CN112011004B

CN112011004B - Covalent adaptive network DOU-CANs and preparation method thereof

Info

Publication number: CN112011004B
Application number: CN202010751570.XA
Authority: CN
Inventors: 游正伟; 张璐之
Original assignee: Donghua University
Current assignee: Donghua University
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2021-07-20
Anticipated expiration: 2040-07-30
Also published as: CN112011004A

Abstract

The invention relates to covalent adaptive network DOU-CANs and a preparation method thereof, which are obtained by polymerizing raw materials containing a dimethyl glyoxime-carbamate cross-linking agent and a vinyl monomer. Compared with conventional plastics, DOU-CANs have excellent thermal and mechanical properties, high reworkability and transparency, and higher creep resistance and solvent resistance, and are suitable for industrial production.

Description

Covalent adaptive network DOU-CANs and preparation method thereof

Technical Field

The invention belongs to the field of polymer networks and preparation methods thereof, and particularly relates to a covalent adaptive network DOU-CANs and a preparation method thereof.

Background

Polymers are widely used in many important areas. High molecular materials are generally classified into thermoplastic plastics and thermosetting plastics according to their structural differences, and these two types of materials have characteristics and are difficult to blend. Thermoplastics that do not have a crosslinked structure are easy to process and recycle, but generally have limited mechanical strength, low thermal stability of the structure, and low solvent resistance. Thermosets with crosslinked networks exhibit improved properties. However, since thermosetting plastics have poor fluidity after heating, they are difficult to process and recycle, which results in a great deal of waste and environmental pollution. Recent advances now allow for the conversion of thermosets to their original monomers, which are then used for remanufacturing. However, the use of strong acids and bases during monomer recovery prevents the use of this process on a large scale. To overcome this problem, polymers with Covalently Adaptable Networks (CANs) have been developed, which constitute a new class of thermoplastic "thermoset" polymers.

CANs are a class of polymer networks based on the exchange of dynamic covalent bonds, which occur through either "dissociation" or "association" processes. At the use temperature, the bond exchange stops and the material behaves like a permanently crosslinked thermoset. However, at elevated temperatures, bond exchange is accelerated and the network can flow like an uncrosslinked thermoplastic. Thus, polymers with CANs have good mechanical properties as well as chemical resistance exhibited by thermosets. While exhibiting the re-processability and recyclability of the thermoplastic. Wudl and colleagues reported earlier in 2001 a thermal healing network crosslinked with Diels-Alder adducts. Since then, various types of CANs have been developed using a series of dynamic chemical methods, such as transesterification, carbamylation, transamination, imine, disulfide bond, and diketoenamine exchange, among others. Polymers formed using vinyl monomers account for over 65% of the 3.5 million tons produced per year. Therefore, it is important to ensure that these polymers contain CANs. However, due to the difficulty in synthesizing CANs, progress in this direction is slow.

Currently, most CANs (vinyl CANs) produced from vinyl monomers require complex multi-step synthetic reactions, including pre-functionalization of the monomers and post-polymerization modification processes. In particular, all previously reported vinyl CANs require the use of large amounts of solvents in the polymerization step, such as dioxane, anisole and toluene. This greatly complicates the process, while increasing cost and environmental impact. In addition, many vinyl CANs are darker or opaque and deterioration in their appearance and optical properties can greatly limit their applicability in the real world. The invention overcomes the existing problems and provides a method for preparing vinyl CANs by a solvent-free method, and the prepared vinyl CANs have the characteristics of colorlessness and transparency.

Disclosure of Invention

The invention aims to solve the technical problem of providing covalent adaptive network DOU-CANs and a preparation method thereof, overcoming the defects of complex treatment process, high production cost and the like in the prior art, and carrying out bulk polymerization on a dynamic dimethylglyoxime-carbamate DOU cross-linking agent and a vinyl monomer.

The invention relates to a vinyl covalent adaptive network shown as the following general formula:

wherein X is one or more of vinyl monomer units, and the values of m, n, X and y are independent and range from 1 to 100000.

