Bio-based liquid crystal copolyester as well as preparation method and application thereof

Abstract

The invention provides bio-based liquid crystal copolyester as well as a preparation method and application thereof, and belongs to the field of high polymer materials. The preparation method of the bio-based liquid crystal copolyester comprises the following steps: adding four monomers, namely acetylated naphthoic acid, acetylated benzoic acid derivatives, 4-diacetoxybenzene and suberic acid, and a catalyst into a reaction container, and carrying out condensation polymerization to obtain the bio-based liquid crystal copolyester. The raw materials adopted by the invention are prepared by acetylation reaction of bio-based monomers, the problem that traditional liquid crystal polyester monomers are derived from fossil raw materials is solved, and the liquid crystal polyester has the advantages of environmental protection and sustainable development. The density of the prepared bio-based liquid crystal copolyester is 0.87-1.42 g / cm < 3 >, the melt index is 20-230, and the bio-based liquid crystal copolyester has the advantages of greenness, sustainability, excellent flowability, liquid crystal property, processability and the like. The bio-based liquid crystal copolyester fiber is obtained by drying the prepared bio-based liquid crystal copolyester and then spinning the dried bio-based liquid crystal copolyester.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to a bio-based liquid crystal copolyester and a preparation method thereof, and a preparation method of a bio-based liquid crystal copolyester fiber. Background Art

[0002] As a renewable energy source, biomass resources can not only be converted into gaseous, liquid, and solid clean fuels through physical, chemical, and biological conversion technologies, but can also be used to prepare fine chemicals such as polyester monomers. Therefore, using biomass resources instead of fossil resources has unique advantages.

[0003] Bio-based polyesters offer advantages such as abundant raw materials, low cost, minimal environmental impact, and low energy consumption. Currently, bio-based monomers obtained from crops such as corn and straw through catalytic conversion and other methods have been studied for use in the synthesis of bio-based polymers. Among these, the synthesis of (semi-)aromatic polymers from lignin derivatives has become a research hotspot. However, research on the synthesis of liquid crystal polyesters from lignin derivatives remains limited. Summary of the Invention

[0004] The purpose of this application is to provide a bio-based liquid crystal copolyester and its preparation method and a preparation method of bio-based liquid crystal copolyester fiber, which overcomes the problem that traditional liquid crystal polyester monomers are derived from fossil raw materials and has the advantages of being green, environmentally friendly and sustainable development.

[0005] In a first aspect, an embodiment of the present application provides a bio-based liquid crystal copolyester, the structural formula of the bio-based liquid crystal copolyester is shown in Formula I: I; Wherein, the value range of m in the structural formula is 10-500, and the value range of n is 10-500.

[0006] Furthermore, the R group in the structural formula is one or more of the following structures; .

[0007] Furthermore, the density of the bio-based liquid crystal copolyester is 0.87-1.42 g / cm 3 , melt index is 20-230.

[0008] In the second aspect, an embodiment of the present application provides a method for preparing a bio-based liquid crystal copolyester, which is used to prepare the bio-based liquid crystal copolyester described in any of the aforementioned technical solutions, comprising the following steps: adding four monomers, acetylated naphthoic acid, acetylated benzoic acid derivatives, 4-diacetoxybenzene, and suberic acid, and a catalyst into a reaction vessel for a condensation reaction to obtain the bio-based liquid crystal copolyester.

[0009] Furthermore, the acetylated benzoic acid derivative is one of acetylated p-coumaric acid, acetylated m-coumaric acid, acetylated ferulic acid, acetylated caffeic acid, acetylated vanillic acid and acetylated syringic acid.

[0010] Furthermore, during the polycondensation reaction, the reaction temperature is 100° C.-330° C., and the reaction time is 2 h-50 h.

[0011] Furthermore, the catalyst is one or more of sodium formate, sodium acetate, zinc acetate, magnesium acetate, sodium propionate, and sodium alginate.

[0012] Furthermore, the molar ratio of the acetylated naphthoic acid to the acetylated benzoic acid derivative is 1:1, the molar ratio of the 4-diacetoxybenzene to suberic acid is 1:1, and the molar ratio of the total molar amount of the acetylated naphthoic acid and the acetylated benzoic acid derivative to the total molar amount of 4-diacetoxybenzene and suberic acid is 1:(0.1-10).

