Oxidized corn starch / sericin / carbon nanotube / nano-silver composite membrane material and preparation method thereof

Abstract

The oxidized corn starch / sericin / carbon nano tube / nano silver composite membrane material comprises oxidized corn starch, sericin, polyvinyl alcohol, carbon nano tubes and nano silver. The preparation method comprises the following steps: carrying out chemical crosslinking on an aldehyde group of oxidized corn starch and an amino group of sericin, carrying out chemical crosslinking on a hydroxyl group of polyvinyl alcohol and the amino group of sericin, adding nano-silver and carbon nanotubes, and carrying out natural drying at room temperature to prepare a composite membrane material which has good antibacterial performance and electrical conductivity; the natural corn starch, sericin and other biological environment resources are effectively utilized, and the prepared composite membrane material has excellent conductivity and is suitable for the fields of flexible conductivity and the like; the raw materials are cheap and easy to obtain, the preparation operation is simple, and the composite membrane material is green, environment-friendly and wide in application field.

Description

Technical Field

[0001] The present invention belongs to the technical field of natural polymer materials, and in particular relates to an oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material and a preparation method thereof. Background Art

[0002] As the global demand for sustainable packaging grows, bio-based materials have become a key direction to replace traditional plastics due to their renewable and degradable properties. The research and development of oxidized corn starch / sericin / carbon nanotube / nanosilver composite film materials focuses on solving the core defects of traditional starch-based materials in functional applications. Existing technologies mainly improve performance through chemical modification, nanofiller doping or blending processes, but still face multiple challenges: First, the hydroxyl-intensive characteristics of the natural starch matrix easily lead to poor interfacial compatibility with other polymers, causing phase separation, significantly weakening the mechanical strength and flexibility of the material; second, the hydrophilic properties of the starch film make it insufficient in water resistance and moisture barrier, and at the same time, the thermal stability is limited, making it difficult to meet the needs of complex environments; third, traditional antibacterial agents have the problems of high addition amount, low efficiency or poor stability, and nano antibacterial agents are prone to aggregation and inactivation due to uneven dispersion or weak interfacial effects; fourth, the processing process often relies on high-cost nanomaterials or organic solvents, which is contrary to the concept of green environmental protection. In response to the above problems, this material achieves performance optimization through multi-component collaborative design: the aldehyde group of oxidized corn starch is used to form a multiple cross-linked network with sericin, carbon nanotubes and nanosilver to enhance the interface bonding force and mechanical properties; the flexible chain segments of sericin complement the rigid skeleton of starch to improve flexibility; carbon nanotubes construct a conductive network and enhance structural stability, while the efficient antibacterial activity and surface functionalization design of nanosilver effectively inhibit agglomeration while reducing the amount of addition. This system comprehensively improves the mechanical properties, water resistance, thermal stability and long-term antibacterial properties of the material while avoiding complex processes and polluting solvents, providing new ideas for the development of high-performance degradable membrane materials. Summary of the invention

[0003] In order to overcome the above-mentioned deficiencies of the prior art, the object of the present invention is to provide an oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material, which has the characteristics of being green, safe, and long-lasting antibacterial.

[0004] To achieve the above object, the technical solution adopted by the present invention is: The oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material is composed of raw materials in the following weight ratio, characterized in that it includes the following components: 1-2g oxidized corn starch, 2-4g sericin, 40-100g water, 10-20g polyvinyl alcohol dispersion, 0.1-1g carbon nanotubes, 0.1-1g nanosilver, and 2-5g glycerol.

[0005] The preparation method of the polyvinyl alcohol dispersion comprises the following steps: Dissolve 1-2g of polyvinyl alcohol in water accounting for 800%-1000% of the mass of polyvinyl alcohol, place in a three-necked flask, adjust the reaction temperature to 40-60°C, adjust the stirring speed to 400-500r / min, and cool to 20-25°C to obtain a polyvinyl alcohol dispersion.

