Temperature-sensitive environment-friendly microcapsule and preparation method thereof

Abstract

This invention provides a temperature-sensitive, environmentally friendly microcapsule and its preparation method, relating to the field of polymer materials. The microcapsule is composed of chitosan, cellulose derivatives, gelatin, and dopamine. The microcapsule can achieve different cross-linking structures depending on the component ratios, and can controllably release the core substance within a temperature range of 90-150℃. The materials provided by this invention eliminate toxic reagents, and the microcapsules are all environmentally friendly materials, causing no environmental pollution. The microcapsule preparation method is characterized by temperature sensitivity and controllability, being green, environmentally friendly, and pollution-free, with a simple preparation method suitable for large-scale industrial production. Utilizing temperature-sensitive, biodegradable, and comprehensively environmentally friendly materials, it has broad application prospects in catalyst coating, drug coating, and other fields, meeting the needs of multiple sectors.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, and specifically relates to a temperature-sensitive, environmentally friendly microcapsule and its preparation method. Background Technology

[0002] Polymer microcapsules are core-shell structured materials with sustained-release capabilities. The core can be a specific substance to be released, which can be a fully encapsulated inert material or a substance with certain responsive characteristics (such as temperature, light, or moisture). Most shells are composed of natural or synthetic polymers, and can be single-shell structures that release the core material in a single step, or multi-shell structures that release different substances gradually through multi-level responses. Among these materials, environmentally friendly polymers have gained more favor in recent years compared to petroleum-based materials, while existing capsule wall materials lack temperature-sensitive properties.

[0003] Chitosan, in particular, is environmentally friendly and pH-sensitive. For example, chitosan microcapsules are pH-sensitive, breaking down under acidic stimuli and releasing the core material into the external environment. Furthermore, cellulose and its derivatives are also promising environmentally friendly materials, characterized by their wide availability, low cost, and biodegradability. It is worth noting that certain environments requiring high-temperature release necessitate temperature-sensitive materials. This temperature sensitivity can be provided by the material's melting behavior. Chitosan has a fixed melting point, while cellulose does not. Combining the two can produce a cross-linked material. By varying the degree of cross-linking, the degree of destruction of the chitosan shell can be controlled, thus achieving controlled release of the core material at a specified temperature within a certain temperature range above the chitosan melting point of 90°C. Using gelatin can increase the cross-linking of chitosan and cellulose derivatives, while also increasing electrostatic interactions, thereby improving the encapsulation rate. Based on this principle, this invention provides a method for preparing temperature-sensitive, environmentally friendly microcapsules. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an environmentally friendly microcapsule material that can be released in a temperature-sensitive and controlled manner at 90-150℃ and its preparation method.

[0005] This invention provides a temperature-sensitive, environmentally friendly microcapsule and its preparation method. The microcapsule can obtain different cross-linking structures according to different component ratios, and can release the core material in a controllable manner within the range of 90-150℃ according to the required temperature.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A temperature-sensitive, environmentally friendly microcapsule comprising chitosan, cellulose derivatives, gelatin, and dopamine.

[0008] Preferably, the temperature-sensitive range of the microcapsules is 90-150°C.

[0009] Preferably, the cellulose derivative is one of methylcellulose, ethylcellulose, and carboxymethylcellulose.

[0010] Preferably, the chitosan has a mass fraction of 60-70%; the cellulose derivative has a mass fraction of 25-30%; the gelatin has a mass fraction of 2-7%; and the dopamine has a mass fraction of 1-6%.

