A method for preparing a heat-stable bio-based polyarylate

Abstract

This application provides a method for preparing a heat-stable bio-based polyarylate, belonging to the field of high-performance polymer technology. A bio-based bisphenol monomer is dissolved in deionized water to obtain an aqueous phase system; an aromatic dichloro monomer is dissolved in an organic solvent to obtain an organic phase system; the aqueous and organic phase systems are mixed and subjected to an interfacial reaction; a precipitant is added to the separated organic phase to induce precipitation; the precipitate is collected, washed, and dried to obtain a heat-stable bio-based polyarylate with a glass transition temperature of 120-200℃ and a thermal decomposition temperature ≥350℃. This method has advantages such as high safety, green and sustainable raw materials, and good thermal stability and mechanical properties of the finished product.

Description

Technical Field

[0001] This application relates to a bio-based polyarylate and its preparation method, belonging to the field of high-performance polymer technology. Background Technology

[0002] Polyarylates (PARs) are a class of high-performance engineering plastics with excellent thermal stability, mechanical properties, and dielectric properties, and are widely used in high-end fields such as electronics, automobile manufacturing, and aerospace. The traditional synthesis of PARs mainly relies on petroleum-based bisphenol monomers and aromatic diacyl chlorides. However, the non-renewable nature of petroleum resources and the significant harm that petroleum-based monomers pose to human health and the environment are problems.

[0003] Compared to petroleum-based phenolic monomers like bisphenol A, bio-based bisphenols have irreplaceable advantages in terms of resource sustainability, biosafety, environmental compatibility, and performance adjustability, making them an ideal alternative to bisphenol A. Current research on the preparation of bio-based bisphenols has achieved key breakthroughs in areas such as the elucidation of lignin condensation mechanisms, regulation of directional transformation pathways, development of green synthesis processes, and verification of material properties. For example, in 2023, the team led by Shuai Li at Fujian Agriculture and Forestry University successfully achieved efficient depolymerization and produced diarylmethane-type bisphenols by treating condensed lignin with phenol, achieving a yield of 42% (GONG ZG, YANG GX, SHUAI L, LUO X L. Chemical Engineering Journal, 2023, 455: 140628). The team led by Wang Feng introduced eugenol as a scavenging agent during formic acid pulping to obtain lignin with highly condensed α-carbons, and then prepared diarylethane-type bisphenols via hydrogenation aryl transfer reaction, achieving a maximum yield of 48% (LI N, WANG F, SAMEC J, et al. Nature, 2024, 630: 381-386).

[0004] Among renewable raw materials such as lignin, non-estrogenically active bio-based bisphenols (such as guaiacol F) can be copolymerized with aromatic dichloro monomers to prepare polyesters with properties comparable to bisphenol A-based materials. These polyesters possess both good thermal stability and flexibility, and pose no risk of endocrine disruption, providing a replicable R&D paradigm for replacing traditional toxic bisphenols. Currently, the preparation of bio-based bisphenols such as guaiacol is relatively mature and has achieved industrial-scale production, providing an industrial foundation for further replacing bisphenol S applications. However, research on polyarylates based on bio-based bisphenols is rarely reported. Summary of the Invention

[0005] In view of this, this application first provides a method for preparing a heat-stable bio-based polyarylate, which can achieve the preparation of polyarylates with good thermal stability, excellent mechanical properties, and high safety.

[0006] Specifically, this application is implemented through the following scheme: A method for preparing a heat-stable bio-based polyarylate, comprising the following steps: Step 1: At room temperature, the bio-based bisphenol monomer is dissolved in deionized water by stirring to obtain a homogeneous and transparent aqueous phase system; Step 2: At room temperature, the aromatic dichloro monomer is stirred and dissolved in an organic solvent to obtain a homogeneous and transparent organic phase system. Step 3: Mix the aqueous phase system obtained in Step 1 with the organic phase system obtained in Step 2 and react at the interface in a constant temperature water bath. Stop stirring and the constant temperature water bath. After the system settles and separates into layers, separate the organic phase. Add a precipitant to the organic phase to carry out a precipitation reaction. After the polymer is fully separated under the action of the precipitant, collect the precipitate, wash it, and dry it to obtain a heat-stable bio-based polyarylate with a glass transition temperature of 120~200℃ and a thermal decomposition temperature ≥350℃.

