CN110483826B

CN110483826B - Polyurethane with polysiloxane nano-film grafted on surface, preparation method and application

Info

Publication number: CN110483826B
Application number: CN201910783689.2A
Authority: CN
Inventors: 侯昭升; 王雪洁; 张小曼; 陈嘉欣; 时文燕
Original assignee: Shandong Normal University
Current assignee: Wuxi Xiangyuan Information Technology Co ltd
Priority date: 2019-08-23
Filing date: 2019-08-23
Publication date: 2022-06-10
Anticipated expiration: 2039-08-23
Also published as: CN110483826A

Abstract

The disclosure belongs to the technical field of macromolecules, and particularly relates to polyurethane with a polysiloxane nano-film grafted on the surface, a preparation method and application. The preparation method provided by the disclosure comprises the following steps: (1) the polyurethane film material A is treated and reacts with micromolecular diisocyanate in anhydrous toluene under the action of a catalyst to obtain a film material B with a surface grafted with-NCO groups; (2) and (3) putting the film B into anhydrous toluene in which a silane coupling agent is dissolved, removing after reaction, naturally drying for 2-5 days at room temperature, and performing a crosslinking reaction on siloxane groups to form a nano film, thereby obtaining a polyurethane film material C with the surface grafted with the polysiloxane film. Compared with the membrane material before grafting, the grafted material has better mechanical property, slower degradation rate and better surface biocompatibility. The method is suitable for common polyurethane materials and different polyurethane profiles.

Description

Polyurethane with polysiloxane nano-film grafted on surface, preparation method and application

Technical Field

The disclosure belongs to the technical field of polyurethane high polymer materials, and particularly relates to a polyurethane material with a surface grafted with a polysiloxane nano-film, and a preparation method and application thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the disclosure and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

Polyurethane (PU) is a high molecular polymer containing urethane groups, has a microphase surface structure very similar to that of a biological membrane, has good biodegradability and excellent mechanical properties, has high freedom of molecular design, and can realize the regulation and control of the physical and chemical properties by regulating the types of soft segments and the proportion of the soft segments, so the Polyurethane is widely applied to the fields of industry and biomedical materials.

In the aspect of building materials, the waterproof performance of the heat preservation box of the external building is mainly polyurethane, and meanwhile, a polyurethane adhesive is a material for producing a formaldehyde-free plate instead of urea-formaldehyde glue. In the aspect of household appliances, polyurethane rigid foam heat insulation layers are generally adopted for heat insulation of various household appliances. In the aspect of transportation, seats, car body heat insulation layers, instrument panels, interior trim parts, paint and accessories of various vehicles are involved. In the aspect of shoemaking, the polyurethane sole material is light, wear-resistant, oil-resistant, beautiful and comfortable … …

In the field of biomedical materials, such as artificial organs, blood vessels, medical blood bags, surgical sutures, drug carriers, artificial skin, artificial tissues, artificial organs, surgical sutures, drug carriers, and the like. In recent years, with the advancement of science and technology and the improvement of research level, new medical polyurethane materials are emerging continuously, and the performance of products is improved continuously.

However, there still exist some problems to be solved in the field of medical materials, and when PU is used as a long-term implantable material or a blood contact material for a human body, it may cause non-specific adsorption of various proteins, and further induce various adverse biological reactions such as platelet activation, blood coagulation, thrombosis, and complement activation, which still cannot meet the needs of clinical operation, and limit its wider application in the medical field. Particularly, medical products which are in direct contact with blood inevitably suffer from coagulation, bacterial infection, or collective damage due to insertion or implantation of instruments, and the like, and these problems are related to the therapeutic effect, and limit the wider application thereof in the medical field. Therefore, the modification research of PU becomes the key for further development of the PU in biomedicine. To this end, researchers have introduced hydrophilic and other compounds that are beneficial to improve the biocompatibility of PU on the surface or bulk of medical PU by physical or chemical means to reduce or avoid these undesirable biological reactions.

