CN117587538A

CN117587538A - Dissolution process of antibacterial and antioxidant composite modifier for flash evaporation cloth

Info

Publication number: CN117587538A
Application number: CN202410063280.4A
Authority: CN
Inventors: 叶孔萌; 吕博; 吴思刚
Original assignee: Jiangsu Qingyun New Materials Co ltd
Current assignee: Jiangsu Qingyun New Materials Co ltd
Priority date: 2024-01-17
Filing date: 2024-01-17
Publication date: 2024-02-23
Anticipated expiration: 2044-01-17
Also published as: CN117587538B

Abstract

The invention provides a dissolution process of an antibacterial and antioxidant composite modifier for flash evaporation cloth and the antibacterial and antioxidant flash evaporation cloth, which comprises the following steps: (1) Firstly, dissolving polyethylene in a spinning solvent in a high-pressure reaction kettle to obtain a polyethylene solution; (2) Then mixing an antibacterial and antioxidant composite modifier with a polyethylene solution in a microreactor; the antibacterial antioxidant is PEG-modified copper-doped graphite-phase carbon nitride quantum dots. The dissolution process ensures that the prepared flash evaporation cloth has better uniformity, and simultaneously, the efficacy of the PEG modified copper-doped graphite phase carbon nitride quantum dot composite modifier is exerted to the maximum extent.

Description

Dissolution process of antibacterial and antioxidant composite modifier for flash evaporation cloth

Technical Field

The invention relates to the technical field of flash spinning, in particular to a dissolution process of an antibacterial and antioxidant composite modifier for flash cloth.

Background

Flash evaporation is also known as instant solvent evaporation and reticulation, instant pressure release spinning, etc. and is characterized by rapid formation of fibers by the polymer when the solvent is flashed. The usual flash spinning process requires the following conditions to be met: the first is that the solvent is a non-solvent for the polymer below the temperature and pressure to which it corresponds to its boiling point; secondly, forming a homogeneous solution with the polymer at high temperature and high pressure; thirdly, when the solution pressure is properly reduced to a certain pressure in the decompression chamber, a certain degree of phase separation occurs, and a two-phase dispersion with one phase being a polymer-rich phase and the other phase being a solvent-rich phase is formed, wherein the pressure is called cloud point pressure; third is that the solvent flash evaporates rapidly as the two-phase dispersion is released through the orifices into the lower pressure region.

The basic process of flash spinning is that the polymer and the solvent are heated and pressurized in an autoclave and stirred for several hours, so that the polymer and the solvent are fully dissolved to form a homogeneous spinning solution; the spinning solution enters a decompression chamber under the action of pressure, and phase separation occurs to a certain extent due to the fact that the pressure is reduced to be lower than cloud point pressure, and then the spinning solution is sprayed out through a spinneret orifice to be solidified into highly oriented reticular superfine fibers. The solution underwent a process from a heterogeneous mixture to a homogeneous solution to a heterogeneous dispersion. As the solution is extruded from the orifices, the solvent rapidly vaporizes due to the sudden release of pressure, creating a supersonic gas stream that stretches the polymer at high velocity; at the same time, the polymer is rapidly cooled and crystallized to solidify into fibers due to the large amount of heat absorbed by the solvent vaporization. The tows are subjected to corona discharge charge after passing through a steering plate rotating at a high speed to open the tows, so that a uniform sheet-shaped fiber net is formed. The fiber net is adsorbed on the net curtain and then is pressed and formed by a roller, so that the high-strength flash evaporation non-woven fabric is obtained. Wherein, the pressure of the solution is reduced below the cloud point pressure of the solution by utilizing a decompression chamber so that the solution is subjected to phase separation, which is the key for preparing the high-performance flash spinning non-woven fabric. If the polymer solution in a homogeneous state is extruded out of a nozzle above the cloud point pressure, the fibers have large diameters and are easy to adhere to each other, and it is difficult to form uniform, fine and high-strength flash fibers.

The existing flash spinning process is generally applicable to polyolefin spinning raw materials, and involves the problems that when some unconventional modifier is required to be added, the dissolution is insufficient or the modifier is denatured or loses efficacy due to poor dissolution process, so that the mechanical property, the uniformity and the expected modification effect of spinning are affected or cannot be exerted.