[0007] Furthermore, as a preferred option: The bio-based bisphenol monomer is a guaiacol monomer, which avoids the adverse effects of impurities on the activity, molecular weight and performance of subsequent interfacial reactions.

[0008] In step one, the pH is adjusted to 10-14 for dissolution. More preferably, the pH is adjusted using one or more of sodium hydroxide or potassium hydroxide.

[0009] The aromatic dichloro monomer is a mixture of terephthaloyl chloride and isophthaloyl chloride, with a molar ratio of terephthaloyl chloride to isophthaloyl chloride of 3:7 to 7:3.

[0010] The organic solvent is dichloromethane or tetrachloromethane.

[0011] The molar ratio of the bio-based bisphenol monomer to the aromatic dichloro monomer is 1:0.9 to 1:1.1.

[0012] The precipitant is methanol, ethanol, or propanol.

[0013] The temperature of the interface reaction is 10~20℃. Too high a temperature may cause the monomer to react rapidly and trigger side reactions, while too low a temperature will reduce the reaction rate and prolong the reaction time.

[0014] The reaction time of the interface reaction is 1 to 3 hours, which effectively ensures that the interface reaction is fully carried out.

[0015] The stirring and mixing speed is 200~300 r / min.

[0016] The washing process involves washing with deionized water 2-3 times.

[0017] The drying process is vacuum drying, with a drying temperature of 50~80℃ and a drying time of 6~12 hours.

[0018] The applicant's second objective is to provide a heat-stable bio-based polyarylate prepared by the above method, wherein the number-average molecular weight of the heat-stable bio-based polyarylate is 1.0 × 10⁻⁶. 4 ~5.0×10 4 g / mol, with a breaking strength of 65~85 MPa and a tensile modulus of 2.0~2.5 GPa.

[0019] The applicant's third objective is to provide the applications of the aforementioned heat-stable bio-based polyarylates in food contact materials, medical devices, electronic and electrical enclosures, medium- and high-performance fibers, and environmentally friendly packaging materials.

[0020] Compared with the prior art, this application has the following advantages: 1) This invention uses renewable guaiacol monomers to replace traditional petroleum-based bisphenol monomers such as bisphenol A. The raw material source is green and sustainable, which reduces the dependence of polyarylates on petroleum resources and avoids the environmental and health risks brought by petroleum-based monomers, which is in line with the trend of green chemical development.

[0021] 2) Bisphenol A (BPA) is a typical endocrine disruptor with strong estrogenic activity and even potential carcinogenic risks. Therefore, it cannot be used in fields with extremely high safety requirements, such as infant products, food contact materials, medical devices, cosmetic packaging, and drinking water contact components. This application introduces a guaiacol monomer (preferably 4,4′-methylenebis(2-methoxyphenol), with a relative molecular weight of 260.29) during the preparation of polyarylates. This monomer, in combination with an aromatic dichloro monomer, forms a steric hindrance due to the methoxy group (-OCH3) on the benzene ring of the guaiacol monomer, effectively blocking the binding of the monomer to estrogen receptors. It exhibits no estrogenic activity, low toxicity, and good biocompatibility. No harmful byproducts are generated during the preparation process, and no free toxic or harmful substances are released after polymerization. The prepared polyarylates can be safely used in scenarios where bisphenol A type polyarylates are prohibited or restricted, such as infant products, food contact materials, medical devices, cosmetic packaging, drinking water contact components, maternal and infant products, and catering utensils. They can pass mainstream global safety certifications, which greatly expands the application boundaries of polyarylate materials and enhances the compliance and market competitiveness of products.

