Preparation of intrinsic yellow alginate / polyvinyl alcohol composite material

Abstract

The invention relates to preparation of a novel intrinsic yellow alginate / polyvinyl alcohol composite material. The method mainly comprises the following steps: (1) respectively preparing a 1-3wt% SA aqueous solution and a 5-10wt% PVA solution; (2) preparing a CaCl2-B (OH) 3 solidification liquid; (3) uniformly mixing the obtained SA and PVA solutions according to different proportions, and forming alginate / polyvinyl alcohol composite particles or fiber materials in a coagulating bath by controlling the conditions of an injection pump; (4) treating the obtained alginate / polyvinyl alcohol composite material with an alkaline solution; (5) washing; and (6) drying. The intrinsic yellow alginate / polyvinyl alcohol composite material is obtained by using the process. The alginate / polyvinyl alcohol composite material can become yellow only through simple treatment without adding any dye or auxiliary agent. The intrinsic yellow alginate / polyvinyl alcohol composite material is expected to be used in the fields of textile, medicine, sensing and the like.

Description

Technical Field

[0001] The invention belongs to the field of alginate-based functional materials, and in particular relates to the preparation of an intrinsic yellow alginate / polyvinyl alcohol composite material. Background Art

[0002] Alginate is a natural polysaccharide derived from seaweed. It has good biocompatibility and is a green marine polysaccharide that is widely used in food, medicine, textiles and other fields. In actual application, alginate-based materials exist in three forms: particles, films and fibers. In order to make full use of this green, environmentally friendly and renewable marine biomaterial, it is usually necessary to compound it with other polymer materials to improve its performance. Among them, the most widely used is polyvinyl alcohol (PVA), which is a cheap and non-toxic synthetic polymer that is easily soluble in water and has the characteristics of non-toxicity, chemical resistance and biodegradability. PVA has a polyhydroxy structure and is often cross-linked with boron or cross-linked by freeze-thaw method to form a gel. By compounding with alginate, the physical and chemical properties of alginate are significantly improved, realizing its application in various fields such as food, textiles, medicine and biology.

[0003] In some application scenarios, alginate-based materials need to be colored, which is usually achieved by adding dyes or additives. Chinese patent publication number CN109267180A reports a stable colored alginate fiber and its preparation method, which is obtained by adding a coloring liquid to a sodium alginate solution. Chinese patent publication number CN117822159A reports a preparation method of an alginate-based artificial muscle with a rotation-color change dual response, which is obtained by introducing a colored ion (Co 2+ and Cu 2+ ) to make alginate fibers present color; Meng Huajie et al. reviewed a series of dyeing methods for alginate fibers of various colors, all of which are to add different dyes to make alginate fibers colored (Dyes and Dyeing (2022) 59(02):22-33). The above studies all add dyes or additives to alginate materials to make them colored, which affects their green and environmental performance and increases costs. Summary of the invention

[0004] The purpose of the invention is to develop a green and environmentally friendly alginate / polyvinyl alcohol composite material with intrinsic yellow color without adding dyes or auxiliaries.

[0005] In order to solve the above technical problems, the present invention adopts the following technical scheme, and the preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material comprises the following steps:

[0006] (1) mixing the SA aqueous solution and the PVA aqueous solution to obtain a SA / PVA mixed solution; dissolving CaCl2 and B(OH)3 in a certain proportion to obtain a coagulation bath solution;

[0007] (2) squeezing the SA / PVA mixed solution obtained in step (1) into a coagulation bath by controlling the conditions of the injection pump, and solidifying to obtain SA / PVA composite particles or fiber materials;

[0008] (3) treating the SA / PVA composite material obtained in step (2) with an alkaline solution;

[0009] (4) Rinse the surface of the SA / PVA composite material obtained in step (3) with deionized water, and then dry it to obtain an intrinsic yellow alginate / polyvinyl alcohol composite material.

[0010] Preferably, in step (1), the mass percentage of sodium alginate is 1-3 wt %, and the mass percentage of PVA is 5-10%.

[0011] Preferably, the content of sodium alginate in the SA / PVA mixed solution in step (1) is 0 to 100%.

[0012] Preferably, the mass ratio of CaCl2 and B(OH)3 in step (1) is 3:4.

[0013] Preferably, the curing time of step (2) is 12 to 24 hours.

[0014] Preferably, the alkaline solution in step (3) is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 1 to 10 mol / L.

[0015] Preferably, the treatment time of step (3) is 0 to 100 min.

[0016] Preferably, the treatment temperature of step (3) is 25-60°C.

[0017] Preferably, the drying temperature in step (4) is 40-60°C.