[0011] The method for preparing the microcapsules includes the following steps:

[0012] S1: The chitosan is dissolved in an aqueous acetic acid solution with a concentration of 1 ml / 25 ml at a ratio of 1 g / 100 ml;

[0013] S2: The cellulose derivative is dissolved in an ethanol-water solution at a ratio of 1g / 50ml;

[0014] S3: The gelatin is dissolved in water at a ratio of 1g / 50ml at 55-65℃;

[0015] S4: The dopamine is dissolved in an ethanol-water solution at a ratio of 1g / 100ml;

[0016] S5: Add 1-5g of core material to the solution obtained in steps S1-S4 above, and stir at high speed at 10000-50000 rpm for 5-30 minutes at 60-70℃ to obtain a mixture;

[0017] S6: In step S5 above, add 1-2 mL of 1M sodium hydroxide solution dropwise within 1 minute of starting to stir, and then add 4-8 mL of 1M sodium hydroxide solution dropwise in the remaining time to adjust the pH of the mixture to neutral.

[0018] S7: Quickly transfer the solution obtained in step S6 to a water bath at 0-10℃ and stir at 400-1000 revolutions per minute for 3-6 hours to obtain temperature-sensitive environmentally friendly microcapsules.

[0019] Preferably, the volume ratio of water to ethanol in step S2 is 1:5 to 1:10.

[0020] Preferably, the volume ratio of water to ethanol in step S4 is 1:5 to 1:10.

[0021] Preferably, the core material in step S5 is selected from one of n-eicosane, titanium dioxide, and n-dodecanoic acid.

[0022] Compared with the prior art, the present invention has the following main advantages:

[0023] (1) Compared with existing microcapsule materials, the microcapsule provided by this invention possesses temperature sensitivity and environmental friendliness based on the inherent properties of the material itself. On the one hand, the melting point of uncrosslinked chitosan is 90℃, while materials with different degrees of crosslinking exhibit varying degrees of increased melting point, thus achieving release behavior at a specified temperature. On the other hand, the materials are all environmentally friendly, causing no pollution to the environment, and have very broad development prospects.

[0024] (2) Compared with existing microcapsule preparation methods, the temperature-sensitive environmentally friendly microcapsule preparation method provided by the present invention has the characteristics of simple and easy operation, short preparation cycle and low cost, and is suitable for large-scale industrial production.

[0025] (3) Based on the above characteristics, the temperature-sensitive environmentally friendly microcapsule provided by the present invention can be applied to multiple application fields that require the release of core material at a specific temperature, such as polymerization catalysis. At a specific temperature, the monomer is kept from polymerization and reaction. When the temperature is raised to a specified temperature, the microcapsule ruptures and releases the catalyst, causing the polymerization reaction to occur. Detailed Implementation

[0026] The specific embodiments of the present invention will be further described in detail below with reference to examples. These examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0027] Example 1

[0028] S1: Dissolve 5g of chitosan in 500ml of acetic acid aqueous solution with a concentration of 1ml / 25ml.

[0029] S2: Dissolve 2g of methylcellulose in 100ml of a mixture of water and ethanol in a volume ratio of 1:5.

[0030] S3: Dissolve 0.5g of gelatin in 25ml of water at 60℃.

[0031] S4: Dissolve 0.1g of dopamine in 10ml of a mixed solution of water and ethanol with a volume ratio of 1:8.

[0032] S5: Mix the solutions obtained from S1 to S4 at 60°C, add 3g of n-eicosane, and stir at 10,000 rpm for 30 minutes.

[0033] S6: In step S5 above, 1 mL of 1M sodium hydroxide solution is added dropwise within 1 minute from the start of stirring, and then 4 mL of 1M sodium hydroxide solution is added dropwise during the remaining time. The pH of the solution is monitored simultaneously and is ultimately neutral.

[0034] S7: Quickly transfer the solution obtained in step S6 to a water bath at 0°C and stir at 400 rpm for 3 hours to obtain temperature-sensitive environmentally friendly microcapsules with soybean oil as the core material.

[0035] The breakage temperature of all embodiments was determined by DSC, which measured the melting point of the microcapsules under test conditions ranging from 30 to 200°C at a heating rate of 5°C / min. The breakage temperature of the temperature-sensitive environmentally friendly microcapsules obtained by this method was 90°C.

