KR20190002820A - Composition for self healing thermoplastic elastomers comprising disulfide bonds and methods of preparing the same - Google Patents

Abstract

Provided is a self-healing elastomer comprising: a repeating unit derived from a polyol compound; a repeating unit derived from an isocyanate compound; and a repeating unit derived from a disulfide compound, and comprises a disulfide bond in a main chain or a branching chain. Embodiments of the present invention provide the self-healing elastomer exhibiting thermoreversible self-healing properties.

Description

Technical Field [0001] The present invention relates to a self-healing elastomer containing a disulfide bond and a process for producing the same. BACKGROUND ART [0002]

The present invention relates to a new self-healing elastomer comprising a disulfide bond and a process for its preparation. More particularly, the present invention relates to a self-healing elastomer exhibiting thermoreversible self-healing properties and a method for producing the same.

The self-healing system is an intelligent system that can extend the life span and recover the physical properties by restoring the self-structure in the molecule instead of passive repair when the structure of the material is destroyed or the physical properties are degraded due to external environmental factors.

In recent years, studies have been made to manufacture self-healing materials using a reversible chemical mechanism system that can be treated by binding in a molecular unit as compared with a capsule system which is difficult to be repeatedly treated. Although studies on individual compounds have been carried out, it has been found that even if the self-healing ability is achieved, the reaction is only performed at a high temperature, is not repeatedly restored, is slow in restoration, does not show excellent performance in terms of ductility or mechanical properties There is a problem that it is difficult to apply it to devices such as flexible devices, aerospace materials, building materials, and medical materials.

Accordingly, there is a desperate need to develop a material exhibiting excellent self-healing performance while exhibiting excellent performance in terms of ductility or mechanical properties.

KR 10-2016-0081052 A1

Embodiments of the present invention provide a self-healing elastomer exhibiting thermoreversible self-healing properties.

In another embodiment of the present invention, there is provided a process for producing the self-healing elastomer.

In one embodiment of the present invention, the repeating unit derived from the polyol compound; A repeating unit derived from an isocyanate compound; And self-healing elastomers comprising a repeating unit derived from a disulfide compound, wherein the self-healing elastomer comprises a disulfide bond in the main chain or the branch chain.

In an exemplary embodiment, the self-healing elastomer comprises repeating units derived from 1 to 40 mole% polyol compound; A repeating unit derived from 30 to 70 mol% of an isocyanate compound; And a repeating unit derived from 5 to 30 mol% of a disulfide compound; . ≪ / RTI >

In an exemplary embodiment, the disulfide bond may be comprised between 5 and 20 mole percent.

In an exemplary embodiment, the polyol compound is selected from the group consisting of polyalkylene ether glycols, polyester polyols, e-caprolactone polyols, polyethylene glycols, polypropylene glycols, polyester polyols, polycaprolactone diols, polycarbonate diols and polytetramethylene ethers Glycol, < / RTI >

In an exemplary embodiment, the isocyanate compound may include one or more selected from the group consisting of toluene diisocyanate, methylenediphenyl diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

In an exemplary embodiment, the disulfide compound is selected from the group consisting of 2-hydroxyl disulfide, 3,3'-dithiodipropionic acid, 2,2 '- (dithiodiethylene) Diazomethane dihydrochloride, 2,2'- (Dithodimethylene) difuran, 4-aminophenyl disulfide, 2,2'-Diaminodiethyl disulfide dihydrochloride and And 3,3'-Dihydroxydiphenyl disulfide. The term " 3,3'-dihydroxydiphenyl disulfide "

In another embodiment of the present invention, there is provided a self-healing film comprising the dried self-healing composition comprising the self-healing elastomer.

Exemplary Implementation Example In one embodiment, the self-healing film may exhibit a self-healing efficiency of 80% or more at a temperature of 20 to 60 ° C.

EXEMPLARY IMPLEMENTATION EXAMPLE By way of example, the self-healing film may exhibit a tensile stress of 15 to 23 MPa.

In another embodiment of the present invention, there is provided a process for preparing a self-healing elastomer comprising mixing a polyol compound and an isocyanate compound and then polymerizing to form a polymer; And reacting the polymer with a disulfide compound to produce a self-healing elastomer; Wherein the self-healing elastomer comprises a disulfide bond in the main chain or the branch chain.

EXEMPLARY EMBODIMENT In this example, 70 to 700 moles of the isocyanate compound may be mixed with 100 moles of the polyol compound.

EXEMPLARY EMBODIMENT In this example, 5 to 100 moles of the disulfide compound may be reacted with 100 moles of the polymer.

The self-healing elastomer according to an embodiment of the present invention can exhibit self-recovery property and adhesion property repeatedly, and can exhibit thermo-reversible self-healing property under specific temperature conditions. In particular, the self-healing elastomer includes a disulfide bond. Since the disulfide bond (SS) exhibits a self-worth ability of a molecule unit through chain exchange with a neighboring sulfur atom at the time of damage, the disulfide bond Self-healing elastomers included can exhibit excellent self-healing properties (shape recovery rate).

Accordingly, it can be widely used in various fields such as aerospace material, building material, medical material, coating agent and adhesive.