The organic silicon molecular chain has unique structure, low surface tension, chemical inertness, large bonding angle, long bonding length, large bonding energy of the siloxane structure, no toxicity, no pollution, no corrosion, aging resistance and long service life. However, pure organic silicon has poor mechanical property and weak adhesive force, so that the organic silicon is introduced into polyurethane for modification, so that the copolymer has low surface property, excellent mechanical property and surface adhesive force. The polysiloxane polyurethane material has the excellent performances of both polysiloxane and polyurethane, and has good water resistance, low-temperature flexibility and excellent biocompatibility.

Patent CN201710879156.5 discloses a "preparation method and application of Si-based polyurethane medical adhesive", in the method, a compound with silica (Si-O) as a main chain and an end group containing an active hydrogen functional group reacts with a compound containing an isocyanate (NCO) functional group to obtain a precursor with an end group of isocyanate, and then the precursor reacts with a cross-linking agent containing an active hydrogen functional group to realize modulus adjustment of the Si-based polyurethane medical adhesive by changing cross-linking density. The polyurethane has good biocompatibility and good chemical adhesion to human tissues. However, the product obtained by the reaction has urea bonds with higher polarity, and can form strong hydrogen bonds with hydrogen in a system, so that the viscosity of the adhesive is too high, and the adhesive is not beneficial to use.

Patent CN109575233A discloses a high mechanical property polysiloxane polyether type polyurethane elastomer and a preparation method thereof, two prepolymers are respectively synthesized by using diphenylmethane diisocyanate and hydroxypropyl terminated polysiloxane, diphenylmethane diisocyanate and polytetramethylene glycol as raw materials, and then the two prepolymers are mixed, chain extended and copolymerized to prepare the high mechanical property polysiloxane polyether type polyurethane elastomer.

And the research on anti-platelet adhesion of phosphorylcholine modified polyurethane material discloses a preparation method of surface area grafted aldehyde-based phosphorylcholine for polycarbon ester polyurethane by allyl amine low-temperature plasma treatment, wherein the aldehyde group and-NH on the surface of the polycarbon ester polyurethane after the low-temperature plasma treatment are utilized₂The phosphorylcholine group is grafted to the surface of the polycarbonate polyurethane, the reaction conditions in the whole process are mild, and the phosphorylcholine group is grafted to the surface of the polycarbonate polyurethane to form a biomimetic knotThe structure and the biocompatibility are improved. However, because the plasma is unstable and the content of phosphorylcholine groups grafted on the surface of the polycarbonate polyurethane membrane is not high, some platelets aggregate and deform on the membrane surface, and the adhesion of the platelets is poor.

The inventor thinks that the modification of the body of the polyurethane can damage the original structure of the polyurethane, improve certain properties of the polyurethane and simultaneously cause the reduction of other properties of the polyurethane; the surface grafting modification inevitably damages the polyurethane base material, so that the mechanical property of the base material is reduced, and meanwhile, the surface grafted substance falls off in the use environment.

Disclosure of Invention

In view of the above research results, the present disclosure provides a polyurethane material with a polysiloxane nanofilm chemically grafted on a surface. The material is prepared through a two-step method, firstly, allophanate salifying reaction is carried out to graft-NCO groups on the surface of polyurethane, and the-NCO groups on the surface and-NH of a silane coupling agent₂The condensation reaction is carried out to graft the silane coupling agent on the surface of the film, and finally, the siloxy on the surface is crosslinked into the film under the action of water in the air. The mechanism of surface siloxy crosslinking is shown in formula I below:

the method has the advantages of mild conditions, simple operation, no damage to the polyurethane base material, good mechanical properties, reduced degradation rate of the material and improved use strength of the polyurethane material. The material can be used as a medical material, has reduced adhesion to blood platelets and enhanced hydrophobicity, can be used as a hemostatic material, and can effectively reduce adhesion to wound parts.

In order to achieve the technical effects, the present disclosure provides the following technical solutions:

in a first aspect of the present disclosure, there is provided a polyurethane with a polysiloxane nanomembrane grafted on the surface, the polyurethane with the polysiloxane nanomembrane grafted on the surface is a membrane material, and the surface of the polyurethane is coated with the polysiloxane nanomembraneThe polyurethane is connected with the polysiloxane nano-film through a chemical bond; the thickness of the polysiloxane nano film is 5-20 nm; the infrared scanning is 3300-3400 cm^-1、2800～3000cm^-1、1000～1200cm^-1With absorption peaks in the range.

