CN116536791A - Modified graphene polylactic acid antibacterial fiber and its preparation method and application - Google Patents

Abstract

The invention provides a modified graphene polylactic acid antibacterial fiber and its preparation method and application. The fiber uses polylactic acid as the fiber substrate, and the polylactic acid is evenly loaded with graphene oxide grafted N-halamine antibacterial material; graphite oxide The ene-grafted N-halamine antibacterial material contains a photosensitive mercapto group, and is combined with an unsaturated bond in the polylactic acid through the photosensitive mercapto group. The present invention uses a silane coupling agent containing photosensitive mercapto groups to combine graphene oxide with N-halamine precursors and polylactic acid in a chemical bond manner, avoiding the grafting of N-halamine from graphene oxide to N-halogen The detachment of the amine antibacterial material and the loss of the graphene oxide grafted N-halamine antibacterial material on the antibacterial fiber make the antibacterial fiber prepared have a stable antibacterial effect and long antibacterial timeliness. The antibacterial fiber obtained by the invention has good antibacterial performance, antistatic performance and strong mechanical performance, and has great industrial and market application value.

Description

Modified graphene polylactic acid antibacterial fiber and its preparation method and application

technical field

The invention relates to the technical field of antibacterial fabric preparation, in particular to a modified graphene polylactic acid antibacterial fiber and its preparation method and application.

Background technique

Various bacteria and viruses are raging in the world today, which brings huge challenges to human survival and social development. Medical filter products have become the main means of defense for people against bacteria. Among the products that filter germs, polylactic acid non-woven fabrics play an important role. Polylactic acid fibers and their non-woven fabrics can form a weakly acidic environment on the surface of the product, and have certain anti-mildew and antibacterial effects. However, pure polylactic acid fabrics The antibacterial effect is not obvious, and the bacteria adsorbed on the fiber still survive.

To solve the above problems, the antibacterial modification of graphene-based PLA fibers and their nonwovens has been extensively studied in the past decades. The invention patent (the application number is CN 202211052980.0) discloses a graphene-polylactic acid antibacterial masterbatch and its preparation method and application, using the improved Hummers method to prepare a uniformly dispersed graphene oxide dispersion; take the guanidinium compound and dissolve it in water , adding to the graphene oxide dispersion, stirring and heating, the guanidinium compound molecules are entangled on the surface of the graphene oxide two-dimensional sheet structure through electrostatic interaction, then suction filtered, washed, and freeze-dried to obtain the guanidinium salt-graphene assembly; Finally, the guanidinium-graphene assembly was melt-blended with the polylactic acid substrate, extruded and granulated to obtain the graphene-polylactic acid antibacterial masterbatch. However, in this patent solution, the antibacterial guanidinium compound molecules are only assembled with graphene oxide through electrostatic interaction, and the guanidinium-graphene assembly and the polylactic acid substrate are only physically melt-blended; in subsequent applications, antibacterial materials are prone to appear The loss of antibacterial molecules or the entire guanidinium-graphene assembly results in poor antibacterial timeliness.

In the prior art, there are other methods for preparing polylactic acid resistant fibers, such as combining inorganic antibacterial agents, organic antibacterial agents or composite antibacterial agents with polylactic acid through surface grafting, surface coating, and melt blending. The matrix modification of polylactic acid was carried out to endow polypropylene with antibacterial groups, thereby improving the antibacterial performance of polylactic acid. However, many antibacterial polylactic acid fibers and their non-woven fabrics currently prepared have more or less problems such as large amount of antibacterial agent, easy loss of antibacterial components, short antibacterial time, high finishing cost, single function, and serious environmental pollution. This has also promoted the development of safer, more efficient and cheaper antibacterial polylactic acid fibers.

In view of this, it is necessary to design an improved modified graphene polylactic acid antibacterial fiber and its preparation method and application to solve the above problems.

Contents of the invention

The object of the present invention is to provide a kind of modified graphene polylactic acid antibacterial fiber and its preparation method and application, by utilizing the silane coupling agent containing photosensitive mercapto group to combine graphene oxide with N-halamine precursor, poly Lactic acid is combined with chemical bonds to avoid the loss of graphene oxide grafted N-halamine antibacterial materials, improve the antibacterial timeliness and mechanical strength of modified graphene polylactic acid antibacterial fibers, and the obtained antibacterial fibers have both antibacterial properties and antibacterial properties. Electrostatic properties and strong mechanical properties have great market application value.

In order to realize the above-mentioned invention object, the present invention provides a kind of modified graphene polylactic acid antibacterial fiber, take polylactic acid as fiber base material, evenly load graphene oxide grafted N-halamine antibacterial material in the polylactic acid; The graphene oxide grafted N-halamine antibacterial material contains a photosensitive mercapto group, and the graphene oxide grafted N-halamine antibacterial material passes through the photosensitive mercapto group and the unsaturated bond in the polylactic acid combined.

