CN113321830B - Photoresponse erasable polymer paper and preparation method thereof - Google Patents

Abstract

The invention relates to photoresponse erasable polymer paper and a preparation method thereof, wherein the polymer paper comprises the following raw materials in parts by weight: 50-70 parts of hydroxyl-terminated polycaprolactone, 15-25 parts of isocyanate, 15-25 parts of hydroxyazobenzene, 1-10 parts of liquid crystal component, 0-5 parts of ferroferric oxide particles, 0.1-0.2 part of initiator and 150 parts of organic solvent. The components are mixed and subjected to in-situ polymerization to prepare the polymer paper. Compared with the prior art, the polymer paper obtained by the invention has the advantages of repeated erasability, stability and remote controllability, is suitable for various extreme environments such as aviation and deep sea exploration, and expands the application range and application field of the polymer-based material.

Description

A light-responsive rewritable polymer paper and preparation method thereof

technical field

The invention belongs to the field of polymer composite materials, in particular to a light-responsive rewritable polymer paper and a preparation method thereof.

Background technique

In recent years, with the shortage of forest resources and the improvement of environmental awareness, the consumption of forest resources by paper made of traditional plant fibers has gradually attracted public attention. Compared with traditional materials, polymer materials have excellent ductility and higher strength. Taking polyurethane materials as an example, such materials have good corrosion resistance and also have shape memory properties, thermal drive and formability. Soft robots, artificial muscles, and medical fields have been widely used, becoming one of the key research and development new materials.

Patent application CN105693990A discloses a synthesis process of a polyurethane shape memory polymer material. The synthesis process includes the following steps in sequence: (1) vacuum dehydration of raw materials; (2) prepolymerization: adding 2,4 under the condition of _N2 protection -Toluene diisocyanate and DMF, add dropwise amount of polyol to obtain prepolymer; (3) chain extension reaction: carry out chain extension reaction with 1,4-BDO and dimethylol propionic acid (DMPA); (4) medium And reaction: the carboxyl group of DMPA is completely neutralized with triethylamine (TEA), and 300-1000 ml of water is added at the same time, and the mass concentration of the final solution is 15-25%. This technology has only shape memory properties and not optical writing properties based on surface self-healing.

Patent application CN110041503A discloses a new shape memory polyurethane material that can be used for bionic 4D printing, including: the components of the shape memory polyurethane material and the mass parts of each component are as follows: 20-50 parts of isocyanate, polycaprolactone 5-20 parts, polyethylene glycol 5-20 parts, polyethylene adipate 5-20 parts, polybutylene adipate 5-20 parts, chain extender 1-6 parts, cross-linking agent, 0.5-2 parts of initiator and 0.02-0.2 part of catalyst. The purpose is to make the shape memory polyurethane material have good shape memory ability and improve the recovery rate of the shape memory polyurethane material by controlling the addition amount of the crosslinking agent, but the material cannot realize the reversible surface separation and repair process.

Patent application CN110078892A discloses a new shape memory polyurethane material under infrared stimulation, including: 35-50 parts of polytetramethylene ether glycol; 15-25 parts of diisocyanate; 10-15 parts of chain extender; 0.05-0.12 part of catalyst parts; 120-250 parts of organic solvent; cross-linking agent. The technology uses control of the amount of cross-linking agent added, so that the shape memory polyurethane material has good memory performance and high recovery rate. However, such polymers cannot respond to near-infrared light and cannot exhibit photo-induced shape memory properties.

The traditional polyurethane material cannot be recovered after "writing" on its surface, and it is difficult to realize the function of a new type of rewritable polymer paper that can be used repeatedly.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a light-responsive rewritable polymer paper and its preparation method in order to overcome the defects of the above-mentioned prior art. On the basis of ensuring the comprehensive mechanical properties and shape memory properties of the material, the composite has Repeatable rewritable properties, enabling polymer paper designs.

The object of the present invention can be achieved by the following technical solutions: a light-responsive rewritable polymer paper, the raw material of the polymer paper comprises the following components in parts by weight: 50-70 parts of hydroxyl-terminated polycaprolactone, isocyanate 15-25 parts, 15-25 parts of hydroxyazobenzene, 1-10 parts of liquid crystal components, 0-5 parts of iron tetroxide particles, 0.1-0.2 parts of initiator, 100-150 parts of organic solvent. The preferred amount of the liquid crystal component is 4-6 parts, and the preferred amount of the ferric oxide particles is 0.5-1.5 parts.