Disclosure of Invention

In view of this, the present invention provides the following technical solutions:

in one aspect of the invention, a dissolution process of an antibacterial and antioxidant composite modifier for flash evaporation cloth is provided, comprising the following steps:

(1) Firstly, dissolving polyethylene in a spinning solvent in a high-pressure reaction kettle to obtain a polyethylene solution;

(2) Then mixing an antibacterial and antioxidant composite modifier with a polyethylene solution in a microreactor;

the antibacterial antioxidant is PEG modified copper-doped graphite-phase carbon nitride quantum dots;

the preparation of the composite modifier comprises the following steps:

A. copper nitrate is weighed and dissolved in water to prepare a copper nitrate aqueous solution, the copper nitrate aqueous solution is dripped into a melamine aqueous solution, the melamine aqueous solution is stirred and then evaporated to dryness, and the obtained solid is calcined at 500-600 ℃ to obtain copper-doped bulk phase graphite-phase carbon nitride;

B. adding the copper-doped bulk graphite phase carbon nitride into a container, adding water and concentrated nitric acid, carrying out reflux reaction for 18-48h, and carrying out ultrasonic treatment to obtain copper-doped graphite phase carbon nitride quantum dots with carboxyl groups on the surfaces;

C. Adding PEG into the prepared copper-doped graphite phase carbon nitride quantum dot solution, and stirring to obtain the PEG-modified graphite phase carbon nitride quantum dot, wherein one end of the PEG is amino, and the other end of the PEG is a hydrophobic group or an amphiphilic group.

In one embodiment, said step (2) is performed at 20-25 ℃.

In one embodiment, the mass fraction of the composite modifier in the spinning raw material is 0.5-1%, for example, 0.5%, 0.6% and 1%, and the spinning raw material is polyethylene and the composite modifier, so that the synergistic antibacterial effect of the composite modifier is exerted to the greatest extent, and the uniformity of the non-flash cloth is not influenced.

In an embodiment, the doping amount of copper in the composite modifier is 3.5-5.5%, for example, may be 3.5%, 4.1% or 5.2%, and the doping amount of the added composite modifier is controlled within the range, so as to be beneficial to maximally exerting the synergistic antibacterial effect of the doped copper in the carbon nitride skeleton and the carbon nitride itself.

In one embodiment, the polyethylene is dissolved in the autoclave at a pressure of 8 to 12Mpa and a temperature of 330 to 360 ℃.

In one embodiment, in step (2), the composite modifier is sonicated for 20-30 minutes before being added to the microreactor. The ultrasound temperature is room temperature, preferably 20-25 ℃.

In one embodiment, the dissolution process comprises: adding polyethylene and a spinning solvent into a high-pressure reaction kettle, and fully mixing for 3 hours under the conditions of the temperature of 350 ℃ and the pressure of 10Mpa to prepare a polyethylene solution;

adding polyethylene solution into a microreactor, adding PEG modified bulk graphite phase carbon nitride, mixing to obtain spinning solution, and performing ultrasonic treatment at room temperature for 20-30min before adding PEG modified bulk graphite phase carbon nitride at 20-25 ℃.

In one embodiment, the concentration of the aqueous copper nitrate solution in the step A is 10-30 g/L, for example, 10g/L, 20g/L, 30g/L; the concentration of the aqueous melamine solution is 100-300 g/L, and may be, for example, 100g/L, 150g/L, 200g/L, 250g/L, 300g/L.

In one embodiment, the volume ratio of the copper nitrate aqueous solution to the melamine aqueous solution is 1: (1-4), for example, may be 1:3, 2:3, 1:2.

In one embodiment, the PEG is amino at one end and carboxyl at the other.

In one embodiment, the PEG has a molecular weight of 200.

In one embodiment, the preparation of the composite modifier comprises the steps of:

weighing copper nitrate, dissolving in water to prepare a copper nitrate aqueous solution, dripping the copper nitrate aqueous solution into a melamine aqueous solution, stirring, heating to 110-130 ℃, evaporating to dry the water, fully grinding the obtained solid, placing the solid in a crucible with a cover, calcining for 2-3 hours at 500-600 ℃ in a muffle furnace, and cooling to room temperature to obtain copper-doped bulk phase graphite-phase carbon nitride;

Taking the copper-doped bulk phase graphite phase carbon nitride, adding water and concentrated nitric acid into a three-necked flask for reflux reaction for 18-48 hours, washing supernatant to be neutral, and carrying out ultrasonic treatment for 2-6 hours to obtain copper-doped graphite phase carbon nitride quantum dots with carboxyl groups on the surfaces;

and adding PEG into the prepared copper-doped graphite phase carbon nitride quantum dot solution, and stirring and reacting for 18-28h to obtain the PEG-modified graphite phase carbon nitride quantum dot, wherein one end of the PEG is amino and the other end is carboxyl.

In one embodiment, the PEG-modified copper-doped graphite phase carbon nitride quantum dots are soluble in the spin solvent.

In one embodiment, the particle size of the PEG-modified copper-doped graphitic carbon nitride quantum dots is less than 10nm.

In still another aspect of the present invention, there is provided an antibacterial and antioxidant flash evaporation fabric, the preparation process of the spinning dope comprising:

(2) Then mixing an antibacterial and antioxidant composite modifier with a polyethylene solution in a micro-reactor to obtain spinning stock solution;

the preparation of the composite modifier comprises the following steps:

In one embodiment, the temperature of the evaporated moisture in step a is 11-130 ℃. In one embodiment, in step a, the resulting solid is calcined in a muffle furnace.