[0006] The mass ratio of polyvinyl alcohol to water is 1:8-10; The stirring time is: 30~60min.

[0007] The method for preparing the oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material comprises the following steps: Step 1, dissolving 1-2 g of oxidized corn starch in water accounting for 500%-600% of the mass of the oxidized corn starch, placing the mixture in a three-necked flask, adjusting the reaction temperature to 30-40° C., and adjusting the stirring speed to 400-500 r / min to obtain an oxidized corn starch dispersion; Step 2, adding 2-4 g of sericin into water, and stirring continuously to completely dissolve the sericin to obtain a clear and transparent solution, i.e., the sericin solution; Step 3, add sericin and water into a round-bottom flask, adjust the temperature to 30-40°C, keep warm for 15-30 minutes, cool to 20-25°C to obtain a sericin solution, stir and mix 10-20g of the oxidized corn starch solution and the sericin solution evenly, add 10-20g of polyvinyl alcohol dispersion with a constant pressure dropping funnel under stirring for cross-linking reaction, the reaction temperature is 40-70°C, the reaction time is 120-180 minutes, then add 0.1-1g of carbon nanotubes, 0.1-1g of nanosilver, and 2-5g of glycerol under stirring, the reaction temperature is 70-80°C, the reaction time is 60-90 minutes, pour the liquid after the reaction into a film-forming plate, let it stand at room temperature to dry and form a film, and obtain an oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material.

[0008] The mass ratio of the oxidized corn starch to water is 1:5-6; The mass ratio of the oxidized corn starch to the sericin is 1:2; The mass ratio of sericin to water is 1:5-10; The mass ratio of the oxidized corn starch to the polyvinyl alcohol is 1:0.5-2; The time for adding the polyvinyl alcohol dispersion dropwise is 5 to 10 minutes; The dropping temperature is: 40~70℃; The stirring speed is 400-500 r / min; The mass ratio of the solid content of the reaction solution to the carbon nanotubes is 1:0.01-0.1; The mass ratio of the solid content of the reaction solution to the nanosilver is 1:0.01-0.1; The mass ratio of the solid content of the reaction solution to glycerol is 1:0.2-0.4.

[0009] The beneficial effects of the present invention are: The present invention uses green and renewable oxidized corn starch and biocompatible sericin as the base material, combines the conductivity enhancement effect of carbon nanotubes with the broad-spectrum antibacterial properties of nanosilver, and constructs a multi-scale functional network structure through the Schiff base cross-linking reaction of oxidized starch aldehyde groups and sericin amino groups, in conjunction with the π-π stacking of carbon nanotubes and the physical dispersion technology of nanosilver, to prepare an oxidized corn starch / sericin / carbon nanotube / nanosilver biomass composite membrane material, which has the following advantages: 1) The sericin-nanosilver synergistic antibacterial system can achieve an antibacterial rate of over 99% against Escherichia coli and Staphylococcus aureus. At the same time, the carbon nanotube network gives the material conductivity, enabling real-time monitoring of packaging damage. 2) The intermolecular hydrogen bonding and Schiff base crosslinking between oxidized starch and sericin significantly improve the mechanical properties and structural stability; 3) Based on the surface plasmon resonance effect of nanosilver, it can respond to amine substances released by food corruption and realize intelligent indication function; 4) The raw materials come from renewable resources such as corn and silk, and the production process does not contain toxic solvents, which complies with the principles of green chemistry; 5) Through the integration of room temperature film formation and nano-dispersion technology, a low-cost, high-value-added multifunctional composite film is developed, which combines the mechanical properties of traditional plastics with the functional characteristics of smart packaging.

[0010] Oxidized corn starch / sericin / carbon nanotube / nanosilver composite film breaks through the performance limitations of single bio-based materials through multi-component synergistic effects: oxidized corn starch is modified to enhance interfacial compatibility, and synergizes with sericin to improve flexibility and barrier properties; carbon nanotubes construct a conductive network, while nano-enhancing tensile strength; nanosilver and sericin form a dual antibacterial system. This material is derived from renewable resources and has intelligent response, long-lasting antibacterial and high mechanical properties. It provides innovative solutions for the intelligent and low-carbonization of food packaging and promotes the upgrading of bio-based materials to functionalization.