Preferably, the polyurethane is passed through a polysiloxane nanomembrane

Chemical bonds are used for connection.

The polyurethane material provided by the disclosure is a film material, and the surface of the polyurethane film layer is provided with a polysiloxane nano film layer structure, so that the use strength of the film material is further increased. Because the polysiloxane nano film is connected with the polyurethane film layer through a chemical bond, the two film layers are tightly combined, the falling-off condition of the polysiloxane nano film in the use process is obviously reduced, and the service life of the material is prolonged.

In a second aspect of the present disclosure, there is provided a method for grafting a polysiloxane nanomembrane on a polyurethane surface, the method comprising the steps of: polyurethane A is reacted with diisocyanate and surface grafting-NCO group is carried out to obtain material B; and reacting the material B with a silane coupling agent to obtain a polyurethane material with siloxane grafted on the surface, wherein the siloxy groups on the surface of the polyurethane material with the siloxane grafted on the surface are subjected to a crosslinking reaction to form polyurethane C with a polysiloxane nano film grafted on the surface.

The reaction route of the preparation method is as follows:

preferably, the polyurethane a further comprises a pretreatment step, the pretreatment step comprising: and (3) washing the polyurethane A by absolute ethyl alcohol, and then putting the polyurethane A into deionized water for ultrasonic washing.

Preferably, the specific steps of the polyurethane A and diisocyanate reaction surface grafting-NCO group to obtain the material B are as follows: and reacting the polyurethane A with diisocyanate under the conditions of toluene and a catalyst for 1.5-2.5 h at 25-40 ℃ to obtain a material B with a surface grafted-NCO group.

Preferably, the polyurethane a is a material containing urethane groups. The disclosed process may be applied to polyurethane materials, whether crosslinked or not, for medical or industrial applications. Uncrosslinked polyurethane materials are preferred, in particular polyurethane materials having a content of urethane groups in the polyurethane of not less than 8% by mass.

Preferably, the polyurethane A is a polyurethane material insoluble in toluene or water; or the equilibrium swelling ratio of the polyurethane A in toluene or water is not more than 10%.

In some specific examples, the polyurethane a is a polyurethane prepared by the method of application No. 201510250602.7, and the chemical structure of the polyurethane is shown in formula ii below:

Wherein n is 3-13; p is 12 to 192, and the number average molecular weight is 40000 to 220000 g/mol.

In some specific embodiments, the polyurethane A is prepared by a solvent evaporation film forming method according to the method provided by the patent with the application number of 201510250602.7, and the thickness of the film is 1.5-3.0 mm.

In addition, the method provided by the disclosure is not only suitable for membrane materials, but also suitable for polyurethane catheter materials, polyurethane sponges or other profiles and the like.

More preferably, the catalyst is an organotin catalyst, and still more preferably dibutyltin dilaurate (DBTDL).

More preferably, the concentration of the catalyst in toluene is 0.001-0.005 g/mL.

Further preferably, the diisocyanate is an aliphatic diisocyanate, preferably 1, 6-Hexamethylene Diisocyanate (HDI), 1, 4-tetramethylene diisocyanate (HDI) or L-Lysine Diisocyanate (LDI).

More preferably, the concentration of the diisocyanate in the toluene is 0.05-0.15 g/mL.

More preferably, the product is washed with toluene after the reaction is completed to obtain material B. The washing mode can adopt an oscillation washing mode until no-NCO absorption peak (2270 cm) is detected by washing liquid IR ^-1)。

Preferably, said material B has a grafting density of-NCO groups higher than 2X 10^-8mol/cm²。

Preferably, the specific steps of reacting the material B with a silane coupling agent to obtain the polyurethane material with the surface grafted with the polysiloxane nano-film are as follows: and (3) putting the material B into a toluene solution of a silane coupling agent, and reacting for 11-15 h at 15-25 ℃.

Preferably, the silane coupling agent is 3-aminopropyltriethoxysilane or 3-aminopropyltrimethoxysilane.

More preferably, the concentration of the silane coupling agent in toluene is 0.1-0.2 g/mL.

Preferably, the polyurethane C of which the surface is grafted with the polysiloxane is formed by the cross-linking reaction of the polyurethane material of which the surface is grafted with the polysiloxane nano film is carried out in the air, and the air humidity is 40-80%.

