Preparation method and application of high-strength polyarylene ether nitrile

Abstract

The invention discloses a preparation method and application of high-strength polyarylene ether nitrile, and belongs to the technical field of special polymer synthesis. The method comprises the following steps: adding 2, 5-dichlorobenzonitrile, dihydric phenol, a catalyst, a dehydrating agent and an antioxidant into an ionic liquid; under the protection of nitrogen, a first stage; pre-polymerizing for 1-2 hours at 115-125 DEG C, and dehydrating; in the second stage, the temperature is raised to 155-165 DEG C, and the reaction is continued for 3-5 hours; in the third stage, the temperature is raised to 175-195 DEG C, and the high-strength polyarylene ether nitrile is continuously reacted for 3-5 hours; wherein the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate, the dehydrating agent is toluene, the antioxidant is triphenyl phosphite, the catalyst is selected from potassium carbonate or sodium carbonate, and the use amount of the antioxidant is 0.2-1.0% of the mass of the dihydric phenol. The polyarylene ether nitrile prepared by the invention has relatively high intrinsic viscosity, relatively narrow molecular weight distribution and relatively high mechanical strength.

Description

Technical Field

[0001] The present invention relates to the technical field of special polymer synthesis, and in particular to a preparation method of high-strength polyarylethernitrile and application thereof. Background Art

[0002] Polyarylene ether nitrile (PEN) is one of the representative polyarylene ether polymers. It is a polymer with a relatively regular structure. Its main chain and side chains contain rigid benzene rings and nitrile groups, respectively, which make polyarylene ether nitrile have high temperature resistance and thermal stability. At the same time, the ether bonds on the main chain give it a certain degree of flexibility.

[0003] The reaction mechanisms of poly(arylene ether nitrile)s are primarily electrophilic and nucleophilic substitution. Due to the harsh reaction conditions of electrophilic substitution, it was gradually replaced by nucleophilic substitution. Currently, most reports on the synthesis of poly(arylene ether nitrile)s in China employ a one-step synthesis process, obtaining poly(arylene ether nitrile)s and their copolymers via nucleophilic substitution. Aromatic diphenols and 2,6-dihalobenzonitrile are first dissolved in a polar aprotic solvent. Under base catalysis, the poly(arylene ether nitrile)s are then synthesized through salt formation, dehydration, polycondensation, and purification stages to ultimately obtain the poly(arylene ether nitrile).

[0004] For example, patent application number CN202310224451.2 discloses a method for synthesizing poly(arylene ether nitrile) in one step using a DMAC solvent, comprising the following steps: a. Feeding: Under a protective atmosphere, feed the raw materials dihydric phenol, 2,6-dichlorobenzonitrile, alkali metal salt and DMAC solvent at one time, mix them evenly, and obtain a mixed material; wherein the DMAC solvent is N,N-dimethylacetamide.

[0005] b. Salt-forming reaction: keep the mixed materials at 120-160°C for 0.5-1h to carry out salt-forming reaction.

[0006] c. Dehydration: The material after the salt formation reaction is heated and controlled to 170-190°C for 3-4 hours to remove the DMAC solvent and the by-product water by azeotropic distillation.

[0007] d. Polycondensation reaction: Raise the temperature to 190-200°C and continue for 2-4 hours to complete the polymerization reaction.

[0008] e. Terminate the reaction to obtain polyarylene ether nitrile resin.

[0009] This patent uses 2,6-dichlorobenzonitrile as the raw material and produces polyarylethernitrile resin through salt formation, dehydration and polycondensation. Its weight-average molecular weight is greater than 110,000 and its flexural strength is greater than 100 MPa.

[0010] The applicant has discovered that if 2,5-dichlorobenzonitrile is used as a raw material, polyarylethernitrile with higher strength can be prepared under specific conditions. Summary of the Invention

[0011] In one aspect, the present invention discloses a method for preparing a high-strength poly(arylene ether nitrile). The method comprises: adding 2,5-dichlorobenzonitrile, dihydric phenol, a catalyst, a dehydrating agent, and an antioxidant to an ionic liquid; under nitrogen protection, performing a first stage of prepolymerization at 115-125°C for 1-2 hours for dehydration; a second stage of heating the reaction to 155-165°C and continuing the reaction for 3-5 hours; and a third stage of heating the reaction to 175-195°C and continuing the reaction for 3-5 hours to obtain the high-strength poly(arylene ether nitrile). The molar ratio of 2,5-dichlorobenzonitrile to dihydric phenol is 1:0.98-1.02, and the molar ratio of the catalyst to 2,5-dichlorobenzonitrile is 1.5-2.0:1. The ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate, the dehydrating agent is toluene, and the antioxidant is triphenyl phosphite. The catalyst is selected from potassium carbonate or sodium carbonate, preferably potassium carbonate. The dosage of the ionic liquid is 1.2-2.0 times the total mass of 2,5-dichlorobenzonitrile, dihydric phenol and catalyst, the dosage of the dehydrating agent is 1 / 5-1 / 2 of the volume of the ionic liquid, and the dosage of the antioxidant is 0.2-1.0% of the mass of the dihydric phenol.