Further, the ferric oxide particles are prepared by the following method: weigh 15-20 parts of iron salt, 8-10 parts of ligands and 100-150 parts of organic solvent by weight, stir and mix evenly, and put them in 100-100 parts by weight. The hydrothermal reaction is carried out at 200° C. for 8-36 hours, the obtained product is subjected to centrifugal separation, and the separated solid is dried, treated at high temperature and ground to obtain submicron ferric oxide particles.

Further, described iron salt is ferric chloride or ferric nitrate;

Described ligand is 2-amino terephthalic acid or terephthalic acid;

The organic solvent is N,N'-dimethylformamide or ethanol.

Further, the solid drying is carried out in a vacuum or protective gas environment, the drying temperature is 100-200°C, and the drying time is 8-24h;

The temperature of the high temperature treatment is 500-800°C, the treatment time is 2-8h, the heating rate is 3-10°C/min, and the high temperature treatment environment is an argon atmosphere.

Further, the liquid crystal component is obtained by the following method: weighing by weight 15-20 parts of azobenzene compounds, 15-20 parts of halogenated hydrocarbons, 30-40 parts of desiccant, 0.05-0.1 part of catalyst, 500-1000 parts of organic solvent, stir and mix, and obtain the liquid crystal component through alkylation reaction, recrystallization, filtration, vacuum drying, silica gel column chromatography, and drying.

Further, the azobenzene compound is 4-ethoxy-4'-hydroxyazobenzene or 4,4'-p-hydroxyazobenzene;

Described desiccant is anhydrous potassium carbonate or anhydrous magnesium carbonate;

Described catalyst is potassium iodide or hexamethylphosphoric triamide;

The organic solvent is absolute ethanol, dichloromethane or tetrahydrofuran.

Further, the temperature of the alkylation reaction is 90-110°C, and the reaction time is 8-36h;

The recrystallization is carried out by adding hydrochloric acid dropwise to the material obtained by the alkylation reaction to adjust its pH value to 4-5;

Described filtration is reduced pressure filtration;

The temperature of the vacuum drying is 80-120°C, and the time is 8-36h;

Described silica gel column chromatography is to dissolve the solid after vacuum drying in methylene chloride, and use silica gel column chromatography to purify;

The drying temperature is 40-80°C.

Further, both ends of the hydroxyl-terminated polycaprolactone are hydroxyl-terminated, and the molecular weight is between 50,000 and 100,000;

The initiator is dibutyltin dilaurate.

The present invention also provides a preparation method of photo-responsive erasable polymer paper, comprising 50-70 parts of hydroxyl-terminated polycaprolactone, 15-25 parts of isocyanate, 15-25 parts of hydroxyazobenzene, and a liquid crystal component. 1-10 parts, 0-5 parts of iron tetroxide particles, 0.1-0.2 parts of initiator, 100-150 parts of organic solvent, in-situ polymerization after mixing to prepare polymer paper.

The in-situ polymerization process needs to be carried out under the protection of nitrogen atmosphere, the polymerization temperature is 60-120 DEG C, and the polymerization time is 8-72 hours;

The ferric tetroxide is first dispersed by a cell crusher and then added to the reaction system.

The isocyanates need to be treated for water removal.

The hydroxyazobenzene needs to be subjected to water removal treatment.

The liquid crystal composition needs to be subjected to water removal treatment.

The ferric oxide particles need to be treated for water removal.

Compared with the prior art, the present invention has the following advantages:

(1) In the present invention, a special liquid crystal phase is introduced into the polyurethane system, so that the polymer surface can show bright colors after being destroyed, and at the same time, it can still be stable in various environments. Due to the characteristics of the liquid crystal phase, it has a certain fluidity between the temperature reaching the melting point and the clearing point, and the surface self-healing behavior with erasable and rewritable functions can be realized.