In a third aspect of the present disclosure, there is provided an application of the polyurethane surface-grafted polysiloxane material according to the first aspect or the polyurethane material with the polysiloxane nanomembrane grafted on the surface obtained by the method according to the second aspect in the fields of light industry, chemical industry, electronics, textiles, medical treatment, building materials, automobiles, national defense, aerospace, aviation, and the like.

Preferably, as a medical consumable.

Compared with the prior art, the beneficial effect of this disclosure is:

(1) The Rozhen atlas et al researches the surface performance of polysiloxane graft modified polyurethane, and the research result shows that the modification mode can improve the surface hydrophobic performance of polyurethane material. Compared with the original polyurethane, the polysiloxane nano-film grafted polyurethane material provided by the disclosure has the advantages of further improved mechanical strength, stable chemical performance, slow degradation speed and good biocompatibility.

(2) The grafting method provided by the disclosure has mild reaction conditions, and compared with the method in the prior art, the method does not damage the mechanical property of the polyurethane material, has simple process, strong practicability, easy popularization and no pollution. In addition, the method is suitable for most polyurethane materials, is not limited to film materials, is also suitable for profiles such as polyurethane catheters, sponges and the like, and has wide application range.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

FIG. 1 is an IR spectrum of A-1, A-2 and A-3 in example 1;

FIG. 2 is a SEM photograph of the platelet adhesion between A-1 and A-3 in example 1;

FIG. 3 is an SEM photograph of A-1 and A-3 in example 1 at a degradation time of 45 days.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

As described in the background, the surface modification techniques for polyurethane materials in the prior art generally cause a decrease in the mechanical properties of the substrate. In order to overcome the defect, the disclosure provides a polyurethane material with a polysiloxane nano-film grafted on the surface, and a preparation method and application thereof.

In order to make the technical solutions of the present disclosure more clearly understood by those skilled in the art, the technical solutions of the present disclosure will be described in detail below with reference to specific examples and comparative examples.

In the following examples, polyurethane material a was a polyurethane film material prepared by the method of the patent application No. 201510250602.7.

Example 1

Subjecting a treated 1cm × 1cm polyurethane film A-1 (M)_n151000g/mol, thickness 2.0mm, prepared according to the method for preparing a polyurethane film of patent example 5, application No. 201510250602.7) was placed in an erlenmeyer flask containing 2g of 1, 6-hexamethylene diisocyanate and 0.02g of dibutyltin dilaurate in 15mL of anhydrous toluene, sealed, shaken by a shaker at 30 rpm, warmed to 30 ℃ and reacted for 2 hours, the film was removed, and the film was washed with anhydrous toluene until the filtrate had no-NCO absorption peak (2270 cm) by IR detection^-1) To obtain the film A-2 with the surface grafted with-NCO groups.

A-2 was placed in a 20mL dry toluene Erlenmeyer flask containing 4g 3-aminopropyltriethoxysilane, sealed and shaken on a shaker at a rate of 40 rpm. Reacting for 13 hours at the temperature of 20 ℃, and washing with anhydrous toluene and distilled water for three times after the reaction is finished. And naturally drying for 3 days under the humidity of 55-65%, and crosslinking the surface grafted siloxy to obtain the polyurethane film A-3 with the surface grafted polysiloxane nano film.

Example 2

Subjecting a treated 1cm × 1cm polyurethane film B-1 (M)_n139000g/mol and 2.1mm thick, prepared according to the method of preparation of polyurethane film of patent example 6, application No. 201510250602.7) was placed in a conical flask containing 1.4g of 1, 4-tetramethylene diisocyanate and 0.02g of dibutyltin dilaurate in 15mL of anhydrous toluene, sealed, shaken on a shaker at a rate of 30 rpm, warmed to 35 ℃ and reacted for 1.5h, the membrane was removed and washed with anhydrous toluene until the filtrate had no-NCO absorption peak (2270 cm) by IR detection^-1) To obtain the film B-2 with the surface grafted with-NCO groups.