As a further improvement of the present invention, the mass ratio of the polylactic acid to the graphene oxide grafted N-halamine antibacterial material is 1000:(3-15).

As a further improvement of the present invention, in step S2, the mass ratio of the lamellar graphene oxide to the mercaptosilane coupling agent is (7-10):100.

The present invention also provides a kind of preparation method of above-mentioned modified graphene polylactic acid antibacterial fiber, comprises the following steps:

S1. Disperse graphene oxide in deionized water, and ultrasonically peel it off to obtain graphene oxide colloid; add alkaline solution to the graphene oxide colloid, stir at 95-100°C, wash, filter, and Dried to obtain layer-like graphene oxide;

S2. Add the layered graphene oxide obtained in step S1 and the mercaptosilane coupling agent in proportion to absolute ethanol to prepare a mixed solution, and add N-halamine precursors and photoinitiators into the mixed solution , after 1.0-2.0 hours of light, centrifuge, wash and vacuum-dry to obtain graphene oxide grafted N-halamine antibacterial powder;

S3. Mix the graphene oxide grafted N-halamine antibacterial powder obtained in step S2 with polylactic acid according to a preset ratio, and put it into a meltblown machine for meltblown treatment after irradiating for 0.5 to 1.5 hours to obtain graphene oxide grafted N-halamine melt blown material;

S4. Soak the graphene oxide grafted N-halamine melt-blown material in step S3 in sodium hypochlorite for 0.5-1.0 h, wash, dry, and heat-treat to obtain the graphene oxide-grafted N-halamine antibacterial melt-blown material ;

S5. Melt-spinning the graphene oxide-grafted N-halamine antibacterial meltblown material prepared in step S4 to obtain the modified graphene polylactic acid antibacterial fiber.

As a further improvement of the present invention, the mass ratio of the lamellar graphene oxide to the mercaptosilane coupling agent is (1-9):100; the added amount of the mercaptosilane coupling agent is 1% of the mass of polylactic acid ~5%.

As a further improvement of the present invention, in step S2, the addition amount of the N-halamine precursor is 0.5% to 1.5% of the mass of the layered graphene oxide, and the addition amount of the photoinitiator is the 0.5% to 5.0% of the mass of the layered graphene oxide.

As a further improvement of the present invention, in step S5, during the melt spinning, deodorant particles are added to the graphene oxide grafted N-halamine antibacterial melt-blown material to participate in the melt spinning together, A modified graphene polylactic acid antibacterial fiber with a deodorizing function is obtained; the deodorizing particles include one or more of activated carbon particles, nano-silver particles, and active oxygen particles.

As a further improvement of the present invention, in step S1, the preparation of graphene oxide includes the following steps:

SS1. Add the solid mixture of graphite powder and sodium nitrate into concentrated sulfuric acid in an ice-water bath under magnetic stirring, then slowly add potassium perchlorate, and at the same time add potassium permanganate in batches for reaction. The reaction temperature does not exceed 20°C, 0.5-1.5 Take out after h;

SS2. Stir and react the solution treated in step SS1 at room temperature for 24 hours, dilute it with 5% H ₂ SO ₄ solution, stir for 0.5-1.0 hours, then add H ₂ O ₂ and stir for 0.5-2.0 hours Centrifuge to obtain solid matter;

SS3. Wash the solid matter obtained in step SS2 with H ₂ SO ₄ , H ₂ O ₂ mixed solution and HCI solution for 1 to 3 times respectively, and finally wash with distilled water for 1 to 3 times to make the pH value 7, and dry Afterwards, the yellow-brown precipitate obtained is the graphene oxide.

As a further improvement of the present invention, in step S2, the mercaptosilane coupling agent includes 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane One of base silane, 3-mercaptopropyltriphenylsilane, 3-(methylpropoxy)propyltrimethoxysilane; the N-halamine precursor includes methacrylamide, 1-ene One of propylhydantoin and 2,4-diamino-6-diallylamino-1,3,5-triazine.

As a further improvement of the present invention, in step S2, the photoinitiator includes one of benzoin dimethyl ether, isopropylthioxanthone, and triaryl iodonium salt.

The present invention also provides an application of a modified graphene polylactic acid antibacterial fiber, wherein the modified graphene polylactic acid antibacterial fiber is prepared by any of the above-mentioned preparation methods, The modified graphene polylactic acid antibacterial fiber is applied to the preparation of antibacterial non-woven fabrics, and the antibacterial non-woven fabrics are used to prepare one or more antibacterial protective products in medical masks, medical protective clothing and industrial clothing.