(2) The present invention can realize the design of rewritable polymer paper with long-range light response by mixing the ferric oxide particles with near-infrared photothermal conversion effect into the system, which can be applied to extreme environments (such as aerospace, deep sea, etc.) , oil wells and other environments), information storage and optical writing are carried out under the conditions of vacuum, low temperature, strong acid and alkali.

(3) The present invention uses a special method to prepare ferric oxide particles with a special structure, and the liquid crystal phase prepared by the special method acts together in the hydroxyl-terminated polycaprolactone, isocyanate and hydroxyazobenzene system, The obtained product takes into account the comprehensive mechanical properties of the polyurethane shape memory matrix, the "writing" and "erasing" properties of the liquid crystal phase and the photothermal conversion properties of the ferric oxide particles.

(4) The light-responsive triiron tetroxide/polyurethane composite material prepared by the present invention not only has the characteristics of water resistance and excellent mechanical properties, but also can realize the function of remote erasing and writing. Therefore, the provided novel polymer paper material has broad application prospects and can replace traditional paper in various environments (water environment, acid solution, alkaline solution, low temperature).

Description of drawings

FIG. 1 is a graph showing the light response properties of the ferric oxide/polyurethane composite materials of Examples 1-6.

Fig. 2 is the erasing and writing performance and SEM image of the iron tetroxide/polyurethane composite material with different liquid crystal component contents (Example 3, Example 5 and Example 6): wherein, a1-a5 are the initial states of Example 5, respectively , surface damage, illumination process, state after illumination, and SEM images after illumination; b1-b5 are the initial state, surface damage, illumination process, state after illumination, and SEM images after illumination; c1-c5 are the SEM images of Example 3, respectively Example 6 Initial state, surface damage, illumination process, state after illumination, and SEM images after illumination.

Fig. 3 is the optical erasing and writing performance of the ferric oxide/polyurethane composite material of embodiment 3: wherein, a is the cycle diagram of optical erasing and writing performance, a1-a6 are respectively surface destruction, utilizing magnet and metal surface adsorption, rubbing, Shape fixing, illumination process and state diagrams after illumination; b-e are the process diagrams of the optical erasing behavior of Example 3 after being stored in a neutral aqueous solution, an acidic solution, an alkaline solution and under ice for one week, respectively.

The optical writing performance of the iron tetroxide/polyurethane composite material of Fig. 4 embodiment 3: wherein, a is a cycle diagram of optical writing performance, a1-a6 are respectively initial state, surface rubbing discoloration, state after rubbing, point light source irradiation, The state after irradiation and the overall irradiation diagram of infrared light; b-c are the process diagrams of the optical writing behavior in the aqueous solution and the ice respectively in Example 3.

Detailed ways

The present invention will be further described below in conjunction with examples. This embodiment is implemented on the premise of the technical solution of the present invention, and provides detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following implementations case.

The technical problem to be solved by this invention is realized through the following technical solutions:

A light-responsive rewritable polymer paper, the key components in the components required for the preparation of the material, the ferric oxide particles and the liquid crystal components with a special structure, need to be synthesized by a special method.

The raw material components required for the preparation of the ferric oxide particles with special structure and the mass fractions of each component are as follows:

15-20 parts of iron salts such as ferric chloride and ferric nitrate;

8-10 parts of ligands such as 2-aminoterephthalic acid and terephthalic acid;

100-150 parts of organic solvents such as N,N'-dimethylformamide and ethanol;

The preparation of the ferric oxide particles with special structure includes the following steps:

1-1) Weigh 15-20 parts of iron salts, 8-10 parts of ligands, and 100-150 parts of organic solvents in the reactor in proportion, and stir for 10-30 minutes to dissolve them;

1-2) The solution in step 1-1) is loaded into a hydrothermal kettle, and a hydrothermal reaction is carried out, and the reaction temperature is 100-200 ° C, 8-36 hours;

1-3) take out the solution in step 1-2), carry out centrifugation, centrifuge rotation speed is 5000-12000 rev/min, centrifugation time is 5-20 minutes/time, a total of 3-5 times, use organic solvent for centrifugation;

1-4) Transfer the solid of step 1-3) into a vacuum oven, 100-200 ° C, 8-24 hours, drying under vacuum or protective gas environment;

1-5) After grinding the dried sample in step 1-4), put it into a tube furnace for high temperature treatment, the treatment temperature is 500-800 ° C, 2-8 hours, the heating rate is 3-10 ° C/min, the reaction environment for argon atmosphere;

1-6) Take out the sample treated in step 1-5) and grind it to obtain submicron ferric oxide particles with special structure.