[0022] 3) Compared with niche diphenol bio-based monomers such as cashew phenol and biphenyl, this invention uses guaiacol monomers to form an aqueous phase and react with the organic phase at the interface. Under the same polymerization process conditions, the monomer raw material cost of this invention is lower, the unit consumption is lower, and the synthesis yield is higher. Its core raw materials are widely available and easy to obtain, which effectively reduces the overall production cost of unit products and can better meet the actual needs of large-scale industrial applications. Detailed Implementation

[0023] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the technical solutions of this application will be further described in detail below with reference to specific examples in the embodiments of this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit the technical solutions of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Example 1

[0025] This embodiment provides a heat-stable bio-based polyarylate, using terephthaloyl chloride and isophthaloyl chloride as aromatic dichloro monomers, and feeding them in a molar ratio of guaiacol monomer to aromatic dichloro monomer of 1:0.9. The preparation process is as follows: Step 1, Preparation of the aqueous system: Add the guaiacol monomer (i.e., 2-methoxyphenol, C7H8O2, molecular weight 124.13) to deionized water, add sodium hydroxide to adjust the pH to 10, and stir until the guaiacol monomer is completely dissolved to obtain the aqueous system.

[0026] Step 2, preparation of the organic phase system: Terephthaloyl chloride and isophthaloyl chloride are added to dichloromethane according to the molar ratio of terephthaloyl chloride: isophthaloyl chloride = 3:7, and stirred until completely dissolved to obtain the organic phase system.

[0027] Step 3, interfacial polymerization reaction: The aqueous phase and organic phase obtained in the above steps are mixed, and the interfacial polycondensation reaction is carried out for 1 hour under the control of 10℃ and mechanical stirring (speed of about 250r / min).

[0028] Step 4, Post-processing: After the reaction is complete, separate the organic phase, add methanol to the organic phase to precipitate, collect the precipitate, wash it three times with deionized water, and dry it under vacuum at 50°C for 6 hours to obtain the final product.

[0029] The number-average molecular weight of the heat-stable bio-based polyarylate prepared by this method was tested to be 1.0 × 10⁻⁶. 4 g / mol, tensile strength of 65 MPa, tensile modulus of 2.0 GPa, glass transition temperature of 120 °C, and thermal decomposition temperature of 350 °C.

[0030] Example 2

[0031] This embodiment provides a heat-stable bio-based polyarylate, using terephthaloyl chloride and isophthaloyl chloride as aromatic dichloro monomers, and feeding them in a molar ratio of guaiacol monomer to aromatic dichloro monomer of 1:1. The preparation process is as follows: Step 1, Preparation of the aqueous system: Add the guaiacol monomer (i.e., 2-methoxyphenol, C7H8O2, molecular weight 124.13) to deionized water, add sodium hydroxide to adjust the pH to 12, and stir until the guaiacol monomer is completely dissolved to obtain the aqueous system.

[0032] Step 2, preparation of the organic phase system: Terephthaloyl chloride and isophthaloyl chloride are added to dichloromethane according to the molar ratio of terephthaloyl chloride: isophthaloyl chloride = 5:5, and stirred until completely dissolved to obtain the organic phase system.

[0033] Step 3, interfacial polymerization reaction: The aqueous phase and organic phase obtained in the above steps are mixed, and the interfacial polycondensation reaction is carried out for 2 hours under the control of 15℃ and mechanical stirring (rotation speed of about 250r / min).

[0034] Step 4, post-processing: After the reaction is complete, separate the organic phase, add ethanol to the organic phase to precipitate, collect the precipitate, wash it three times with deionized water, and dry it under vacuum at 65°C for 9 hours to obtain the final product.

[0035] The number-average molecular weight of the heat-stable bio-based polyarylate prepared by this method was tested to be 2.6 × 10⁻⁶. 4 It has a g / mol content, a tensile strength of 72 MPa, a tensile modulus of 2.2 GPa, a glass transition temperature of 140 °C, and a thermal decomposition temperature of 360 °C.

[0036] Example 3

[0037] This embodiment provides a heat-stable bio-based polyarylate, using terephthaloyl chloride and isophthaloyl chloride as aromatic dichloro monomers, and feeding them in a molar ratio of guaiacol monomer to aromatic dichloro monomer of 1:1.1. The preparation process is as follows: Step 1, Preparation of the aqueous system: Add the guaiacol monomer (i.e., 2-methoxyphenol, C7H8O2, molecular weight 124.13) to deionized water, add sodium hydroxide to adjust the pH to 14, and stir until the guaiacol monomer is completely dissolved to obtain the aqueous system.

