High-barrier and high-hydrophobicity methyl cellulose intelligent packaging film

Abstract

The invention belongs to the technical field of polymer composite materials, and particularly relates to a high-barrier high-hydrophobicity methyl cellulose intelligent packaging film which is prepared from the following raw materials: methyl cellulose and 4-hydroxycinnamic acid complex crystals. The methyl cellulose intelligent packaging film prepared by the invention has excellent ultraviolet barrier property, high-energy blue light barrier property and hydrophobicity, also has excellent mechanical property, ammonia response discoloration property, antioxidant activity and the like, and can be used as an intelligent indicating material to timely and effectively indicate the freshness change condition of meat foods such as shrimps in the storage process; the membrane material is simple in preparation process and has wide application value in the fields of food packaging, intelligent materials, biomedicine, ammonia response materials, ammonia detection, environmental monitoring, safety and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer composite materials, and in particular relates to a high-barrier and highly hydrophobic methyl cellulose intelligent packaging film. Background Art

[0002] Methylcellulose is a water-soluble cellulose derivative. By introducing –CH into the cellulose chain, it is favored for its unique properties, such as water solubility, non-toxicity, hydrophilicity, high transparency, and thermal gelation properties. In addition, methylcellulose is a biopolymer with outstanding film-forming ability. It has the characteristics of low price and excellent biocompatibility, so it has potential applications in the fields of food packaging films. However, methylcellulose film materials have strong hydrophilicity, resulting in poor moisture barrier properties; in addition, methylcellulose film materials have poor UV barrier properties, poor high-energy blue light barrier properties, and poor mechanical properties, and lack ammonia response, antioxidant activity and other functions. These factors are not conducive to the actual application effect of methylcellulose packaging films. Therefore, based on the above-mentioned performance shortcomings of methylcellulose film materials, the present invention synthesized a 4-hydroxycinnamic acid-based complex crystal, which was used as a functional filler to improve the barrier properties, hydrophobicity, mechanical properties, ammonia response color change, antioxidant activity and other properties of methylcellulose packaging film, thereby broadening its application in food packaging, smart materials, biomedicine, ammonia response materials, ammonia detection, environmental monitoring and safety and other fields. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a high-barrier and high-hydrophobic methylcellulose smart packaging film. The smart packaging film material has excellent ultraviolet barrier, high-energy blue light barrier, hydrophobicity, and excellent mechanical, ammonia response color change, antioxidant activity and other properties. It can be used as an intelligent indicator material to timely and effectively indicate the freshness changes of meat foods (such as shrimp, pork, fish, etc.) during storage. The film material preparation process is simple, environmentally friendly, low-cost, and suitable for scale-up production.

[0004] Technical solution of the present invention:

[0005] The present invention provides a high-barrier and high-hydrophobic methylcellulose intelligent packaging film, characterized in that it is composed of the following components in parts by weight: 150 parts of methylcellulose, 3-9 parts of 4-hydroxycinnamic acid complex crystals;

[0006] The preparation method of the 4-hydroxycinnamic acid complex crystal comprises the following steps:

[0007] (1) Dissolve 16.61 parts of 4-hydroxycinnamic acid in 5000 parts of ethanol, and stir at room temperature for 30 minutes to obtain a 4-hydroxycinnamic acid dispersion for later use;

[0008] (2) Take 20.85 parts of ferrous sulfate heptahydrate and dissolve it in 1000 parts of deionized water to obtain a uniform ferrous sulfate solution for later use;

[0009] (3) adding the ferrous sulfate solution obtained in step (2) to the 4-hydroxycinnamic acid dispersion obtained in step (1), stirring the mixture at room temperature for 20 min, and then centrifuging, washing, and drying the mixture in sequence to obtain 4-hydroxycinnamic acid complex crystals.

[0010] The present invention also provides a method for preparing the above-mentioned high-barrier and high-hydrophobicity methylcellulose intelligent packaging film, which is characterized by comprising the following steps:

[0011] (1) Add 150 parts of methyl cellulose to 4500 parts of deionized water, stir at 85°C for 60 minutes to obtain a uniform blend solution, cool to room temperature and set aside;

[0012] (2) Dispersing 3-9 parts of 4-hydroxycinnamic acid complex crystals in 500 parts of deionized water, stirring at room temperature for 5 minutes to obtain a uniform dispersion for later use;

[0013] (3) adding the dispersion obtained in step (2) to the blended solution obtained in step (1), stirring at room temperature for 30 min to obtain a uniform film-forming solution for later use;

[0014] (4) The film-forming liquid obtained in step (3) is poured into a plexiglass dish and dried in an oven at 55°C for 12 h to obtain a high-barrier and high-hydrophobic methyl cellulose intelligent packaging film.