On the other hand, the raw material components required for the preparation of liquid crystal components such as 4-ethoxy-4'-undecyloxyazobenzene (AZO-11) and the mass fractions of each component are as follows:

The preparation of the liquid crystal components such as 4-ethoxy-4'-undecyloxyazobenzene includes the following steps:

2-1) Weigh 15-20 parts of azobenzene compounds, 15-20 parts of halogenated hydrocarbons, 30-40 parts of desiccant, 0.05-0.1 parts of catalyst in proportion, and dissolve in 75-100 parts of organic solvent ;

2-2) stirring the mixed solution in step 2-1) in an oil bath environment, the reaction temperature is 90-110 ° C, and the reaction time is 8-36 hours;

2-3) Add hydrochloric acid dropwise to the solution in step 2-2), adjust the pH value, and make it between 4-5;

2-4) The solution in step 2-3) is filtered under reduced pressure;

2-5) Transfer the solid remaining after filtration in step 2-4) to a vacuum oven, 80-120 ° C, 8-36 hours, vacuum drying;

2-6) Dissolve the dried solid in step 2-5) in dichloromethane (DCM), purify with silica gel column chromatography, and the eluent is an organic solvent such as dichloromethane and petroleum ether;

2-7) Transfer the solution obtained in step 2-6) to a rotary evaporator at a temperature of 40-80°C to obtain pure liquid crystal components such as 4-ethoxy-4'-undecyloxyazobenzene .

Finally, for a light-responsive rewritable polymer paper, the required raw material components and the mass fraction of each component are as follows:

Wherein, for the hydroxyl-terminated polycaprolactone, it is necessary to ensure that both ends of the molecular weight are hydroxyl-terminated, and the molecular weight needs to be between 50,000 and 100,000.

The isocyanates need to be treated for water removal.

The hydroxyazobenzene needs to be subjected to water removal treatment.

The liquid crystal composition needs to be subjected to water removal treatment.

The ferric oxide particles (Fe ₃ O ₄ ) need to be treated with water removal.

The initiator is dibutyltin dilaurate, which is commercially available and has no special requirements.

The preparation method of light-responsive rewritable polymer paper comprises the following steps:

3-1) Add 0-5 parts of prepared ferric oxide particles (Fe ₃ O ₄ ) with a special structure into 50-75 parts of DMF, and use a cell disrupter to disperse for 5-10 minutes;

3-2) Add 50-70 parts of hydroxyl terminated polycaprolactone, 15-25 parts of isocyanate, 15-25 parts of hydroxyazobenzene and 1-10 parts of liquid crystal components into 50-75 parts of organic The solvent is dissolved in a water bath environment of 60-120°C;

3-3) Add the mixed solution in step 3-1) to the mixed solution in step 3-2), and stir for 10-60 minutes in a water bath environment of 60-120°C, while keeping it under a protective atmosphere;

3-4) Add 0.1-0.2 parts of initiator dropwise to the mixed solution in step 3-3), and keep stirring for 3-10 minutes in a water bath environment of 60-120 ° C, while keeping in a protective atmosphere;

3-5) Transfer the mixed solution in step 3-4) to a polytetrafluoroethylene (PTFE) mold for reaction, and the reaction conditions are 60-120° C., 8-72 hours, under a protective atmosphere.

The present invention is described below by specific embodiment, the infrared thermal imager adopted is FLIR E50, the scanning electron microscope adopted is TALOS F200X field emission electron microscope, and the near-infrared light adopted is the xenon lamp of Shanghai Yuming Instrument Co., Ltd. The light source, the filter band is 800-900nm, and the output power is 0.7W/cm ² . In the following examples, the consumption of each raw material is in parts by weight unless otherwise specified.