In an embodiment, in the step B, after the reflow reaction, the supernatant is washed to neutral as primarily exfoliated copper-doped graphene carbon nitride quantum dots.

In one embodiment, in step B, the sonication time is from 2 to 6 hours.

In one embodiment, the copper doped graphite phase carbon nitride quantum dots have carboxyl groups on the surface.

In one embodiment, the particle size of the copper-doped graphite phase carbon nitride quantum dots is less than 5nm, for example, may be 2-5nm.

In one embodiment, in step C, the stirring time is 18 to 28 hours.

In one embodiment, the spinning solvent is one or more of aromatic hydrocarbon, aliphatic hydrocarbon, alicyclic hydrocarbon, unsaturated hydrocarbon, halogenated hydrocarbon, alcohol, ester, ether, ketone, nitrile, amide, fluorocarbon.

In one embodiment, the aromatic hydrocarbon is selected from one or more of benzene, toluene, xylene and chlorobenzene.

In one embodiment, the aliphatic hydrocarbon is selected from one or more of butane, pentane, 3-methylpentane, hexane, heptane, octane and their isomers and homologs.

In one embodiment, the alicyclic hydrocarbon is selected from one of cyclohexane, cyclopentane or a mixture thereof.

In one embodiment, the unsaturated hydrocarbon is selected from one or more of 1, 2-dichloroethylene, cis-1, 2-dichloroethylene (cis-1, 2-DCE), trans-1, 2-dichloroethylene (trans-1, 2-DCE).

In one embodiment of the present invention, in one embodiment, the halogenated hydrocarbon is selected from trichlorofluoromethane, dichloromethane, carbon tetrachloride, chloroform, chloroethane, chloromethane, 1-dichloro-2, 2-trifluoroethane, 1, 2-dichloro-1, 2-trifluoroethane, and 1, 1-dichloro-2, 2-difluoroethane, 1, 2-dichloro-1, 1-difluoroethane, 1-dichloro-1-fluoroethane, monochlorodichloromethane, 1, 2-tetrafluoro-2-chloroethane, 1-dichloro-1-chloroethane, or a mixture of two or more thereof.

In one embodiment of the present invention, in one embodiment, the fluorocarbon is selected from the group consisting of 1, 2-tetrafluoroethane, 1-difluoroethane 1, 3-pentafluoropropane, 1,2, 3, 4-octafluorobutane, 1, 3-pentafluorobutane 2, 3-dihydrodecafluoropentane, 1H, 6H-perfluorohexane, 1H-perfluoroheptane, 1H-perfluorohexane, and one or a combination of two or more of the isomers of the above solvents.

In one embodiment, the ethereal solvent is tetrahydrofuran.

In one embodiment, the spinning solvent is a mixed solvent of halogenated hydrocarbons and ethers.

In one embodiment, the spinning solvent is a mixed solvent containing one or two of dichloromethane, 1-difluoroethane and trichlorofluoromethane.

In an embodiment, the mass fraction of the spinning raw material in the spinning solution is 8% -18%, for example, 10%, 14%, 16%, 18%.

In one embodiment, the flash cloth has a thickness of 0.1 to 0.3mm.

In one embodiment, the flash evaporation cloth has a ratio of the area of the polymer sheet material having a thickness in the range of (0.2 mm,0.25 mm) to the total area of the polymer sheet material of 75% or more.

In still another aspect of the present invention, the use of the above-described antimicrobial antioxidant flash fabric in the manufacture of a medical package or medical protective product is provided.

The invention has the beneficial effects that:

the dissolution process of the PEG modified quantum dot modifier for the flash evaporation cloth is provided, the prepared flash evaporation cloth is guaranteed to have better uniformity and toughness, and meanwhile, the efficacy of the PEG modified copper doped graphite phase carbon nitride quantum dot composite modifier is exerted to the maximum extent.

In the flash evaporation cloth prepared by the invention, the doped copper and the carbon nitride exert synergistic antibacterial effect, and the antibacterial rate of the flash evaporation cloth on staphylococcus aureus, klebsiella pneumoniae and escherichia coli is over 99 percent. And the doped copper is embedded in the carbon nitride framework, and the carbon nitride material has durable antibacterial property, and the antibacterial rate is still more than 99% after being stored for 6 months.

The flash evaporation cloth prepared by the invention has good oxidation resistance and better comprehensive performance due to successful addition of the carbon nitride material.

The preparation process has simple steps and low process cost, and the doped copper element and carbon nitride material are low in price. And avoid: due to the addition of modifiers which are more difficult to dissolve in the spinning solvent, higher pressures are required to dissolve the high energy process of the spinning raw material.