[0015] The application of the high-barrier and high-hydrophobic methyl cellulose intelligent packaging film is characterized by being used in the fields of food packaging, intelligent materials, biomedicine, ammonia responsive materials, ammonia detection, environmental monitoring and safety, etc.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The methyl cellulose intelligent packaging film material prepared by the present invention has excellent ultraviolet blocking, high-energy blue light blocking, hydrophobicity, and also has excellent mechanical properties, ammonia response color change, antioxidant activity and other properties, and can also maintain a relatively high visible light transparency. It can be used as an intelligent indicator material to timely and effectively indicate the freshness changes of meat foods (such as shrimp, pork, fish, etc.) during storage. The preparation process of the intelligent packaging film material is simple, environmentally friendly, low-cost, and suitable for scale-up production. It has wide application value in the fields of food packaging, intelligent materials, biomedicine, ammonia response materials, ammonia detection, environmental monitoring and safety, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a scanning electron microscope image of the 4-hydroxycinnamic acid complex crystal involved in the present invention;

[0019] Figure 2 These are optical photographs of the methyl cellulose film prepared in the comparative example of the present invention and the methyl cellulose smart packaging film sample materials prepared in the example. DETAILED DESCRIPTION

[0020] 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.

[0021] In the following specific embodiments and comparative example formulas and preparation methods, the methyl cellulose used is a product provided by Shanghai Aladdin Biochemical Technology Co., Ltd. (item number: M112866-500g); the 4-hydroxycinnamic acid used is a product provided by Bid Pharmaceutical Co., Ltd. (CAS number: 7400-08-0); ferrous sulfate heptahydrate is an analytically pure reagent provided by Xilong Chemical Co., Ltd.; and ethanol is an analytically pure reagent provided by Tianjin Fuyu Fine Chemical Co., Ltd.

[0022] In the following specific embodiments and comparative example formulations and preparation methods, the preparation method of the 4-hydroxycinnamic acid complex crystals comprises the following steps:

[0023] (1) Dissolve 16.61 parts of 4-hydroxycinnamic acid in 5000 parts of ethanol, and stir at room temperature for 30 minutes to obtain a 4-hydroxycinnamic acid dispersion for later use;

[0024] (2) Take 20.85 parts of ferrous sulfate heptahydrate and dissolve it in 1000 parts of deionized water to obtain a uniform ferrous sulfate solution for later use;

[0025] (3) adding the ferrous sulfate solution obtained in step (2) to the 4-hydroxycinnamic acid dispersion obtained in step (1), stirring the mixture at room temperature for 20 min, and then centrifuging, washing, and drying the mixture in sequence to obtain 4-hydroxycinnamic acid complex crystals.

[0026] Example 1

[0027] A high-barrier and high-hydrophobic methylcellulose intelligent packaging film, characterized in that it is composed of the following components in parts by weight: 150 parts of methylcellulose and 3 parts of 4-hydroxycinnamic acid complex crystals.

[0028] The preparation method comprises the following steps:

[0029] (1) Add 150 parts of methyl cellulose to 4500 parts of deionized water, stir at 85°C for 60 minutes to obtain a uniform blend solution, cool to room temperature and set aside;

[0030] (2) Dispersing 3 parts of 4-hydroxycinnamic acid complex crystals in 500 parts of deionized water, stirring at room temperature for 5 minutes to obtain a uniform dispersion for later use;

[0031] (3) adding the dispersion obtained in step (2) to the blended solution obtained in step (1), stirring at room temperature for 30 min to obtain a uniform film-forming solution for later use;

[0032] (4) The film-forming liquid obtained in step (3) is poured into a plexiglass dish and dried in an oven at 55°C for 12 h to obtain a high-barrier and high-hydrophobic methyl cellulose intelligent packaging film.