[0013] Furthermore, the amount of the catalyst used is 0.1%-10% of the total mass of the four monomers.

[0014] In a third aspect, an embodiment of the present application provides a method for preparing a bio-based liquid crystal copolyester fiber, using the bio-based liquid crystal copolyester described in any of the foregoing items, comprising the following steps: melt-extruding the bio-based liquid crystal copolyester through a screw at 280°C-340°C into a spinning beam, then entering a booster pump and a metering pump, and ejecting the bio-based liquid crystal copolyester through a spinneret of a spinning assembly to form a filament, which is then cooled and wound in an air cooling zone to obtain a bio-based liquid crystal copolyester fiber; wherein the spinning beam temperature is 280°C-340°C, the booster pump speed is 5-100 rpm, the metering pump speed is 5-100 rpm, the spinneret aperture is 0.15-0.25 mm, and the air cooling zone temperature is 10-100°C.

[0015] The beneficial effects of the present invention are: (1) The present invention provides a method for preparing a bio-based liquid crystal copolyester. Four monomers, acetylated naphthoic acid, acetylated ferulic acid, 4-diacetoxybenzene, and suberic acid, and a catalyst are added to a reaction vessel for polycondensation to produce a bio-based liquid crystal copolyester. This method overcomes the problem that conventional liquid crystal polyester monomers are derived from fossil raw materials and has the advantages of being green, environmentally friendly, and sustainable.

[0016] (2) The density of the bio-based liquid crystal copolyester prepared by the present invention is 0.87-1.42 g / cm 3 , melt index is 20-230. It has the advantages of green sustainability and excellent fluidity, liquid crystal properties, and processability.

[0017] (3) The preparation method of the bio-based liquid crystal copolyester fiber of the present invention solves the fiber-forming problems existing in the prior art, such as poor fluidity of the liquid crystal polymer itself, narrow processing window, and easy breakage of the fiber.

[0018] (4) The preparation method of the bio-based liquid crystal copolyester fiber of the present invention is easy to control the conditions and has good production repeatability. The prepared liquid crystal polyester fiber can replace the traditional petroleum-based liquid crystal polyester and be used in the fields of protective equipment, airship skins and cable reinforcement materials.

[0019] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0021] Figure 1 This is the infrared spectrum of the bio-based liquid crystal copolyester prepared in Example 1.

[0022] Figure 2 This is a polarizing microscope image of the bio-based liquid crystal copolyester prepared in Example 1.

[0023] Figure 3 This is the thermogravimetric analysis diagram of the bio-based liquid crystal copolyester prepared in Example 1.

[0024] Figure 4 This is a physical picture of the bio-based liquid crystal copolyester fiber prepared in Example 1.

[0025] Figure 5 This is a storage modulus diagram of the bio-based liquid crystal copolyester fiber prepared in Example 1.

[0026] Figure 6 This is a polarizing microscope image of the polymer prepared in Comparative Example 2. DETAILED DESCRIPTION

[0027] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0029] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0030] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0032] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0033] For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0034] Please refer to Figures 1 to Figure 6 As shown, the present application provides a bio-based liquid crystal copolyester, the structural formula of the bio-based liquid crystal copolyester is shown in Formula I: I; Wherein, the value range of m in the structural formula is 10-500, and the value range of n is 10-500.

[0035] The R group in the structural formula is one or more of the following structures; .

[0036] The density of bio-based liquid crystal copolyester is 0.87-1.42 g / cm 3 , melt index is 20-230.

[0037] The present application also provides a method for preparing a bio-based liquid crystal copolyester, comprising the following steps: adding four monomers, acetylated naphthoic acid, acetylated benzoic acid derivatives, 4-diacetoxybenzene, and suberic acid, and a catalyst into a reaction vessel for a polycondensation reaction to obtain the bio-based liquid crystal copolyester.

[0038] The acetylated benzoic acid derivative is one of acetylated p-coumaric acid, acetylated m-coumaric acid, acetylated ferulic acid, acetylated caffeic acid, acetylated vanillic acid and acetylated syringic acid.

