Flame-retardant flexible fiber catalyst based on marine organism polysaccharide as well as preparation and application thereof

Abstract

The invention discloses a marine organism polysaccharide-based flame-retardant flexible fiber catalyst, which is characterized in that alginate fibers are used as a substrate, and substitution reaction of halogen atoms is carried out in a polar solvent to form crown ether-embedded alginate fibers. By grafting the crown ether derivative on the alginate fiber, the electro-catalytic performance, selectivity, stability and interface performance of the alginate fiber can be remarkably improved, and multifunctional integration and high-added-value application are achieved at the same time. The composite material has a very high application prospect in electrocatalytic oxygen reduction reaction, and a new thought and method are provided for promoting sustainable development of related industries.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocatalytic materials, and in particular to a flame-retardant-flexible fiber catalyst based on marine biopolysaccharide, and the preparation and application thereof. Background Art

[0002] With the upgrading of global safety regulations and the growing public awareness of environmental protection, the demand for flame-retardant materials has exploded. In this context, marine biopolysaccharide flame-retardant flexible fibers, with their natural flame retardancy, biocompatibility, and biodegradability, have become a breakthrough solution to replace traditional materials.

[0003] Traditional electrocatalyst materials (such as carbon-based materials and metal oxides) have problems such as poor mechanical flexibility and insufficient high-temperature stability, making it difficult to meet the high requirements for substrate materials in the field of electrocatalysis. Marine biopolysaccharide flame-retardant flexible fibers (such as seaweed fibers) have become an ideal choice to replace traditional materials due to their inherent flame retardancy (limiting oxygen index ≥45%) and high flexibility (breaking strength 1.6-2.6 cN / dtex). The addition of crown ethers and their derivatives further increases the active sites on the surface of seaweed fibers, improving their chemical reactivity and adsorption properties.

[0004] In the emerging interdisciplinary field of electrocatalysis, the unique physicochemical properties of seaweed fibers have yet to be fully explored and utilized. Their rich functional groups, excellent biocompatibility, and designability make them a highly promising natural polymer material, offering potential opportunities for constructing excellent flame-retardant and flexible electrocatalytic materials. This present invention addresses these challenges and aims to develop a crown ether-containing flame-retardant and flexible fiber electrocatalyst through a supramolecular assembly strategy, thereby advancing the practical application of flexible electronics and green catalysis technologies. Summary of the Invention

[0005] The present invention aims to provide a flame-retardant and flexible fiber electrocatalyst material based on marine polysaccharides, which exhibits excellent hydrogen peroxide selectivity and yield. Seaweed fibers are prepared using a wet spinning technique, and crown ethers and their derivatives are incorporated into the fibers via a one-step condensation reaction. By grafting crown ether derivatives onto seaweed fibers, their electrocatalytic performance, selectivity, stability, and interfacial properties can be significantly improved, while enabling multifunctional integration and high-value-added applications. This composite material has great application prospects in electrocatalytic oxygen reduction reactions and provides new ideas and methods for promoting the sustainable development of related industries.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The invention is based on a marine biopolysaccharide flame retardant-flexible fiber catalyst. The catalyst uses seaweed fiber as a substrate and undergoes a halogen atom substitution reaction in a polar solvent to form seaweed fiber embedded with crown ether.

[0008] A method for preparing the above-mentioned marine biopolysaccharide-based flame retardant-flexible fiber catalyst comprises the following steps:

[0009] S1. Modification of Sodium Alginate

[0010] (1) Prepare sodium alginate solution: Prepare a sodium alginate aqueous solution with a mass percentage of 1%-5%. Sodium alginate, as a marine polysaccharide, has natural flame retardant properties and good flexibility, and is the basic material for this experiment.

[0011] (2) Catalytic carboxyl-amino reaction: Adding dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) aqueous solution to the sodium alginate solution catalyzes the reaction between the carboxyl group and the amino group. This step aims to enhance the flexibility and chemical stability of sodium alginate through chemical modification.

[0012] (3) Introduction of amantadine: Under nitrogen protection, a solution of amantadine dissolved in dimethyl sulfoxide (DMSO) was added dropwise. The introduction of amantadine further enhanced the mechanical properties and flame retardant characteristics of the material.