[0036] Example 2

[0037] S1: Dissolve 5g of chitosan in 500ml of acetic acid aqueous solution with a concentration of 1ml / 25ml.

[0038] S2: Dissolve 2g of ethyl cellulose in 100ml of a mixture of water and ethanol in a volume ratio of 1:5.

[0039] S3: Dissolve 0.5g of gelatin in 25ml of water at 60℃.

[0040] S4: Dissolve 0.5g of dopamine in 50ml of a mixture of water and ethanol in a volume ratio of 1:5.

[0041] S5: Mix the solutions obtained from S1 to S4 at 60°C, add 1g of n-eicosanoic acid, and stir at high speed at 50,000 rpm for 5 minutes.

[0042] S6: In step S5 above, 2 mL of 1M sodium hydroxide solution is added dropwise within 1 minute from the start of stirring, and then 8 mL of 1M sodium hydroxide solution is added dropwise over the remaining time. The pH of the solution is monitored simultaneously and is ultimately neutral.

[0043] S7: Quickly transfer the solution obtained in step S6 to a water bath at 10°C and stir at 1000 rpm for 6 hours to obtain temperature-sensitive environmentally friendly microcapsules with soybean oil as the core material.

[0044] The temperature-sensitive environmentally friendly microcapsules obtained had a breakage temperature of 150℃.

[0045] Example 3

[0046] S1: Dissolve 6g of chitosan in 600ml of acetic acid aqueous solution with a concentration of 1ml / 25ml.

[0047] S2: Dissolve 2.5g of carboxymethyl cellulose in 125ml of a mixed solution of water and ethanol in a volume ratio of 1:5.

[0048] S3: Dissolve 0.1g of gelatin in 5ml of water at 60℃.

[0049] S4: Dissolve 0.3g of dopamine in 30ml of a mixed solution of water and ethanol with a volume ratio of 1:10.

[0050] S5: Mix the solutions obtained from S1 to S4 at 700°C, add 5g of titanium dioxide, and stir at high speed of 30,000 rpm for 15 minutes.

[0051] S6: In step S5 above, 2 mL of 1M sodium hydroxide solution is added dropwise within 1 minute from the start of stirring, and then 6 mL of 1M sodium hydroxide solution is added dropwise over the remaining time. The pH of the solution is monitored simultaneously and is ultimately neutral.

[0052] S7: Quickly transfer the solution obtained in step S6 to a water bath at 5°C and stir at 600 rpm for 5 hours to obtain temperature-sensitive environmentally friendly microcapsules with soybean oil as the core material.

[0053] The temperature-sensitive environmentally friendly microcapsules obtained had a breakage temperature of 123℃.

[0054] Example 4

[0055] S1: Dissolve 6g of chitosan in 600ml of acetic acid aqueous solution with a concentration of 1ml / 25ml.

[0056] S2: Dissolve 2.5g of carboxymethyl cellulose in 125ml of a mixed solution of water and ethanol in a volume ratio of 1:5.

[0057] S3: Dissolve 0.3g of gelatin in 15ml of water at 60℃.

[0058] S4: Dissolve 0.3g of dopamine in 30ml of a mixed solution of water and ethanol with a volume ratio of 1:10.

[0059] S5: Mix the solutions obtained from S1 to S4 at 700°C, add 2.5g of n-eicosane, and stir at high speed of 30,000 rpm for 15 minutes.

[0060] S6: In step S5 above, 2 mL of 1M sodium hydroxide solution is added dropwise within 1 minute from the start of stirring, and then 6 mL of 1M sodium hydroxide solution is added dropwise over the remaining time. The pH of the solution is monitored simultaneously and is ultimately neutral.

[0061] S7: Quickly transfer the solution obtained in step S6 to a water bath at 5°C and stir at 600 rpm for 5 hours to obtain temperature-sensitive environmentally friendly microcapsules with soybean oil as the core material.