B-2 was placed in a 20mL dry toluene Erlenmeyer flask containing 2g 3-aminopropyltriethoxysilane, sealed and shaken on a shaker at a rate of 40 rpm. Reacting for 11 hours at the temperature of 22 ℃, and washing with anhydrous toluene and distilled water for three times after the reaction is finished. And naturally drying for 4 days under the humidity of 65-80%, and crosslinking the surface grafted siloxy to obtain the polyurethane film B-3 with the surface grafted polysiloxane nano film.

Example 3

Subjecting a treated 1cm × 1cm polyurethane film C-1 (M)_n156000g/mol, 2.2mm thick, according to the preparation of the polyurethane film of patent example 8, application No. 201510250602.7) was placed in a conical flask containing 1.8g L-lysine diisocyanate and 0.02g dibutyltin dilaurate in 15mL of anhydrous toluene, sealed, shaken on a shaker at a rate of 30 rpm, warmed to 28 ℃ and reacted for 2.5h, the film was removed, and the film was washed with anhydrous toluene until the filtrate had no-NCO absorption peak (2270 cm) by IR detection ^-1) To obtain the film C-2 with the surface grafted with-NCO groups.

C-2 was placed in an Erlenmeyer flask containing 2.87g of 3-aminopropyltrimethoxysilane in 20mL of anhydrous toluene, sealed and shaken at a rate of 40 revolutions per minute on a shaker. Reacting for 15 hours at 18 ℃, and washing with anhydrous toluene and distilled water for three times after the reaction is finished. And naturally drying for 2 days under the humidity of 45-60%, and crosslinking the surface grafted silicon alkoxide group to obtain the polyurethane film C-3 with the surface grafted polysiloxane nano film.

Example 4

The treated 1cm X1 cm polyurethane film D-1 (M)_n151000g/mol, thickness 2.5mm, prepared according to the method of preparation of polyurethane film of patent example 5, application No. 201510250602.7) was placed in a 15mL dry toluene conical flask containing 2g of 1, 6-hexamethylene diisocyanate and 0.02g of dibutyltin dilaurate, sealed, shaken in a shaker at 30 rpm, warmed to 30 ℃ for 2h, the film was removed, and the film was rinsed with dry toluene until the filtrate had no-NCO absorbance peak (2270 cm) as detected by IR^-1) To obtain the film D-2 with the surface grafted with the-NCO group.

D-2 was placed in a 20mL dry toluene Erlenmeyer flask containing 2.15g of 3-aminopropyltrimethoxysilane, sealed and shaken at a rate of 40 revolutions per minute on a shaker. Reacting for 14 hours at the temperature of 20 ℃, and washing with anhydrous toluene and distilled water for three times after the reaction is finished. And naturally drying for 3 days under the humidity of 55-65%, and crosslinking the surface grafted silicon alkoxide group to obtain the polyurethane film D-3 with the surface grafted polysiloxane nano film.

Example 5 Performance testing

The following analytical methods were used for all examples unless otherwise indicated.

Infrared: fourier transform infrared (FT-IR) spectroscopy is performed on a Bruker Alpha spectrometer, a proper amount of samples are directly and uniformly spread on transmission panel glass, and the samples are pressed by a rotary upper arm to be scanned. Solid samples are carefully ground and measured if the particles are large. Setting the scanning range to be 4000-400 cm^-1Resolution of 4cm^-1。

Degradation performance: the polyurethane film material before and after grafting the silicone nano film on the surface of 1cm × 1cm is soaked in a PBS (pH 7.4) solution, the temperature is maintained at 37 ℃, the state of the film material is observed for 7 days, when the material generates fragments and loses mechanical properties, the degradation is considered to be completed, and the degradation time is determined.

And (3) testing mechanical properties: the mechanical property tests of the polyurethane film materials before and after the surface grafting of the silicone nano film are carried out on a microcomputer-controlled universal material experiment machine of Shenzhen Ruigler instrument Limited. The used test sample is processed into a dumbbell shape, the neck length and the neck width are respectively 30mm and 4mm, and the test sample is dried in an oven at 40 ℃ for 4 hours before testing so as to eliminate the influence of moisture on the mechanical property of the test sample. The test was carried out at room temperature at a rate of 50mm/min, the samples were tested in parallel 3 times and the test results were averaged.