[0013] (4) Separation and drying: After the reaction is completed, the product is precipitated with acetone and freeze-dried to obtain adamantane-modified alginate fiber powder. This powder retains the flame retardant properties and flexibility of sodium alginate, while further improving its performance through modification with adamantane.

[0014] S2. Preparation of seaweed spinning solution

[0015] (1) Mixing seaweed fiber powder: Ordinary seaweed fiber powder is mixed with the adamantane-modified seaweed fiber powder prepared in step S1 in a ratio of 1: (0.1-3). This mixing method aims to balance the flexibility and flame retardancy of the material.

[0016] (2) Prepare the spinning solution: Dissolve the mixed seaweed fiber powder in deionized water to prepare a spinning solution with a mass percentage of 2%-5%, and perform a degassing treatment. The degassing treatment helps to improve the uniformity and flexibility of the fiber.

[0017] S3. Wet spinning and fiber forming

[0018] (1) Wet spinning: The spinning solution prepared in step S2 is placed in a syringe and wet-spinned to form fibers. The coagulation bath solution is a divalent metal ion salt solution (calcium chloride), which can promote the gelation of the seaweed fiber and form solid fibers.

[0019] (2) Post-treatment: The formed seaweed fiber is soaked in ethanol to remove surface impurities and further enhance the fiber's flexibility. It is then dried to obtain seaweed fiber with excellent flexibility and flame retardancy.

[0020] S4. Embedding crown ethers and their derivatives into seaweed fibers

[0021] (3) Monomer addition: The seaweed fiber obtained in step S3 is immersed in a DMF solution containing potassium carbonate and crown ether molecules.

[0022] (4) Heating and stirring: Heat and stir at 40°C for 2 hours, then raise the temperature to 60°C and continue stirring for 48 hours. This process helps the formation and stabilization of the crown ether molecules into the seaweed fiber structure, and finally obtains seaweed fibers containing crown ethers.

[0023] Preferably, the structural formula is as shown in the following formula (I) and formula (II):

[0024]

[0025] Preferably, the crown ether and its derivatives embedded in the seaweed fiber have the following structural formula (III):

[0026]

[0027] Preferably, in step S4,

[0028] The mass ratio of the seaweed fiber to the crown ether and its derivative (I) is 1:(0.01-5);

[0029] The mass ratio of the seaweed fiber to the crown ether and its derivative (II) is 1:(0.01-5).

[0030] In addition, the present application also provides the use of the above-mentioned marine biopolysaccharide-based flame retardant-flexible fiber catalyst in the two-electron electrocatalytic reaction of producing hydrogen peroxide.

[0031] The beneficial effects of the present invention are as follows:

[0032] (1) The present invention prepares a flexible seaweed fiber substrate through wet spinning technology, which is biocompatible, environmentally friendly, and safe;

[0033] (2) The present invention innovatively embeds crown ethers and their derivatives into seaweed fibers, resulting in a simple preparation process and easy large-scale preparation.

[0034] (3) The fiber material prepared by the present invention has also been put into practical application in the field of flame retardant properties. The limiting oxygen index of the flame retardant-flexible fiber electrocatalyst material is ≥45%, which is higher than the oxygen concentration in the air (21%), indicating that it has good flame retardant properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a high-resolution transmission image of the seaweed fiber SA-CD prepared in Example 1.

[0036] Figure 2 This is a high-resolution transmission image of the seaweed fiber SA-CE prepared in Example 2.

[0037] Figure 3 This is the hydrogen peroxide selectivity diagram of the seaweed fibers SA-CD and SA-CE prepared in Examples 1 and 2.

[0038] Figure 4 This is a graph showing the hydrogen peroxide yield of the agglomerated fibers SA-CD and SA-CE prepared in Examples 1 and 2. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making any creative work should fall within the scope of protection of this application.

