CN114015237B - Antibacterial composite material and preparation method thereof - Google Patents

Abstract

The invention discloses an antibacterial composite material which comprises a base material, ferric oxide micro-nano particles and organic antibacterial molecules; the base material is formed by solidifying a viscous flow state or molten gel state non-Newtonian fluid, the ferric oxide micro-nano particles are dispersed in the base material and on the surface of the base material, the organic antibacterial molecules have coordination groups, and the organic antibacterial molecules are anchored in the base material through coordination of the coordination groups and the ferric oxide micro-nano particles. The invention also discloses a preparation method of the material. According to the invention, the long-acting antibacterial capacity of the antibacterial composite material is improved on the premise of not reducing the antibacterial performance by utilizing the coordination effect between the organic antibacterial molecule coordination group and the iron ions of the iron oxide micro-nano particles embedded in the base material.

Description

Antibacterial composite material and preparation method thereof

Technical Field

The invention relates to the technical field of antibiosis, in particular to an antibacterial composite material and a preparation method thereof.

Background

Along with the gradual strengthening of health and public health safety awareness of people, the antibacterial performance of products is more and more valued. However, most of the products at present, such as clothes, utensils, toys and other daily necessities, do not have the sterilization capability. In the daily use process, a large amount of bacteria can grow on the surfaces of the products, and the health and safety of the public are seriously harmed. Although timed periodic environmental disinfection has become a common public recognition, one-time disinfection has limited microbial inhibition, and too frequent disinfection not only causes high economic and time costs, but also causes potential environmental damage. Therefore, the long-acting antibacterial science and technology is developed, and various products or objects are subjected to antibacterial enabling treatment, so that the existing various products have long-acting antibacterial effects, the dependence on disinfection work is reduced, and the long-acting antibacterial technology has important significance and value in promoting public health safety and protecting the health of people.

Silver ions as an antibacterial additive are widely used in various products, such as mobile phone shells, keyboard films, underwear, shoes and socks, and even in food appliances. However, although silverware has an antibacterial effect, silver ions themselves are not suitable as an antibacterial additive from a scientific point of view. Firstly, since silver ions are heavy metals and toxic, adding a large amount of silver ions not only greatly increases the cost, but also brings about serious potential safety hazards. In addition, the coating of a small amount of silver ions on the surface of the product reduces the amount of addition and cost, but the antibacterial ability is lost with the rapid loss of silver ions, and the product does not have a so-called long-lasting antibacterial effect. Therefore, it is urgent to select an appropriate antimicrobial additive.

With the development of antibacterial technology, organic antibacterial molecules have gradually received attention. Organic antibacterial molecules represented by quaternary ammonium salts, guanidines, and heterocycles can form a positively charged functional group region due to the presence of groups that are easily protonated inside the molecule. These charged groups can combine with microbial cell wall, cell membrane and virus capsid to disturb the normal physiological process of microbes, thus achieving the effect of killing bacteria and viruses in broad spectrum. Compared with silver ions, the organic antibacterial molecules have higher safety, less pollution to skin and environment, difficult absorption by human bodies and lower toxicity. However, organic molecules are generally used as disinfectant for wound mucosa care and other applications. Compared with silver ions, organic molecules are rarely used as antibacterial components to be doped in objects or products to energize the products.

In the existing patents, such as CN101351163, CN107032015, CN101595880, etc., organic antibacterial molecules are coated on the surface of an object by designing a coating to form an antibacterial layer, so as to realize antibacterial energization of the object. However, the surface antibacterial layer needs to take many factors into consideration during the preparation process, such as the surface properties of the object, whether the use environment is harsh, and the like. Of course, the long-lasting effect is naturally inferior to the object with antibacterial ability, and the process flow of the product is complicated in the processing technology. Clearly, it is a more promising strategy to deliver antimicrobial activity directly by incorporating organic antimicrobial molecules into the guest during the manufacturing process. However, the problem to be solved in the first place is the problem of the binding form, in which the organic antibacterial molecule is doped in the guest to achieve a stable and long-lasting antibacterial effect. If the antibacterial molecules are simply fixed in the object under the action of chemical bonds and completely lose activity, the antibacterial ability of the antibacterial effect is inevitably greatly reduced; if the antibacterial molecules are not bonded to the substrate, the antibacterial ability of the antibacterial molecules will be lost rapidly during the use process. The chemical contradiction mechanism of the material makes it difficult for organic antibacterial molecules to modify objects through doping.