Detailed Description

I. Definition of the definition

In the present invention, unless otherwise indicated, scientific and technical terms used herein have the meanings commonly understood by one of ordinary skill in the art. Also, the relative terms and laboratory procedures used herein are terms and conventional procedures that are widely used in the corresponding arts. Meanwhile, in order to better understand the present invention, definitions and explanations of related terms are provided below.

As used herein and unless otherwise indicated, the term "about" or "approximately" means within plus or minus 10% of a given value or range. Where integers are required, the term refers to rounding up or down to the nearest integer within plus or minus 10% of a given value or range.

In the description herein, reference is made to "some embodiments," "some implementations," or "some implementations," which describe a subset of all possible embodiments, but it is to be understood that "some embodiments" may be the same subset or different subsets of all possible embodiments and may be combined with one another without conflict.

As used herein and unless otherwise indicated, the terms "comprising," "including," "having," "containing," and their grammatical equivalents are generally understood to be open-ended and not to be limiting, e.g., not to exclude other, unrecited elements or steps.

The term "polyethylene" is intended to include not only homopolymers of ethylene but also copolymers of ethylene in which at least 85% of the repeat units of the copolymer are ethylene units. One preferred polyethylene is a high density polyethylene having an upper melting range of about 130 ℃ to 140 ℃, a density in the range of 0.94 to 0.98 g/cc, and a Melt Index (MI) between 0.1 and 100, preferably less than 4.

The term "spin dope" refers to the total composition spun using the spinning apparatus described herein. The spinning solution comprises a polymer and a modifier.

The term "spin solvent" refers to the solvent or mixture of solvents used to initially dissolve the polymer to form the spin dope, as well as any modifiers, solubility aids, and blends therewith.

The term "microreactor" refers to a microreactor commonly used in the art, such as the heart-shaped microreactor disclosed in CN116926692 a. "decompression chamber" or "decompression chamber" refers to the common decompression chamber equipment in the art.

Examples II

The present invention will be described in further detail below for the purpose of making the objects, technical solutions and advantages of the present invention more apparent, and the described embodiments should not be construed as limiting the present invention, and all other embodiments obtained by those skilled in the art without making any inventive effort are within the scope of the present invention.

Before describing embodiments of the present invention in further detail, the terms and terminology involved in the embodiments of the present invention will be described, and the terms and terminology involved in the embodiments of the present invention will be used in the following explanation.

The materials and equipment used in the embodiments of the present disclosure are all known products and are obtained by purchasing commercially available products.

The elongation at break according to the invention is, unless otherwise specified, the average value of the tensile strength in the longitudinal and transverse directions of the test piece, i.e. the average elongation at break.

Example 1

(1) Dissolving a polymer spinning raw material in a spinning solvent to obtain a spinning solution;

the polymer spinning raw material comprises polyethylene and a modifier;

the modifier is PEG modified copper-doped graphite phase carbon nitride quantum dots; the mass fraction of the modifier in the polymer spinning raw material is 1%;

The mass fraction of the polymer spinning raw material in the spinning stock solution is 18%;

the spinning solvent is methylene dichloride and 1, 1-difluoroethane with the mass ratio of 4: 5.

Dissolution of spinning raw materials: adding polyethylene and spinning solvent into a high-pressure reaction kettle, and fully mixing for 3 hours under the conditions of temperature of 350 ℃ and pressure of 10Mpa to prepare polyethylene solution. Adding polyethylene solution into a microreactor, adding PEG modified bulk graphite phase carbon nitride, mixing to obtain spinning solution, and performing ultrasonic treatment at room temperature for 20-30min before adding PEG modified bulk graphite phase carbon nitride at 20-25 ℃.

The preparation method of the modifier comprises the following steps:

bulk graphite phase carbon nitride: adding aqueous solution of copper nitrate (10 g/L,10 mL) into aqueous solution of melamine (100 g/L,30 mL) by a syringe pump under stirring at a speed of 0.8mL/h, stirring for a period of time, heating the mixed solution to 120 ℃ and stirring in an oil bath until the water is completely evaporated, weighing 10g of the obtained solid after being fully ground, placing the crucible cover in a crucible with a cover, reacting for 2h at 550 ℃ in a muffle furnace, cooling to room temperature to obtain bulk phase graphite-phase carbon nitride powder doped with copper, and measuring the doping amount of copper by SEM elemental analysis to be 3.5%.

Copper doped graphite phase carbon nitride quantum dots: and (3) taking 500mg of the copper-doped bulk graphite phase carbon nitride in a three-necked flask, adding water and concentrated nitric acid, and carrying out reflux reaction for one day, wherein the volume ratio of the water to the concentrated nitric acid is 2:1. Washing the supernatant to neutrality after refluxing, and then ultrasonic crushing for 2-6 hours, wherein the surface of the supernatant is provided with carboxyl groups and is water-soluble, and the particle size of the supernatant is 2-5nm under a transmission electron microscope.