The beneficial effects of the present invention are:

1. A modified graphene polylactic acid antibacterial fiber provided by the present invention uses polylactic acid as the fiber substrate, and uniformly loads graphene oxide grafted N-halamine antibacterial materials in polylactic acid; graphene oxide grafted N-halogen The amine antibacterial material contains a photosensitive mercapto group, which is combined with an unsaturated bond in polylactic acid through the photosensitive mercapto group. The present invention combines graphene oxide with N-halamine precursors and polylactic acid in a chemical bond manner by using a silane coupling agent containing photosensitive mercapto groups, thereby avoiding the problem of graphene oxide grafting N-halamine antibacterial materials. The loss improves the antibacterial timeliness and mechanical strength of the modified graphene polylactic acid antibacterial fiber, and the obtained antibacterial fiber has antibacterial performance, antistatic performance and strong mechanical properties, and has great market application value.

2. In the present invention, the N-halamine precursor is chemically bonded to graphene oxide. In order to prevent the loss of the N-halamine precursor, a silane coupling agent containing a photosensitive mercapto group is added at the same time; The coupling agent can react with graphene oxide, N-halamine precursor, and polylactic acid. Under light conditions, not only the N-halamine precursor can react with the active groups on the surface of graphene oxide through the silane coupling agent, but also The photosensitive mercapto group on the graphene oxide is combined with the unsaturated bond in the polylactic acid through a chemical bond; thereby avoiding the detachment of N-halamine from the graphene oxide grafted N-halamine antibacterial material, graphene oxide The loss of the grafted N-halamine antibacterial material on the antibacterial fiber based on polylactic acid makes the prepared antibacterial fiber or antibacterial non-woven fabric have good antibacterial effect and long antibacterial timeliness.

3, the graphene oxide specific surface area of the lamellar structure that the present invention selects is big, the surface contains a large amount of active groups, and the grafting rate is high, and the addition of mercaptosilane coupling agent has further improved the grafting rate of graphene oxide, is Coupling agents containing N-halamine and photosensitive mercapto groups provide more reaction sites; the presence of photosensitive mercapto groups on the surface of graphene oxide realizes graphene oxide-grafted N-halamine antibacterial materials and The stable combination of polylactic acid resin in a short period of time improves the antibacterial performance of the prepared material and the load fastness of the antibacterial material. In addition, graphene oxide with a lamellar structure has good electrical conductivity, and after melt blending with polylactic acid, it gives it an antistatic function; and graphene oxide with a lamellar structure has anisotropy in the fiber, which improves the The strength of the antibacterial fiber makes the fiber have good overall performance when applied to antibacterial non-woven fabrics.

4. The present invention imparts photosensitive mercapto groups to graphene oxide while modifying the antibacterial properties. By limiting the addition of mercaptosilane coupling agent and N-halamine precursor, it is better to avoid N-halamine antibacterial agents. While preventing the detachment of graphene oxide; at the same time, the mass ratio of graphene oxide grafted N-halamine antibacterial material to polylactic acid is limited, and the antibacterial performance is maximized on the basis of saving costs, which has the value of industrial mass production.

Description of drawings

Fig. 1 is the schematic flow sheet of the preparation method of modified graphene polylactic acid antibacterial fiber of the present invention.

Fig. 2 is the diagram of the molecular structure change process of the graphene oxide grafted N-halamine antibacterial powder prepared in Example 1.

Fig. 3 is the electron micrograph of the modified graphene polylactic acid antibacterial fiber prepared in embodiment 1.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Here, it should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only the structures and/or processing steps closely related to the solution of the present invention are shown in the drawings, and the steps related to the present invention are omitted. Invent other details that don't really matter.

Additionally, it should be noted that the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, but also Other elements not expressly listed, or inherent to the process, method, article, or apparatus are also included.

A modified graphene polylactic acid antibacterial fiber, with polylactic acid as the fiber base material, the polylactic acid is evenly loaded with graphene oxide grafted N-halamine antibacterial material; the graphene oxide grafted N-halamine antibacterial material contains photosensitive The graphene oxide grafted N-halamine antibacterial material is combined with the unsaturated bond in polylactic acid through the photosensitive mercapto group. Wherein, the mass ratio of polylactic acid and graphene oxide grafted N-halamine antibacterial material is 1000:(3～15), and the mass ratio of layered graphene oxide and mercaptosilane coupling agent is preferably (7～10) :100. The present invention combines graphene oxide with N-halamine precursors and polylactic acid in a chemical bond manner by using a silane coupling agent containing photosensitive mercapto groups, thereby avoiding the problem of graphene oxide grafting N-halamine antibacterial materials. The loss improves the antibacterial timeliness and mechanical strength of the modified graphene polylactic acid antibacterial fiber, and the obtained antibacterial fiber and antibacterial non-woven fabric have both antibacterial performance, antistatic performance and strong mechanical properties, and have great market applications value.

