A sodium alginate / starch-based nanocomposite with excellent comprehensive performance and a preparation method and application thereof

Abstract

The application belongs to the technical field of polymer composite materials, and particularly relates to a sodium alginate / starch-based nanocomposite material with excellent comprehensive performance and a preparation method and application thereof, which is prepared from the following raw materials: sodium alginate, starch, glycerol and functional nanorods. The application also provides a preparation method of the sodium alginate / starch-based nanocomposite material with excellent comprehensive performance. The prepared nanocomposite material has excellent mechanical strength, toughness, ultraviolet blocking, high-energy blue light blocking, water vapor blocking, oxygen blocking, antibacterial, ammonia gas response color changing and other performances, and can maintain high visible light transparency. The nanocomposite material can be used as an intelligent indicating material and effectively indicates the freshness change of shrimp and other meat food during storage. The preparation process of the nanocomposite material is simple, and the nanocomposite material has wide application value in the fields of food packaging, intelligent materials, ammonia gas detection, environmental monitoring and safety.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer composites, and particularly relates to a sodium alginate / starch-based nanocomposite with excellent comprehensive performance and a preparation method and application thereof. BACKGROUND

[0002] Sodium alginate and starch are biodegradable materials with good film-forming properties, biocompatibility, and environmentally friendly organic polymer, and have wide application prospects in food packaging, biomedical, intelligent gel and other fields. However, pure sodium alginate has defects such as brittleness, poor strength and elasticity, poor water vapor barrier property, poor water resistance and heat resistance. Starch has the characteristics of renewable and biodegradable, and starch-based film has become a research hotspot. Starch film can replace petroleum-based plastic in terms of economy and sustainable development. However, starch film has certain limitations, such as poor mechanical properties, poor hydrophobicity, and unsuitable for film conversion, and therefore needs to add plasticizers to optimize its performance. Adding starch to sodium alginate material can produce more economical and environmentally friendly sodium alginate / starch composite material. However, the sodium alginate / starch composite material has poor mechanical properties, water vapor barrier, oxygen barrier and other properties, and lacks ammonia response, ultraviolet barrier, antibacterial and other functions, which limits its practical application. In the present application, sodium alginate / starch is used as the matrix, and functional nanorods obtained by the reaction of L-phenylalanine and copper are used as the filler to improve the mechanical strength, toughness, ultraviolet barrier, high-energy blue light barrier, water vapor barrier, oxygen barrier, antibacterial, ammonia response and other properties of the sodium alginate / starch composite material, and to develop a sodium alginate / starch-based nanocomposite with excellent comprehensive performance, thereby widening its application in food packaging, intelligent materials, ammonia detection, environmental monitoring and safety. SUMMARY

[0003] The present application aims to overcome the shortcomings of the prior art and provide a sodium alginate / starch-based nanocomposite with excellent comprehensive performance and a preparation method and application thereof. The composite material has excellent mechanical strength, toughness, ultraviolet barrier, high-energy blue light barrier, water vapor barrier, oxygen barrier, antibacterial, ammonia response and other properties, and also maintains high visible light transparency, and can be used as an intelligent indicator material to effectively indicate the freshness change of meat food (such as shrimp, pork, fish, etc.) during storage. The preparation process of the composite material is simple, environmentally friendly, low in cost and suitable for large-scale production.

[0004] Technical scheme of the present application:

[0005] The present application provides a sodium alginate / starch-based nanocomposite with excellent comprehensive performance, which is characterized by being composed of the following components in parts by weight: 80 parts of sodium alginate, 20 parts of starch, 25 parts of glycerol and 3-9 parts of functional nanorods.

[0006] The functional nanorod has a diameter of 70-300 nm, and the preparation method comprises the following steps:

[0007] (1) 8.3 parts of L-phenylalanine are dissolved in 4000 parts of ethanol, and 1 mol / L NaOH ethanol solution is added dropwise while stirring, so that the pH of the L-phenylalanine solution is 9, and the solution is stirred at room temperature for 40 min to obtain a uniform L-phenylalanine solution for standby;

[0008] (2) 15 parts of copper acetate are dissolved in 2000 parts of ethanol to obtain a uniform copper acetate solution for standby;

[0009] (3) The copper acetate solution obtained in step (2) is added to the L-phenylalanine solution obtained in step (1), and 1 mol / L NaOH ethanol solution is used to adjust the pH of the solution to 9, and the solution is stirred at room temperature for 20 min, and then centrifugal separation, ethanol washing and drying are sequentially performed to obtain the functional nanorod (the color of which is green).