Further, the values of m, n, x and y are respectively independent positive integers in the range of 1-10000.

The vinyl covalent adaptive network is obtained by bulk polymerization of starting materials comprising a dynamic dimethylglyoxime-carbamate (DOU) crosslinker, an initiator, a vinyl monomer.

The structural formula of the dynamic dimethylglyoxime-carbamate cross-linking agent is as follows:

the initiator is 2,2' -azobis (2-methyl propionitrile) (AIBN);

the vinyl monomer is a vinyl monomer capable of dissolving the DOU cross-linking agent.

Further, the vinyl monomer is one or more of methyl methacrylate, methyl acrylate and styrene.

The mass ratio of the vinyl monomer to the DOU cross-linking agent is 1000: 1-50: 1, and the amount of the initiator is 0.05-1% of the mass of the vinyl monomer.

The method specifically comprises the following steps:

wherein the values of m, n, x and y are independent and range from 1 to 100000.

The invention discloses a preparation method of a vinyl covalent adaptive network, which comprises the following steps:

mixing a dynamic dimethylglyoxime-carbamate DOU cross-linking agent, an initiator and a vinyl monomer, reacting and drying to obtain a vinyl covalent adaptive network.

The preferred mode of the above preparation method is as follows:

the structural formula of the dynamic dimethylglyoxime-carbamate DOU cross-linking agent is as follows:

the initiator is 2,2' -azobis (2-methyl propionitrile) (AIBN); the vinyl monomer is one or more of methyl methacrylate, methyl acrylate and styrene.

The reaction is carried out for 1-2h under the condition of water bath at the temperature of 60-90 ℃.

The invention relates to a vinyl covalent adaptive network prepared by the method.

The invention also relates to the application of the vinyl covalent adaptive network, such as building, automobile, biomedical and the like.

All DOU-CANs (exemplified by DOU-PMMA, DOU-PMA and DOU-PS) in the present invention are polymerized by the presence of commercial vinyl monomers (methyl methacrylate, methyl acrylate and styrene, respectively), DOU-crosslinker and initiator 2,2' -azobis (2-methylpropanenitrile) (AIBN). Briefly, the DOU-crosslinking agent and AIBN are dissolved in a vinyl monomer and the resulting homogeneous solution is subsequently bulk polymerized at a suitable temperature to yield the corresponding DOU-CANs.

The invention discloses CANs for synthesizing commodity thermoplastics based on dynamic oxime-urethane bonds. The invention develops a solvent-free method for synthesizing CANs from vinyl monomers for the first time. The key of the method is a dynamic DOU cross-linking agent which can be synthesized from commercial chemicals through a one-step reaction. The good solubility of the DOU-crosslinker in most vinyl monomers and allows bulk polymerization, and the process can be incorporated directly into existing industrial production lines. In addition, unlike other colored dynamic crosslinkers, DOU crosslinkers are colorless and therefore have no effect on the color and clarity of the resulting CANs. The DOU-CANs obtained by synthesizing the CANs corresponding to three common plastics (PMMA, PMA and PS) have excellent mechanical properties, processability, transparency, creep and solvent resistance. The present invention belongs to an economical and efficient green technology to produce CANs suitable for industrial use and to excite a series of new polymers that combine the advantages of thermoplastics and thermosets and thus can be widely used. In addition, oxime-carbamates are unique dynamic bonds that respond to a variety of stimuli and thus have great potential for building functional materials. The present invention demonstrates the role of oxime-carbamate linkages in a widely used olefin system. Therefore, the present invention will enlighten the introduction of oxime-urethane bonds into other polymers and contribute to the development of various functional materials.

Advantageous effects

(1) According to the invention, through a simple one-step synthesis method, the DOU-crosslinking agent and the vinyl monomer are adopted for bulk polymerization, the DOU-group-based CANs (DOU-CANs) can be produced in a large scale without using any solvent, and the synthesis process is easy to implement by using the existing industrial production line.