Please refer to shown in Fig. 1, a kind of preparation method of modified graphene polylactic acid antibacterial fiber, comprises the following steps:

S1. Disperse graphene oxide in deionized water, and ultrasonically peel it off to obtain graphene oxide colloid; add alkaline solution to graphene oxide colloid, stir at 95-100°C, wash, filter, and dry after the reaction is completed. Obtain lamellar graphene oxide; wherein, the ultrasonic power is 60W, and the time is 2-4h;

S2. Add the layered graphene oxide obtained in step S1 and the mercaptosilane coupling agent in proportion to absolute ethanol to prepare a mixed solution, add the N-halamine precursor and photoinitiator to the mixed solution, and light for 1.0~ After 2.0h, centrifugation, washing and vacuum drying were carried out to obtain graphene oxide grafted N-halamine antibacterial powder;

Among them, the mass ratio of lamellar graphene oxide to mercaptosilane coupling agent is (1-9):100, and the addition amount of mercaptosilane coupling agent is 1% to 5% of the mass of polylactic acid; N-halamine precursor The addition amount of body is 0.5%～1.5% of the mass of layered graphene oxide, and the addition amount of photoinitiator is 0.5%～5.0% of the mass of layered graphene oxide; At the same time, by endowing it with a photosensitive mercapto group, by limiting the addition amount of mercaptosilane coupling agent and N-halamine precursor, it is better to prevent the detachment of graphene oxide while avoiding the loss of N-halamine antibacterial agent; The mass ratio of graphene oxide grafted N-halamine antibacterial material to polylactic acid maximizes the antibacterial performance on the basis of saving costs, and has the value of industrial mass production;

S3. Mix the graphene oxide-grafted N-halamine antibacterial powder obtained in step S2 with polylactic acid in a preset ratio, and put it into a melt-blown machine after irradiating for 0.5 to 1.5 hours for melt-blown treatment to obtain graphene oxide-grafted N- Haloamine melt blown material;

S4. Soak the graphene oxide grafted N-halamine melt-blown material in step S3 in sodium hypochlorite for 0.5-1.0 h, wash, dry, and heat-treat to obtain the graphene oxide-grafted N-halamine antibacterial melt-blown material; Graphene oxide grafted N-halamine melt-blown material is chlorinated, which can realize the regeneration of antibacterial properties;

S5. Melt-spinning the graphene oxide-grafted N-halamine antibacterial melt-blown material prepared in step S4 to obtain the modified graphene polylactic acid antibacterial fiber.

In particular, in the preparation method, the N-halamine precursor is chemically bonded to graphene oxide, and in order to prevent the loss of the N-halamine precursor, a silane coupling agent containing a photosensitive mercapto group is added at the same time; The coupling agent can react with graphene oxide, N-halamine precursor, and polylactic acid. Under light conditions, not only the N-halamine precursor can react with the active groups on the surface of graphene oxide again through the silane coupling agent , also makes the photosensitive mercapto group on the graphene oxide and the unsaturated bond in the polylactic acid combined by chemical bond; thereby avoiding the detachment and oxidation of N-halamine from the graphene oxide grafted N-halamine antibacterial material The loss of the graphene-grafted N-halamine antibacterial material on the antibacterial fiber makes the antibacterial fiber prepared have good antibacterial effect and long antibacterial timeliness.

Specifically, in step S1, the improved Hummers method of graphene oxide is prepared, comprising the following steps:

SS1. Add the solid mixture of graphite powder and sodium nitrate into concentrated sulfuric acid in an ice-water bath under magnetic stirring, then slowly add potassium perchlorate, and at the same time add potassium permanganate in batches for reaction. The reaction temperature does not exceed 20°C, 0.5-1.5 Take out after h; The mass ratio of potassium perchlorate and potassium permanganate is 5:3;

SS2. Stir and react the solution treated in step SS1 at room temperature for 24 hours, dilute it with 5% H ₂ SO ₄ solution, stir for 0.5-1.0 hours, then add H ₂ O ₂ and stir for 0.5-2.0 hours Centrifuge to obtain solid matter;

SS3. Wash the solid matter obtained in step SS2 with H ₂ SO ₄ , H ₂ O ₂ mixed solution and HCI solution for 1 to 3 times respectively, and finally wash with distilled water for 1 to 3 times to make the pH value 7, and dry to obtain The yellow-brown precipitate is graphene oxide.

It should be noted that the graphene oxide with a lamellar structure selected in the preparation method has a large specific surface area, a large amount of active groups on the surface, and a high grafting rate, and the addition of a mercaptosilane coupling agent further improves the grafting of graphene oxide. Branching rate provides more reaction sites for N-halamines and coupling agents containing photosensitive mercapto groups. The existence of photosensitive mercapto groups on the surface of graphene oxide realizes the grafting of graphene oxide with N-halogen The stable combination of amine antibacterial material and polylactic acid resin in a short period of time improves the antibacterial performance and antibacterial load fastness of the prepared material. In addition, graphene oxide with a lamellar structure has good electrical conductivity, and after melt blending with polylactic acid, it gives it an antistatic function; and graphene oxide with a lamellar structure has anisotropy in the fiber, which improves the The strength of the antibacterial fiber makes it have good comprehensive performance.