[0011] This composite film combines the degradability of oxidized starch, the film-forming advantages of sericin and the reinforcing effect of nanomaterials. It not only solves the technical bottlenecks of insufficient mechanical strength and single function of bio-based materials, but also provides an environmentally friendly alternative for smart food packaging and flexible electronic devices, with significant ecological and economic benefits. DETAILED DESCRIPTION

[0012] The present invention is further described in detail below with reference to specific embodiments. Example

[0013] The oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material is composed of raw materials in the following weight ratio, including the following components: 1g oxidized corn starch, 2g sericin, 40g water, 10g polyvinyl alcohol dispersion, 0.1g carbon nanotubes, 0.1g nanosilver, 2g glycerol. The preparation method of the polyvinyl alcohol dispersion comprises the following steps: Dissolve 1g of polyvinyl alcohol in water accounting for 800% of the mass of polyvinyl alcohol, place in a three-necked flask, adjust the reaction temperature to 40°C, adjust the stirring speed to 400r / min, and cool to 20°C to obtain a polyvinyl alcohol dispersion.

[0014] In the polyvinyl alcohol dispersion: The mass ratio of polyvinyl alcohol to water is 1:8; The stirring time is: 30min.

[0015] The method for preparing the oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material comprises the following steps: Step 1, dissolving oxidized corn starch in water accounting for 500% of the mass of the oxidized corn starch, placing the mixture in a three-necked flask, adjusting the reaction temperature to 30° C., and adjusting the stirring speed to 400 r / min to obtain an oxidized corn starch dispersion; Step 2, adding 2 g of sericin into water, stirring continuously to completely dissolve the sericin to obtain a clear and transparent solution, adjusting the temperature to 30° C., keeping the temperature for 15 minutes, and cooling to 20° C. to obtain a sericin solution; Step 3, 10g of oxidized corn starch solution and sericin solution were stirred and mixed evenly, and 10g of polyvinyl alcohol dispersion was added dropwise using a constant pressure dropping funnel under stirring for cross-linking reaction, the reaction temperature was 40°C, and the reaction time was 120min. Subsequently, 0.1g of carbon nanotubes, 0.1g of nanosilver, and 2g of glycerol were added under stirring, the reaction temperature was 70°C, and the reaction time was 60min. After the reaction, the liquid was poured into a film-forming plate, and allowed to stand at room temperature to dry and form a film, thereby obtaining an oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material.

[0016] The mass ratio of the oxidized corn starch to water is 1:5; The mass ratio of the oxidized corn starch to the sericin is 1:2; The mass ratio of sericin to water is 1:5; The mass ratio of the oxidized corn starch to the polyvinyl alcohol is 1:0.5; The time for adding the polyvinyl alcohol dispersion dropwise is: 5 min; The dropping temperature is: 40°C; The stirring speed is 400r / min; The mass ratio of the solid content of the reaction solution to the carbon nanotubes is 1:0.01; The mass ratio of the solid content of the reaction solution to the nanosilver is 1:0.01; The mass ratio of the solid content of the reaction solution to glycerol is 1:0.2. Example

[0017] The oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material is composed of raw materials in the following weight ratio, including the following components: The preparation method of the polyvinyl alcohol dispersion comprises the following steps: 2g oxidized corn starch, 4g sericin, 100g water, 20g polyvinyl alcohol dispersion, 1g carbon nanotubes, 1g nanosilver, 5g glycerol.

[0018] Dissolve 2g of polyvinyl alcohol in water accounting for 1000% of the mass of polyvinyl alcohol, place in a three-necked flask, adjust the reaction temperature to 60°C, adjust the stirring speed to 500r / min, and cool to 25°C to obtain a polyvinyl alcohol dispersion.