Therefore, it is a problem to be solved how to design a composition to achieve a secure and free incorporation of organic antibacterial molecules into objects without degrading the antibacterial properties of the molecules.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides an antibacterial composite material and a preparation method thereof, which can stably combine effective antibacterial components in the composite material without weakening the antibacterial capacity of the antibacterial components.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

the invention provides an antibacterial composite material, which comprises a base material, iron oxide micro-nano particles and organic antibacterial molecules; the base material is formed by solidifying non-Newtonian fluid in a viscous flow state or a molten gel state, the ferric oxide micro-nano particles are dispersed in the base material and on the surface of the base material, the organic antibacterial molecules have coordination groups, and the organic antibacterial molecules are anchored in the base material through the coordination effect of the coordination groups and the ferric oxide micro-nano particles.

Preferably, the raw material of the substrate comprises polyvinylidene fluoride, polydimethylsiloxane, polylactic acid and derivatives or copolymers of the above materials. The substrate is in a non-newtonian fluid state having a viscosity under certain conditions, such as a viscous state or a sol state; meanwhile, the iron oxide micro-nano particles and organic antibacterial molecules can be contained by means of curing and forming.

Preferably, the particle size range of the iron oxide micro-nano particles is 10-1000 nm. More preferably, the particle size is in the range of 50 to 500nm. The preferred ranges allow better incorporation into the substrate on the one hand and a larger specific surface area on the other hand.

Preferably, the iron oxide micro-nano particles are mainly ferric oxide, and the proportion of iron ions in a +3 valence state is more than 90%.

Preferably, the weight ratio of the base material, the ferric oxide micro-nano particles and the organic antibacterial molecules is 100:0.1 to 20:0.1 to 20.

Further preferably, the weight ratio of the iron oxide micro-nano particles to the organic antibacterial molecules is 1:1 to 20.

Preferably, the coordinating group of the organic antibacterial molecule contains oxygen lone-pair electrons and nitrogen lone-pair electrons; the organic antibacterial molecule comprises at least one of octenidine, polyhexamethylene biguanide and polyhexamethylene guanidine.

Preferably, the composite material further comprises an additive, wherein the additive comprises at least one of a coupling agent, a cross-linking agent, an antioxidant, a heat stabilizer, a dispersing agent and a processing aid. The additive can better improve the performance of the antibacterial composite material. For example, the coupling agent may be a silane-based coupling agent, a titanate-based coupling agent, or an aluminate-based coupling agent; the crosslinking agent may be one that is required for the substrate to be crosslinked and cured, such as Sylgard 184PDMS crosslinking agent; the antioxidant can be dilauryl thiodipropionate, butyl hydroxy anisole, vitamin E, etc.; the heat stabilizer can be selected from organotin heat stabilizers such as methyl tin mercaptide; the dispersant can be polyethylene glycol ester, etc.; the rest processing aids can be added according to the specific processing scene of the antibacterial composite material on the premise of not influencing the antibacterial performance of the composite material.

Preferably, the content of the desired nano metal oxide is 0.1 to 20 parts by weight, the content of the organic antibacterial molecule containing a coordinating group is 0.1 to 20 parts by weight, the content of the cross-linking agent is 0.1 to 2 parts by weight, the content of the antioxidant is 0.1 to 2 parts by weight, the content of the heat stabilizer is 0.1 to 1 part by weight, and the content of the processing aid is 0.1 to 5 parts by weight, relative to 100 parts by weight of the substrate.