(2) In contrast to the prior reports that polymers with dynamic bond groups are dark or opaque, the DOU crosslinkers employed in the present invention are colorless and the resulting DOU-CANs retain transparency.

(3) The DOU-CANs obtained in the invention have excellent mechanical properties and high solvent resistance, have a cross-linked network structure, and show good elastic recovery and high thermal stability and chemical stability (such as excellent solvent resistance and creep resistance).

Drawings

FIG. 1 is a design of DOU-CANs wherein (A) the synthesis of DOU-crosslinkers; (B) synthesis and structural schematic of DOU-CANs;

FIG. 2 is a study of the dynamic exchange reaction of DOU-cross-linkers by small molecule reactions; wherein (A) a small molecule reaction scheme; (B) of mixtures of DOU-crosslinking agents and ethylenediamine obtained at different times¹H NMR spectrum, two dashed red lines indicate chemical shifts of 1.92 and 5.68 ppm; (C) formation of DMG versus time;

FIG. 3 illustrates the processability and thermal, mechanical and optical properties of DOU-CANs; wherein (A) the DSC curves of DOU-PMMA, DOU-PMA and DOU-PMA; (B) DOU-PMMA, and the mechanical properties of the reprocessed DOU-PMMA and the conventional PMMA; (C) DOU-PMA, recovered DOU-PMA and conventional PMA; (D) processing a DOU-PS sheet; (E) a photograph of the sheet of DOU-PMMA and DOU-PMA after reprocessing;

FIG. 4 structural stability of DOU-CANs; wherein (A) the results of the elongation creep test at 80 ℃ and 1MPa for conventional PMMA and DOU-PMMA; (B) conventional PS and DOU-PS at 80 ℃ and 1 MPa; (C) 10 cycles of cyclic tensile curves (no interval between consecutive cycles) for DOU-PMA and conventional PMA at 50% strain; (D) comparing the elastic recoverability of DOU-PMA and conventional PMA; (E) schematic representation of dissolution tests performed on DOU-CANs and corresponding conventional thermoplastics in organic solvents; wherein i) conventional thermoplastics and DOU-CANs are immersed in THF at 55 ℃; ii) after 1 hour, the conventional thermoplastics dissolved, while the DOU-CANs did not; iii) schematic and photograph of DOU-PMMA sheet loaded with the object after 2 hours at 55 ℃;

FIG. 5 is a view of DMG¹H NMR spectrum;

FIG. 6 shows DOU-crosslinking agents¹H NMR spectrum;

FIG. 7 is ATR-FTIR spectra of (A) DOU-PMMA and conventional PMMA, (B) DOU-PMA and conventional PMA, and (C) DOU-PS and conventional PS;

FIG. 8 is a TGA curve for (A) DOU-PMMA, (B) DOU-PMA and (C) DOU-PS;

FIG. 9 is a DMA curve for (A) DOU-PMMA, (B) DOU-PS and (C) DOU-PMA;

FIG. 10 is a photograph of DOU-PS and DOU-PMA sheets soaked in THF at 55 deg.C for 3 hours.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Sample source: styrene, methyl methacrylate, methyl acrylate, Dimethylglyoxime (DMG), 2,2' -azobis (2-methylpropanenitrile) (AIBN), ethylenediamine, hexane and toluene were purchased from national pharmaceutical chemicals GmbH. 2-isocyanatoethyl methacrylate and dibutyltin dilaurate (DBTDL) were purchased from Aladdin Regent Co., Ltd. All reagents were used as received without further purification unless otherwise stated. Deuterated solvents for NMR analysis were purchased from Cambridge Isotope Laboratories, inc. AIBN was recrystallized twice in ethanol. All other reagents were used as received without further purification.

And (3) testing and characterizing:

all tests were performed at room temperature unless otherwise indicated.

Structural characterization:

¹h NMR spectra were recorded on a Bruker AVANCE III 600MHz spectrometer.

Attenuated total reflectance fourier transform infrared (ATR-FTIR) spectra were recorded on a ThermoFisher Scientific Nicolet 8700 spectrometer with ATR accessory.