Protein adsorption amount: the membrane of 1cm × 1cm was placed in 10mL PBS (pH 7.4), washed with ultrasound for half an hour to wash out impurities, taken out into an equal amount of 45 μ g/mL Bovine Serum Albumin (BSA) solution, left to stand at 37 ± 0.5 ℃ for 2 hours, taken out, then washed three times with fresh PBS to remove unbound BSA, and then washed with 0.06% (w/w) sodium dodecylsulfonate solution with ultrasound for 20 min. The concentration of adsorbed BSA was determined on a microplate reader using the micro-Bradford protein assay kit. Naturally cooling to room temperature, measuring absorbance at 595nm with ultraviolet-visible spectrophotometer, calculating according to standard curve to obtain adsorption amount, and taking average value of 3 samples.

Platelet adhesion experiments: extracting fresh blood from the heart of a healthy rabbit, adding 3.8% by mass of sodium citrate solution as an anticoagulant, wherein the ratio of the whole blood to the anticoagulant is 9:1, putting the whole blood added with the anticoagulant into a centrifugal machine, setting the rotation speed of 1400r/min for primary centrifugation, and centrifuging for 10 min; then sucking supernatant liquid, centrifuging again, setting the rotating speed to be 1400r/min, centrifuging for 15min, wherein the supernatant liquid is platelet poor plasma, sucking about 3/4 supernatant liquid, and discarding the residual liquid, namely PPP; the membrane material was placed in a 24-well plate, immersed in PBS buffer at pH 7.4 for 4h, and then incubated in PRP solution at 37 ℃ for 1 h. The membrane material was taken out, washed repeatedly 3 times with PBS buffer solution to remove unadsorbed platelets, and then soaked in 2.5% glutaraldehyde PBS solution for 30min to fix the surface platelets. Sequentially placing the membrane material into ethanol water solution (50, 60, 70, 80, 90, 100%) with different concentration gradients, dewatering step by step, soaking in each concentration solution for 30min, drying at room temperature, spraying gold, and observing the platelet adhesion condition on the membrane material surface by using S-4800 type SEM (Hitachi, Japan).

The measuring method of the nano film comprises the following steps: according to the difference of the mechanical properties between the nano film and the substrate, a proper scribing tool is selected, the film is directly scribed to generate a scratch which penetrates through the film and does not influence the substrate, and then an atomic force microscope is used for scanning to obtain the micro-morphology of a scratch area, so that the thickness of the nano film is calculated. Known as well as "a new method for measuring thickness of nanometer film" from Jiang Tao.

The properties of the non-grafted polysiloxane film and the grafted polysiloxane nanofilm on the polyurethane surface in examples 1-4 are shown in Table 1.

TABLE 1 Properties of polyurethane materials surface-grafted with polysiloxane nanofilm in examples 1-4

According to the polyurethane material with the polysiloxane nano film grafted on the surface, the existence of the cross-linked polysiloxane film obviously improves the breaking strength and the breaking elongation of the polyurethane material, and shows excellent mechanical properties. Due to the hydrophobicity of polysiloxane, the degradation rate of the grafted membrane material in a water environment is reduced, and the service time of the material is prolonged. Meanwhile, the adsorption capacity of the polyurethane film grafted with the polysiloxane nano film to protein is also obviously reduced, and the biocompatibility of the medical polyurethane material is greatly improved. The nano polysiloxane film on the surface is crosslinked, so that the nano polysiloxane film is very firm and is not easy to fall off in application, and the nano polysiloxane film has wider application in the aspect of improving polyurethane, particularly medical polyurethane.

The infrared spectra of samples A-1, A-2 and A-3 are shown in FIG. 1. As can be seen by comparing the infrared spectrograms of A-1 and A-2, the infrared spectrogram of A-2 is 2270cm^-1An absorption peak of-NCO appeared in the vicinity, indicating that isocyanate groups had been successfully grafted to the surface of the polyurethane film. As can be seen by comparing the infrared spectrograms of A-2 and A-3, the-NCO absorption peak (2270 cm) of the nano-film with the polysiloxane grafted on the surface^-1) Disappeared and is at 1100cm^-1An absorption peak of a siloxane bond appears nearby, and the siloxane is proved to exist on the surface of the polyurethane film in a chemical grafting mode.