[0039] Specifically, during the polycondensation reaction, the reaction temperature is 100° C.-330° C., and the reaction time is 2 h-50 h.

[0040] The molar ratio of acetylated naphthoic acid to the acetylated benzoic acid derivative is 1:1, the molar ratio of 4-diacetoxybenzene to suberic acid is 1:1, and the molar ratio of the total molar amount of acetylated naphthoic acid and the acetylated benzoic acid derivative to the total molar amount of 4-diacetoxybenzene and suberic acid is 1:(0.1-10).

[0041] The amount of the catalyst used is 0.1%-10% of the total mass of the four monomers.

[0042] The catalyst is one or more of sodium formate, sodium acetate, zinc acetate, magnesium acetate, sodium propionate and sodium alginate.

[0043] The present application also provides a method for preparing bio-based liquid crystal copolyester fiber, which uses the aforementioned bio-based liquid crystal copolyester and includes the following steps: the bio-based liquid crystal copolyester is melt-extruded into a spinning box through a screw at 280°C-340°C, then enters a booster pump and a metering pump, and is ejected through the spinneret of the spinning assembly to form filaments, which are then cooled and wound in an air cooling zone to obtain bio-based liquid crystal copolyester fiber.

[0044] Among them, the spinning box temperature is 280℃-340℃, the speed of the booster pump is 5-100 rpm, the speed of the metering pump is 5-100 rpm, the aperture of the spinneret is 0.15-0.25mm, the number of holes in the spinneret is 8-32, the air cooling zone temperature is 10-100℃, and the winding speed is 100-5000m / min.

[0045] The bio-based liquid crystal copolyester fiber produced has a diameter of 0.5-100µm and has high strength, modulus, excellent heat resistance, chemical corrosion resistance and low moisture absorption. It can be used in fields such as airship skins and cable reinforcement materials.

[0046] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are all commercially available conventional products.

[0047] Example 1 This embodiment provides a method for preparing a bio-based liquid crystal copolyester fiber, comprising the following steps: In step S1, acetylated naphthoic acid (20.70 g, 0.1 mol), acetylated ferulic acid (21.30 g, 0.1 mol), 4-diacetoxybenzene (1.9695 g, 0.01 mol), suberic acid (1.7485 g, 0.01 mol), and sodium acetate (0.23 g, 0.5 wt%) were added to a polymerization apparatus and heated with stirring. The reaction was continued at 260°C for 3 h before being terminated. The product was then washed three times with deionized water and filtered. The crude solid was collected and dried under vacuum at 60°C for 24 h. The polymer product (bio-based liquid crystal copolyester) was obtained in a yield of 76.3%.

[0048] S2, the prepared bio-based liquid crystal copolyester is melted through a screw with a melting section temperature of 300°C, extruded into a spinning manifold with a spinning manifold temperature of 310°C, and then enters a booster pump with a rotation speed of 15 rpm and a metering pump with a rotation speed of 17 rpm. Subsequently, it is ejected through the spinneret of the spinning assembly to form filaments, and then cooled and wound in an air cooling zone to obtain bio-based liquid crystal copolyester fibers.

[0049] The spinneret aperture is 0.15 mm, the number of spinneret holes is 8, the air cooling zone temperature is 80° C., and the winding speed is 500 m / min.

[0050] Figure 1 This is the infrared spectrum of the bio-based liquid crystal copolyester prepared in Example 1. -1 The characteristic peak of ester group indicates that the bio-based liquid crystal copolyester was successfully prepared.

[0051] Figure 2 This is a polarizing microscope image of the bio-based liquid crystal copolyester prepared in Example 1. The liquid crystal phase structure can be observed from the image, indicating that the bio-based liquid crystal copolyester was successfully prepared.

[0052] Figure 3 This is a thermogravimetric analysis diagram of the bio-based liquid crystal copolyester prepared in Example 1. It can be seen that its initial degradation temperature is around 300°C, indicating that it has good heat stability.

[0053] Figure 4 This is a photo of the bio-based liquid crystal copolyester fiber prepared in Example 1. The average diameter of the prepared bio-based liquid crystal copolyester fiber is 22 μm.