[0040] Example 1: This example relates to a method for preparing a flame-retardant-flexible fiber electrocatalyst material based on marine biopolysaccharide, and the specific steps are as follows:

[0041] (1) Accurately weigh sodium alginate and prepare a 2% aqueous solution by mass. Add appropriate amounts of dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) aqueous solution to the sodium alginate solution, and use the DCC / NHS system to catalyze the reaction between the carboxyl group and the amino group. Under nitrogen protection, slowly add 2 equivalents of adamantane solution (dissolved in dimethyl sulfoxide (DMSO)). React at room temperature for 24 hours. After the reaction is completed, precipitate the product with acetone and obtain adamantane-modified sodium alginate powder by freeze-drying.

[0042] (2) Ordinary sodium alginate powder and the adamantane-modified sodium alginate powder prepared in step (1) are mixed in a ratio of 1:0.5, the mixed alginate fiber powder is dissolved in deionized water, a spinning solution with a mass percentage of 3% is prepared, and a degassing treatment is performed.

[0043] (3) The spinning solution obtained in step (2) was placed in a 10 mL syringe for wet spinning, with the extrusion speed set to 0.5 mL / min. The coagulation bath solution was a calcium chloride solution to form solid calcium alginate fibers. After crosslinking for 2 hours, the fibers were soaked in ethanol for 4 hours and dried at 50° C. for 8 hours to obtain adamantane-grafted alginate fibers.

[0044] (4) Monomer addition: The seaweed fiber obtained in step (3) is immersed in a DMF solution containing potassium carbonate and crown ether molecules. The solution is then heated and stirred at 40°C for 2 hours, then heated to 60°C and stirred for 48 hours. This process facilitates the formation and stabilization of the crown ether molecules incorporated into the seaweed fiber structure, ultimately yielding seaweed fiber SA-CD containing crown ethers.

[0045] Example 2: This example relates to a method for preparing a flame-retardant-flexible fiber electrocatalyst material based on marine polysaccharides, and the specific steps are as follows:

[0046] (1) Accurately weigh sodium alginate and prepare a 2% aqueous solution by mass. Add appropriate amounts of dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) aqueous solution to the sodium alginate solution, and use the DCC / NHS system to catalyze the reaction between the carboxyl group and the amino group. Under nitrogen protection, slowly add 2 equivalents of adamantane solution (dissolved in dimethyl sulfoxide (DMSO)). React at room temperature for 24 hours. After the reaction is completed, precipitate the product with acetone and obtain adamantane-modified sodium alginate powder by freeze-drying.

[0047] (2) dissolving sodium alginate powder and adamantane-modified sodium alginate powder in step (1) in deionized water at a ratio of 1:0.5 to prepare a spinning solution of 3% by mass, and performing a degassing treatment;

[0048] (3) The spinning solution obtained in step (2) was placed in a 10 mL syringe for wet spinning, with the extrusion speed set to 0.5 mL / min. The coagulation bath solution was a calcium chloride solution to form solid calcium alginate fibers. After crosslinking for 2 hours, the fibers were soaked in ethanol for 4 hours and dried at 50° C. for 8 hours to obtain adamantane-grafted alginate fibers.

[0049] (4) Monomer addition: The seaweed fiber obtained in step 3 is immersed in a DMF solution containing potassium carbonate and crown ether molecules. The mixture is then heated and stirred at 40°C for 2 hours, then heated to 60°C and stirred for 48 hours. This process facilitates the formation and stabilization of the crown ether molecules incorporated into the seaweed fiber structure, ultimately yielding seaweed fiber SA-CE containing crown ethers.

[0050] The test was carried out using a three-electrode half-cell system, with the prepared crown ethers and their derivatives embedded in seaweed fibers SA-CD and SA-CE as working electrodes, the auxiliary electrode and the reference electrode being a platinum electrode and a silver / silver chloride / potassium chloride saturated solution reference electrode, respectively.

[0051] (1) Morphology test:

[0052] Figure 1Transmission electron microscopy (TEM) images of crown ether-embedded seaweed fibers SA-CD are presented, clearly revealing the microstructure inside the fibers and the distribution of crown ethers.

[0053] Figure 2 Transmission electron microscopy (TEM) images of crown ether-embedded seaweed fibers SA-CE are presented, clearly revealing the microstructure inside the fibers and the distribution of crown ethers.