In step S2, the mercaptosilane coupling agent includes 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, One of phenylsilane, 3-(methylpropoxy)propyltrimethoxysilane; N-halamine precursors include methacrylamide, 1-allylhydantoin, 2,4- One of diamino-6-diallylamino-1,3,5-triazine; the photoinitiator includes one of benzoin dimethyl ether, isopropylthioxanthone, and triaryl iodonium salt.

In some specific embodiments, in step S5, when the graphene oxide grafted N-halamine antibacterial melt-blown material is melt-spun, deodorant particles are added therein to participate in melt-spinning together to obtain a deodorizing function The modified graphene polylactic acid antibacterial fiber; the deodorant particles include one or more of activated carbon particles, nano-silver particles, and active oxygen particles.

In some specific embodiments, in step S1, the alkaline solution is sodium hydroxide solution.

An application of a modified graphene polylactic acid antibacterial fiber, the modified graphene polylactic acid antibacterial fiber is used to prepare antibacterial non-woven fabrics, and the antibacterial non-woven fabrics are used to prepare one or more of medical masks, medical protective clothing and industrial clothing A variety of antibacterial protection products.

Example 1

The present embodiment provides a kind of preparation method of modified graphene polylactic acid antibacterial fiber, comprises the following steps:

S1, using the improved Hummers method to prepare lamellar graphene oxide;

S11. Add the solid mixture of 2g of graphite powder and 1g of sodium nitrate into concentrated sulfuric acid in an ice-water bath under magnetic stirring, then slowly add 10g of potassium perchlorate, and at the same time add 6g of potassium permanganate in batches for reaction. The reaction temperature does not exceed 20°C , take it out after 1.5h;

S12. Stir and react the solution treated in step S11 at room temperature for 24 h, dilute it with 5% H ₂ SO ₄ solution, stir for 1 h, then add 6 mL of H ₂ O ₂ solution, the solution turns bright yellow , stirred and reacted for 2h and centrifuged to obtain a solid substance;

S13. Wash the solid matter obtained in step S12 twice with H ₂ SO ₄ , H ₂ O ₂ mixed solution and HCI solution respectively, and finally wash it three times with distilled water to make the pH value 7, and put it in a vacuum oven at 40°C Fully dried in medium to obtain a yellow-brown precipitate which is graphene oxide (GO).

S14. Disperse the graphene oxide in deionized water, and use 60W power to ultrasonically peel off for 3 hours to obtain the graphene oxide colloid; add an alkaline solution to the graphene oxide colloid, stir at 95°C, wash and filter after the reaction is completed , put it into an oven and dry at 40°C to obtain layered graphene oxide;

S2, adding the layered graphene oxide and 3-mercaptopropyltrimethoxysilane obtained in step S1 to absolute ethanol in a mass ratio of 5:100 to prepare a mixed solution, and methacrylamide, photoinitiator benzoin Dimethyl ether is added to the mixed solution, centrifuged, washed and vacuum-dried after 1h of light to obtain graphene oxide grafted N-halamine antibacterial powder; wherein, the amount of methacrylamide added is 1/2 of the mass of lamellar graphene oxide. 1%, the addition of photoinitiator is 0.5% of the mass of lamellar graphene oxide, and the addition of 3-mercaptopropyltrimethoxysilane is 3% of the mass of polylactic acid;

S3, the graphene oxide grafted N-halamine antibacterial powder obtained in step S2 is mixed with polylactic acid (PLA) in a mass ratio of 9:1000, and added to the melt-blown machine after 1h of light for melt-blown treatment to obtain graphite oxide Alkene-grafted N-halamine melt-blown material;

S4. Soak the graphene oxide grafted N-halamine melt-blown material in step S3 in sodium hypochlorite for 30 minutes, wash, dry, and heat-treat to obtain the graphene oxide-grafted N-halamine antibacterial melt-blown material;

S5. Melt-spinning the graphene oxide-grafted N-halamine antibacterial melt-blown material prepared in step S4 to obtain the modified graphene polylactic acid antibacterial fiber.

Please refer to FIG. 2 , which is a diagram of the molecular structure change process of the graphene oxide grafted N-halamine antibacterial powder prepared in this embodiment. As can be seen from the figure, the molecular structure change process diagram of graphene oxide grafted N-halamine antibacterial powder is as follows: the first step is to react graphene oxide with mercaptosilane coupling agent to generate graphene oxide containing reactive functional groups- Silane coupling agent compound; in the second step, the graphene oxide-mercaptosilane coupling agent compound reacts with N-halamine through a nucleophilic substitution reaction to form a graphene oxide-grafted N-halamine compound.