[0018] The invention provides a method for preparing an intrinsic yellow alginate / polyvinyl alcohol composite material, which has the advantages that the prepared alginate / polyvinyl alcohol composite material can show bright yellow without adding a colorant or other additives, has intrinsic yellow color, and has a simple processing method and is green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 These are optical photographs of alginate / polyvinyl alcohol composite particles having intrinsic yellow color prepared in Examples 1 to 10 of the present invention and Comparative Examples 1 to 2.

[0020] Figure 2 These are optical photographs of alginate / polyvinyl alcohol composite particles having intrinsic yellow color prepared in Examples 1 and 11 to 15 of the present invention.

[0021] Figure 3 These are optical photographs of alginate / polyvinyl alcohol composite particles obtained by treating with alkaline solution for different time periods in Example 10 and Examples 16 to 19 of the present invention.

[0022] Figure 4 The alginate fibers with intrinsic yellow color and the colorless alginate fibers prepared in Example 20 of the present invention and Comparative Example 3 are shown.

[0023] Figure 5 This is the alginate / polyvinyl alcohol composite fiber with intrinsic yellow color prepared in Example 21 of the present invention.

[0024] Figure 6 This is a process flow chart of Example 21 of the present invention. DETAILED DESCRIPTION

[0025] The following examples are provided to facilitate a better understanding of the present invention, but are not intended to limit the present invention. The experimental methods in the following examples are conventional methods unless otherwise specified.

[0026] Example 1

[0027] (1) dissolving sodium alginate in water at 80° C. with stirring to prepare a 1 wt % sodium alginate aqueous solution, and cooling the aqueous solution to room temperature for degassing and use;

[0028] (2) dissolving polyvinyl alcohol in water at 95° C. with stirring to prepare a 5 wt % polyvinyl alcohol aqueous solution, and cooling the aqueous solution to room temperature for degassing and standby use;

[0029] (3) Prepare SA / PVA according to the volume ratio of SA:PVA = 1:1 1:1 Mixing solutions;

[0030] (4) preparing CaCl2 and B(OH)3 coagulation bath in a mass ratio of 3:4;

[0031] (5) The mixed solution obtained in step (3) was squeezed into the coagulation bath obtained in step (4) by using a syringe pump, and cured and cross-linked for 24 hours to obtain SA / PVA 1:1 Hydrogel microbeads.

[0032] (6) The SA / PVA obtained in step (5) 1:1 The hydrogel microbeads were treated with 1M alkaline solution for 10 min to obtain SA / PVA 1:1(alkaline) Hydrogel microbeads.

[0033] (7) Rinse the SA / PVA obtained in step (6) with deionized water 1:1(alkaline) The surface of the hydrogel microbeads was then placed in an oven at 50 °C and dried for 24 h to obtain alginate / polyvinyl alcohol composite particles with intrinsic yellow color, such as Figure 1 shown.

[0034] Embodiments 2 to 10

[0035] The difference between Examples 2 to 10 and Example 1 is that the volume ratios of SA:PVA in step (3) are 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 and 1:10, respectively, and the rest are the same as in Example 1. Figure 1 shown.

[0036] Comparative Example 1

[0037] (1) dissolving sodium alginate in water at 80° C. with stirring to prepare a 1 wt % sodium alginate aqueous solution, and cooling the aqueous solution to room temperature for degassing and use;

[0038] (2) preparing CaCl2 and B(OH)3 coagulation bath in a mass ratio of 3:4;

[0039] (3) The mixed solution obtained in step (1) was squeezed into the coagulation bath obtained in step (2) by using a syringe pump, and cured and cross-linked for 24 hours to obtain SA hydrogel microbeads.

[0040] (4) The SA hydrogel microbeads obtained in step (3) were treated with 1M alkaline solution for 10 min to obtain SA alkaline (5) Rinse the SA obtained in step (4) with deionized water. alkaline The surface of the hydrogel microbeads was then placed in an oven at 50 °C and dried for 24 h to obtain SA particles with intrinsic yellow color, such as Figure 1 shown.

[0041] Depend on Figure 1 It can be seen that the SA hydrogel treated by this method can show a bright yellow color, but is easily cross-linked after drying.

[0042] Comparative Example 2

[0043] (1) dissolving polyvinyl alcohol in water at 95° C. with stirring to prepare a 5 wt % polyvinyl alcohol aqueous solution, and cooling the aqueous solution to room temperature for degassing and standby use;

[0044] (2) preparing CaCl2 and B(OH)3 coagulation bath in a mass ratio of 3:4;

[0045] (3) The mixed solution obtained in step (1) is squeezed into the coagulation bath obtained in step (2) by using a syringe pump, and cured and cross-linked for 24 hours to obtain a PVA hydrogel.