The invention also provides a preparation method of the antibacterial composite material, which comprises the following steps:

1) Adding iron oxide micro-nano particles into a base material in a non-Newtonian fluid state, and stirring for 12-36 hours to uniformly disperse the iron oxide micro-nano particles in the base material;

2) Adding organic antibacterial molecules in a powder or solution state into the mixture, stirring for 12-36 hours, and mixing, wherein the organic antibacterial molecules are contacted with the iron oxide micro-nano particles to form a coordination effect;

3) And curing the substrate.

Optionally, in step 1), the substrate material is a non-newtonian fluid, such as polydimethylsiloxane, and in step 3), crosslinking and curing are performed by adding a crosslinking agent; or, in the step 1), the substrate raw material is heated to form a non-Newtonian fluid, such as polylactic acid, and in the step 3), the substrate raw material is solidified by cooling; or, in step 1), the substrate material is mixed with a solvent to form a non-newtonian fluid, such as polyvinylidene fluoride and derivatives or copolymers thereof, and in step 3), the solvent is evaporated to solidify, and the solvent may be DMF, chloroform, methylene disulfone, and the like.

The invention also provides another preparation method of the antibacterial composite material, which comprises the following steps:

1) Taking ferric acetylacetonate as a precursor, dispersing 10-80 parts by weight of ferric acetylacetonate and 100 parts by weight of polyvinylidene fluoride or polyvinylidene fluoride-hexafluoroethylene copolymer in 500-5000 parts by weight of dimethylformamide solvent according to a proportion, and stirring to a sol state;

2) Heating the sol material in an air environment at 100-180 ℃ for 12-36 hours, and performing condensation reflux to form iron oxide micro-nano particles; then adding 0.1-5 parts by weight of coupling agent into the mixture, and uniformly stirring;

3) Adding 2-10 parts by weight of organic antibacterial molecules into the mixture, ultrasonically stirring for 12-36 hours, and mixing, wherein the organic antibacterial molecules are contacted with the iron oxide micro-nano particles to form a coordination effect;

4) Stirring in a ventilation device at 20-80 ℃ to volatilize the solvent, and solidifying the material to form the antibacterial composite material.

The invention has the beneficial effects that:

(1) The long-acting antibacterial capacity of the antibacterial composite material is improved on the premise of not reducing the antibacterial performance by utilizing the coordination effect between the organic antibacterial molecule coordination group and the iron ions of the ferric oxide micro-nano particles embedded in the base material; meanwhile, the iron ions are fixed in the form of oxides, so that the weakening of antibacterial capacity caused by coordination and combination between organic antibacterial molecules and free iron ions is effectively avoided; the use of metal oxides instead of metal simple substances leads to stronger oxidation resistance of the antibacterial composite material and more stable product performance;

(2) The preparation process is simple and easy to implement, the cost is controllable, and the method is suitable for practical production and application;

(3) The in-situ growth method adopting the iron oxide micro-nano particles has the following advantages: 1. the nano particles formed are not required to be dried and processed, and the agglomeration phenomenon in the processing process is not generated, so that the particle size of the nano particles can be smaller and more uniform, the nano particles have larger specific surface area under the same condition and higher physical-effect ratio, and 3, the surface property of the nano particles generated in situ is more active, most of surface metal ions are in a naked state, and the coordination effect between the nano particles and organic antibacterial molecules is more obvious.

Drawings

FIG. 1 is a schematic diagram of a combination mode of organic antibacterial molecules and iron oxide micro-nano particles in an embodiment.

Detailed Description

The invention is further explained below with reference to the figures and the specific embodiments.

In the examples disclosed below, the polyvinylidene fluoride-hexafluoropropylene copolymer is sold as Solef 21510 from Solvay, suwei, USA; polydimethyl siloxane and crosslinker were purchased from the Sylgard 184 Silicone Elastomer Kit from Dow Corning; octenidine hydrochloride was purchased from wuhananabai chemical; the polylactic acid master batch is provided by the biological science and technology company of the Chinese food grain; the rest chemical reagents are general commercial products.