Please refer to shown in Fig. 3, is the electron micrograph of the modified graphene polylactic acid antibacterial fiber that embodiment 1 prepares. It can be seen from the figure that the protrusions on the surface of the polylactic acid graphene oxide composite fiber can indicate that graphene oxide has been mixed into the polylactic acid, and these raised structures are formed due to the dispersion and aggregation of graphene on the fiber surface. In the process of fiber preparation, graphene oxide is often treated together with polylactic acid, and after steps such as heating and extrusion, a mixture is formed for fiberization; during this process, graphene will interact with polylactic acid molecules, which may be in the fiber The surface aggregates to form bumps, and this structure can effectively enhance the physical combination of graphene and PLA, thereby improving the performance of the composite. Therefore, the convex structure can be used to characterize the composite of graphene and PLA.

Embodiment 2-4

Embodiment 2～4 provides a kind of preparation method of modified graphene polylactic acid antibacterial fiber, compared with embodiment 1, difference is that in embodiment 2～4, graphene oxide grafts N-halamine antibacterial powder The mass ratios to polylactic acid are 3:1000, 6:1000, and 12:1000 respectively; the rest are roughly the same as in Example 1, and will not be repeated here.

Comparative example 1

Comparative example 1 provides a kind of preparation method of modified graphene polylactic acid antibacterial fiber, compared with embodiment 1, difference is that in step S2, 3-mercaptopropyltrimethoxysilane and photoinitiator are not added, Illumination treatment was not carried out either, and the rest is roughly the same as that of Embodiment 1, and will not be repeated here.

Comparative example 2～3

Comparative examples 2-3 provide a kind of preparation method of modified graphene polylactic acid antibacterial fiber, compared with embodiment 1, the difference is that in comparative examples 2-3, graphene oxide grafted N-halamine antibacterial powder The mass ratios to polylactic acid are 1:1000 and 20:1000 respectively; the rest are roughly the same as those in Example 1 and will not be repeated here.

Comparative example 4

Comparative example 4 provides a kind of preparation method of modified graphene polylactic acid antibacterial fiber, compared with embodiment 1, difference is that the chlorination treatment of step S4 is not carried out; All the other are roughly the same as embodiment 1, here No longer.

Comparative example 5

Comparative example 5 provides a kind of preparation method of modified graphene polylactic acid antibacterial fiber, compared with embodiment 1, difference is that step S1 is not carried out, and in step S2, replace lamellar shape with nano-silica Graphene oxide; All the others are roughly the same as in Example 1, and will not be repeated here.

The antibacterial properties and mechanical properties of the modified graphene polylactic acid antibacterial fibers prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were tested, and the results obtained are shown in the table below.

The antibacterial fiber performance test result of table 1 embodiment 1～4 and comparative example 1～5

It can be seen from Table 1 that the antibacterial fiber prepared by mixing a certain quality of graphene oxide grafted N-halamine antibacterial powder with polylactic acid has good antibacterial ability. It is obtained from Examples 1-4 and Comparative Examples 2 and 3. With the increase of the content of graphene-grafted N-halamine antibacterial powder, the antibacterial ability of polylactic acid composite fiber showed a trend of first rising and then declining, which indicated that the addition of graphene oxide-grafted N-halamine antibacterial powder had a certain effect. threshold. In comparative example 1, without adding mercaptosilane coupling agent, the antibacterial ability of the fiber is relatively reduced. The principle is that the antibacterial performance of the graphene oxide grafted N-halamine antibacterial powder is agglomerated inside the fiber, which affects its antibacterial performance, and When no mercaptosilane coupling agent was added, the graphene oxide-grafted N-halamine antibacterial material did not bond with the polylactic acid resin, which affected the strength, and the antibacterial performance was greatly lost after repeated chlorination. In Comparative Example 4, the antibacterial ability of the fiber without chlorination is reduced, because the graphene oxide grafted N-halamine antibacterial powder needs to be chlorinated to activate its functional group to enhance the antibacterial ability of the composite fiber. In comparative example 5, graphene oxide is replaced by silicon dioxide inorganic particles, and its antibacterial rate and strength and other properties are all reduced. Its antibacterial ability is reduced. It can be seen that the mass ratio of graphene oxide grafted N-halamine antibacterial powder to polylactic acid, the addition of mercaptosilane coupling agent and the structure of inorganic particles have an impact on the antibacterial and mechanical properties of the fiber.

Embodiment 5～6

Embodiment 5～6 provides a kind of preparation method of modified graphene polylactic acid antibacterial fiber, compared with embodiment 1, difference is, in embodiment 5～6, the addition amount of mercaptosilane coupling agent is poly 1% and 5% of the lactic acid mass, and the rest are roughly the same as in Example 1, and will not be repeated here.