Example 1

(1) Weigh 60 parts of PCL-OH, 20 parts of HDI, 20 parts of AZO-OH and 5 parts of AZO-11, add 75 parts of DMF and dissolve in a water bath environment of 80°C;

(2) 0.1 part of initiator is added dropwise to the mixed solution in step (1), and stirred for 10 minutes in a water bath environment of 80° C., while maintaining a nitrogen atmosphere;

(3) Transfer the mixed solution in step (2) to a polytetrafluoroethylene (PTFE) mold for reaction, and the reaction conditions are 80° C., 12 hours, and nitrogen atmosphere protection.

The properties of the resulting light-responsive ferric oxide/polyurethane composite are shown in Figure 1.

Example 2

(1) Weigh 0.5 part of prepared ferric oxide particles (Fe ₃ O ₄ ) with special structure, add it to 75 parts of DMF, and use a cell disruptor to disperse for 5 minutes;

(2) Weigh 60 parts of PCL-OH, 20 parts of HDI, 20 parts of AZO-OH and 5 parts of AZO-11, add 75 parts of DMF and place them in a water bath environment of 80°C to dissolve;

(3) adding the mixed solution in the step (1) to the mixed solution in the step (2), and stirring for 10 minutes in a water bath environment of 80 ° C, while maintaining a nitrogen atmosphere;

(4) dropwise add 0.1 part of initiator to the mixed solution in step (3), and stir for 10 minutes in a water bath environment of 80° C., while maintaining a nitrogen atmosphere;

(5) Transfer the mixed solution in step (4) to a polytetrafluoroethylene (PTFE) mold for reaction, and the reaction conditions are 80° C., 12 hours, and nitrogen atmosphere protection.

The properties of the resulting light-responsive ferric oxide/polyurethane composite are shown in Figure 1.

Example 3

(1) Weigh 1 part of prepared ferric oxide particles (Fe ₃ O ₄ ) with a special structure, add it to 75 parts of DMF, and use a cell crusher to disperse for 5 minutes;

(2) Weigh 60 parts of PCL-OH, 20 parts of HDI, 20 parts of AZO-OH and 5 parts of AZO-11, add 75 parts of DMF and place them in a water bath environment of 80°C to dissolve;

(3) adding the mixed solution in the step (1) to the mixed solution in the step (2), and stirring for 10 minutes in a water bath environment of 80 ° C, while maintaining a nitrogen atmosphere;

(4) dropwise add 0.1 part of initiator to the mixed solution in step (3), and stir for 10 minutes in a water bath environment of 80° C., while maintaining a nitrogen atmosphere;

(5) Transfer the mixed solution in step (4) to a polytetrafluoroethylene (PTFE) mold for reaction, and the reaction conditions are 80° C., 12 hours, and nitrogen atmosphere protection.

The properties of the resulting light-responsive ferric oxide/polyurethane composites are shown in Figure 1, Figure 2(b), Figure 3, and Figure 4.

Example 4

(1) Weigh 5 parts of prepared ferric oxide particles (Fe ₃ O ₄ ) with a special structure, add them to 75 parts of DMF, and use a cell disruptor to disperse for 5 minutes;

(2) Weigh 60 parts of PCL-OH, 20 parts of HDI, 20 parts of AZO-OH and 5 parts of AZO-11, add 75 parts of DMF and place them in a water bath environment of 80°C to dissolve;

(3) adding the mixed solution in the step (1) to the mixed solution in the step (2), and stirring for 10 minutes in a water bath environment of 80 ° C, while maintaining a nitrogen atmosphere;

(4) dropwise add 0.1 part of initiator to the mixed solution in step (3), and stir for 10 minutes in a water bath environment of 80° C., while maintaining a nitrogen atmosphere;

(5) Transfer the mixed solution in step (4) to a polytetrafluoroethylene (PTFE) mold for reaction, and the reaction conditions are 80° C., 12 hours, and nitrogen atmosphere protection.

The properties of the resulting light-responsive ferric oxide/polyurethane composite are shown in Figure 1.