Example 1

Dispersing 0.05g of iron oxide micro-nano particles in 10g of polydimethylsiloxane monomer, fully performing ultrasonic treatment, and stirring at a high speed to uniformly disperse the iron oxide micro-nano particles in the polydimethylsiloxane, wherein the particle size of the used iron oxide micro-nano particles is about 100 nm; then, 0.025g of polyethylene glycol ester is added, and the mixture is fully stirred uniformly; subsequently, 0.1g of octenidine is added into the system and stirred for dispersion, and because the octenidine is easy to generate agglomeration, the octenidine needs to be dispersed by matching with ultrasound; then, 1g of Sylgard 184PDMS crosslinker was added, sufficiently stirred, and the colloidal mixture was placed in vacuum for negative pressure treatment to discharge the internal air, and repeated 3 to 5 times; and then, placing the mixture into a glass culture dish, and placing the glass culture dish into a forced convection oven at 70 ℃ for cross-linking, curing and molding to obtain the antibacterial composite material.

Example 2

10g of polyvinylidene fluoride-hexafluoroethylene copolymer was dissolved in 55g of dimethylformamide and stirred for 24 hours to form a gum-like mixture; subsequently, 0.25g of ferric oxide nanoparticles with the particle size of about 200nm are added into the mixture, fully stirred for 24 hours and mixed; subsequently, 0.25g of octenidine was added, and the octenidine was sufficiently dispersed using ultrasound and sufficiently stirred for 24 hours. And (3) carrying out spinning or film forming on the sol-gel mixture, and heating to quickly volatilize and shape the solvent to form the antibacterial composite material. In this example, for the subsequent antibacterial experiment, about 20 ml of the composition was placed in a petri dish, and the solvent was rapidly evaporated by heating to form an antibacterial composite material in the petri dish.

Example 3

The composition of this example contains: 10g of polyvinylidene fluoride-hexafluoroethylene copolymer, 2g of iron acetylacetonate, 0.5g of octenidine, 100g of dimethylformamide, 0.25g of aminotrimethoxysilane and 0.25g of aluminate. 2g of iron acetylacetonate was dissolved in 100g of dimethylformamide solvent, and then 10g of polyvinylidene fluoride-hexafluoroethylene copolymer was added thereto and stirred for 24 hours to form a gelatinous mixture; then, heating the mixture to 140 ℃ under the stirring state, preserving the heat for 12 hours, carrying out condensation reflux, and decomposing the iron acetylacetonate to obtain the nano iron oxide uniformly dispersed in the polyvinylidene fluoride-hexafluoroethylene copolymer, wherein the chemical reaction equation is as follows:

after the mixture returns to room temperature, adding 0.25g of aluminate and 0.25g of amino trimethoxy silane, fully stirring and mixing; then, 0.5g of octenidine is added, and the octenidine is fully dispersed by using ultrasound and fully stirred for 24 hours; and (3) carrying out spinning or film forming on the sol-gel mixture, and heating to quickly volatilize and shape the solvent to form the antibacterial composite material. In this example, for the subsequent antibacterial experiment, about 20 ml of the composition was placed in a petri dish, and the solvent was rapidly evaporated by heating to form an antibacterial composite material in the petri dish.

Example 4

The composition of this example contains: 100 parts by weight of polylactic acid (with a molecular weight of 10-30 ten thousand), 10 parts by weight of ferric oxide nanoparticles, 2 parts by weight of amino triethoxysilane, 2 parts by weight of stearic acid, 10 parts by weight of octenidine, 1 part by weight of aluminate, 1 part by weight of dilauryl thiodipropionate, and 1 part by weight of methyltin mercaptide.

Mixing 2.5kg of ferric oxide nanoparticles with the particle size of less than 100nm, 0.5kg of amino triethoxysilane and 0.5kg of stearic acid, and stirring for 30 minutes to obtain surface-modified ferric oxide nanoparticles. Then, adding 25kg of polylactic acid into a mixer, heating to a viscous state, and fully and uniformly mixing; subsequently, 2.5kg of octenidine, 0.25kg of aluminate, 0.25kg of dilauryl thiodipropionate and 0.25kg of methyltin mercaptide were added in this order. If needed, before adding octenidine, elastomer such as polyethylene glycol can be added to improve the mechanical properties of polylactic acid material. And transferring the mixture to a double-screw extruder for mixing, and obtaining the polylactic acid antibacterial master batch after extrusion and cooling. In this example, a small amount of the viscous mixture was cooled and solidified in a glass petri dish for the subsequent antibacterial experiment to form a composite material.

