellow viscous liquid. The reaction liquid is cooled, and solids precipitate. A solvent is added to dilute the reaction liquid, and the reaction liquid is subjected to solid-liquid separation. A solvent is added for ultrasonic washing, filtering, and drying to obtain a yellow powder novel modified oxadiazole polymer.
2. The method for preparing the novel modified oxadiazole polymer according to claim 1, characterized in that: In the step S1, the ester compound is any one of dimethyl terephthalate, dimethyl 1,4-naphthalene dicarboxylate, dimethyl 2,6-naphthalene dicarboxylate, dimethyl 2,7-naphthalene dicarboxylate, dimethyl 1,8-naphthalene dicarboxylate, and diethyl 5-(hydroxymethyl)isophthalate.
3. The method for preparing the novel modified oxadiazole polymer according to claim 1, characterized in that: In step S1, the structural formula of the hydrazine compound is: Wherein R1 can be -C2H4-, Either one.
4. The method for preparing the novel modified oxadiazole polymer according to claim 1, characterized in that: In the step S1, the solvent used is any one or any combination of trifluoromethanesulfonic acid, NMP, acetic acid, phosphoric acid, and dimethyl sulfoxide; the catalyst is any one or any combination of anhydrous magnesium sulfate, Al(i-Bu)3, Nd(naph)3, and CoCl; the molar ratio of the ester compound to the hydrazine compound is (2:1) to (10:1), and the amount of the catalyst accounts for 1% to 5% by mass of the total material.
5. The method for preparing the novel modified oxadiazole polymer according to claim 1, characterized in that: In the step S1, the reaction temperature is 80-150° C. and the reaction time is 12-18 hours.
6. The method for preparing the novel modified oxadiazole polymer according to claim 1, characterized in that: In the step S2, the reaction time is 8-14 hours, and the reaction temperature is 120-135° C.; the detergent for multiple washings is saturated sodium bicarbonate or sodium hydroxide, purified water, or ethanol.
7. The method for preparing the novel modified oxadiazole polymer according to claim 1, characterized in that: In the step S3, the alcohol compound is any one of ethylene glycol, propylene glycol, butylene glycol and hexylene glycol; the molar ratio of the alcohol compound to the oxadiazole ester compound in step S2 is 1.3:1-1.8:1; the catalyst is any one or more of antimony trioxide, titanium dioxide, germanium oxide, zirconium oxide and tungsten oxide, and the catalyst accounts for 10-15% of the total material mass ratio; the stabilizer is any one or more of phosphoric acid, acetic acid and nitric acid, and the stabilizer accounts for 10-15% of the total material mass ratio.
8. The method for preparing the novel modified oxadiazole polymer according to claim 1, characterized in that: In step S3, the reaction temperature is 275-290 degrees and the reaction time is 6-10 hours.
9. A novel modified oxadiazole polymer prepared according to the method for preparing a novel modified oxadiazole polymer according to claim 1.
10. Use of the novel modified oxadiazole polymer according to claim 9, characterized in that: The polymer is melt-molded into dumbbell-shaped sheets through high-temperature injection, and is prepared into high-strength foam plastics.