[0033] Example 2

[0034] A high-barrier and high-hydrophobic methylcellulose intelligent packaging film, characterized in that it is composed of the following components in parts by weight: 150 parts of methylcellulose and 6 parts of 4-hydroxycinnamic acid complex crystals.

[0035] The preparation method comprises the following steps:

[0036] (1) Add 150 parts of methyl cellulose to 4500 parts of deionized water, stir at 85°C for 60 minutes to obtain a uniform blend solution, cool to room temperature and set aside;

[0037] (2) Disperse 6 parts of 4-hydroxycinnamic acid complex crystals in 500 parts of deionized water, stir at room temperature for 5 minutes to obtain a uniform dispersion, and set aside;

[0038] (3) adding the dispersion obtained in step (2) to the blended solution obtained in step (1), stirring at room temperature for 30 min to obtain a uniform film-forming solution for later use;

[0039] (4) The film-forming liquid obtained in step (3) is poured into a plexiglass dish and dried in an oven at 55°C for 12 h to obtain a high-barrier and high-hydrophobic methyl cellulose intelligent packaging film.

[0040] Example 3

[0041] A high-barrier and high-hydrophobic methylcellulose intelligent packaging film, characterized in that it is composed of the following components in parts by weight: 150 parts of methylcellulose and 9 parts of 4-hydroxycinnamic acid complex crystals.

[0042] The preparation method comprises the following steps:

[0043] (1) Add 150 parts of methyl cellulose to 4500 parts of deionized water, stir at 85°C for 60 minutes to obtain a uniform blend solution, cool to room temperature and set aside;

[0044] (2) Dispersing 9 parts of 4-hydroxycinnamic acid complex crystals in 500 parts of deionized water, stirring at room temperature for 5 minutes to obtain a uniform dispersion for later use;

[0045] (3) adding the dispersion obtained in step (2) to the blended solution obtained in step (1), stirring at room temperature for 30 min to obtain a uniform film-forming solution for later use;

[0046] (4) The film-forming liquid obtained in step (3) is poured into a plexiglass dish and dried in an oven at 55°C for 12 h to obtain a high-barrier and high-hydrophobic methyl cellulose intelligent packaging film.

[0047] Comparative Example

[0048] As a comparison standard of the above embodiments, the present invention provides a methylcellulose film prepared without 4-hydroxycinnamic acid complex crystals, comprising the following steps:

[0049] (1) Add 150 parts of methyl cellulose to 4500 parts of deionized water, stir at 85°C for 60 minutes to obtain a uniform blend solution, cool to room temperature and set aside;

[0050] (2) Add 500 parts of deionized water to the blended solution obtained in step (1), and stir at room temperature for 30 minutes to obtain a uniform film-forming solution for later use;

[0051] (3) pouring the film-forming solution obtained in step (2) into a plexiglass dish and drying it in an oven at 55°C for 12 h to obtain a methylcellulose film;

[0052] Structure and performance test:

[0053] The structure and performance tests were carried out on the methyl cellulose film prepared in the above comparative example and the methyl cellulose intelligent packaging film material prepared in the embodiment, wherein the UV-visible performance was tested by UV-visible spectrometer, and the average UV transmittance was calculated with reference to GB / T18830-2009; the tensile performance was tested in accordance with GB / T 1040-2006; hydrophobicity was characterized by measuring the water contact angle of the sample material using a static contact angle tester; 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.

[0054] The DPPH free radical scavenging experimental method is as follows:

[0055] In the experimental group, 0.2 g of the membrane sample was cut into pieces and soaked in 5 mL of ethanol. After soaking for 24 h, 2 mL of the supernatant of the soaking solution was extracted and set aside. Then, 1 ml of 50 mg / L DPPH solution was added to the 2 mL of the supernatant, and the mixture was shaken and placed in the dark at room temperature for 1 h. Then, the absorbance of the mixture at 517 nm (denoted as A) was measured using an ultraviolet spectrophotometer. sample ); for the control group, 1 mL of 50 mg / L DPPH solution was added to 2 mL of ethanol, and the mixture was shaken and placed in the dark at room temperature for 1 h; then, the absorbance of the mixture at 517 nm (denoted as A) was measured by a UV spectrophotometer. control );DPPH free radical scavenging rate (%)=100*(A control -A sample ) / A control .