[0019] The mass ratio of polyvinyl alcohol to water is 1:10; The stirring time is: 60min.

[0020] The method for preparing the oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material comprises the following steps: Step 1, dissolving 2 g of oxidized corn starch in water accounting for 600% of the mass of the oxidized corn starch, placing the mixture in a three-necked flask, adjusting the reaction temperature to 40° C., and adjusting the stirring speed to 500 r / min to obtain an oxidized corn starch dispersion; Step 2, add 4 g of sericin into water, stir continuously to completely dissolve the sericin to obtain a clear and transparent solution, adjust the temperature to 40° C., keep warm for 30 minutes, and cool down to 25° C. to obtain a sericin solution; Step 3, 20g of oxidized corn starch solution and sericin solution were stirred and mixed evenly, and 20g of polyvinyl alcohol dispersion was added dropwise using a constant pressure dropping funnel under stirring for cross-linking reaction, the reaction temperature was 70°C, and the reaction time was 180min. Subsequently, 1g of carbon nanotubes, 1g of nanosilver, and 5g of glycerol were added under stirring, the reaction temperature was 80°C, and the reaction time was 90min. After the reaction, the liquid was poured into a film-forming plate, and allowed to stand at room temperature to dry and form a film, thereby obtaining an oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material.

[0021] The mass ratio of the oxidized corn starch to water is 1:6; The mass ratio of the oxidized corn starch to the sericin is 1:2; The mass ratio of sericin to water is 1:10; The mass ratio of the oxidized corn starch to the polyvinyl alcohol is 1:2; The time for adding the polyvinyl alcohol dispersion dropwise is: 10 min; The dropping temperature is: 70°C; The stirring speed is 500r / min; The mass ratio of the solid content of the reaction solution to the carbon nanotubes is 1:0.1; The mass ratio of the solid content of the reaction solution to the nanosilver is 1:0.1; The mass ratio of the solid content of the reaction solution to glycerol is 1:0.4. Example

[0022] The oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material is composed of raw materials in the following weight ratio, including the following components: The preparation method of the polyvinyl alcohol dispersion comprises the following steps: 1.5g oxidized corn starch, 3g sericin, 60g water, 15g polyvinyl alcohol dispersion, 0.5g carbon nanotubes, 0.5g nanosilver, and 3g glycerol.

[0023] Dissolve 1.5 g of polyvinyl alcohol in water accounting for 900% of the mass of polyvinyl alcohol, place in a three-necked flask, adjust the reaction temperature to 50°C, adjust the stirring speed to 450 r / min, and cool to 23°C to obtain a polyvinyl alcohol dispersion.

[0024] The mass ratio of polyvinyl alcohol to water is 1:9; The stirring time is: 45min.

[0025] The method for preparing the oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material comprises the following steps: Step 1, dissolving 1.5 g of oxidized corn starch in water accounting for 550% of the mass of the oxidized corn starch, placing the mixture in a three-necked flask, adjusting the reaction temperature to 35° C., and adjusting the stirring speed to 450 r / min to obtain an oxidized corn starch dispersion; Step 2, add 3g of sericin into water, and stir continuously to completely dissolve the sericin to obtain a clear and transparent solution, i.e., the sericin solution; add sericin and water into a round-bottom flask, adjust the temperature to 35°C, keep warm for 23 min, and cool to 23°C to obtain the sericin solution; stir and mix 15g of the oxidized corn starch solution and the sericin solution evenly, and add 15g of polyvinyl alcohol dispersion dropwise with a constant pressure dropping funnel under stirring for cross-linking reaction, the reaction temperature is 55°C, the reaction time is 150min, and then add 0.5g of carbon nanotubes, 0.5g of nanosilver, and 3g of glycerol under stirring, the reaction temperature is 75°C, the reaction time is 75min, and the liquid after the reaction is completed is poured into a film-forming plate, and allowed to stand at room temperature to dry and form a film, to obtain an oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material.