FIG. 2 is a SEM photograph of the platelet adhesion of A-1 and A-3. As can be seen from the figure, a large number of platelets are adsorbed on the surface of the polyurethane film before grafting, and the morphology of the adsorbed platelets is obviously changed, such as aggregation, pseudopodia and the like, which indicates that the platelets are in an active state. Different from the membrane before modification, the number of platelets adhered to the surface grafted polysiloxane nano-film is greatly reduced, and the platelets have no aggregation phenomenon and still keep the original appearance. The material is shown to have excellent anti-platelet adhesion performance.

FIG. 3 is an SEM photograph of A-1 and A-3 at 35 days of degradation time, from which it can be seen that the polyurethane film A-1 before surface grafting of polysiloxane was fragmented at 35 days of degradation time, the surface was rough, many irregular depressions appeared and the mechanical properties were lost. The nano-film A-3 with the surface grafted with polysiloxane has slower degradation rate and relatively smooth surface, which proves that the nano-polysiloxane film on the surface is firmer due to crosslinking, is not easy to degrade and has improved chemical stability.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. The polyurethane with the surface grafted with the polysiloxane nano film is characterized in that the polyurethane with the surface grafted with the polysiloxane nano film is a film material, the surface of the polyurethane is coated with the polysiloxane nano film, and the polyurethane is connected with the polysiloxane nano film through chemical bonds; the thickness of the polysiloxane nano film is 5-20 nm; the infrared scanning is 3300-3400 cm^-1、2800~3000 cm^-1、1000~1200cm^-1Having an absorption peak within the range; the polyurethane and polysiloxane nano film are coated by

Chemical bonds are connected;

the preparation method of the surface grafted polysiloxane nano-film polyurethane comprises the following steps: polyurethane A is reacted with diisocyanate and surface grafting-NCO group is carried out to obtain material B; the material B reacts with a silane coupling agent to obtain a polyurethane material with siloxane grafted on the surface, and the siloxy groups on the surface of the polyurethane material with the siloxane grafted on the surface are subjected to a crosslinking reaction to form polyurethane C with a polysiloxane nano film grafted on the surface;

The crosslinking reaction is carried out in air, the air humidity is 40% -80%, and the drying is carried out naturally.

2. The polyurethane with polysiloxane nanomembrane grafted on the surface according to claim 1, wherein the polyurethane a further comprises a pretreatment step of: and washing the polyurethane A by adopting absolute ethyl alcohol, and then putting the polyurethane A into deionized water for ultrasonic washing.

3. The polyurethane with polysiloxane nanomembrane grafted on the surface as claimed in claim 1, wherein the step of reacting polyurethane A with diisocyanate to graft-NCO groups on the surface to obtain material B comprises the following steps: and reacting the polyurethane A with diisocyanate under the conditions of toluene and a catalyst for 1.5-2.5 h at 25-40 ℃ to obtain a material B with a surface grafted-NCO group.

4. The polyurethane with polysiloxane nanomembrane grafted on the surface according to claim 1, wherein the polyurethane a is a material containing urethane groups; or the polyurethane A is a polyurethane material which is insoluble in toluene or water; or the swelling ratio of the polyurethane A in toluene or water is not more than 10%.

5. The polyurethane surface-grafted polysiloxane nanomembrane of claim 3, wherein the catalyst is dibutyltin dilaurate; or the diisocyanate is 1, 6-hexamethylene diisocyanate, 1, 4-tetramethylene diisocyanate or L-lysine diisocyanate.

6. The polyurethane with polysiloxane nanomembrane grafted on the surface according to claim 1, wherein the specific steps of reacting the material B with a silane coupling agent to obtain the polyurethane material with polysiloxane grafted on the surface are as follows: and (3) putting the material B into a toluene solution of a silane coupling agent, and reacting for 11-15 h at 15-25 ℃ to obtain the polyurethane material with the surface grafted with polysiloxane.

7. The polyurethane with polysiloxane nanomembrane grafted on the surface according to claim 6, wherein the silane coupling agent is 3-aminopropyltriethoxysilane or 3-aminopropyltrimethoxysilane; or the concentration of the silane coupling agent in toluene is 0.1-0.2 g/mL.

8. Use of the polyurethane surface-grafted with polysiloxane nanomembrane according to claim 1 as a medical consumable.