[0056] Shrimp freshness monitoring experiment: Fresh shrimps were purchased from the market, and the shrimps (mass: 30 g) were placed in a Petri dish and sealed with a Petri dish cover. The methylcellulose film prepared in the comparative example and the methylcellulose smart packaging film sample prepared in Example 3 (pre-cut into sample materials with a diameter of 1 cm) were attached under the cover. The shrimp samples were then stored in an oven at 25°C, and the changes in the freshness of the shrimps and the color changes of the sample materials were observed and recorded.

[0057] The above performance test data are shown in Table 1 and Table 2.

[0058] Table 1 Sample performance test data

[0059]

[0060] Table 2 Shrimp freshness monitoring experiment results (where t is the storage time of fresh shrimp)

[0061]

[0062] The results of the ammonia response test experiment show that the methylcellulose film 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 methylcellulose smart packaging film prepared in Example 1 is light yellow, and after being exposed to an ammonia environment, its color changes to light brown; the methylcellulose smart packaging film prepared in Example 2 is light yellow, and after being exposed to an ammonia environment, its color changes to light brown; the methylcellulose smart packaging film prepared in Example 3 is yellow, and after being exposed to an ammonia environment, its color changes to brown.

[0063] The results of the DPPH free radical scavenging experiment show that the methyl cellulose film material prepared in the comparative example has no obvious antioxidant activity, while the methyl cellulose smart packaging film material prepared in Example 3 has a DPPH free radical scavenging rate of 92.6%, that is, the methyl cellulose smart packaging film material prepared in the example has excellent antioxidant activity.

[0064] In summary, it can be seen from the sample performance test data (see Tables 1 and 2) that the methyl cellulose intelligent packaging film material prepared by the present invention has excellent ultraviolet blocking, high-energy blue light blocking, hydrophobicity, and excellent mechanical, ammonia response color change, DPPH free radical scavenging rate (i.e., antioxidant activity) and other properties, and can also maintain a high visible light transparency. It can be used as an intelligent indicator material to timely and effectively indicate the freshness changes of meat foods such as shrimp during storage (see Table 2). The preparation process of the composite material 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.

[0065] 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. A high-barrier and high-hydrophobic methylcellulose intelligent packaging film, characterized in that: The method is composed of the following components in parts by weight: 150 parts of methylcellulose and 3-9 parts of 4-hydroxycinnamic acid complex crystals; The preparation method of the 4-hydroxycinnamic acid complex crystal comprises the following steps: (1) Dissolve 16.61 parts of 4-hydroxycinnamic acid in 5000 parts of ethanol, and stir at room temperature for 30 minutes to obtain a 4-hydroxycinnamic acid dispersion for later use; (2) Take 20.85 parts of ferrous sulfate heptahydrate and dissolve it in 1000 parts of deionized water to obtain a uniform ferrous sulfate solution for later use; (3) adding the ferrous sulfate solution obtained in step (2) to the 4-hydroxycinnamic acid dispersion obtained in step (1), stirring the mixture at room temperature for 20 min, and then centrifuging, washing, and drying the mixture in sequence to obtain 4-hydroxycinnamic acid complex crystals.

2. The method for preparing a high-barrier and high-hydrophobic methylcellulose intelligent packaging film according to claim 1, characterized in that The steps include: (1) Add 150 parts of methyl cellulose to 4500 parts of deionized water, stir at 85°C for 60 minutes to obtain a uniform blend solution, cool to room temperature and set aside; (2) Dispersing 3-9 parts of 4-hydroxycinnamic acid complex crystals in 500 parts of deionized water, stirring at room temperature for 5 minutes to obtain a uniform dispersion for later use; (3) adding the dispersion obtained in step (2) to the blended solution obtained in step (1), stirring at room temperature for 30 min to obtain a uniform film-forming solution for later use; (4) The film-forming liquid obtained in step (3) is poured into a plexiglass dish and dried in an oven at 55°C for 12 h to obtain a high-barrier and high-hydrophobic methyl cellulose intelligent packaging film.

3. The use of a high-barrier and high-hydrophobic methylcellulose intelligent packaging film according to claim 1, characterized in that: Used in food packaging, smart materials, ammonia responsive materials, ammonia detection, environmental monitoring and safety fields.

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