阅读说明：本技术 一种具有紫外屏蔽功能的淀粉基纳米复合材料及其制备方法 (Starch-based nano composite material with ultraviolet shielding function and preparation method thereof ) 是由 邹志明 余劲灵 胡文凯 黄雪雯 李和平 于 2021-09-13 设计创作，主要内容包括：本发明属于淀粉基复合材料技术领域,涉及一种具有紫外屏蔽功能的淀粉基纳米复合材料及其制备方法,按重量份计,由以下组分组成：淀粉100份,甘油30份,单宁酸修饰的埃洛石1～7份。本发明利用单宁酸修饰的埃洛石作为改性剂,能够有效地改善淀粉的性能。本发明制备得到的淀粉基纳米复合材料具有优异的紫外线屏蔽性能、高能短波蓝光阻隔性能、力学性能、水汽阻隔性能、DPPH自由基清除活性(即抗氧化活性)以及低的吸湿性,此外,该复合膜制备工艺简单环保,成本低廉,适于放大生产,在包装、紫外线防护等领域具有很好的应用前景。(The invention belongs to the technical field of starch-based composite materials, and relates to a starch-based nano composite material with an ultraviolet shielding function and a preparation method thereof, wherein the starch-based nano composite material comprises the following components in parts by weight: 100 parts of starch, 30 parts of glycerol and 1-7 parts of tannin modified halloysite. The halloysite modified by tannic acid is used as a modifier, so that the performance of the starch can be effectively improved. The starch-based nano composite material prepared by the invention has excellent ultraviolet shielding performance, high-energy short-wave blue light blocking performance, mechanical property, water vapor blocking performance, DPPH free radical scavenging activity (namely antioxidant activity) and low hygroscopicity, and in addition, the composite film has the advantages of simple and environment-friendly preparation process, low cost, suitability for amplified production and good application prospect in the fields of packaging, ultraviolet protection and the like.)

1. The starch-based nano composite material with the ultraviolet shielding function is characterized by comprising the following components in parts by weight: 100 parts of starch, 30 parts of plasticizer and 1-7 parts of tannin modified halloysite;

the starch is corn starch;

the plasticizer is glycerol;

the halloysite modified by the tannic acid has the diameter of 40-80 nm and the length of 200-1000 nm.

2. The starch-based nanocomposite material with ultraviolet shielding function as claimed in claim 1, wherein the preparation method of the tannin-modified halloysite comprises the following steps:

firstly, halloysite nanotubes are dispersed in Tris buffer solution with the pH value of 8.0, then tannic acid is added into the halloysite nanotube dispersion solution, the mixture is stirred and reacts for 24 hours at the temperature of 30 ℃, and finally, the halloysite modified by the tannic acid is obtained through centrifugal separation, water washing and drying;

the concentration of the Tris buffer solution is 0.01 mol/L;

the mass ratio of the Tris buffer solution to the halloysite nanotube to the tannic acid is 100:1: 0.2.

3. The method for preparing the starch-based nanocomposite material with the ultraviolet shielding function according to any one of claims 1 to 2, comprising the steps of:

(1) adding 100 parts of starch and 30 parts of plasticizer into 1600 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 1-7 parts of tannin modified halloysite in 1200 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(3) adding the dispersion liquid obtained in the step (2) into the starch solution obtained in the step (1), and stirring for 1h at 85 ℃ to obtain uniform film forming liquid;

(4) and (4) pouring the film forming liquid in the step (3) onto an organic glass dish, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain the starch-based nano composite material with the ultraviolet shielding function.

Technical Field

The invention relates to the technical field of starch-based composite materials, in particular to a starch-based nano composite material with an ultraviolet shielding function and a preparation method thereof.

Background

Among the natural high molecular materials of many edible films, starch is known as one of the most promising raw materials. After the starch and the plasticizer are blended, the thermoplastic starch can be prepared. The thermoplastic starch has good film forming property, and also has a series of advantages of rich resources, low price, edible property, renewability and the like. However, the thermoplastic starch film also has the disadvantages of poor water vapor barrier property, poor ultraviolet shielding property, poor mechanical property, poor radical scavenging activity (i.e., antioxidant activity), and the like. Therefore, the method has important significance for improving the ultraviolet shielding performance, the mechanical property, the water vapor barrier property and the free radical scavenging activity (namely the antioxidant activity) of the thermoplastic starch-based material and widening the application field of the thermoplastic starch-based material.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a starch-based nano composite material with an ultraviolet shielding function and a preparation method thereof by taking thermoplastic starch as a base material and tannic acid modified halloysite as a filler.