The number average molecular weights (Mn) of conventional vinyl thermoplastics, for PMMA, PMA and PS, as determined by Gel Permeation Chromatography (GPC), were 65kDa, 2027kDa and 119kDa, respectively.

And (3) performance characterization:

under nitrogen atmosphere, at 10 ℃ for min^-1Thermal Gravimetric Analysis (TGA) of Discovery TGA (TA, usa) at temperatures from 40 ℃ to 500 ℃.

Differential Scanning Calorimetry (DSC) was performed on a TA-Q20 differential scanning calorimeter. The sample was heated from 25 ℃ to 150 ℃, cooled to 0 ℃, and then heated at 10 ℃ min under nitrogen atmosphere^-1Re-heating to 150 ℃. All data were obtained from the second heating curve.

The dynamic mechanical analysis was performed on a DMA1(METTLER TOLEDO) dynamic mechanical analyzer. Rectangular samples (approximately 1 millimeter (T) × 3 millimeters (W) × 20 millimeters (L)) were tested at a frequency of 1Hz and a strain of 0.01%. Applying at-20 deg.C to 150 deg.C for 10 min^-1The heating rate of (c).

The elongation creep test was performed on TA-Q800 DMA using rectangular sheets (approximately 1 millimeter (T) × 3 millimeters (W) × 20 millimeters (L)). The elongation creep test was conducted in a stress control (1MPa) mode at 80 ℃.

Mechanical testing was performed using rectangular sheets (approximately 1 millimeter (T) × 3 millimeters (W) × 20 millimeters (L)) on an electronic universal material tester. The rate of uniaxial tensile measurement was 5 mm. min^-1(conventional PMA and DOU-PMA are 50 mm. min.)^-1). At least three samples were tested for each set of materials and an average was taken for each sample. The cyclic tensile test is carried out at 5mm min^-1Is performed at the speed of (1).

The material is reshaped by crushing the sample with a crusher or shearing with scissors and then reprocessing the sample at a pressure of 5MPa for a specified time and temperature.

Example 1

The specific reaction equation in this example is as follows:

preparation of a dynamic dimethylglyoxime-carbamate crosslinker based on vinyl-blocked oxime-carbamate bonds (DOU-crosslinker):

DMG (1.16g, 10mmol), 2-methacryloyloxyethyl isocyanate (3.41g, 22mmol) and DBTDL (0.05g) were charged into a reaction flask containing 15ml of toluene and stirred at 60 ℃ for 12 hours under a nitrogen atmosphere. After cooling to room temperature, the reaction solution was poured into 200mL of hexane, and a white solid was precipitated. The precipitate was filtered and washed with 200mL of hexane and dried at room temperature under reduced pressure for 5h to yield a white powder.

As shown in FIG. 1A, the DOU crosslinker was synthesized from commercially available 2-isocyanatoethyl methacrylate (DMG) and Dimethylglyoxime (DMG) by a simple one-step reaction.

Each DOU crosslinker molecule contains two oxime-urethane linkages, which are reversible, first, the present invention assesses the kinetics of oxime-urethane linkages in DOU crosslinkers by small molecule reactions, as shown in figure 2A.

DOU-crosslinker was mixed with excess ethylenediamine in DMSO-d6 at room temperature. The kinetics of the DOU crosslinker were monitored by measuring the amount of DMG formed using real-time Nuclear Magnetic Resonance (NMR) methods (e.g., B to C in FIG. 2, FIGS. 5 and 6). In that¹In H NMR, the signals due to the vinyl protons in the ═ CH2 group of 2-isocyanatoethyl methacrylate remained unchanged at 5.68 and 6.06ppm, since these protons are far from the center of the reaction. With addition of ethylenediamine, with free CH of DMG molecules₃The corresponding signal for protons appears at 1.92 ppm. The DMG generation rate is calculated using the following expression: DMG (%) ═ Σ 1.92/3(5.66) × 100, where Σ 1.92 and Σ 5.68 are integrals of protons at 1.92 and 5.68 ppm. After 33 hours, the formation (%) of DMG reached 100% and there was no subsequent change, indicating that all DMG had been released from the DOU crosslinker. This indicates that all oxime-urethane bonds have been substituted with urea bonds, indicating that the DOU-crosslinker is dynamic.