[0012] The catalyst-ionic liquid composite system, with the ionic liquid acting as a phase transfer catalyst, accelerates the nucleophilic substitution reaction between monomers, shortening the reaction time by over 30%. The antioxidant provides in-situ protection, inhibiting the oxidation of diphenols and increasing the product's color (L* value) to 85 (compared to 70 using conventional methods).

[0013] The parameters of the prepared high-strength poly (arylene ether nitrile) are: viscosity average molecular weight of 50,000-100,000, PDI = 1.5-2.0, crystallinity of 20-25%, T 5% =505-550, intrinsic viscosity is 0.8-1.5dL / g, tensile strength is 120-150Mpa, tensile modulus is 2.5-4.2Gpa, and elongation at break is 6.4-11.3%.

[0014] The dihydric phenol is selected from 4,4'-biphenol, resorcinol or hydroquinone, etc.; preferably, the dihydric phenol is 4,4'-biphenol.

[0015] Furthermore, after the reaction is completed, water is added, and the solid-liquid separation, washing, and drying are performed to obtain high-strength polyarylethernitrile.

[0016] Preferably, the method for preparing high-strength poly(arylene ether nitrile) provided by the present invention comprises: (1) Add 2,5-dichlorobenzonitrile, 4,4'-biphenol, potassium carbonate, toluene and triphenyl phosphite to 1-butyl-3-methylimidazolium tetrafluoroborate. The molar ratio of 2,5-dichlorobenzonitrile to 4,4'-biphenol is 1:0.98-1.02, the molar ratio of potassium carbonate to 2,5-dichlorobenzonitrile is 1.5-2.0:1, the amount of 1-butyl-3-methylimidazolium tetrafluoroborate is 1.5 times the sum of the mass of 2,5-dichlorobenzonitrile, 4,4'-biphenol and potassium carbonate, the amount of toluene is 1 / 4 of the volume of 1-butyl-3-methylimidazolium tetrafluoroborate, and the amount of triphenyl phosphite is 0.5% of the mass of the dihydric phenol.

[0017] (2) Under nitrogen protection, the first stage: prepolymerization at 115-125 ° C for 1-2 hours to dehydrate; the second stage: heating to 155-165 ° C and continuing the reaction for 3-5 hours; the third stage: heating to 175-195 ° C and continuing the reaction for 3-5 hours.

[0018] (3) After the reaction is completed, water is added, and the high-strength polyarylether nitrile is obtained after solid-liquid separation, washing, and drying.

[0019] Under the optimized conditions, the parameters of the prepared high-strength poly(arylene ether nitrile) are as follows: viscosity average molecular weight 79000, PDI = 1.9, crystallinity 22.3%, T 5% =525, intrinsic viscosity is 1.3dL / g, tensile strength is 132Mpa, tensile modulus is 3.8Gpa, and elongation at break is 6.5%.

[0020] On the other hand, the polyarylethernitrile prepared by the aforementioned method can be used as a special engineering plastic, which has good heat resistance, low density and high strength. For example, it can be used to make impellers, equipment housings, pipes, lithium battery casings, etc.

[0021] The poly(arylene ether nitrile) prepared in this patent has a high intrinsic viscosity, a narrow molecular weight distribution, and very high strength (tensile strength can reach over 120 MPa). The product's color (L* value) is increased to 85, and its viscosity-average molecular weight (Mv) is greater than 50,000. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention are described in further detail below.

[0023] Example 1: (1) In a reaction kettle, add 11.7 g (9.67 mL) of 1-butyl-3-methylimidazolium tetrafluoroborate, 1.95 g (10 mmol) of 2,5-dichlorobenzonitrile, 1.86 g (10 mmol) of 4,4'-diphenol, 2.07 g (15 mmol) of potassium carbonate, 2.43 mL of toluene, and 10 mg of triphenyl phosphite.