The technical scheme of the invention is as follows:

the starch-based nano composite material with the ultraviolet shielding function is characterized by comprising the following components in parts by weight: 100 parts of starch, 30 parts of plasticizer and 1-7 parts of tannin modified halloysite.

The starch is corn starch; the plasticizer is glycerol.

The halloysite modified by the tannic acid has the diameter of 40-80 nm and the length of 200-1000 nm.

The preparation method of the tannin modified halloysite comprises the following steps:

firstly, halloysite nanotubes are dispersed in Tris buffer solution with the pH value of 8.0, then tannic acid is added into the halloysite nanotube dispersion solution, the mixture is stirred and reacts for 24 hours at the temperature of 30 ℃, and finally, the halloysite modified by the tannic acid is obtained through centrifugal separation, water washing and drying;

the concentration of the Tris buffer solution is 0.01 mol/L; the mass ratio of the Tris buffer solution to the halloysite nanotube to the tannic acid is 100:1: 0.2.

A preparation method of a starch-based nano composite material with an ultraviolet shielding function comprises the following steps:

(1) adding 100 parts of starch and 30 parts of plasticizer into 1600 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 1-7 parts of tannin modified halloysite in 1200 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(3) adding the dispersion liquid obtained in the step (2) into the starch solution obtained in the step (1), and stirring for 1h at 85 ℃ to obtain uniform film forming liquid;

(4) and (4) pouring the film forming liquid in the step (3) onto an organic glass dish, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain the starch-based nano composite material with the ultraviolet shielding function.

Compared with the prior art, the invention has the following beneficial effects:

the starch-based nano composite material prepared by the invention has excellent ultraviolet shielding performance, thermal stability, water vapor barrier property, DPPH free radical scavenging activity (namely antioxidant activity) and low hygroscopicity, and in addition, the preparation process of the composite film is simple and environment-friendly, has low cost and is suitable for large-scale production.

Drawings

FIG. 1 is a photograph of a pure starch film obtained in comparative example 1.

FIG. 2 is a photograph of a starch-based composite film obtained in example 4.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

In the specific examples and comparative example formulations, tannic acid is the product provided by Ron's reagent; the halloysite nanotube is a high-purity product provided by Guangzhou Runwo materials science and technology limited; the hydrochloric acid is a product provided by Xiong science corporation; tris (hydroxymethyl) aminomethane (Tris) is a product provided by chemical industry Co., Ltd of Waverrucaceae, Beijing; corn starch (CAS number: 9005-25-8) was purchased from Allantin Biotechnology Ltd; glycerol (glycerin) is an analytical pure grade reagent supplied by west longa science ltd.

In the specific examples and the formula of the comparative examples, the halloysite modified by tannic acid is self-made nanoparticles (the average diameter is 40-80 nm, and the average length is 200-1000 nm), and the preparation method of the halloysite modified by tannic acid comprises the following steps:

firstly, halloysite nanotubes are dispersed in Tris buffer solution with the pH value of 8.0, then tannic acid is added into the halloysite nanotube dispersion solution, the mixture is stirred and reacts for 24 hours at the temperature of 30 ℃, and finally, the halloysite modified by the tannic acid is obtained through centrifugal separation, water washing and drying;

the concentration of the Tris buffer solution is 0.01 mol/L; the mass ratio of the Tris buffer solution to the halloysite nanotube to the tannic acid is 100:1: 0.2.

Example 1

A starch-based nano composite material with an ultraviolet shielding function comprises the following components in parts by weight: 100 parts of starch, 30 parts of glycerol and 1 part of tannin modified halloysite.

The preparation method comprises the following steps:

(1) adding 100 parts of starch and 30 parts of glycerol into 1600 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 1 part of tannin modified halloysite in 1200 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(3) adding the dispersion liquid obtained in the step (2) into the starch solution obtained in the step (1), and stirring for 1h at 85 ℃ to obtain uniform film forming liquid;

(4) and (4) pouring the film forming liquid in the step (3) onto an organic glass dish, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain the starch-based nano composite material with the ultraviolet shielding function.

Example 2

A starch-based nano composite material with an ultraviolet shielding function comprises the following components in parts by weight: 100 parts of starch, 30 parts of glycerol and 3 parts of tannin modified halloysite.

The preparation method comprises the following steps:

(1) adding 100 parts of starch and 30 parts of glycerol into 1600 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 3 parts of tannin modified halloysite in 1200 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(3) adding the dispersion liquid obtained in the step (2) into the starch solution obtained in the step (1), and stirring for 1h at 85 ℃ to obtain uniform film forming liquid;

(4) and (4) pouring the film forming liquid in the step (3) onto an organic glass dish, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain the starch-based nano composite material with the ultraviolet shielding function.