Comparative example 6～7

Comparative example 6～7 provides a kind of preparation method of modified graphene polylactic acid antibacterial fiber, compared with embodiment 1, difference is that, in embodiment 6～7, the addition amount of mercaptosilane coupling agent is poly 0.5% and 7% of the lactic acid mass, the rest are roughly the same as in Example 1, and will not be repeated here.

Comparative example 8～9

Comparative examples 8～9 provide a kind of preparation method of modified graphene polylactic acid antibacterial fiber, compared with embodiment 1, difference is, the addition amount of N-halamine precursor in comparative examples 8～9 is layer 0.1%, 2% of the mass of flaky graphene oxide, and the rest are roughly the same as those in Example 1, and will not be repeated here.

The modified graphene polylactic acid antibacterial fibers prepared in Examples 5-6 and Comparative Examples 6-9 were tested for their antibacterial performance and mechanical properties, and the results obtained are shown in the table below.

The antibacterial fiber performance testing result of table 2 embodiment 5～6 and comparative example 6～9

Antibacterial rate (%) Antibacterial rate after 20 times of chlorination (%) Tensile strength (MPa) Example 5 99.9 95.6 58 Example 6 99.9 99.5 63 Comparative example 6 99.9 94.8 56 Comparative example 7 99.9 99.6 58 Comparative example 8 96.7 95.4 56 Comparative example 9 99.9 98.8 60

It can be seen from Table 2 that, in general, doping with an appropriate amount of N-halamine precursors can increase the tensile strength of PLA composites, but the increase in tensile strength is not linear with the content of N-halamine precursors relationship, but follow a certain saturation trend. When the content is lower than a certain range, with the increase of N-halamine precursor content, the tensile strength of PLA composites will first increase and then decrease. The mercaptosilane coupling agent can be used to improve the bonding strength between polylactic acid and graphene oxide, thereby improving the mechanical properties and durability of the material; Influence on the strength; the dosage of mercaptosilane coupling agent is in the range of 1% to 5% of the mass of polylactic acid, which can significantly improve the tensile strength of the material and make its mechanical properties more excellent. Appropriate addition of mercaptosilane coupling agent can significantly improve the bonding effect of polylactic acid and graphene oxide, thereby improving the mechanical properties and durability of polylactic acid materials, and then improving the tensile strength of polylactic acid materials, which is very useful for the application of polylactic acid materials. Significance.

In summary, the present invention provides a modified graphene polylactic acid antibacterial fiber and its preparation method and application. The fiber uses polylactic acid as the fiber substrate, and the polylactic acid is evenly loaded with graphene oxide grafted N-halamine Antibacterial material; graphene oxide grafted N-halamine antibacterial material contains photosensitive mercapto groups, and is combined with unsaturated bonds in polylactic acid through photosensitive mercapto groups. In the preparation method of the present invention, the silane coupling agent containing photosensitive mercapto groups is used to combine the graphene oxide with the N-halamine precursor and polylactic acid in a chemical bond mode, which avoids the N-halamine from graphene oxide. The detachment of the grafted N-halamine antibacterial material and the loss of the graphene oxide grafted N-halamine antibacterial material on the antibacterial fiber make the antibacterial fiber prepared have good antibacterial effect and long antibacterial timeliness. In addition, the selected graphene oxide with lamellar structure provides more reaction sites, realizing the stable combination of graphene oxide grafted N-halamine antibacterial material and polylactic acid resin in a short time; it also has good Conductivity, after melting and blending with polylactic acid, endow it with antistatic function; and graphene oxide with lamellar structure has anisotropy in the fiber, which improves the strength of antibacterial fiber, and is used in the preparation of antibacterial non-woven fabrics , so that the comprehensive performance is good; the antibacterial fiber and antibacterial non-woven fabric obtained in the present invention have antibacterial performance, antistatic performance and strong mechanical performance, and have great market application value.

The above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced. Without departing from the spirit and scope of the technical solution of the present invention.

Claims (10)

1. The modified graphene polylactic acid antibacterial fiber is characterized in that polylactic acid is used as a fiber base material, and graphene oxide grafted N-halamine antibacterial material is uniformly loaded in the polylactic acid; the graphene oxide grafted N-halamine antibacterial material contains photosensitive sulfhydryl groups, and the graphene oxide grafted N-halamine antibacterial material is combined with unsaturated bonds in the polylactic acid through the photosensitive sulfhydryl groups.

2. The modified graphene polylactic acid antibacterial fiber according to claim 1, wherein the mass ratio of polylactic acid to graphene oxide grafted N-halamine antibacterial material is 1000 (3-15).