Comparative example 1

The difference from the example 1 is that iron oxide micro-nano particles are not added, and the rest is the same as the example 1.

Comparative example 2

10g of polyvinylidene fluoride-hexafluoroethylene copolymer was dissolved in 55g of dimethylformamide and stirred for 24 hours to form a gum-like mixture; subsequently, 0.25g of octenidine was added, and the octenidine was sufficiently dispersed using ultrasound and sufficiently stirred for 24 hours. The sol-gel mixture is shaped in a spun or film-forming form and the solvent is rapidly evaporated by heating to form the comparative example. In this comparative example, for the subsequent antibacterial experiment, about 20 ml of the composition was placed in a petri dish, and the solvent was rapidly volatilized by heating, forming an antibacterial composite material in the petri dish.

Comparative example 4

The difference from the example 4 is that no iron oxide micro-nano particles are added, and the rest is the same as the example 4.

Method for testing antibacterial performance of material

9ml of staphylococcus aureus liquid (OD =0.02, adjusted to zero) was added to the medium. Incubate at 37 ℃ for 24h. After shaking, 100. Mu.L of the suspension was aspirated into a 96-well plate, and the OD value was measured. Wherein, the bacteria-added control group (without antibacterial substrate, adding bacteria liquid) and the blank control group (without antibacterial substrate, adding blank culture liquid) are also tested at the same time to serve as controls. The test results are as follows (three significant digits retained):

sample (I)	OD value
		Blank control group	0.039
Example 1	0.0475
		Example 2	0.0552
Example 3	0.0485
		Example 4	0.0533
Comparative example 1	0.0487
		Comparative example 2	0.0443
Comparative example 4	0.0601
		Bacteria-added control group	0.646

The examples and comparative examples which had been sufficiently solidified in the petri dish were immersed in 2L of ultrapure water for 24 hours, taken out and dried at room temperature, and then subjected to the antibacterial performance test, with the following test results:

sample (I)	OD value
		EXAMPLE 1 soaking for 24h	0.0650
Comparative example 1 soaking for 24h	0.790
		EXAMPLE 2 soaking for 24h	0.0516
Comparative example 2 soaking for 24h	0.526
		EXAMPLE 4 soaking for 24h	0.0552
Comparative example 4 soaking for 24h	0.529
		EXAMPLE 3 soaking for 24h	0.0439

It can be observed that the examples and the comparative examples both show obvious antibacterial performance, which is shown in that the OD value of the bacterial liquid is obviously reduced after 24h of surface incubation. However, after soaking the examples and the comparative examples in water for 24 hours, it is observed that examples 1, 2, 3 and 4 still show obvious antibacterial performance, which proves that no obvious loss of the antibacterial molecules occurs, the antibacterial performance of the comparative examples is obviously reduced, and the antibacterial molecules are obviously lost.

The antibacterial composite material is shown in a schematic diagram of a combination mode of an organic antibacterial molecule and iron oxide micro-nano particles in figure 1, a positive group in an organic antibacterial molecule ligand contains oxygen lone-pair electrons (hydroxyl, sulfydryl and the like) and nitrogen lone-pair electrons (amino, amido and the like), a transition metal center with an empty d electron track and a coordination group containing lone-pair electrons generate coordination connection, and the iron oxide micro-nano particles are adopted to realize the combination of the organic antibacterial molecule; and the iron oxide micro-nano particles are embedded and fixed in the base material, so that the organic antibacterial molecules are anchored in the base material, and the antibacterial durability of the composite material is improved on the premise of not influencing the antibacterial activity of the organic antibacterial molecules. In addition, ferric ions have a higher coordination number (Fe) than other transition metals, such as copper ions, zinc ions ³⁺ Coordination number of 6,Cu ²⁺ 、Zn ²⁺ The coordination number is 4) and the coordination capacity can provide more ideal coordination effect, so that the anchoring effect of the antibacterial molecule is more obvious and remarkable.