[0024] (2) nitrogen is passed through to remove oxygen; The first stage: prepolymerization at 120℃ for 1.5 hours and dehydration; The second stage: heating to 160℃ and continuing the reaction for 3 hours; The third stage: heating to 190°C and continuing the reaction for 4 hours.

[0025] (3) After the reaction is completed, the reaction solution is cooled and poured into deionized water to precipitate the polymer, which is then filtered, washed with ethanol, and vacuum-dried at 80°C for 24 hours to obtain a white fibrous product.

[0026] FTIR: 2240cm - The characteristic peak of nitrile group is shown at 1240 cm - ¹ is the absorption peak of aromatic ether bond.

[0027] GPC: viscosity average molecular weight (Mv) is 64,000, PDI=1.9.

[0028] TGA: 5% weight loss temperature is 525℃, and the carbon residue rate at 800℃ is >55%.

[0029] The intrinsic viscosity is 1.3 dL / g (test conditions: 25°C, Nmp as solvent).

[0030] The product color (L* value) of the product is 86.

[0031] Example 2: (1) In a reaction kettle, add 9.72 g (8.0 mL) of 1-butyl-3-methylimidazolium tetrafluoroborate, 1.95 g (10 mmol) of 2,5-dichlorobenzonitrile, 1.1 g (10 mmol) of resorcinol, 2.35 g (17 mmol) of potassium carbonate, 3.8 mL of toluene, and 5 mg of triphenyl phosphite.

[0032] (2) nitrogen is passed through to remove oxygen; The first stage: prepolymerization at 122℃ for 1.5 hours and dehydration; The second stage: heating to 160℃ and continuing the reaction for 4 hours; The third stage: heating to 194°C and continuing the reaction for 4 hours.

[0033] (3) After the reaction is completed, the reaction solution is cooled and poured into deionized water to precipitate the polymer, which is then filtered, washed with ethanol, and vacuum-dried at 80°C for 24 hours to obtain a white fibrous product.

[0034] GPC: viscosity average molecular weight (Mv) is 71000, PDI=1.8.

[0035] TGA: 5% weight loss temperature is 513℃, and the carbon residue rate at 800℃ is >55%.

[0036] The intrinsic viscosity is 1.2 dL / g (test conditions: 25° C., Nmp as solvent).

[0037] The product color (L* value) of the product is 85.

[0038] Example 3: (1) In a reaction kettle, add 7.45 g (6.16 mL) of 1-butyl-3-methylimidazolium tetrafluoroborate, 1.95 g (10 mmol) of 2,5-dichlorobenzonitrile, 1.1 g (10 mmol) of hydroquinone, 2.07 g (15 mmol) of potassium carbonate, 1.6 mL of toluene, and 6 mg of triphenyl phosphite.

[0039] (2) nitrogen is passed through to remove oxygen; The first stage: prepolymerization at 120℃ for 1.5 hours and dehydration; The second stage: heating to 160℃ and continuing the reaction for 4 hours; The third stage: heating to 190°C and continuing the reaction for 4 hours.

[0040] (3) After the reaction is completed, the reaction solution is cooled and poured into deionized water to precipitate the polymer, which is then filtered, washed with ethanol, and vacuum-dried at 80°C for 24 hours to obtain a white fibrous product.

[0041] GPC: viscosity average molecular weight (Mv) is 79,000, PDI=1.9.

[0042] TGA: 5% weight loss temperature is 513℃, and the carbon residue rate at 800℃ is >55%.

[0043] The intrinsic viscosity is 1.3 dL / g (test conditions: 25°C, Nmp as solvent).

[0044] The product color (L* value) of the product is 85.

[0045] Comparative Example 1 The reaction was basically the same as in Example 3, except that the reaction temperature was kept constant at 180° C. The intrinsic viscosity of the product was only 0.6 dL / g, and the molecular weight distribution (PDI) was 3.1.

[0046] Comparative Example 2 The reaction was essentially the same as in Example 3, except that DMAC was used instead of 1-butyl-3-methylimidazolium tetrafluoroborate. The amount of DMAC was 5 times the amount of the starting material, and the total reaction time was 12 h. The product had an intrinsic viscosity of 1.1 dL / g and a molecular weight distribution (PDI) of 2.3.

[0047] Comparative Example 3 The process with application number CN202310224451.2 is used, with 2,6-dichlorobenzonitrile and bisphenol A as raw materials. The product has an intrinsic viscosity of 0.9 dL / g and a molecular weight distribution PDI of 2.7.

[0048] The comparative effects of this patent, the comparative examples and the commercially available products are shown in Table 1: Table 1

[0049] Table 2

[0050] As can be seen from Table 1, the thermal stability of this patent is better than that of the existing polyarylethernitrile, and it has a higher intrinsic viscosity and a narrow molecular weight distribution.