[0054] (2) Performance testing:

[0055] Figure 3 This is a characterization diagram of the electrochemical performance of crown ether-embedded seaweed fibers SA-CD and SA-CE in an oxygen-saturated 0.1M potassium hydroxide electrolyte system. The results show that SA-CE has excellent two-electron oxygen reduction performance. When the operating potential is 0.4V VS.RHE, the selectivity of SA-CE for hydrogen peroxide reaches an optimal value of 90.20%, and its electron transfer number is reduced to 2.23.

[0056] Figure 4 Figure 2 shows the hydrogen peroxide yield of crown ether-embedded seaweed fibers SA-CD and SA-CE. The yield per unit catalyst loading was calculated based on the valence change of cerium ions using cerium sulfate solution titration. As can be seen from the figure, the crown ether-embedded seaweed fiber (SA-CE) has a better hydrogen peroxide yield of 8.7 mol g -1 cat h -1 .

[0057] Table 1 lists in detail the limiting oxygen index (LOI) test results of the seaweed fibers prepared in the examples. By comparing the LOI values ​​of the seaweed fibers SA-CE and SA-CE, the difference in the flame retardant properties of the fibers is intuitively demonstrated, providing an important reference for optimizing the fiber preparation process.

[0058] Table 1

[0059]

[0060] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. Based on marine biopolysaccharide flame retardant-flexible fiber catalyst, characterized in that, The catalyst uses seaweed fiber as a substrate, undergoes a halogen atom substitution reaction in a polar solvent, and forms seaweed fiber embedded with crown ether.

2. A method for preparing the marine biopolysaccharide-based flame retardant-flexible fiber catalyst according to claim 1, characterized in that: The following steps are involved: S1. Modification of Sodium Alginate (1) Prepare sodium alginate solution: prepare a sodium alginate aqueous solution with a mass percentage of 1% to 5%. (2) Catalytic carboxyl-amino reaction: Add dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) aqueous solution to the sodium alginate solution to catalyze the reaction between carboxyl and amino groups; (3) Introducing amantadine: under nitrogen protection, add a solution of amantadine dissolved in dimethyl sulfoxide (DMSO) dropwise; (4) Separation and drying: After the reaction is completed, the product is precipitated with acetone and freeze-dried to obtain adamantane-modified alginate fiber powder; S2. Preparation of seaweed spinning solution (1) Mixing seaweed fiber powder: mixing ordinary seaweed fiber powder and the adamantane-modified seaweed fiber powder prepared in step S1 in a mass ratio of 1: (0.1-3); (2) preparing a spinning solution: dissolving the mixed seaweed fiber powder in deionized water to prepare a spinning solution with a mass percentage of 2% to 5%, and performing a degassing treatment; S3. Wet spinning and fiber forming (1) Wet spinning: The spinning solution prepared in step S2 is placed in a syringe and fiber is formed by a wet spinning process, and the coagulation bath solution is a divalent metal ion salt solution; (2) Post-treatment: soaking the formed seaweed fiber in ethanol and drying it to obtain seaweed fiber with flexibility and flame retardant properties; S4. Embedding crown ethers and their derivatives into seaweed fibers (1) Monomer addition: immersing the seaweed fiber obtained in step S3 in a DMF solution containing potassium carbonate and crown ether molecules; (2) Heating and stirring: heating and stirring at 40°C for 2 hours, then heating to 60°C and stirring for 48 hours to obtain seaweed fiber containing crown ether.

3. The preparation method according to claim 2, characterized in that The crown ether compound is any one of the following, and its structural formula is shown in the following formula (I) or formula (II):

4. The preparation method according to claim 2, characterized in that The crown ether and its derivatives embedded in the seaweed fiber have the following structural formula (III):

5. The preparation method according to claim 2, characterized in that In the step S4, The mass ratio of the seaweed fiber to the crown ether and its derivative (I) is 1:(0.01-5); The mass ratio of the seaweed fiber to the crown ether and its derivative (II) is 1:(0.01-5).

6. Use of the marine biopolysaccharide-based flame retardant-flexible fiber catalyst as claimed in claim 1 in a two-electron electrocatalytic reaction to produce hydrogen peroxide.

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