Example 5

(1) Weigh 1 part of prepared ferric oxide particles (Fe ₃ O ₄ ) with a special structure, add it to 75 parts of DMF, and use a cell crusher to disperse for 5 minutes;

(2) Weigh 60 parts of PCL-OH, 20 parts of HDI, 20 parts of AZO-OH and 2.5 parts of AZO-11, add 75 parts of DMF and place them in a water bath environment of 80°C to dissolve;

(3) adding the mixed solution in the step (1) to the mixed solution in the step (2), and stirring for 10 minutes in a water bath environment of 80 ° C, while maintaining a nitrogen atmosphere;

(4) dropwise add 0.1 part of initiator to the mixed solution in step (3), and stir for 10 minutes in a water bath environment of 80° C., while maintaining a nitrogen atmosphere;

(5) Transfer the mixed solution in step (4) to a polytetrafluoroethylene (PTFE) mold for reaction, and the reaction conditions are 80° C., 12 hours, and nitrogen atmosphere protection.

The properties of the obtained light-responsive ferric oxide/polyurethane composites are shown in Fig. 1 and Fig. 2(a).

Example 6

(1) Weigh 1 part of prepared ferric oxide particles (Fe ₃ O ₄ ) with a special structure, add it to 75 parts of DMF, and use a cell crusher to disperse for 5 minutes;

(2) Weigh 60 parts of PCL-OH, 20 parts of HDI, 20 parts of AZO-OH and 10 parts of AZO-11, add 75 parts of DMF and place them in a water bath environment of 80°C to dissolve;

(3) adding the mixed solution in the step (1) to the mixed solution in the step (2), and stirring for 10 minutes in a water bath environment of 80 ° C, while maintaining a nitrogen atmosphere;

(4) dropwise add 0.1 part of initiator to the mixed solution in step (3), and stir for 10 minutes in a water bath environment of 80° C., while maintaining in a nitrogen atmosphere;

(5) Transfer the mixed solution in step (4) to a polytetrafluoroethylene (PTFE) mold for reaction, and the reaction conditions are 80° C., 12 hours, and nitrogen atmosphere protection.

The properties of the resulting light-responsive ferric oxide/polyurethane composites are shown in Fig. 1 and Fig. 2(c).

The preparation methods of the ferric oxide particles (Fe ₃ O ₄ ) and the liquid crystal component AZO-11 in the above examples 1-6 are as follows:

The preparation of the ferric oxide particles with special structure includes the following steps:

1-1) Weigh 18 parts of ferric chloride, 9 parts of 2-aminoterephthalic acid, 120 parts of N,N'-dimethylformamide in the reactor in proportion, and stir for 20 minutes to dissolve them ;

1-2) The solution in step 1-1) was loaded into a hydrothermal kettle, and a hydrothermal reaction was carried out, and the reaction temperature was 150 ° C for 12 hours;

1-3) The solution in step 1-2) is taken out, centrifuged, the centrifugation speed is 10,000 rev/min, the centrifugation time is 10 minutes/time, a total of 4 times, and the centrifugation is carried out with an organic solvent;

1-4) Transfer the solid of step 1-3) to a vacuum oven, dry at 150° C. for 12 hours under vacuum or a protective gas environment;

1-5) After grinding the dried sample in step 1-4), put it into a tube furnace for high temperature treatment, the treatment temperature is 600 ° C, 5 hours, the heating rate is 5 ° C/min, and the reaction environment is an argon atmosphere;

1-6) Take out the sample treated in step 1-5) and grind it to obtain submicron ferric oxide particles with special structure.

The 4-ethoxy-4'-undecyloxyazobenzene (AZO-11) liquid crystal component is prepared by the following method:

2-1) Weigh in proportion 18 parts of 4-ethoxy-4'-hydroxyazobenzene, 18 parts of 1-bromoundecane, 35 parts of anhydrous potassium carbonate, 0.08 part of HMPA, and dissolved in 80 parts of in water ethanol;

2-2) The mixed solution in step 2-1) was stirred in an oil bath environment, the reaction temperature was 100°C, and the reaction time was 12 hours;

2-3) Add hydrochloric acid dropwise to the solution in step 2-2), adjust the pH value, and make it between 4-5;

2-4) The solution in step 2-3) is filtered under reduced pressure;

2-5) Transfer the solid remaining after filtration in step 2-4) to a vacuum oven, 100° C. for 12 hours, and vacuum drying;

2-6) Dissolve the dried solid in step 2-5) in dichloromethane (DCM), purify with silica gel column chromatography, and the eluent is an organic solvent such as dichloromethane and petroleum ether;

2-7) Transfer the solution obtained in step 2-6) to a rotary evaporator at a temperature of 50° C. to obtain a pure 4-ethoxy-4′-undecyloxyazobenzene liquid crystal component.