3. A method for preparing the modified graphene polylactic acid antibacterial fiber according to claim 1 or 2, which is characterized by comprising the following steps:

s1, dispersing graphene oxide in deionized water, and performing ultrasonic stripping to obtain graphene oxide colloid; adding an alkaline solution into the graphene oxide colloid, stirring at 95-100 ℃, and washing, filtering and drying after the reaction is finished to obtain lamellar graphene oxide;

s2, adding the lamellar graphene oxide obtained in the step S1 and a mercaptosilane coupling agent into absolute ethyl alcohol according to a proportion to prepare a mixed solution, adding an N-halamine precursor and a photoinitiator into the mixed solution, and carrying out centrifugation, washing and vacuum drying after illumination for 1.0-2.0 h to obtain graphene oxide grafted N-halamine antibacterial powder;

s3, mixing the graphene oxide grafted N-halamine antibacterial powder obtained in the step S2 with polylactic acid according to a preset proportion, and adding the mixture into a melt-blowing machine for melt-blowing treatment after illumination for 0.5-1.5 h to obtain a graphene oxide grafted N-halamine melt-blowing material;

s4, soaking the graphene oxide grafted N-halamine melt-blown material obtained in the step S3 in sodium hypochlorite for 0.5-1.0 h, and washing, drying and heat treating to obtain the graphene oxide grafted N-halamine antibacterial melt-blown material;

and S5, carrying out melt spinning on the graphene oxide grafted N-halamine antibacterial melt-blown material prepared in the step S4 to obtain the modified graphene polylactic acid antibacterial fiber.

4. The method for preparing the modified graphene polylactic acid antibacterial fiber according to claim 3, wherein the mass ratio of the lamellar graphene oxide to the mercaptosilane coupling agent is (1-9) 100; the addition amount of the sulfhydryl silane coupling agent is 1-5% of the mass of the polylactic acid.

5. The method for preparing the modified graphene polylactic acid antibacterial fiber according to claim 3, wherein in the step S2, the addition amount of the N-halamine precursor is 0.5-1.5% of the mass of the lamellar graphene oxide, and the addition amount of the photoinitiator is 0.5-5.0% of the mass of the lamellar graphene oxide.

6. The method for preparing the modified graphene polylactic acid antibacterial fiber according to claim 3, wherein in the step S5, deodorizing particles are added into the graphene oxide grafted N-halamine antibacterial melt-blown material during the melt spinning, and the graphene oxide grafted N-halamine antibacterial melt-blown material and the deodorizing particles participate in the melt spinning together to obtain the modified graphene polylactic acid antibacterial fiber with a deodorizing function; the deodorizing particles comprise one or more of active carbon particles, nano silver particles and active oxygen particles.

7. The method for preparing the modified graphene polylactic acid antibacterial fiber according to claim 3, wherein in the step S1, the graphene oxide preparation comprises the following steps:

SS1, adding a solid mixture of graphite powder and sodium nitrate into concentrated sulfuric acid in an ice water bath under magnetic stirring, slowly adding potassium perchlorate, simultaneously adding potassium permanganate in batches for reaction, and taking out after the reaction temperature is not more than 20 ℃ and 0.5-1.5 h;

SS2, stirring the solution treated by the step SS1 at room temperature for 24 hours, and using H with the mass fraction of 5 percent ₂ SO ₄ Diluting the solution, stirring for 0.5-1.0H, and adding H ₂ O ₂ Stirring and reacting for 0.5-2.0 h, and centrifuging to obtain a solid substance;

SS 3H for the solid matter obtained in step SS2 ₂ SO ₄ 、H ₂ O ₂ And respectively washing the mixed solution and the HCI solution for 1-3 times, and finally washing the mixed solution and the HCI solution for 1-3 times by using distilled water to ensure that the pH value of the mixed solution is 7, and drying to obtain a yellow brown precipitate, namely the graphene oxide.

8. The method for preparing the modified graphene polylactic acid antibacterial fiber according to claim 3, wherein in the step S2, the mercaptosilane coupling agent comprises one of 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane, 3-mercaptopropyl trimethyloxysilane, 3-mercaptopropyl triphenylsilane, 3- (methylpropyloxy) propyl trimethoxysilane; the N-halamine precursor comprises one of methacrylamide, 1-allyl hydantoin and 2, 4-diamino-6-diallylamino-1, 3, 5-triazine.

9. The method for preparing a modified graphene polylactic acid antibacterial fiber according to claim 3, wherein in the step S2, the photoinitiator comprises one of benzoin dimethyl ether, isopropyl thioxanthone and triaryl iodonium salt.

10. The application of the modified graphene polylactic acid antibacterial fiber is characterized in that the modified graphene polylactic acid antibacterial fiber is prepared by the preparation method of any one of claims 1-2 or any one of claims 3-9, and the modified graphene polylactic acid antibacterial fiber is applied to the preparation of antibacterial non-woven fabrics, and the antibacterial non-woven fabrics are used for preparing one or more antibacterial protection products in medical masks, medical protective clothing and industrial clothing.