PEG-modified copper-doped graphite-phase carbon nitride quantum dots: activating carboxyl on the graphene carbon nitride quantum dot by EDC and NHS, then adding PEG (molecular weight is 200) with amino at one end into the activated copper-doped graphene carbon nitride quantum dot solution, stirring and reacting at normal temperature overnight to obtain PEG-modified graphite phase carbon nitride quantum dot, and dissolving in dichloroethane for standby. Wherein the mass ratio of EDC to NHS is 1:1, and the activation time is 1-4 hours.

The microreactor was a heart-shaped microreactor having a structure as disclosed in example 1 of CN116926692 a.

(2) Decompressing the spinning solution to be below cloud point pressure through a decompression chamber, spraying out the spinning solution through a spinning nozzle to obtain flash fiber, and paving the flash fiber into a net to obtain initial cloth; and rolling and winding the initial cloth to obtain the flash cloth.

Example 2

the polymer spinning raw material comprises polyethylene and a modifier;

the modifier is PEG modified copper-doped graphite phase carbon nitride quantum dots; the mass fraction of the modifier in the polymer spinning raw material is 0.5%;

the mass fraction of the polymer spinning raw material in the spinning stock solution is 14%;

the adopted spinning solvent is methylene dichloride and trichlorofluoromethane with the volume ratio of 8: 1.

Dissolution of spinning raw materials: adding polyethylene and spinning solvent into a high-pressure reaction kettle, and fully mixing for 5 hours under the conditions of the temperature of 340 ℃ and the pressure of 10Mpa to prepare polyethylene solution. Adding polyethylene solution into a microreactor, adding PEG modified bulk graphite phase carbon nitride, mixing to obtain spinning solution, and performing ultrasonic treatment at room temperature for 20-30min before adding PEG modified bulk graphite phase carbon nitride at 20-25 ℃.

The preparation method of the modifier comprises the following steps:

bulk graphite phase carbon nitride: adding aqueous solution of copper nitrate (30 g/L,20 mL) into aqueous solution of melamine (300 g/L,30 mL) by a syringe pump at a speed of 0.8mL/h, stirring for a period of time, heating the mixed solution to 120 ℃ and stirring in an oil bath until the water is completely evaporated, weighing 10g of the obtained solid after being fully ground, placing the crucible cover in a crucible with a cover, reacting for 2h at 550 ℃ in a muffle furnace, cooling to room temperature to obtain bulk phase graphite-phase carbon nitride powder doped with copper, and measuring the doping amount of copper by SEM elemental analysis to be 4.1%.

Example 3

the polymer spinning raw material comprises polyethylene and a modifier;

the modifier is PEG modified copper-doped graphite phase carbon nitride quantum dots; the mass fraction of the modifier in the polymer spinning raw material is 0.6%;

the mass fraction of the polymer spinning raw material in the spinning stock solution is 8%;

the spinning solvent adopted is dichloromethane, 1-difluoroethane and tetrahydrofuran with the mass ratio of 4:4: 1.

Dissolution of spinning raw materials: adding polyethylene and spinning solvent into a high-pressure reaction kettle, and fully mixing for 4 hours under the conditions of 320 ℃ and 10Mpa pressure to prepare polyethylene solution. Adding polyethylene solution into a microreactor, adding PEG modified bulk graphite phase carbon nitride, mixing to obtain spinning solution, and performing ultrasonic treatment at room temperature for 20-30min before adding PEG modified bulk graphite phase carbon nitride at 20-25 ℃.

The preparation method of the modifier comprises the following steps:

bulk graphite phase carbon nitride: adding aqueous solution of copper nitrate (20 g/L,20 mL) into aqueous solution of melamine (200 g/L,40 mL) by a syringe pump under stirring at a speed of 0.8mL/h, stirring for a period of time, heating the mixed solution to 120 ℃ and stirring in an oil bath until the water is completely evaporated, weighing 10g of the obtained solid after being sufficiently ground, placing the crucible cover in a crucible with a cover, reacting for 2h at 550 ℃ in a muffle furnace, cooling to room temperature to obtain bulk phase graphite-phase carbon nitride powder doped with copper, and measuring the doping amount of copper by SEM elemental analysis to be 5.2%.

Comparative example 1

the polymer spinning raw material comprises polyethylene and a modifier;

Dissolution of spinning raw materials: adding polyethylene, PEG modified bulk graphite phase carbon nitride and a spinning solvent into a high-pressure reaction kettle, fully mixing for 3 hours at the temperature of 350 ℃ and the pressure of 10Mpa to prepare a spinning solution, and carrying out ultrasonic treatment for 20-30min at room temperature before adding the PEG modified bulk graphite phase carbon nitride.

The preparation method of the modifier is the same as in example 1.