The materials obtained in Examples 1-6 are detected:

1. Detect the light response performance. The specific detection method is: cut the prepared polymer into a standard sample of 1cm×1cm×1mm, and use near-infrared light with a wavelength of 800-1000nm and a light intensity of 0.7W/cm ² to test the sample. Irradiation was performed, and the temperature was recorded by an infrared thermal imager (FLIR E50) and the supporting software SmartView. In order to ensure the scientificity and rigor of the experiment, the obtained temperature was the maximum value of the average temperature of the sample.

2. Detect the optical erasing performance. The specific detection method is as follows: after the surface of the sample is destroyed with pointed tweezers and its shape is recorded, the sample is placed in a neutral solution, an acidic solution (pH=3), and an alkaline solution (pH=3), respectively. = 11) and in a low temperature (ice) environment, the sample was irradiated with near-infrared light with a wavelength of 800-1000 nm and a light intensity of 1.0 W/cm ² and a high-speed camera (Leica) was used to record the condition of the sample.

3. Detect the optical writing performance. The specific detection method is as follows: after rubbing the surface of the sample to analyze the liquid crystal components and the matrix, place it in an environment of air, water and ice, and use a near-infrared wavelength of 800-1000nm. The sample was irradiated with a point light source and recorded with a high-speed camera (Leica). The light intensity used in the air test was 2.0W/cm ² , the light intensity used in the underwater test was 3.0W/cm ² , and the light intensity used in the ice test was 2.0W/cm 2 . The strength is 4.0W/cm ² .

4. Test the mechanical properties. The specific test method is: according to the national standard GB/T1447 test method, the test sample is cut into a dumbbell-shaped test sample of 42.5mm × 5mm × 0.75mm according to the proportion, and a computer-controlled electronic universal testing machine (Li Shike) is used. Tester) at a tensile rate of 10 mm/min.

5. To test the stability performance, the specific test method is: use pointed tweezers to destroy the surface of the sample and record its shape, then place the sample in a neutral solution, an acidic solution (pH=3), and an alkaline solution (pH=11) ) and stored in a low temperature (ice) environment for 1 week, the optical erasure performance test was carried out on the sample, that is, the near-infrared light with a wavelength of 800-1000nm and a light intensity of 1.0W/cm ² was used to irradiate the sample and a high-speed camera ( Leica) to record the sample condition.

The test results are shown in Table 1 below:

According to Fig. 1, Fig. 2, Fig. 3 and Fig. 4, it can be seen that the triiron tetroxide/polyurethane composite material prepared by the present invention has excellent light response properties, mechanical properties and multi-environmental stability. The added liquid crystal phase will form π-π stacking with the azobenzene functional groups of the matrix. This dynamic and reversible physical force will make the liquid crystal phase behave like an "ink" and record scratches when the surface is destroyed. When the temperature is between the melting point and clearing point of the liquid crystal phase, it rearranges to achieve surface self-healing. As can be seen from Figure 2 and Table 1, when the liquid crystal component content is low (Example 5), the surface damage will not cause the liquid crystal phase portion to be analyzed, so that traces cannot be recorded; when the liquid crystal component content is too high ( In Example 6), although the surface damage can be recorded, but after irradiation, the liquid crystal component itself will form agglomeration and cannot achieve complete repair: the polymer paper in these two cases does not have the functions of optical erasing and optical writing. In addition, the iron tetroxide particles (Fe ₃ O ₄ ) with a special structure show excellent photothermal conversion performance. As in Example 2, only 0.5 part of the content can make the composite reach 111.62 ° C, which exceeds the photoresponse erasing and writing. The trigger temperature can realize optical erasing and optical writing behaviors in air, aqueous solution (neutral, acidic, alkaline) and low temperature (ice). In addition, due to the particle reinforcement effect, with the increase of the fraction, the mechanical properties of the composite first increased and then decreased, and Example 3, which added 1 part of ferric oxide particles (Fe ₃ O ₄ ), showed the most excellent comprehensive performance. .