Example 2

The reaction equation in this example is as follows:

the specific preparation method of the polystyrene (DOU-PS) containing dimethylglyoxime-carbamate is as follows:

DOU crosslinker (0.426g, 1mmol) and AIBN (0.1g, 0.61mmol) were dissolved in styrene (20.8g, 200mmol) in a test tube, sealed and placed in a water bath at 80 ℃ for 2 hours. Finally, the reaction mixture was placed in an oven at 100 ℃ for 1 hour to obtain DOU-PS (wherein the values of m, n, x, and y are each independently 25 to 100).

Example 3

The reaction equation in this example is as follows:

the specific preparation method of the polymethyl methacrylate (DOU-PMMA) containing dimethyl glyoxime-carbamate comprises the following steps: DOU crosslinker (0.426g, 1mmol) and AIBN (0.1g, 0.61mmol) were dissolved in methyl methacrylate (20g, 200mmol), sealed and placed in a water bath at 80 ℃ for 2 hours. Finally, the reaction mixture was placed in an oven at 100 ℃ for 1 hour to obtain DOU-PMMA (wherein the values of m, n, x, and y are each independently 25 to 100).

Example 3

The reaction equation in this example is as follows:

the preparation method of the polymethyl acrylate (DOU-PMA) containing the dimethyl glyoxime-carbamate group comprises the following steps: DOU crosslinker (0.426g, 1mmol) and AIBN (0.1g, 0.61mmol) were dissolved in methyl methacrylate (17.2g, 200mmol), sealed and placed in a 70 ℃ water bath for 2 hours. Finally, the reaction was treated in an oven at 100 ℃ for 1 hour to give DOU-PMA (where m, n, x, y have values of 25 to 100, independently of one another).

Comparative example 1

The reaction equation is as follows:

preparation of conventional polystyrene (conventional PS): AIBN (0.1g, 0.61mmol) was dissolved in styrene (20.8g, 200mmol) in a test tube, sealed and placed in a water bath at 80 ℃ for 2 hours. Finally, the reaction was treated in an oven at 100 ℃ for 1 hour to give conventional PS (n)_Average≈1144)。

Comparative example 2

The reaction equation is as follows:

preparation of conventional polymethyl methacrylate (conventional PMMA): AIBN (0.1g, 0.61mmol) was dissolved in methyl methacrylate in a test tubeEster (20g, 200mmol), sealed and placed in a water bath at 80 ℃ for 2 hours. Finally, the reaction was treated in an oven at 100 ℃ for 1 hour to give conventional PMMA (n)_Average≈650)。

Comparative example 3

The reaction equation is as follows:

preparation of conventional poly (methyl acrylate) (conventional PMA): AIBN (0.1g, 0.61mmol) was dissolved in methyl acrylate (17.2g, 200mmol) in a test tube, sealed and placed in a water bath at 80 ℃ for 2 hours. Finally, the reaction was treated in an oven at 100 ℃ for 1 hour to obtain conventional PMA (n)_Average≈23570)。

The materials obtained in the examples and the comparative examples are specifically analyzed and explained by combining the drawings in the specification:

the structure of DOU-CANs and conventional vinyl thermoplastics was determined by attenuated total reflectance Fourier transform Infrared Spectroscopy (ATR-FTIR) (as shown in FIG. 7). The ATR-FTIR spectra of DOU-CANs and conventional thermoplastics are similar, indicating that their structures are also similar. Furthermore, the fact that DOU-CANs are insoluble in Tetrahydrofuran (THF), a common solvent for PMMA, PMA and PS, confirms that DOU-crosslinkers have been successfully incorporated into DOU-CANs. In addition, the DOU crosslinks remained frozen under ambient conditions (25 ℃), and the CANs polymers exhibited thermosets. Furthermore, due to the rapid dynamic exchange of DOU groups at high temperatures, crosslinked DOU-CANs dissociate rapidly in the heated state (100 ℃) and flow even like thermoplastics.