Comparative example 2

the polymer spinning raw material comprises polyethylene and a modifier;

Dissolution of spinning raw materials: and (3) carrying out ultrasonic treatment on the PEG-modified bulk graphite phase carbon nitride at room temperature for 20-30min, respectively adding the PEG-modified bulk graphite phase carbon nitride and part of spinning solvent into a microreactor, and mixing to obtain a PEG-modified bulk graphite phase carbon nitride solution, wherein the process is carried out at 20-25 ℃. Adding the PEG modified bulk graphite phase carbon nitride solution, polyethylene and the rest of spinning solvent into a high-pressure reaction kettle, and fully mixing for 3 hours under the conditions of the temperature of 350 ℃ and the pressure of 15Mpa to obtain a spinning solution, wherein the volume ratio of the part of spinning solvent for dissolving the modifier to the spinning solvent for dissolving the polyethylene is 1:18.

The preparation method of the modifier is the same as in example 1.

Comparative example 3

the polymer spinning raw material comprises polyethylene and a modifier;

the modifier is copper-doped graphite phase carbon nitride quantum dots modified by amino PEG at two ends; the mass fraction of the modifier in the polymer spinning raw material is 1%;

The preparation method of the graphite phase carbon nitride quantum dot modified by the PEG with two ends comprises the following steps:

the preparation method of the copper-doped graphite-phase carbon nitride quantum dot is the same as that of example 1.

Copper modified by two-end amino PEG is doped to obtain graphite phase carbon nitride quantum dots: activating carboxyl on the carbon quantum dot by EDC and NHS, adding PEG (molecular weight of 200) with two amino ends into the activated quantum dot solution, stirring at normal temperature for reaction overnight to obtain PEG modified copper-doped graphite phase carbon nitride quantum dot, and dissolving in dichloroethane for standby. Wherein the mass ratio of EDC to NHS is 1:1, and the activation time is 1-4 hours.

Comparative example 4

the polymer spinning raw material comprises polyethylene and a modifier;

the modifier is F127 modified graphene quantum dots; the mass fraction of the modifier in the polymer spinning raw material is 1%;

The preparation method of the F127 modified graphene quantum dot comprises the following steps:

Graphene quantum dots: prepared as described in example 1 of CN113260692a with an average diameter of about 3.5nm.

F127 modified graphene quantum dots: 300mg of polyether F127 is weighed and dissolved in 5mL of ethanol, then graphene quantum dot aqueous solution is added into the solution, and the mixture is stirred for 24 hours at room temperature. And after the self-assembly process is finished, centrifugally separating to obtain F127 modified graphene quantum dots, centrifugally washing with ethanol for three times to obtain oil-soluble F127 modified graphene quantum dots, and dissolving in dichloroethane for later use.

Comparative example 5

the polymer spinning raw material comprises polyethylene and a modifier;

the modifier is PEG modified doped graphite phase carbon nitride quantum dot; the mass fraction of the modifier in the polymer spinning raw material is 1%;

The preparation method of the modifier comprises the following steps:

bulk graphite phase carbon nitride: 10g of melamine is weighed and placed in a crucible with a cover, the cover of the crucible is placed in a muffle furnace for reaction for 2 hours at 550 ℃, and the temperature is reduced to room temperature to obtain bulk phase graphite phase carbon nitride powder.

Graphite phase carbon nitride quantum dots: and (3) taking 500mg of bulk graphite phase carbon nitride in a three-necked flask, adding water and concentrated nitric acid, and carrying out reflux reaction for one day, wherein the volume ratio of the water to the concentrated nitric acid is 2:1. Washing the supernatant to neutrality after refluxing, and then ultrasonic crushing for 2-6 hours, wherein the surface of the supernatant is provided with carboxyl groups and is water-soluble, and the particle size of the supernatant is 2-5nm under a transmission electron microscope.

PEG-modified graphitic carbon nitride quantum dots: activating carboxyl on the graphene carbon nitride quantum dot by EDC and NHS, then adding PEG (molecular weight is 200) with amino at one end into the activated graphene carbon nitride quantum dot solution, stirring and reacting at normal temperature overnight to obtain PEG modified graphite phase carbon nitride quantum dot, and dissolving in dichloroethane for standby. Wherein the mass ratio of EDC to NHS is 1:1, and the activation time is 1-4 hours.