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (8)

1. a light-responsive rewritable polymer paper, characterized in that the raw material of the polymer paper comprises the following components in parts by weight: 50-70 parts of hydroxyl terminated polycaprolactone, 15-25 parts of isocyanate, hydroxyl 15-25 parts of azobenzene, 1-10 parts of liquid crystal components, 0-5 parts of ferric oxide particles, 0.1-0.2 parts of initiator, 100-150 parts of organic solvent; The ferric oxide particles are prepared by the following method: weigh 15-20 parts of iron salt, 8-10 parts of ligands and 100-150 parts of organic solvent by weight, stir and mix evenly, put them in water at 100-200° C. The thermal reaction is carried out for 8 to 36 hours, and the obtained product is subjected to centrifugal separation, and the separated solid is dried, treated at high temperature, and ground to obtain submicron ferric oxide particles; The liquid crystal component is obtained by the following method: weighing 15-20 parts of azobenzene compounds, 15-20 parts of halogenated hydrocarbons, 30-40 parts of desiccant, 0.05-0.1 part of catalyst, and 500 parts of organic solvent by weight -1000 parts, stir and mix, and obtain the liquid crystal component through alkylation reaction, recrystallization, filtration, vacuum drying, silica gel column chromatography, and drying. 2. a kind of photoresponse rewritable polymer paper according to claim 1, is characterized in that, described iron salt is ferric chloride or ferric nitrate; Described ligand is 2-amino terephthalic acid or terephthalic acid; The organic solvent is N,N'-dimethylformamide or ethanol. 3. a kind of photoresponse rewritable polymer paper according to claim 1, is characterized in that, described solid drying is carried out under vacuum or protective gas environment, and drying temperature is 100-200 ℃, and drying Dry time is 8-24h; The temperature of the high temperature treatment is 500-800°C, the treatment time is 2-8h, the heating rate is 3-10°C/min, and the high temperature treatment environment is an argon atmosphere. 4. a kind of light-responsive rewritable polymer paper according to claim 1, is characterized in that, described azobenzene family compound is 4-ethoxy-4'-hydroxyazobenzene or 4, 4'-p-hydroxyazobenzene; Described desiccant is anhydrous potassium carbonate or anhydrous magnesium carbonate; Described catalyst is potassium iodide or hexamethylphosphoric triamide; The organic solvent is absolute ethanol, dichloromethane or tetrahydrofuran. 5. A light-responsive rewritable polymer paper according to claim 1, wherein the temperature of the alkylation reaction is 90-110°C, and the reaction time is 8-36h; The recrystallization is carried out by adding hydrochloric acid dropwise to the material obtained by the alkylation reaction to adjust its pH value to 4-5; Described filtration is reduced pressure filtration; The temperature of the vacuum drying is 80-120°C, and the time is 8-36h; Described silica gel column chromatography is to dissolve the solid after vacuum drying in methylene chloride, and use silica gel column chromatography to purify; The drying temperature is 40-80°C. 6. A light-responsive rewritable polymer paper according to claim 1, wherein both ends of the hydroxyl-terminated polycaprolactone are hydroxyl-terminated, and the molecular weight is 50,000-100,000 between; The initiator is dibutyltin dilaurate. 7 . The method for preparing a light-responsive rewritable polymer paper according to claim 1 , wherein 50-70 parts of hydroxyl-terminated polycaprolactone, 15-25 parts of isocyanate parts, 15-25 parts of hydroxyazobenzene, 1-10 parts of liquid crystal components, 0-5 parts of ferric oxide particles, 0.1-0.2 parts of initiator, 100-150 parts of organic solvent, in-situ polymerization after mixing, A polymer paper was produced. 8. The preparation method of light-responsive rewritable polymer paper according to claim 7, wherein the in-situ polymerization process needs to be carried out under the protection of a nitrogen atmosphere, the polymerization temperature is 60-120 ° C, and the polymerization The time is 8-72 hours; The ferric tetroxide is first dispersed by a cell crusher and then added to the reaction system.

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