[0010] The application also provides a preparation method of the sodium alginate / starch-based nanocomposite material with excellent comprehensive performance, and has the characteristics that the preparation method comprises the following steps:

[0011] (1) 80 parts of sodium alginate, 20 parts of starch and 25 parts of glycerol are added to 4000 parts of deionized water, and stirred at room temperature for 30 min to obtain a uniform blending solution for standby;

[0012] (2) 3-9 parts of the functional nanorod are dispersed in 2000 parts of deionized water, and stirred at room temperature for 30 min to obtain a uniform dispersion liquid for standby;

[0013] (3) The dispersion liquid obtained in step (2) is added to the blending solution obtained in step (1), and stirred at 60°C for 120 min to obtain a uniform film-forming liquid for standby;

[0014] (4) The film-forming liquid obtained in step (3) is poured into an organic glass dish, and dried in an oven at 60°C for 24 h to obtain the sodium alginate / starch-based nanocomposite material with excellent comprehensive performance.

[0015] The application of the sodium alginate / starch-based nanocomposite material with excellent comprehensive performance has the characteristics that it is used in the fields of food packaging, intelligent materials, ammonia detection, environmental monitoring and safety, etc.

[0016] Compared with the prior art, the application has the beneficial effects that:

[0017] The sodium alginate / starch-based nanocomposite prepared by the application has excellent mechanical strength, toughness, ultraviolet blocking, high-energy blue light blocking, water vapor blocking, oxygen blocking, ammonia gas response color changing, antibacterial and other properties, while still maintaining high visible light transparency, can be used as intelligent indicating material and effectively indicates the freshness change of meat food (such as shrimp, pork, fish and the like) during storage, and the composite material has simple preparation process, environmental protection, low cost and is suitable for large-scale production, and has wide application value in the fields of food packaging, intelligent materials, ammonia gas detection, environmental monitoring and safety. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The scanning electron microscope image of the functional nanorod involved in the application;

[0019] Figure 2 The infrared spectrum of the functional nanorod involved in the application;

[0020] Figure 3 The ultraviolet-visible absorption spectrum of the functional nanorod involved in the application;

[0021] Figure 4 The powder X-ray diffraction pattern of the functional nanorod involved in the application;

[0022] Figure 5 The optical photograph of the sodium alginate / starch composite material prepared in the comparative example and the sodium alginate / starch-based nanocomposite material prepared in the example. DETAILED DESCRIPTION

[0023] The application will be specifically described below by examples, and it is necessary to point out here that the examples are only used to further illustrate the application and cannot be understood as limiting the scope of the application, and those skilled in the art can make some non-essential improvements and adjustments according to the content of the application, wherein the raw material parts are weight parts unless otherwise specified.

[0024] In the following specific examples and comparative example formulations and preparation methods, the sodium alginate used is a product provided by Shanghai Yinan Chemical Technology Co., Ltd. (CAS No.: 9005-38-3); the starch used is soluble starch (CAS No.: 9005-84-9) provided by Xilong Scientific Co., Ltd.; L-phenylalanine is an analytical pure grade reagent provided by Shanghai Yinan Chemical Technology Co., Ltd.; copper acetate, glycerol, sodium hydroxide, and ethanol are analytical pure grade reagents provided by Xilong Scientific Co., Ltd.

[0025] In the following specific examples and comparative example formulations, preparation methods, the functional nanorods, diameter is 70~300 nm, its preparation method includes the following steps:

[0026] (1) 8.3 parts of L-phenylalanine is dissolved in 4000 parts of ethanol, 1 mol / L NaOH ethanol solution is added dropwise while stirring, the pH of the L-phenylalanine solution is 9, and the solution is stirred at room temperature for 40 min to obtain a uniform L-phenylalanine solution, which is ready for use;

[0027] (2) 15 parts of copper acetate is dissolved in 2000 parts of ethanol to obtain a uniform copper acetate solution, which is ready for use;

[0028] (3) The copper acetate solution obtained in step (2) is added to the L-phenylalanine solution obtained in step (1), and the pH of the solution is adjusted to 9 with 1 mol / L NaOH ethanol solution, and the solution is stirred at room temperature for 20 min, then centrifuged, washed with ethanol, and dried to obtain functional nanorods (the color is green).

[0029] Example 1

[0030] A sodium alginate / starch-based nanocomposite with excellent comprehensive performance, characterized by consisting of the following components by weight: 80 parts of sodium alginate, 20 parts of starch, 25 parts of glycerol, and 3 parts of functional nanorods.