Comparative example 6

the polymer spinning raw material comprises polyethylene and a modifier;

the modifier is copper oxide; the mass fraction of the modifier in the polymer spinning raw material is 1%;

Comparative example 7

the polymer spinning raw material comprises polyethylene and a modifier;

The preparation method of the modifier comprises the following steps:

bulk graphite phase carbon nitride: adding aqueous solution of copper nitrate (10 g/L,10 mL) into aqueous solution of melamine (100 g/L,30 mL) by a syringe pump under stirring at a speed of 0.8mL/h, stirring for a period of time, heating the mixed solution to 120 ℃ and stirring in an oil bath until the water is completely evaporated, weighing 10g of the obtained solid after being sufficiently ground, placing the crucible cover in a crucible with a cover, reacting for 2h at 550 ℃ in a muffle furnace, cooling to room temperature to obtain bulk phase graphite-phase carbon nitride powder doped with copper, and measuring the doping amount of copper by SEM elemental analysis to be 10%.

PEG-modified copper-doped graphite-phase carbon nitride quantum dots were prepared by the procedure described in example 1.

Test example 1 uniformity test

The thickness of the polymer sheet materials prepared in the above examples and comparative examples was measured, and the thickness was measured as follows: on a 10 square meter sample, 50 samples were randomly taken, wherein the size of individual samples was 100mm x 100mm; the thickness of the sample was measured, and the thickness of the sample was obtained by averaging the thickness measurements three times, and the test results are shown in Table 1.

The specific test steps are as follows:

(1) Classifying 50 samples into the above intervals according to the thickness of [0.1mm,0.15mm ], (0.15 mm,0.2mm ], (0.2 mm,0.25mm ], (0.25 mm,0.3mm ], obtaining the number of samples distributed in different thickness intervals, and finally using the ratio of the number of samples in the (0.15 mm,0.2 mm) to the total number of samples as the ratio of the area of the polyolefin polymer sheet material with the thickness of (0.15 mm,0.2 mm) to the area of the total polyolefin polymer sheet material;

(2) The thicknesses of the 50 samples were further averaged to obtain the thickness of the sample.

TABLE 1

Wherein: A. b, C, D are the ratios of the areas of the polyolefin polymer sheet materials to the areas of the total polyolefin polymer sheet materials, respectively, in the thickness ranges of [0.1mm,0.15mm ], (0.15 mm,0.2mm ], (0.2 mm,0.25mm ], (0.25 mm,0.3mm ].

The flash cloths prepared in comparative examples 1 and 3 were not tested for uniformity as observed by the human eye and as perceived by hand touch. The reason may be that the polyethylene and the composite modifier are dissolved in a high-pressure reaction kettle under the same temperature and pressure conditions as in example 1, and the PEG-modified copper-doped graphite-phase carbon nitride quantum dots are agglomerated at high temperature and high pressure, so that the spinning dope is unevenly mixed, and the thickness and uniformity of the obtained non-manufactured cloth are affected. In the comparative example 3, the graphene carbon nitride quantum dot prepared by modifying the PEG with two amino ends is formed by respectively connecting the amino solutions at the two ends of the PEG with the carbon nitride quantum dot with carboxyl groups on the quantum dot, so that the improvement effect of the water solubility of the graphene carbon nitride quantum dot is weakened, and the solubility of the modifier in the spinning solution is influenced.

From the above results in Table 1, it can be seen that examples 1 to 3 of the present invention were prepared to obtain a nonwoven fabric having a uniform thickness by improving the dissolution process thereof with respect to the spinning raw material containing the antibacterial antioxidant property composite modifier, wherein the ratio in the range of (0.2 mm,0.25 mm) was more than 75%, and comparative example 2 was prepared to have poor uniformity by mixing the quantum dots with a portion of the spinning solvent through a microreactor and then mixing and dissolving with a polyethylene solution in a high pressure autoclave, because the PEG-modified graphite-phase carbon nitride quantum dots of the present invention had a better effect with the polyethylene mixed solvent in the microreactor providing a shearing force, except that the quantum dot agglomeration may be caused by a high temperature, but if the polyethylene and the quantum dot modifier were dissolved together in the microreactor, the dissolution of the polyethylene was poor.

In comparative example 4, F127 modified graphene quantum dots are added, and the self-assembly of the F127 graphene quantum dots is destroyed after mixing in a micro-reactor because the F127 graphene quantum dots are in a self-assembly form in a solution, and the water-soluble graphene quantum dots are poorly dissolved in an oily solvent, so that the uniformity of the prepared non-woven fabric is also poor.

Test example 2 antibacterial test

Test of antibacterial ratio: the nonwoven fabrics prepared in the above examples and comparative examples were tested for antimicrobial properties with reference to standard GB/T20944.2-2007 (evaluation of antimicrobial properties of textiles part 2: absorption method), and the test results are shown in Table 2.

The specific test conditions are as follows:

the bacterial used in the antibacterial test is staphylococcus aureus, klebsiella pneumoniae and escherichia coli.

Culture conditions: 37 ℃ +/-2 ℃ and 90% +/-2%; the culture time is 18-24 hours.

The antibacterial rate (namely, bacteriostatic rate) shows that more than 95 percent of the antibacterial agent has antibacterial performance, and the antibacterial agent has better antibacterial function when the antibacterial agent is more than 99 percent.