[0026] The mass ratio of the oxidized corn starch to water is 1:5.5; The mass ratio of the oxidized corn starch to the sericin is 1:2; The mass ratio of sericin to water is 1:7.5; The mass ratio of the oxidized corn starch to the polyvinyl alcohol is 1:1; The time for adding the polyvinyl alcohol dispersion dropwise is 7.5 min; The dropping temperature is: 55°C; The stirring speed is 450r / min; The mass ratio of the solid content of the reaction solution to the carbon nanotubes is 1:0.05; The mass ratio of the solid content of the reaction solution to the nanosilver is 1:0.05; The mass ratio of the solid content of the reaction solution to glycerol is 1:0.3.

Claims

1. Oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material, composed of the following raw materials in the following weight ratio, characterized in that: Includes the following components: 1-2g oxidized corn starch, 2-4g sericin, 40-100g water, 10-20g polyvinyl alcohol dispersion, 0.1-1g carbon nanotubes, 0.1-1g nanosilver, and 2-5g glycerol.

2. The oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material according to claim 1, characterized in that: The preparation method of the polyvinyl alcohol dispersion comprises the following steps: Dissolve 1-2g of polyvinyl alcohol in water accounting for 800%-1000% of the mass of polyvinyl alcohol, place in a three-necked flask, adjust the reaction temperature to 40-60°C, adjust the stirring speed to 400-500r / min, and cool to 20-25°C to obtain a polyvinyl alcohol dispersion.

3. The oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material according to claim 2, characterized in that: In the polyvinyl alcohol dispersion: The mass ratio of polyvinyl alcohol to water is 1:8-10; The time for adjusting the stirring is 30 to 60 minutes.

4. The method for preparing the oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material according to claim 1, characterized in that: The following steps are involved: Step 1, dissolving 1-2 g of oxidized corn starch in water accounting for 500%-600% of the mass of the oxidized corn starch, placing the mixture in a three-necked flask, adjusting the reaction temperature to 30-40° C., and adjusting the stirring speed to 400-500 r / min to obtain an oxidized corn starch dispersion; Step 2, adding 2-4 g of sericin into water, stirring continuously to completely dissolve the sericin into a clear and transparent solution, adjusting the temperature to 30-40° C., keeping the temperature for 15-30 minutes, and cooling to 20-25° C. to obtain a sericin solution; Step 3, 10-20g of oxidized corn starch solution and sericin solution are stirred and mixed evenly, and 10-20g of polyvinyl alcohol dispersion is added dropwise using a constant pressure dropping funnel under stirring for cross-linking reaction, the reaction temperature is 40-70°C, and the reaction time is 120-180min. Subsequently, 0.1-1g of carbon nanotubes, 0.1-1g of nanosilver, and 2-5g of glycerol are added under stirring, the reaction temperature is 70-80°C, and the reaction time is 60-90min. The liquid after the reaction is completed is poured into a film-forming plate, and allowed to stand at room temperature to dry and form a film, thereby obtaining an oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material.

5. The oxidized corn starch / sericin / carbon nanotube / nanosilver composite film material according to claim 4, characterized in that: The mass ratio of the oxidized corn starch to water is 1:5-6; The mass ratio of the oxidized corn starch to the sericin is 1:2; The mass ratio of sericin to water is 1:5-10; The mass ratio of the oxidized corn starch to the polyvinyl alcohol is 1:0.5-2; The time for adding the polyvinyl alcohol dispersion dropwise is 5 to 10 minutes; The temperature of the dropwise addition is 40-70°C; The stirring speed is 400-500 r / min; The mass ratio of the solid content of the reaction solution to the carbon nanotubes is 1:0.01-0.1; The mass ratio of the solid content of the reaction solution to the nanosilver is 1:0.01-0.1; The mass ratio of the solid content of the reaction solution to glycerol is 1:0.2-0.4.