[0062] The temperature-sensitive environmentally friendly microcapsules obtained had a breakage temperature of 123℃.

[0063] Example 5

[0064] S1: Dissolve 6g of chitosan in 600ml of acetic acid aqueous solution with a concentration of 1ml / 25ml.

[0065] S2: Dissolve 3g of carboxymethyl cellulose in 150ml of a mixed solution of water and ethanol in a volume ratio of 1:5.

[0066] S3: Dissolve 0.5g of gelatin in 30ml of water at 60℃.

[0067] S4: Dissolve 0.5g of dopamine in 50ml of a mixed solution of water and ethanol with a volume ratio of 1:10.

[0068] S5: Mix the solutions obtained from S1 to S4 at 65°C, add 3.5g of n-eicosanoic acid, and stir at high speed of 40,000 rpm for 10 minutes.

[0069] S6: In step S5 above, 1 mL of 1M sodium hydroxide solution is added dropwise within 1 minute from the start of stirring, and then 5 mL of 1M sodium hydroxide solution is added dropwise over the remaining time. The pH of the solution is monitored simultaneously and is ultimately neutral.

[0070] S7: Quickly transfer the solution obtained in step S6 to a water bath at 5°C and stir at 600 rpm for 5 hours to obtain temperature-sensitive environmentally friendly microcapsules with soybean oil as the core material.

[0071] The temperature-sensitive environmentally friendly microcapsules obtained had a breakage temperature of 135℃.

[0072] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A temperature-sensitive, environmentally friendly microcapsule, characterized in that, The temperature-sensitive microcapsules include chitosan, cellulose derivatives, gelatin, and dopamine; The temperature-sensitive range of the microcapsules is 90-150℃; The chitosan has a mass fraction of 60-70%; the cellulose derivative has a mass fraction of 25-30%; the gelatin has a mass fraction of 2-7%; and the dopamine has a mass fraction of 1-6%.

2. The temperature-sensitive, environmentally friendly microcapsule according to claim 1, characterized in that, The cellulose derivative is one of methylcellulose, ethylcellulose, and carboxymethylcellulose.

3. A method for preparing microcapsules according to any one of claims 1-2, characterized in that, Includes the following steps: S1: The chitosan is dissolved in an aqueous acetic acid solution with a concentration of 1 ml / 25 ml at a ratio of 1 g / 100 ml; S2: The cellulose derivative is dissolved in an ethanol-water solution at a ratio of 1g / 50ml; S3: The gelatin is dissolved in water at a ratio of 1g / 50ml at 55-65℃; S4: The dopamine is dissolved in an ethanol-water solution at a ratio of 1g / 100ml; S5: Add 1-5g of core material to the solution obtained in steps S1-S4 above, and stir at high speed at 10000-50000 rpm for 5-30 minutes at 60-70℃ to obtain a mixture. S6: In step S5 above, add 1-2 mL of 1M sodium hydroxide solution dropwise within 1 minute of starting to stir, and then add 4-8 mL of 1M sodium hydroxide solution dropwise in the remaining time to adjust the pH of the mixture to neutral. S7: Quickly transfer the solution obtained in step S6 to a water bath at 0-10℃ and stir at 400-1000 revolutions per minute for 3-6 hours to obtain temperature-sensitive environmentally friendly microcapsules.

4. The method for preparing the environmentally friendly microcapsules according to claim 3, characterized in that, In step S2, the volume ratio of water to ethanol is 1:5 to 1:

10.

5. The method for preparing the environmentally friendly microcapsules according to claim 3, characterized in that, In step S4, the volume ratio of water to ethanol is 1:5 to 1:

10.

6. The method for preparing the environmentally friendly microcapsules according to claim 3, characterized in that, The core material in step S5 is selected from one of n-eicosane, titanium dioxide, and n-dodecanoic acid.