[0038] Step 2, preparation of the organic phase system: Terephthaloyl chloride and isophthaloyl chloride are added to dichloromethane according to the molar ratio of terephthaloyl chloride: isophthaloyl chloride = 7:3, and stirred until completely dissolved to obtain the organic phase system.

[0039] Step 3, interfacial polymerization reaction: The aqueous phase and organic phase obtained in the above steps are mixed, and the interfacial polycondensation reaction is carried out for 3 hours under the control of 20℃ and mechanical stirring (rotation speed of about 250r / min).

[0040] Step 4, post-processing: After the reaction is complete, the organic phase is separated, propanol is added to the organic phase for precipitation, the precipitate is collected, washed three times with deionized water, and dried under vacuum at 80°C for 12 hours to obtain the final product.

[0041] The number-average molecular weight of the heat-stable bio-based polyarylate prepared by this method was tested to be 5.0 × 10⁻⁶. 4 g / mol, tensile strength of 85 MPa, tensile modulus of 2.5 GPa, glass transition temperature of 200 ℃, thermal decomposition temperature of 375 ℃.

[0042] Example 4

[0043] This embodiment provides a heat-stable bio-based polyarylate, using terephthaloyl chloride and isophthaloyl chloride as aromatic dichloro monomers, and feeding them in a molar ratio of guaiacol monomer to aromatic dichloro monomer of 1:0.9. The preparation process is as follows: Step 1, Preparation of the aqueous system: Add the guaiacol monomer (i.e., 2-methoxyphenol, C7H8O2, molecular weight 124.13) to deionized water, add potassium hydroxide to adjust the pH to 10, and stir until the guaiacol monomer is completely dissolved to obtain the aqueous system.

[0044] Step 2, preparation of the organic phase system: Terephthaloyl chloride and isophthaloyl chloride are added to tetrachloromethane according to the molar ratio of terephthaloyl chloride: isophthaloyl chloride = 3:7, and stirred until completely dissolved to obtain the organic phase system.

[0045] Step 3, interfacial polymerization reaction: The aqueous phase and organic phase obtained in the above steps are mixed, and the interfacial polycondensation reaction is carried out for 1 hour under the control of 10℃ and mechanical stirring (speed of about 250r / min).

[0046] Step 4, Post-processing: After the reaction is complete, separate the organic phase, add methanol to the organic phase to precipitate, collect the precipitate, wash it three times with deionized water, and dry it under vacuum at 50°C for 6 hours to obtain the final product.

[0047] The number-average molecular weight of the heat-stable bio-based polyarylate prepared by this method was tested to be 1.1 × 10⁻⁶. 4 It has a g / mol content, a tensile strength of 67 MPa, a tensile modulus of 2.1 GPa, a glass transition temperature of 125 °C, and a thermal decomposition temperature of 355 °C.

[0048] Example 5

[0049] This embodiment provides a heat-stable bio-based polyarylate, using terephthaloyl chloride and isophthaloyl chloride as aromatic dichloro monomers, and feeding them in a molar ratio of guaiacol monomer to aromatic dichloro monomer of 1:1. The preparation process is as follows: Step 1, Preparation of the aqueous system: Add the guaiacol monomer (i.e., 2-methoxyphenol, C7H8O2, molecular weight 124.13) to deionized water, add potassium hydroxide to adjust the pH to 12, and stir until the guaiacol monomer is completely dissolved to obtain the aqueous system.

[0050] Step 2, preparation of the organic phase system: Terephthaloyl chloride and isophthaloyl chloride are added to tetrachloromethane according to the molar ratio of terephthaloyl chloride: isophthaloyl chloride = 5:5, and stirred until completely dissolved to obtain the organic phase system.

[0051] Step 3, interfacial polymerization reaction: The aqueous phase and organic phase obtained in the above steps are mixed, and the interfacial polycondensation reaction is carried out for 2 hours under the control of 15℃ and mechanical stirring conditions (speed of about 250r / min).

[0052] Step 4, post-processing: After the reaction is complete, separate the organic phase, add ethanol to the organic phase to precipitate, collect the precipitate, wash it three times with deionized water, and dry it under vacuum at 65°C for 9 hours to obtain the final product.