TABLE 2

After the flash cloth was stored for 6 months, the antibacterial function was again tested according to the above method, and the test results are shown in table 3.

TABLE 3 Table 3

From the results shown in tables 2 and 3, the nonwoven fabric prepared by the invention has excellent antibacterial performance, in examples 1 and 3, copper doped in a carbon nitride skeleton plays a synergistic antibacterial role with carbon nitride, for example, for staphylococcus aureus, klebsiella pneumoniae and escherichia coli, the antibacterial rate of the non-manufactured fabric obtained by using graphite-phase carbon nitride quantum dots as the modifier in comparative example 5 is 75.6%, the antibacterial rate of the non-manufactured fabric obtained by using the graphite-phase carbon nitride quantum dots as the modifier in comparative example 6 is 62.7, the antibacterial rate of the graphene carbon nitride quantum dots doped with copper is above 99%, and the graphene carbon nitride quantum dots doped with copper have an effect of 1+1 > 2, especially have excellent antibacterial performance for staphylococcus aureus, klebsiella pneumoniae and escherichia coli. The reduction in antibacterial performance is relatively small after long-term placement, and excellent antibacterial persistence is achieved.

Test example 3 mechanical Properties and Oxidation resistance test

The specific test method is as follows:

elongation at break: testing according to the GB/T24218.18-2014 standard, and recording the average value of the transverse and longitudinal elongation at break as the elongation at break of the fabric;

oxidation procedure: the test specimens were suspended in a conventional laboratory non-forced air oven and left to stand at 100℃for one week for heat aging.

TABLE 4 Table 4

Note that: "-" indicates no test.

As can be seen from the results of Table 4, the nonwoven fabrics prepared in examples 1-3 of the present application all had tensile elongations of 90% or more, and had better toughness. The copper doping amount of comparative example 7 exceeds 5.5%, the tensile elongation is greatly reduced, and the toughness is greatly affected.

Meanwhile, the non-woven fabrics prepared in examples 1-3 have excellent oxidation resistance and aging resistance, and the elongation at break is less reduced after the heat aging treatment. In the process of dissolving polyethylene and modifier in comparative example 1, the spinning raw material is not uniformly dissolved in the high-pressure reaction kettle, so that the mechanical property and oxidation resistance of the product are also poor. The graphene quantum dots modified by F127 in comparative example 4 and the carbon nitride quantum dots modified by PEG in comparative example 5 also have reduced aging resistance compared with example 1. In comparative example 6, only copper was added to the spinning raw material, and the aging resistance was remarkably inferior.

The foregoing descriptions of specific exemplary embodiments of the present invention are presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application to thereby enable one skilled in the art to make and utilize the invention in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.

Claims

1. The dissolution process of the antibacterial and antioxidant composite modifier for the flash evaporation cloth is characterized by comprising the following steps of:

the preparation of the composite modifier comprises the following steps:

2. The process for dissolving the antibacterial and antioxidant composite modifier for flash fabric according to claim 1, wherein the step (2) is performed at 20-25 ℃.

3. The process for dissolving the antibacterial and antioxidant composite modifier for the flash evaporation cloth according to claim 1, wherein the mass fraction of the composite modifier in a spinning raw material is 0.5-1%, and the spinning raw material is polyethylene and the composite modifier.

4. The process for dissolving the antibacterial and antioxidant composite modifier for flash fabric according to claim 1, wherein the doping amount of copper in the composite modifier is 3.5-5.5%.

5. The dissolution process of the antibacterial and antioxidant composite modifier for flash fabric according to claim 1, which is characterized by comprising the following steps: adding polyethylene and a spinning solvent into a high-pressure reaction kettle, and fully mixing for 3 hours under the conditions of the temperature of 350 ℃ and the pressure of 10Mpa to prepare a polyethylene solution;

6. The process for dissolving the antibacterial and antioxidant composite modifier for flash evaporation cloth according to claim 1, wherein the concentration of the copper nitrate aqueous solution in the step A is 10-30 g/L; the concentration of the melamine water solution is 100-300 g/L; the volume ratio of the copper nitrate aqueous solution to the melamine aqueous solution is 1: (1-4).

7. The process for dissolving the antibacterial and antioxidant composite modifier for flash fabric according to claim 1, wherein one end of the PEG is amino and the other end is carboxyl; the molecular weight of the PEG was 200.

8. The dissolution process of the antibacterial and antioxidant composite modifier for flash fabric according to claim 1, wherein the preparation of the composite modifier comprises the following steps:

9. The antibacterial and antioxidant flash evaporation cloth is characterized in that the preparation process of the spinning solution comprises the following steps:

the preparation of the composite modifier comprises the following steps:

10. Use of the antimicrobial antioxidant flash fabric of claim 9 in the manufacture of a medical package or medical protective product.