[0051] As can be seen from Table 2, the tensile strength of the product of this patent is better than that of the commercially available product.

[0052] 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 principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing high-strength poly(arylene ether nitrile), characterized in that: The method comprises: adding 2,5-dichlorobenzonitrile, dihydric phenol, catalyst, dehydrating agent and antioxidant into ionic liquid; under nitrogen protection, in the first stage: prepolymerizing at 115-125° C. for 1-2 hours for dehydration; in the second stage: heating to 155-165° C. and continuing reaction for 3-5 hours; in the third stage: heating to 175-195° C. and continuing reaction for 3-5 hours to obtain high-strength polyarylethernitrile; wherein the molar ratio of the 2,5-dichlorobenzonitrile to the dihydric phenol is 1:0.98-1.02, the catalyst and The molar ratio of 2,5-dichlorobenzonitrile to diphenol is 1.5-2.0:1, the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate, the dehydrating agent is toluene, the antioxidant is triphenyl phosphite, and the catalyst is selected from potassium carbonate or sodium carbonate. The amount of the ionic liquid is 1.2-2.0 times the sum of the mass of 2,5-dichlorobenzonitrile, diphenol and catalyst, the amount of the dehydrating agent is 1 / 5-1 / 2 of the volume of the ionic liquid, and the amount of the antioxidant is 0.2-1.0% of the mass of the diphenol.

2. The method for preparing high-strength poly(arylene ether nitrile) according to claim 1, wherein The dihydric phenol is selected from 4,4'-biphenol, resorcinol or hydroquinone.

3. The method for preparing high-strength poly (arylene ether nitrile) according to claim 1, wherein: The dihydric phenol is 4,4'-biphenyl diphenol.

4. The method for preparing high-strength polyarylene ether nitrile according to claim 1, wherein The catalyst is potassium carbonate.

5. The method for preparing high-strength poly (arylene ether nitrile) according to claim 1, wherein After the reaction is completed, water is added, and the high-strength polyarylether nitrile is obtained after solid-liquid separation, washing, and drying.

6. The method for preparing high-strength poly(arylene ether nitrile) according to claim 1, wherein: The method comprises: (1) Adding 2,5-dichlorobenzonitrile, 4,4'-biphenol, potassium carbonate, toluene and triphenyl phosphite to 1-butyl-3-methylimidazolium tetrafluoroborate, wherein the molar ratio of 2,5-dichlorobenzonitrile to 4,4'-biphenol is 1:0.98-1.02, the molar ratio of potassium carbonate to 2,5-dichlorobenzonitrile is 1.5-2.0:1, the amount of 1-butyl-3-methylimidazolium tetrafluoroborate is 1.5 times the sum of the mass of 2,5-dichlorobenzonitrile, 4,4'-biphenol and potassium carbonate, the amount of toluene is 1 / 4 of the volume of 1-butyl-3-methylimidazolium tetrafluoroborate, and the amount of triphenyl phosphite is 0.5% of the mass of the dihydric phenol; (2) Under nitrogen protection, the first stage: prepolymerization at 115-125 ° C for 1-2 hours for dehydration; the second stage: heating to 155-165 ° C and continuing the reaction for 3-5 hours; the third stage: heating to 175-195 ° C and continuing the reaction for 3-5 hours; (3) After the reaction is completed, water is added, and the high-strength polyarylether nitrile is obtained after solid-liquid separation, washing, and drying.

7. The method for preparing high-strength poly (arylene ether nitrile) according to claim 1, wherein: The parameters of the prepared high-strength poly (arylene ether nitrile) are: The viscosity average molecular weight is 50000-100000, PDI=1.5-2.0, crystallinity is 20-25%, T 5% =505-550, intrinsic viscosity is 0.8-1.5dL / g, tensile strength is 120-150Mpa, tensile modulus is 2.5-4.2Gpa, and elongation at break is 6.4-11.3%.

8. The method for preparing high-strength poly(arylene ether nitrile) according to claim 6, wherein: The parameters of the prepared high-strength poly (arylene ether nitrile) are: viscosity average molecular weight 79000, PDI = 1.9, crystallinity 22.3%, T 5% =525, intrinsic viscosity is 1.3dL / g, tensile strength is 132Mpa, tensile modulus is 3.8Gpa, and elongation at break is 6.5%.

9. Use of the polyarylene ether nitrile prepared by the method according to any one of claims 1 to 8 in special engineering plastics.

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