[0031] The preparation method comprises the following steps:

[0032] (1) 80 parts of sodium alginate, 20 parts of starch, and 25 parts of glycerol are added to 4000 parts of deionized water, and stirred at room temperature for 30 min to obtain a uniform blending solution, which is ready for use;

[0033] (2) 3 parts of functional nanorods are dispersed in 2000 parts of deionized water, and stirred at room temperature for 30 min to obtain a uniform dispersion, which is ready for use;

[0034] (3) The dispersion obtained in step (2) is added to the blending solution obtained in step (1), and stirred at 60°C for 120 min to obtain a uniform film-forming solution, which is ready for use;

[0035] (4) The film-forming solution obtained in step (3) is poured into an organic glass dish, and dried in an oven at 60°C for 24 h to obtain a sodium alginate / starch-based nanocomposite with excellent comprehensive performance.

[0036] Example 2

[0037] A sodium alginate / starch-based nanocomposite material with excellent comprehensive performance, characterized in that it is composed of the following components in parts by weight: 80 parts of sodium alginate, 20 parts of starch, 25 parts of glycerol, and 6 parts of functional nanorods.

[0038] A preparation method, comprising the following steps:

[0039] (1) 80 parts of sodium alginate, 20 parts of starch, and 25 parts of glycerol are added to 4000 parts of deionized water, stirred at room temperature for 30 min to obtain a uniform blending solution, which is ready for use;

[0040] (2) 6 parts of functional nanorods are dispersed in 2000 parts of deionized water, stirred at room temperature for 30 min to obtain a uniform dispersion, which is ready for use;

[0041] (3) The dispersion obtained in step (2) is added to the blending solution obtained in step (1), stirred at 60°C for 120 min to obtain a uniform film-forming solution, which is ready for use;

[0042] (4) The film-forming solution obtained in step (3) is poured into a petri dish, dried in an oven at 60°C for 24 h to obtain a sodium alginate / starch-based nanocomposite material with excellent comprehensive performance.

[0043] Example 3

[0044] A sodium alginate / starch-based nanocomposite material with excellent comprehensive performance, characterized in that it is composed of the following components in parts by weight: 80 parts of sodium alginate, 20 parts of starch, 25 parts of glycerol, and 6 parts of functional nanorods.

[0045] A preparation method, comprising the following steps:

[0046] (1) 80 parts of sodium alginate, 20 parts of starch, and 25 parts of glycerol are added to 4000 parts of deionized water, stirred at room temperature for 30 min to obtain a uniform blending solution, which is ready for use;

[0047] (2) 9 parts of functional nanorods are dispersed in 2000 parts of deionized water, stirred at room temperature for 30 min to obtain a uniform dispersion, which is ready for use;

[0048] (3) The dispersion obtained in step (2) is added to the blending solution obtained in step (1), stirred at 60°C for 120 min to obtain a uniform film-forming solution, which is ready for use;

[0049] (4) The film-forming solution obtained in step (3) is poured into a petri dish, dried in an oven at 60°C for 24 h to obtain a sodium alginate / starch-based nanocomposite material with excellent comprehensive performance.

[0050] Comparative Example

[0051] As a contrast standard of the above examples, the present application provides a sodium alginate / starch composite prepared without containing functional nanorods, comprising the following steps:

[0052] (1) 80 parts of sodium alginate, 20 parts of starch, and 25 parts of glycerol were added into 4000 parts of deionized water, and stirred at room temperature for 30 min to obtain a uniform blending solution, which was prepared for use;

[0053] (2) 2000 parts of deionized water was added to the blending solution obtained in step (1), and stirred at 60°C for 120 min to obtain a uniform film-forming solution, which was prepared for use;

[0054] (3) The film-forming solution obtained in step (2) was poured into an organic glass dish, and dried in an oven at 60°C for 24 h to obtain a sodium alginate / starch composite.

[0055] Structure and performance test:

[0056] The structure and performance of the sodium alginate / starch composite prepared by the above comparative example and the sodium alginate / starch-based nanocomposite prepared by the examples were tested, in which the UV-Vis performance was tested by a UV-Vis spectrometer (Lamdba365, PerkinElmer Instruments Co.), and the average UV transmittance was calculated according to GB / T 18830-2009; the tensile performance was tested according to GB / T 1040-2006; the water vapor transmission coefficient was tested according to ASTM E 96; the antibacterial property of the material was tested according to QBT2591-2003; the ammonia gas response test method was as follows: the sample material was exposed to an ammonia gas environment, and the color change of the sample material was observed.

[0057] The oxygen transmission coefficient experiment method was as follows:

[0058] A film sample (diameter: 1.8 cm) was sealed in a glass vial containing 3 g of deoxidizer (including 1.0 g of activated carbon, 1.5 g of sodium chloride, and 0.5 g of reduced iron powder), and the vial was weighed (recorded as W1); then it was placed in a closed container with a relative humidity of 90% and a temperature of 25°C, and after 48 h, the vial was reweighed (recorded as W2); the oxygen transmission coefficient OP = (W2-W1) / (S×t), where S and t represent the area of the film sample and the placement time.