The above examples are only intended to further illustrate an antibacterial composite material and a method for preparing the same according to the present invention, but the present invention is not limited to the examples, and any simple modification, equivalent change and modification made to the above examples according to the technical spirit of the present invention fall within the scope of the technical solution of the present invention.

Claims (6)

1. An antimicrobial composite characterized by: comprises a base material, ferric oxide micro-nano particles and organic antibacterial molecules; the base material is solidified and formed by non-Newtonian fluid in a viscous state or a molten gel state, the iron oxide micro-nano particles are dispersed in the base material and on the surface of the base material, and the particle size range of the iron oxide micro-nano particles is 10-1000 nm; the weight ratio of the base material, the ferric oxide micro-nano particles to the organic antibacterial molecules is 100:0.1 to 20: 0.1-20, wherein the weight ratio of the iron oxide micro-nano particles to the organic antibacterial molecules is 1:1 to 20; the organic antibacterial molecules are octenidine, and the organic antibacterial molecules are anchored in the base material through the coordination of the coordination groups and the iron oxide micro-nano particles.

2. The antimicrobial composite of claim 1, wherein: the raw materials of the base material comprise polyvinylidene fluoride, polydimethylsiloxane, polylactic acid and derivatives or copolymers of the materials.

3. The antimicrobial composite of claim 1, wherein: the composite material also comprises an additive, wherein the additive comprises at least one of a coupling agent, a cross-linking agent, an antioxidant, a heat stabilizer and a dispersing agent.

4. A method for preparing the antibacterial composite material according to any one of claims 1 to 3, characterized by comprising the steps of:

1) Adding iron oxide micro-nano particles into a base material in a non-Newtonian fluid state, and stirring for 12-36 hours to uniformly disperse the iron oxide micro-nano particles in the base material;

2) Adding the organic antibacterial molecules in a powder or solution state into the mixture, ultrasonically stirring for 12-36 hours, and mixing, wherein the organic antibacterial molecules are contacted with the iron oxide micro-nano particles to form a coordination effect;

3) And curing the substrate.

5. The method of claim 4, wherein: in the step 1), the base material is non-Newtonian fluid, and in the step 3), crosslinking and curing are carried out by adding a crosslinking agent; or, in the step 1), the substrate raw material is heated to form non-Newtonian fluid, and in the step 3), the curing is realized by cooling; or, in the step 1), the substrate raw material is mixed with a solvent to form the non-Newtonian fluid, and in the step 3), the solvent is volatilized to solidify.

6. A method for preparing the antibacterial composite material according to any one of claims 1 to 3, characterized by comprising the steps of:

1) Taking ferric acetylacetonate as a precursor, dispersing 10-80 parts by weight of ferric acetylacetonate and 100 parts by weight of polyvinylidene fluoride or polyvinylidene fluoride-hexafluoroethylene copolymer in 500-5000 parts by weight of dimethylformamide solvent according to a proportion, and stirring until the ferric acetylacetonate and the polyvinylidene fluoride-hexafluoroethylene copolymer are dissolved in a colloidal state;

2) Heating the sol material in an air environment at 100-180 ℃ for 12-36 hours, and performing condensation reflux to form iron oxide micro-nano particles; then adding 0.1-5 parts by weight of coupling agent into the mixture, and uniformly stirring;

3) Adding 2-10 parts by weight of organic antibacterial molecules into the mixture, ultrasonically stirring for 12-36 hours, and mixing, wherein the organic antibacterial molecules are contacted with the iron oxide micro-nano particles to form a coordination effect;

4) Stirring in a ventilation device at 20-80 ℃ to volatilize the solvent, and solidifying the material to form the antibacterial composite material.

Images