Intelligent packaging material with high sensitivity and long-term color stability and application thereof

Abstract

The invention belongs to the technical field of polymer composite materials, and particularly relates to an intelligent packaging material with high sensitivity and long-term color stability, which is prepared from the following raw materials: ethyl cellulose and ammonia-sensitive nanoparticles. The invention further provides a preparation method of the intelligent packaging material, the prepared intelligent packaging material has excellent mechanical strength, toughness, ultraviolet blocking, high-energy blue light blocking, ammonia response discoloration, long-term color stability, biodegradability and the like, and the composite material is simple in preparation process, low in cost and suitable for industrial production. The method has wide application value in the fields of food packaging, intelligent materials, biomedicine, ammonia response materials, ammonia detection, environment monitoring, safety and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer composite films, and in particular relates to an intelligent packaging material having both high sensitivity and long-term color stability and an application thereof. Background Art

[0002] Smart packaging is a new packaging technology that combines smart functions with traditional packaging systems. It can reflect the freshness of food in a timely manner without destroying the packaging, and "actively" sense the environmental information in the package by adding various indicators. Bio-based materials have become one of the new green packaging materials due to their sustainable regeneration, easy degradation, and green environmental protection. The use of bio-based food packaging materials can not only reduce the consumption of oil and solve the environmental problems caused by plastic packaging, but also make full use of existing resources and have good social and economic benefits. However, bio-based materials (such as ethyl cellulose, starch, sodium alginate, etc.) usually have poor mechanical and water vapor barrier properties, and lack ammonia-sensitive color change, UV blocking and other functions, which restricts their application in smart active food packaging and UV protection.

[0003] Smart packaging materials with ammonia-sensitive color change function can be used to indicate the deterioration of meat products (such as shrimp, pork, fish, etc.) during storage. At present, the most popular method for manufacturing smart packaging materials is to add natural dyes with pH / ammonia-sensitive functions (including anthocyanins, curcumin, betaine and alizarin) to bio-based materials (such as ethyl cellulose, starch, sodium alginate, etc.). However, these natural dyes derived from plants usually have the following disadvantages: such as expensive and overly complicated extraction methods, and poor stability under light and heat, which is not conducive to their practical application in smart active packaging. Therefore, it is urgent to develop simple, economical, green smart packaging with high sensitivity and long-term color stability to broaden its application areas. The present invention uses environmentally friendly ethyl cellulose as a membrane matrix and utilizes homemade ammonia-sensitive nanoparticles as functional fillers to improve the mechanical strength, toughness, ultraviolet blocking, ammonia response color change and other properties of the ethyl cellulose film, develops simple and economical ethyl cellulose-based intelligent active packaging materials with high sensitivity and long-term color stability, and broadens its application in food packaging, intelligent materials, biomedicine, ammonia response materials, ammonia detection, environmental monitoring and safety and other fields. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an intelligent packaging material with high sensitivity and long-term color stability and its application. The intelligent packaging material has excellent mechanical strength, toughness, ultraviolet blocking, high-energy blue light blocking, ammonia response color change, long-term color stability and other properties, and can be used as an intelligent indicator packaging material to indicate the deterioration of meat foods (such as shrimp, pork, fish, etc.) during storage. The composite material has a simple preparation process, is environmentally friendly, low cost, and is suitable for scale-up production.

[0005] Technical solution of the present invention:

[0006] The present invention provides an intelligent packaging material having both high sensitivity and long-term color stability, characterized in that it is composed of the following components in parts by weight: 100 parts of ethyl cellulose, 3-9 parts of ammonia-sensitive nanoparticles;

[0007] The ammonia-sensitive nanoparticles are nanocomplexes prepared by reacting L-malic acid with ferric sulfate, and the preparation method comprises the following steps:

[0008] (1) Take 13.41 parts of L-malic acid and dissolve it in 5000 parts of ethanol to obtain a uniform L-malic acid solution for later use;

[0009] (2) taking 20 parts of ferric sulfate, dissolving it in a mixed solvent of 1000 parts of deionized water and 1000 parts of ethanol to obtain a uniform ferric sulfate solution for later use;

[0010] (3) Add the ferric sulfate solution obtained in step (2) to the L-malic acid solution obtained in step (1), control the pH to 7 with 1 mol / L sodium hydroxide solution, stir the reaction at room temperature for 20 min, then centrifuge, wash, and dry to obtain ammonia-sensitive nanoparticles.

[0011] The present invention also provides a method for preparing the above-mentioned intelligent packaging material having both high sensitivity and long-term color stability, which is characterized by comprising the following steps:

[0012] (1) Add 100 parts of ethyl cellulose to 3000 parts of ethanol and stir at room temperature for 3 h to obtain a uniform ethyl cellulose solution for later use;

[0013] (2) Dispersing 3-9 parts of ammonia-sensitive nanoparticles in 1000 parts of ethanol, stirring at room temperature for 30 min to obtain a uniform dispersion for later use;

[0014] (3) adding the dispersion obtained in step (2) to the ethyl cellulose solution obtained in step (1), stirring at room temperature for 30 min to obtain a uniform film-forming solution for later use;

[0015] (4) The film-forming liquid obtained in step (3) is poured into a flat-bottomed glass dish and dried in an oven at 55°C for 36 h to obtain a smart packaging material with both high sensitivity and long-term color stability.