[0046] (4) The PVA hydrogel obtained in step (3) was treated with a 1M alkaline solution for 10 min to obtain PVA alkaline Hydrogel.

[0047] (5) Rinse the PVA obtained in step (4) with deionized water alkaline The hydrogel surface was then placed in an oven at 50 °C and dried for 24 h to obtain a white PVA block, such as Figure 1 shown.

[0048] Depend on Figure 1 It can be seen that the PVA hydrogel has no color after being treated by this method, and small particles cannot be obtained by containing only PVA. Adding a small amount of SA can improve the disadvantage of easy agglomeration of PVA materials.

[0049] Examples 11 to 15

[0050] The difference between Examples 11 to 15 and Example 1 is that the volume ratios of SA:PVA in step (3) are 2:1, 3:1, 4:1, 5:1 and 6:1 respectively, and the other ratios are the same as in Example 1. Figure 2 shown.

[0051] from Figure 2 It can be seen that increasing the content of SA has little effect on the color of SA / PVA particles. When the volume ratio of SA:PVA is 1:1, the obtained alginate / polyvinyl alcohol particles already have intrinsic yellow color and have a complete morphology under this condition. This shows that adding a small amount of SA to PVA can bring color and also have a good morphology.

[0052] Embodiments 16 to 19

[0053] The difference between Examples 16 to 19 and Example 10 is that the treatment time with 1M alkaline solution in step (6) is 20, 30, 40 and 50 min respectively, and the other aspects are the same as Example 10. Figure 3 shown.

[0054] from Figure 3 It can be seen that at 25°C, SA / PVA hydrogel microspheres can turn yellow after being treated with 1M alkaline solution for 10 minutes, and the color will not deepen if the treatment time is extended.

[0055] Embodiment 20

[0056] The difference between Example 20 and Comparative Example 1 is that the SA fiber is obtained in step (3), and the other parts are the same as those in Comparative Example 1. Figure 4It can be seen that the color change is due to the color of sodium alginate after alkali treatment. By compounding with other materials (such as PVA), adding a small amount of sodium alginate therein can make the composite material appear yellow.

[0057] Embodiment 21

[0058] The difference between Example 21 and Example 1 is that the SA / PVA obtained in step (5) 1:1(alkaline) Fiber, other than the same as in Example 1, such as Figure 5 shown.

[0059] Figure 6 This is a process flow chart of Example 21.

[0060] Comparative Example 3

[0061] The difference between Comparative Example 3 and Example 21 is that step (4) is omitted, and the other steps are the same as those of Example 21. Figure 4 As shown. Figure 4 It can be seen that the sodium alginate fiber without alkali bath treatment will not show color.

[0062] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Preparation of intrinsic yellow alginate / polyvinyl alcohol composite material, characterized in that: The following steps are involved: (1) mixing a sodium alginate (SA) aqueous solution and a polyvinyl alcohol (PVA) aqueous solution in a certain proportion to obtain a SA / PVA mixed solution; dissolving CaCl2 and B(OH)3 in a certain proportion to obtain a coagulation bath solution; (2) squeezing the SA / PVA mixed solution obtained in step (1) into a coagulation bath by controlling the conditions of the injection pump, and solidifying to obtain SA / PVA composite particles or fiber materials; (3) treating the SA / PVA composite material obtained in step (2) with an alkaline solution; (4) Rinse the surface of the SA / PVA composite material obtained in step (3) with deionized water, and dry it to obtain an intrinsic yellow alginate / polyvinyl alcohol composite material.

2. The preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material according to claim 1, characterized in that: In step (1), the mass percentage of SA is 1-3wt%, and the mass percentage of PVA is 5-10%.

3. The preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material according to claim 1, characterized in that: The content of SA in the SA / PVA mixed solution in step (1) is 0 to 100%.

4. The preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material according to claim 1, characterized in that: The mass ratio of CaCl2 and B(OH)3 in step (1) is 3:

4.

5. The preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material according to claim 1, characterized in that: The curing time of step (2) is 12 to 24 hours.

6. The preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material according to claim 1, characterized in that: The alkaline solution in step (3) is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 1 to 10 mol / L.

7. The preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material according to claim 1, characterized in that: The processing time of step (3) is 0 to 100 minutes.

8. The preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material according to claim 1, characterized in that: The treatment temperature of step (3) is 25-60°C.

9. The preparation of the intrinsic yellow alginate / polyvinyl alcohol composite material according to claim 1, characterized in that: The drying temperature of step (4) is 40-60°C.

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