[0053] The number-average molecular weight of the heat-stable bio-based polyarylate prepared by this method was tested to be 3.2 × 10⁻⁶. 4 It has a g / mol content, a tensile strength of 77 MPa, a tensile modulus of 2.3 GPa, a glass transition temperature of 155 °C, and a thermal decomposition temperature of 370 °C.

[0054] Example 6

[0055] This embodiment provides a heat-stable bio-based polyarylate, using terephthaloyl chloride and isophthaloyl chloride as aromatic dichloro monomers, and feeding them in a molar ratio of guaiacol monomer to aromatic dichloro monomer of 1:1.1. The preparation process is as follows: Step 1, Preparation of the aqueous system: Add the guaiacol monomer (i.e., 2-methoxyphenol, C7H8O2, molecular weight 124.13) to deionized water, add potassium hydroxide to adjust the pH to 12, and stir until the guaiacol monomer is completely dissolved to obtain the aqueous system.

[0056] Step 2, preparation of the organic phase system: Terephthaloyl chloride and isophthaloyl chloride are added to tetrachloromethane according to the molar ratio of terephthaloyl chloride: isophthaloyl chloride = 7:3, and stirred until completely dissolved to obtain the organic phase system.

[0057] Step 3, interfacial polymerization reaction: The aqueous phase and organic phase obtained in the above steps are mixed, and the interfacial polycondensation reaction is carried out for 3 hours under the control of 20℃ and mechanical stirring conditions (speed of about 250r / min).

[0058] Step 4, post-processing: After the reaction is complete, the organic phase is separated, propanol is added to the organic phase for precipitation, the precipitate is collected, washed three times with deionized water, and dried under vacuum at 80°C for 12 hours to obtain the final product.

[0059] The number-average molecular weight of the heat-stable bio-based polyarylate prepared by this method was tested to be 4.8 × 10⁻⁶. 4 g / mol, tensile strength of 80 MPa, tensile modulus of 2.5 GPa, glass transition temperature of 190 °C, and thermal decomposition temperature of 380 °C.

[0060] Comparative Example 1

[0061] This comparative example provides a conventional bisphenol A type polyarylate, using terephthaloyl chloride and isophthaloyl chloride as aromatic dichloro monomers, with a molar ratio of bisphenol A to aromatic dichloro monomers of 1:1. The preparation process is as follows: Step 1, Preparation of the aqueous system: Bisphenol A (i.e., 2,2-bis(4-hydroxyphenyl)propane, C 15 H 16 O2 (molecular weight 228.29) was added to deionized water, sodium hydroxide was added to adjust the pH to 12, and the mixture was stirred until bisphenol A was completely dissolved to obtain an aqueous system.

[0062] Step 2, preparation of the organic phase system: Terephthaloyl chloride and isophthaloyl chloride are added to dichloromethane at a molar ratio of 5:5 and stirred until completely dissolved to obtain the organic phase system.

[0063] Step 3, interfacial polymerization reaction: The aqueous phase and organic phase obtained in the above steps are mixed, and the interfacial polycondensation reaction is carried out for 3 h under the control of 15℃ and mechanical stirring conditions (speed of about 250 r / min).

[0064] Step 4, post-processing: After the reaction is complete, the organic phase is separated, ethanol is added to the organic phase for precipitation, the precipitate is collected, washed three times with deionized water, and dried under vacuum at 80 °C for 6 h to obtain the final product.

[0065] The number-average molecular weight of the bisphenol A type polyarylate prepared by this method was tested to be 3.0 × 10⁻⁶. 4 g / mol, tensile strength of 75 MPa, tensile modulus of 2.2 GPa, glass transition temperature of 152 °C, and thermal decomposition temperature of 365 °C.