The thermal properties of the DOU-CANs were studied by Differential Scanning Calorimetry (DSC) as shown in FIG. 3A, Dynamic Mechanical Analysis (DMA) as shown in FIG. 9, and thermogravimetric analysis (TGA) as shown in FIG. 8. According to DSC results, DOU-PMMA and DOU-PS remain rigid at ambient conditions, with glass transition temperatures (Tg) of 110.5 ℃ and 101.1 ℃ respectively, whereas DOU-PMA is relatively soft and has a Tg of 21.3 ℃. The DMA results further confirmed the Tg values of DOU-CANs. In addition, the DMA curves for DOU-PMMA and DOU-PS plateau at temperature levels below the respective glass transition temperatures, indicating that the polymer remains rigid over a wide temperature range. The DMA curve of DOU-PMA shows a marked downward trend at almost room temperature, indicating that its mechanical properties are closely related to temperature. This demonstrates that the DOU-CANs proposed by the present invention are versatile and can be applied to a wide variety of materials from rigid to soft. According to the TGA results, DOU-CANs have good thermal stability, showing a 5% weight loss at 221 ℃ (DOU-PMMA), 334 ℃ (DOU-PMA) and 357 ℃ (DOU-PS). Thus, they can be used over a wide temperature range.

The invention carries out thermoplastic treatment on DOU-CANs. DOU-PS and DOU-PMMA were pulverized into powder using a pulverizer, and then hot-pressed at 140 ℃ for 10 minutes to perform remodeling. DOU-PMA was cut into pieces and then remolded by hot pressing at 120 ℃ for 10 minutes. As a preliminary demonstration, all three DOU-CANs can be easily processed into flat films (as shown in fig. 3D and 3E). The treatment conditions for DOU-CANs are relatively mild compared to most existing CANs (temperatures above 150 ℃ C., treatment times of several hours). This can be attributed to the excellent dynamics of the oxime-urethane bond.

The mechanical properties of the material play an important role in determining its end use. The mechanical properties of DOU-CANs are compared in the present invention with DOU-PMMA and DOU-PMA representing conventional plastics for rigid and soft materials, respectively (as shown in FIGS. 3B and 3C). The tensile strength (epsilon) and Young's modulus (E) of DOU-PMMA were 37.15 + -3.48 MPa and 1.20 + -0.14 GPa, respectively, similar to that of conventional PMMA (epsilon: 38.06 + -3.31 MPa, E: 1.27 + -0.10 GPa). The tensile strength (4.37 + -0.52 MPa) and Young's modulus (7.72 + -0.44 MPa) of DOU-PMA are an order of magnitude higher than those of conventional PMA (E ═ 0.33 + -0.03 MPa, E ═ 0.38 + -0.07 MPa). Furthermore, the tensile strength and Young's modulus of DOU-CANs remain substantially unchanged after rework, thus confirming their high reworkability.

Colorless transparent materials have important uses in applications such as automotive, medical, and electronic devices. However, most CANs are colored and have low transparency due to the color of the dynamic bonds and the heterogeneity of the materials due to the use of processing methods such as mixing. The DOU groups of the present invention are colorless, and the DOU-CANs obtained by directly introducing the present invention during homogeneous polymerization are colorless and exhibit excellent transparency. The transparency of DOU-PS, DOU-PMMA and DOU-PMA was evaluated against plants, logos and text (as shown in FIGS. 3D and 3E), respectively.

The invention studies the creep resistance of DOU-CANs. The strain of the DOU-PMMA and DOU-PS strips was monitored at 80 ℃ under an applied stress of 1 MPa. Strips of ordinary PMMA and PS were used as controls (as shown in fig. 4A and 4B). After 2000s, the creep strains of DOU-PMMA and DOU-PS were only 0.6% and 0.5%, respectively, while the creep strains of ordinary PMMA and PS were 5.5 and 4 times, 3.3% and 2%, respectively. These results demonstrate that the introduction of DOU groups into conventional vinyl polymers improves their thermal stability and creep resistance.