[0054] Figure 5 This is a storage modulus diagram of the bio-based liquid crystal copolyester prepared in Example 1. It can be seen that it has a relatively high storage modulus below 200°C.

[0055] Examples 2-3 and Comparative Examples 1-2 Example 2-3 and Comparative Example 1-2 provide a method for preparing a bio-based liquid crystal copolyester. Compared with Example 1, the difference is that the molar ratio of the raw materials is changed, as shown in the table below. The rest is roughly the same as Example 1 and will not be repeated here.

[0056] Figure 6 This is a polarizing microscope image of the polymer prepared in Comparative Example 2. No liquid crystal phase structure is observed in the image, indicating that the bio-based liquid crystal copolyester cannot be prepared.

[0057] Examples 4-8 Example 4-8 provides a method for preparing a bio-based liquid crystal copolyester. Compared with Example 1, the difference is that the type of acetylated benzoic acid derivative is changed, as shown in the table below. The rest is roughly the same as Example 1 and will not be repeated here.

[0058] Experiments show that Examples 4-8 can successfully produce bio-based liquid crystal copolyesters.

[0059] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A bio-based liquid crystal copolyester, characterized in that: The structural formula of the bio-based liquid crystal copolyester is shown in Formula I: I； Wherein, the value range of m in the structural formula is 10-500, and the value range of n is 10-500.

2. The bio-based liquid crystal copolyester according to claim 1, characterized in that In the structural formula, the R group is one or more of the following structures: 。 3. The bio-based liquid crystal copolyester according to claim 1, characterized in that The density of the bio-based liquid crystal copolyester is 0.87-1.42 g / cm 3 , melt index is 20-230.

4. A method for preparing a bio-based liquid crystal copolyester, for preparing the bio-based liquid crystal copolyester according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: adding four monomers, acetylated naphthoic acid, acetylated benzoic acid derivative, 4-diacetoxybenzene and suberic acid, and a catalyst into a reaction container for polycondensation reaction to obtain the bio-based liquid crystal copolyester.

5. The method for preparing the bio-based liquid crystal copolyester according to claim 4, characterized in that: The acetylated benzoic acid derivative is one of acetylated p-coumaric acid, acetylated m-coumaric acid, acetylated ferulic acid, acetylated caffeic acid, acetylated vanillic acid and acetylated syringic acid.

6. The method for preparing the bio-based liquid crystal copolyester according to claim 4, characterized in that: During the polycondensation reaction, the reaction temperature is 100°C-330°C, and the reaction time is 2h-50h.

7. The method for preparing the bio-based liquid crystal copolyester according to claim 4, characterized in that: The catalyst is one or more of sodium formate, sodium acetate, zinc acetate, magnesium acetate, sodium propionate, and sodium alginate.

8. The method for preparing the bio-based liquid crystal copolyester according to claim 4, wherein: The molar ratio of the acetylated naphthoic acid to the acetylated benzoic acid derivative is 1:1, the molar ratio of the 4-diacetoxybenzene to suberic acid is 1:1, and the molar ratio of the total molar amount of the acetylated naphthoic acid and the acetylated benzoic acid derivative to the total molar amount of 4-diacetoxybenzene and suberic acid is 1:(0.1-10).

9. The method for preparing the bio-based liquid crystal copolyester according to claim 4, characterized in that: The amount of the catalyst used is 0.1%-10% of the total mass of the four monomers.

10. A method for preparing bio-based liquid crystal copolyester fiber, characterized in that: The bio-based liquid crystal copolyester according to any one of claims 4 to 8 is used, comprising the following steps: melt-extruding the bio-based liquid crystal copolyester through a screw at 280°C-340°C into a spinning beam, then entering a booster pump and a metering pump, and ejecting the bio-based liquid crystal copolyester through a spinneret of a spinning assembly to form filaments, which are then cooled and wound in an air cooling zone to obtain bio-based liquid crystal copolyester fibers; wherein the spinning beam temperature is 280°C-340°C, the booster pump speed is 5-100 rpm, the metering pump speed is 5-100 rpm, the spinneret aperture is 0.15-0.25 mm, and the air cooling zone temperature is 10-100°C.

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