[0016] The application of the intelligent packaging material with both high sensitivity and long-term color stability is characterized by being used in the fields of food packaging, intelligent materials, ammonia responsive materials, ammonia detection, environmental monitoring and safety.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The ethyl cellulose-based intelligent packaging material prepared by the present invention has excellent mechanical strength, toughness, ultraviolet blocking, high-energy blue light blocking, ammonia response color change, long-term color stability, biodegradability and other properties. The material preparation process is simple, environmentally friendly, low-cost, and suitable for large-scale production. It has wide application value in food packaging, intelligent materials, biomedicine, ammonia response materials, ammonia detection, environmental monitoring and safety and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a scanning electron microscope image of the ammonia-sensitive nanoparticles involved in the present invention;

[0020] Figure 2 This is a cross-sectional scanning electron microscope image of the smart packaging material sample prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0021] In order to better explain the present invention, the present invention is further explained in detail below in conjunction with specific examples, but the embodiments of the present invention are not limited thereto.

[0022] In the following specific embodiments and comparative examples, the formulas and preparation methods, the ethyl cellulose used is a product provided by Shanghai MacLean Biochemical Technology Co., Ltd. (item number: E915394-500g); the L-malic acid used is a product provided by Yuanye Biotechnology (CAS number: 97-67-6); ferric sulfate is an analytically pure reagent provided by Xilong Science Co., Ltd.; and ethanol is an analytically pure reagent provided by Tianjin Fuyu Fine Chemical Co., Ltd.

[0023] In the following specific embodiments and comparative examples, the preparation method of the ammonia-sensitive nanoparticles comprises the following steps:

[0024] (1) Take 13.41 parts of L-malic acid and dissolve it in 5000 parts of ethanol to obtain a uniform L-malic acid solution for later use;

[0025] (2) taking 20 parts of ferric sulfate, dissolving it in a mixed solvent of 1000 parts of deionized water and 1000 parts of ethanol to obtain a uniform ferric sulfate solution for later use;

[0026] (3) Add the ferric sulfate solution obtained in step (2) to the L-malic acid solution obtained in step (1), control the pH to 7 with 1 mol / L sodium hydroxide solution, stir the reaction at room temperature for 20 min, then centrifuge, wash, and dry to obtain ammonia-sensitive nanoparticles.

[0027] Example 1

[0028] The intelligent packaging material has both high sensitivity and long-term color stability, characterized in that it is composed of the following components in parts by weight: 100 parts of ethyl cellulose and 3 parts of ammonia-sensitive nanoparticles.

[0029] The preparation method comprises the following steps:

[0030] (1) Add 100 parts of ethyl cellulose to 3000 parts of ethanol and stir at room temperature for 3 h to obtain a uniform ethyl cellulose solution for later use;

[0031] (2) Disperse 3 parts of ammonia-sensitive nanoparticles in 1000 parts of ethanol and stir at room temperature for 30 min to obtain a uniform dispersion for later use;

[0032] (3) adding the dispersion obtained in step (2) to the ethyl cellulose solution obtained in step (1), stirring at room temperature for 30 min to obtain a uniform film-forming solution for later use;

[0033] (4) The film-forming liquid obtained in step (3) is poured into a flat-bottomed glass dish and dried in an oven at 55°C for 36 h to obtain a smart packaging material with both high sensitivity and long-term color stability.

[0034] Example 2

[0035] The intelligent packaging material has both high sensitivity and long-term color stability, characterized in that it is composed of the following components in parts by weight: 100 parts of ethyl cellulose and 9 parts of ammonia-sensitive nanoparticles.

[0036] The preparation method comprises the following steps:

[0037] (1) Add 100 parts of ethyl cellulose to 3000 parts of ethanol and stir at room temperature for 3 h to obtain a uniform ethyl cellulose solution for later use;

[0038] (2) Disperse 9 parts of ammonia-sensitive nanoparticles in 1000 parts of ethanol and stir at room temperature for 30 min to obtain a uniform dispersion for later use;

[0039] (3) adding the dispersion obtained in step (2) to the ethyl cellulose solution obtained in step (1), stirring at room temperature for 30 min to obtain a uniform film-forming solution for later use;

[0040] (4) The film-forming liquid obtained in step (3) is poured into a flat-bottomed glass dish and dried in an oven at 55°C for 36 h to obtain a smart packaging material with both high sensitivity and long-term color stability.