Example 3

A starch-based nano composite material with an ultraviolet shielding function comprises the following components in parts by weight: 100 parts of starch, 30 parts of glycerol and 5 parts of tannin modified halloysite.

The preparation method comprises the following steps:

(1) adding 100 parts of starch and 30 parts of glycerol into 1600 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 5 parts of tannin modified halloysite in 1200 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(3) adding the dispersion liquid obtained in the step (2) into the starch solution obtained in the step (1), and stirring for 1h at 85 ℃ to obtain uniform film forming liquid;

(4) and (4) pouring the film forming liquid in the step (3) onto an organic glass dish, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain the starch-based nano composite material with the ultraviolet shielding function.

Example 4

A starch-based nano composite material with an ultraviolet shielding function comprises the following components in parts by weight: 100 parts of starch, 30 parts of glycerol and 7 parts of tannin modified halloysite.

The preparation method comprises the following steps:

(1) adding 100 parts of starch and 30 parts of glycerol into 1600 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 7 parts of tannic acid modified halloysite in 1200 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(3) adding the dispersion liquid obtained in the step (2) into the starch solution obtained in the step (1), and stirring for 1h at 85 ℃ to obtain uniform film forming liquid;

(4) and (4) pouring the film forming liquid in the step (3) onto an organic glass dish, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain the starch-based nano composite material with the ultraviolet shielding function.

Comparative example 1

As a comparative standard to each of the above examples, the present invention provides a thermoplastic starch material prepared without tannic acid modified halloysite comprising the steps of:

(1) adding 100 parts of starch and 30 parts of glycerol into 1600 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) adding 1200 parts of deionized water into the starch solution obtained in the step (1), and stirring for 1h at 85 ℃ to obtain uniform film forming liquid;

(3) and (3) pouring the film forming liquid in the step (2) onto an organic glass dish, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain the thermoplastic starch material.

And (3) testing structure and performance:

performing performance tests on the thermoplastic starch film material prepared in the comparative example and the starch-based nano composite film material prepared in the embodiment, wherein the tensile property is tested according to GB/T1040-2006, the ultraviolet visible property is tested by adopting an ultraviolet spectrophotometer (TU-1901, Beijing Pujingyan general instruments, Inc.), and the average transmittance of ultraviolet rays (UVA, UVB and UVC) is calculated by referring to GB/T18830-2009; the water vapor transmission coefficient was measured according to astm e 96.

The hygroscopicity test method is as follows:

a film sample having dimensions of 20mm by 0.1mm was placed in a vacuum drying oven at 105 ℃ and, after drying for 3 hours, the mass of the film sample (noted as M)₀) (ii) a Then, the dried film sample was placed in a closed container at a relative humidity of 75% and a temperature of 25 ℃ for 48 hours, and the mass (denoted as M) of the film sample was measured₁) (ii) a Moisture absorption (%) of the film sample was 100 ═ M (M)₁-M₀)/M₀。

The DPPH free radical scavenging assay was as follows:

an experimental group, cutting 0.2g of a membrane sample, soaking in 5mL of ethanol for 24 hours, and extracting 2mL of supernatant of the soaking solution for later use; then, 1mL of 50mg/L DPPH solution is added into 2mL of the supernatant, and the mixture is shaken up and then placed for standing for 1h under the dark condition at room temperature; the mixture was then tested for absorbance at 517nm (denoted A) using an ultraviolet spectrophotometer (Lambda750, Perkin Elmer instruments Inc.)_sample) (ii) a In a control group, 1mL of 50mg/L DPPH solution is added into 2mL of ethanol, the mixture is shaken up and then placed for standing for 1h under the dark condition at room temperature; the mixture was then tested for absorbance at 517nm (denoted A) using an ultraviolet spectrophotometer (Lambda750, Perkin Elmer instruments Inc.)_control) (ii) a DPPH radical clearance (%) -100 ═ a_control-A_sample)/A_control。

The above performance test data are shown in table 1.

Table 1 composite performance test data

As can be seen from Table 1, the starch-based nanocomposite prepared by the method has excellent ultraviolet shielding performance, high-energy short-wave blue light blocking performance, mechanical property, water vapor blocking performance, DPPH free radical scavenging activity (namely antioxidant activity) and low hygroscopicity, and in addition, the composite film is simple and environment-friendly in preparation process, low in cost, suitable for large-scale production and capable of expanding the application field of the starch-based composite.

The invention is not limited to the examples, and any equivalent changes to the technical solution of the invention by a person skilled in the art after reading the description of the invention are covered by the claims of the invention.