The elastic recoverability of the deformed DOU-PMA was evaluated by performing ten cycles of cyclic tensile testing at a constant strain of 50%. With no breaks between each successive cycle (as shown in fig. 4C and 4D). Conventional PMA was used as a control. The area of the hysteresis loop in the cycle test curve represents the energy dissipated during deformation. The recovery of the hysteresis loop is used to characterize the elastic recovery of the material. In the case of DOU-PMA, the area under the hysteresis loop is from 0.1997MJ m of the first period (. epsilon.1)^-30.1079MJ m reduced to the tenth period (. epsilon.10)^-3. Thus, in the tenth cycle, the recovery of DOU-PMA was 54.0% (ε 10/ε 1), which is significantly higher than that of conventional PMA (ε 1 ═ 0.0095MJ m^-3，ε10＝0.0044MJ m^-3) The latter was 46.3%. Furthermore, after ten cycles, the residual strain of DOU-PMA was 5%, significantly less than that of conventional PMA (13%). These results demonstrate that the crosslinked structure of DOU-PMA has higher recovery than conventional PMA.

Regarding the solvent resistance of the materials, sheets of three DOU-CANs (DOU-PMMA, DOU-PMA and DOU-PS) and corresponding conventional vinyl plastics (PMMA, PMA and PS) were immersed in THF at 55 deg.C (as shown in FIGS. 4E and 10). Even after 3 hours, the DOU-CANs only swelled and retained their original rectangular parallelepiped shape and supported the weight, while all three conventional vinyl plastics completely dissolved within 1 hour. The dissolution test demonstrated excellent chemical solvent resistance of DOU-CANs also due to their crosslinked structure.

Claims

1. A vinyl covalent adaptable network of the general formula:

(ii) a Wherein X is one or more of vinyl monomer units, and the values of m, n, X and y are independent and range from 1 to 100000.

2. The vinyl covalent adaptive network of claim 1, wherein the vinyl covalent adaptive network is obtained by polymerization of starting materials comprising dimethylglyoxime-carbamate DOU crosslinker, initiator, vinyl monomer.

3. The vinyl covalent adaptive network of claim 2, wherein the dimethylglyoxime-carbamate DOU crosslinker has the formula:

(ii) a The initiator is 2,2' -azobis (2-methyl propionitrile) AIBN; the vinyl monomer is a vinyl monomer capable of dissolving the DOU crosslinking agent.

4. The vinyl covalent adaptive network of claim 3, wherein the vinyl monomer is one or more of methyl methacrylate, methyl acrylate, and styrene.

5. The vinyl covalent adaptive network of claim 2, wherein the mass ratio of vinyl monomer to DOU crosslinker is 1000:1 to 50:1, and the amount of initiator is 0.05% to 1% of the mass of vinyl monomer.

6. The vinyl covalent adaptive network according to claim 1, characterized in that it is in particular:

、

、

wherein the values of m, n, x and y are independent and range from 1 to 100000.

7. A method of making the vinyl covalent adaptive network of claim 1, comprising:

and mixing the dynamic dimethylglyoxime-carbamate cross-linking agent, the initiator and the vinyl monomer, reacting and drying to obtain the vinyl covalent adaptive network.

8. The method of claim 7, wherein the dynamic dimethylglyoxime-carbamate cross-linking agent has the formula:

(ii) a The initiator is 2,2' -azobis (2-methyl propionitrile) AIBN; the vinyl monomer is one or more of methyl methacrylate, methyl acrylate and styrene.

9. The preparation method of claim 7, wherein the reaction is carried out for 1-2h under the condition of water bath at the temperature of 60-90 ℃.

10. Use of the vinyl covalent adaptive network of claim 1 in construction or automotive applications.