[0041] Comparative Example

[0042] As a comparison standard of the above embodiments, the present invention provides a comparative example material prepared without containing ammonia-sensitive nanoparticles, comprising the following steps:

[0043] (1) Add 100 parts of ethyl cellulose to 3000 parts of ethanol and stir at room temperature for 3 h to obtain a uniform ethyl cellulose solution for later use;

[0044] (2) Add 1000 parts of ethanol to the ethyl cellulose solution obtained in step (1), and stir at room temperature for 30 minutes to obtain a uniform film-forming solution for later use;

[0045] (3) The film-forming solution obtained in step (2) was poured into a flat-bottomed glass dish and dried in an oven at 55°C for 36 h to obtain a comparative example material.

[0046] Structure and performance test:

[0047] The comparative materials prepared in the above comparative examples and the smart packaging materials prepared in the examples were subjected to structure and performance tests, wherein the cross-sectional morphology of the smart packaging materials was characterized by a SEM (SU-5000, Japan High-Tech Corporation) instrument; the UV-visible performance was tested by a UV-visible spectrometer, and the average UV transmittance was calculated with reference to GB / T 18830-2009; the tensile performance was tested in accordance with GB / T 1040-2006; the ammonia response test method was as follows: the sample material was exposed to an ammonia environment, and the color change of the sample material was observed; the long-term color stability test method was as follows: the sample material was stored at 25°C and 57% humidity for 45 days, and the color change of the sample material was observed.

[0048] The above performance test data is shown in Table 1.

[0049] Table 1 Sample performance test data

[0050]

[0051] The SEM results of the smart packaging material showed that the ammonia-sensitive nanoparticles could be evenly dispersed in the ethylcellulose matrix (see Figure 2), which is conducive to obtaining smart packaging materials with excellent performance. The results of the ammonia response test show that the comparative material prepared in the comparative example is colorless and transparent. After being exposed to an ammonia environment, its color does not change, and it still presents colorless and transparent optical properties; the smart packaging material prepared in Example 1 is light yellow, and after being exposed to an ammonia environment, its color changes to light brown; the smart packaging material prepared in Example 2 is yellow, and after being exposed to an ammonia environment, its color changes to brown.

[0052] The long-term color stability test results show that the color of the smart packaging materials prepared in Example 1 and Example 2 did not change significantly after being stored at 25°C and 57% humidity for 45 days. The above results show that the smart packaging materials prepared in the present invention have excellent long-term color stability.

[0053] In summary, it can be seen from the sample performance test data (see Table 1) that the smart packaging material prepared by the present invention has excellent mechanical strength, toughness, ultraviolet blocking, high-energy blue light blocking, ammonia response color change, long-term color stability, biodegradability and other properties, and the material preparation process is simple, environmentally friendly, low-cost, and suitable for large-scale production. It has wide application value in food packaging, smart materials, biomedicine, ammonia response materials, ammonia detection, environmental monitoring and safety and other fields.

[0054] The content of the present invention is not limited to the embodiments listed, and any equivalent changes made to the technical solution of the present invention by ordinary technicians in this field after reading the description of the present invention are covered by the claims of the present invention.

Claims

1. Intelligent packaging material with both high sensitivity and long-term color stability, characterized in that: The method is composed of the following components in parts by weight: 100 parts of ethyl cellulose, 3-9 parts of ammonia-sensitive nanoparticles; The preparation method of the ammonia-sensitive nanoparticles comprises the following steps: (1) Take 13.41 parts of L-malic acid and dissolve it in 5000 parts of ethanol to obtain a uniform L-malic acid solution for later use; (2) taking 20 parts of ferric sulfate, dissolving it in a mixed solvent of 1000 parts of deionized water and 1000 parts of ethanol to obtain a uniform ferric sulfate solution for later use; (3) Add the ferric sulfate solution obtained in step (2) to the L-malic acid solution obtained in step (1), control the pH to 7 with 1 mol / L sodium hydroxide solution, stir the reaction at room temperature for 20 min, then centrifuge, wash, and dry to obtain ammonia-sensitive nanoparticles.

2. The method for preparing the intelligent packaging material with high sensitivity and long-term color stability according to claim 1, characterized in that: The steps include: (1) Add 100 parts of ethyl cellulose to 3000 parts of ethanol and stir at room temperature for 3 hours to obtain a uniform ethyl cellulose solution for later use; (2) Dispersing 3-9 parts of ammonia-sensitive nanoparticles in 1000 parts of ethanol, stirring at room temperature for 30 minutes to obtain a uniform dispersion for later use; (3) adding the dispersion obtained in step (2) to the ethyl cellulose solution obtained in step (1), stirring at room temperature for 30 minutes to obtain a uniform film-forming solution for later use; (4) The film-forming liquid obtained in step (3) is poured into a flat-bottomed glass dish and dried in an oven at 55° C. for 36 hours to obtain a smart packaging material having both high sensitivity and long-term color stability.

3. The use of the intelligent packaging material with high sensitivity and long-term color stability according to claim 1, characterized in that: Used in food packaging, food freshness indication, smart materials, ammonia detection, environmental monitoring and safety fields.

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