[0059] Shrimp freshness monitoring experiment: Fresh shrimp was purchased from the market, and the shrimp (mass: 30 g) was placed in a petri dish and sealed with a petri dish cover, and the lower surface of the cover was attached with the sodium alginate / starch composite prepared in the comparative example and the sodium alginate / starch-based nanocomposite prepared in Example 3 (precut into a sample material with a diameter of 1 cm), and then the shrimp sample was stored in a 25℃ oven, and the freshness change of the shrimp and the color change of the sample material were observed and recorded.

[0060] The performance test data of the above-mentioned samples are shown in Tables 1 and 2.

[0061] Table 1: Performance test data of samples

[0062]

[0063] Table 2: Results of shrimp freshness monitoring experiment (where t is the storage time of fresh shrimp)

[0064]

[0065] The results of the ammonia response test experiment prove that the sodium alginate / starch composite prepared in the comparative example is colorless and transparent, and its color does not change after being exposed to an ammonia environment, still showing colorless and transparent optical properties; the sodium alginate / starch-based nanocomposite prepared in Example 1 is light green, and its color changes to light blue after being exposed to an ammonia environment; the sodium alginate / starch-based nanocomposite prepared in Example 2 is light green, and its color changes to light blue after being exposed to an ammonia environment; the sodium alginate / starch-based nanocomposite prepared in Example 3 is green, and its color changes to blue after being exposed to an ammonia environment.

[0066] In summary, from the performance test data of the samples (see Tables 1 and 2), it can be seen that the sodium alginate / starch-based nanocomposite prepared in the present application has excellent mechanical strength, toughness, ultraviolet blocking, high-energy blue light blocking, water vapor blocking, oxygen blocking, ammonia response color changing, antibacterial properties, etc., while still maintaining high visible light transparency, and can be used as an intelligent indicating material to effectively indicate the freshness change of shrimp and other meat foods during storage (see Table 2). The preparation process of the composite material is simple, environmentally friendly, low in cost, suitable for large-scale production, and has wide application value in the fields of food packaging, intelligent materials, ammonia detection, environmental monitoring and safety, etc.

[0067] The content of the present application is not limited to the examples listed, and any equivalent transformation of the technical solutions of the present application made by a person of ordinary skill in the art by reading the specification of the present application is covered by the claims of the present application.

Claims

1. A method for preparing a sodium alginate / starch-based nanocomposite having excellent comprehensive performance, characterized in that The method comprises the following steps: (1) 80 parts of sodium alginate, 20 parts of starch, and 25 parts of glycerol are added to 4000 parts of deionized water, stirred at room temperature for 30 min to obtain a uniform blending solution, which is prepared for use; (2) 3-9 parts of functional nanorods are dispersed in 2000 parts of deionized water, stirred at room temperature for 30 min to obtain a uniform dispersion, which is prepared for use; (3) The dispersion obtained in step (2) is added to the blending solution obtained in step (1), stirred at 60°C for 120 min to obtain a uniform film-forming solution, which is prepared for use; (4) The film-forming solution obtained in step (3) is poured into an organic glass dish, dried in an oven at 60°C for 24 h to obtain a sodium alginate / starch-based nanocomposite with excellent comprehensive performance; The functional nanorods have a diameter of 70-300 nm, and the preparation method comprises the following steps: (1) 8.3 parts of L-phenylalanine are dissolved in 4000 parts of ethanol, and 1 mol / L NaOH ethanol solution is added dropwise while stirring to make the pH of the L-phenylalanine solution 9, and the solution is stirred at room temperature for 40 min to obtain a uniform L-phenylalanine solution, which is prepared for use; (2) 15 parts of copper acetate are dissolved in 2000 parts of ethanol to obtain a uniform copper acetate solution, which is prepared for use; (3) The copper acetate solution obtained in step (2) is added to the L-phenylalanine solution obtained in step (1), and the pH of the solution is adjusted to 9 with 1 mol / L NaOH ethanol solution, and the solution is stirred at room temperature for 20 min, and then centrifuged, washed with ethanol, and dried in sequence to obtain the functional nanorods.

2. The sodium alginate / starch-based nanocomposite with excellent comprehensive performance obtained by the preparation method of claim 1.

3. Use of the sodium alginate / starch-based nanocomposite having excellent comprehensive properties, which is obtained by the preparation method according to claim 1, characterized in that, It is used in the fields of food packaging, smart materials, ammonia detection, environmental monitoring and safety.

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