[0066] Comparative Example 1 prepared polyarylates via interfacial polymerization of bisphenol A with terephthaloyl chloride and isophthaloyl chloride. BPA is a petroleum-based chemical, dependent on fossil resources, and its production process generates phenolic wastewater and organic waste liquid, resulting in a significant environmental impact and contradicting the development trend of "two-carbon" and bio-based materials. Compared to Comparative Example 1, this application uses guaiacol monomers to replace bisphenol A in the preparation of polyarylates, offering the following significant advantages: 1) Significantly improved safety: The monomer has no estrogenic activity and low toxicity, and the prepared polyarylate can be safely used in food packaging, infant products, medical consumables and other scenarios where bisphenol A is prohibited; 2) Sustainability advantages: The monomer is derived from bio-based guaiacol, which is renewable and in line with the development trend of green materials.

[0067] The above-mentioned method uses guaiacol monomers as one of the raw materials, which inherently possesses the characteristics of sustainability and green and safe sourcing. Combined with the effects of the finished product, it can be seen that this method can replace bisphenol A in the preparation of polyarylates, without the non-renewable and safety issues associated with bisphenol A. Under a specific ratio of guaiacol monomers to aromatic dichloro compounds, the number-average molecular weight of the prepared polyarylates remains at 1.0 × 10⁻⁶. 4 ~4.8×10 4 The high g / mol content endows polyarylates with excellent mechanical properties such as tensile strength and tensile modulus. Its glass transition temperature is ≥120℃, thermal degradation temperature is ≥350℃, and it exhibits good thermal stability. Its application in food packaging films and other materials that come into direct contact with food, or in heat-sensitive or heat-generating devices such as electronic appliance casings, demonstrates excellent practicality and application effectiveness.

[0068] The above-described embodiments are merely illustrative of several feasible implementations of the present invention, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention, nor are the embodiments intended to limit the scope of protection in the claims of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention. All equivalent implementations or changes that do not depart from the present invention should be included in the technology of the present invention.

Claims

1. A method for preparing a heat-stable bio-based polyarylate, characterized in that, The steps are as follows: Step 1: Dissolve the bio-based bisphenol monomer in deionized water to obtain an aqueous system; Step 2: Dissolve the aromatic dichloro monomer in an organic solvent to obtain an organic phase system; Step 3: Mix the aqueous phase system obtained in Step 1 with the organic phase system obtained in Step 2 and perform an interfacial reaction. Then, add a precipitant to the separated organic phase to carry out a precipitation reaction. Collect the precipitate, wash it, and dry it to obtain a heat-stable bio-based polyarylate with a glass transition temperature of 120~200℃ and a thermal decomposition temperature of ≥350℃.

2. The method for preparing a heat-stable bio-based polyarylate according to claim 1, characterized in that: The bio-based bisphenol monomer is a guaiacol monomer.

3. The method for preparing a heat-stable bio-based polyarylate according to claim 1, characterized in that: In step one, adjust the pH to 10-14 to dissolve the substance.

4. The method for preparing a heat-stable bio-based polyarylate according to claim 3, characterized in that: The pH is adjusted using one or more of sodium hydroxide or potassium hydroxide.

5. The method for preparing a heat-stable bio-based polyarylate according to claim 1, characterized in that: The aromatic dichloro monomer is a mixture of terephthaloyl chloride and isophthaloyl chloride, with a molar ratio of terephthaloyl chloride to isophthaloyl chloride of 3:7 to 7:

3.

6. The method for preparing a heat-stable bio-based polyarylate according to claim 1, characterized in that: The organic solvent is dichloromethane or tetrachloromethane.

7. The method for preparing a heat-stable bio-based polyarylate according to claim 1, characterized in that: The molar ratio of the bio-based bisphenol monomer to the aromatic dichloro monomer is 1:0.9 to 1:1.

1.

8. The method for preparing a heat-stable bio-based polyarylate according to claim 1, characterized in that: The precipitant is methanol, ethanol, or propanol.

9. The method for preparing a heat-stable bio-based polyarylate according to claim 1, characterized in that: The temperature of the interfacial reaction is 10~20℃, and the reaction time is 1~3h.

10. The method for preparing a heat-stable bio-based polyarylate according to claim 1, characterized in that: The number-average molecular weight of bio-based polyarylates is 1.0 × 10⁻⁶. 4 ~5.0×10 4 g / mol, with a breaking strength of 65~85 MPa and a tensile modulus of 2.0~2.5 GPa.