In addition, the self-healing elastomer can be manufactured by a very simple method, and thus is useful for commercialization.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram showing a self-healing elastic body manufactured according to an embodiment of the present invention and its self-healing properties. FIG.
Figure 2 is a Fourier transform infrared spectroscopy (FT-IR) spectrum of a self-healing elastomer prepared in accordance with embodiments of the present invention.
Figure 3 is a Raman spectrum of self-healing elastomers prepared in accordance with embodiments of the present invention.
Figures 4a and 4b are graphs illustrating the results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) analysis of self-healing elastomers prepared in accordance with embodiments of the present invention.
5 is a graph showing mechanical properties (tensile stress and tensile strain) of self-healing elastomers prepared according to embodiments of the present invention before and after self-healing.
Figure 6 is a graph illustrating the self-healing efficiency of self-healing elastomers prepared in accordance with embodiments of the present invention.
Figure 7 is a photograph showing self-healing performance of a self-healing film comprising self-healing elastomers prepared in accordance with embodiments of the present invention.
8A and 8B are conceptual diagrams showing self-healing compositions and their self-healing properties according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. This is illustrated for illustrative purposes, and the technical idea of the present invention and its constitution and application are not limited thereby.

Self-healing elastomer

In one embodiment of the present invention, the repeating unit derived from the polyol compound; A repeating unit derived from an isocyanate compound; And a repeating unit derived from a disulfide compound; And a self-healing elastomer comprising a disulfide bond in the main chain or branching chain is provided.

 Since the disulfide bond of the self-healing elastomer exhibits the self-value capability of the molecular unit through chain exchange with neighboring sulfur atom at the time of damage, the self-healing elastomer containing disulfide bond as described in the present invention exhibits excellent self- Characteristics can be shown.

In an exemplary embodiment, the polyol compound is selected from the group consisting of polyalkylene ether glycols, polyester polyols, e-caprolactone polyols, polyethylene glycols, polypropylene glycols, polyester polyols, polycaprolactone diols, polycarbonate diols and polytetramethylene ethers Glycol, < / RTI >

In an exemplary embodiment, the repeating unit derived from the polyol compound may correspond to a soft-segment in the self-healing elastomer, wherein the self-healing polymer comprises repeating units derived from 1 to 40 mole% Units, specifically 1 to 30 mol% of repeating units derived from polyol compounds.

 If the self-healing polymer (100 mol%) contains less than 1 mol% of repeating units derived from the polyol compound, the ductility may be lowered, and if it contains more than 40 mol% of repeating units derived from the polyol compound Self-healing performance may be degraded.

In an exemplary embodiment, the isocyanate compound may include one or more selected from the group consisting of toluene diisocyanate, methylenediphenyl diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

In an exemplary embodiment, the repeating unit derived from the isocyanate compound may correspond to a hard-segment in the self-healing elastomer, wherein the self-healing polymer comprises repeating units derived from 30 to 70 mole percent of the isocyanate compound Unit.

If the self-healing polymer contains repeating units derived from an isocyanate compound in an amount less than 30 mol%, the mechanical performance such as tensile strength may be deteriorated. If the self-healing polymer contains more than 70 mol% of repeating units derived from an isocyanate compound Self-healing performance, ductility, etc. may be lowered.

On the other hand, the disulfide compound may be selected from the group consisting of 2-hydroxyl disulfide, 3,3'-dithiodipropionic acid, 2,2 '- (dithiodiethylene) , 2 '- (Dithodimethylene) difuran, 4-aminophenyl disulfide, 2,2'-Diaminodiethyl disulfide dihydrochloride, and 3,3' -Dihydroxydiphenyl disulfide, and the like.

In an exemplary embodiment, the repeating unit derived from the disulfide compound contributes to improving the self-healing efficiency of the self-healing elastomer, and the self-healing polymer comprises a repeating unit derived from 5 to 30 mol% of the disulfide compound, May comprise repeating units derived from 5 to 20 mole percent of disulfide compounds.

When the self-healing polymer contains repeating units derived from the disulfide compound at less than 5 mol%, the self-healing performance may be degraded. If the self-healing polymer contains more than 30 mol% repeating units derived from the disulfide compound, Performance may be degraded.

In one embodiment, the self-healing elastomer may be represented by the following formula (1).

[Chemical Formula 1]

(Wherein n is an integer of 5 to 20 and x is an integer of 10 to 40)

EXEMPLARY EMBODIMENTS By way of example, the self-healing elastomer may have a weight average molecular weight (Mw) in the range of 10,000 to 100,000. If it has a weight average molecular weight of more than 100,000, the self-healing performance may be insufficient due to a decrease in ductility and the like, and if the weight average molecular weight is less than 10,000, mechanical properties and the like may be lowered.

In an exemplary embodiment, the self-healing elastomer may have a linear or non-linear structure and may have a linear structure in particular.

On the other hand, the self-healing elastomer of the present invention may contain 5 to 20 mol% of disulfide bonds. If it is less than 5 mol%, the self-healing property may not be developed, and if it exceeds 20 mol%, the mechanical properties of the self-healing elastomer may be deteriorated.

On the other hand, the self-healing elastic body can exhibit self-healing performance even at room temperature. Specifically, the self-healing elastic body exhibits self-healing efficiency (%) of 80% or more at a temperature of 20 to 60 ° C, Efficiency can be seen.

The self-healing elastomer of the present invention exhibits the so-called " thermoreversible self-healing property " Thus, even if the self-healing elastic body is damaged, it can be cured by applying heat thereto. Thus, it is possible to perform repeated healing by controlling the heat applied to the self-healing elastic body.

In addition, the self-healing elastomer can exhibit excellent mechanical properties and exhibit, for example, a tensile stress of 15 to 23 MPa.

In addition, the self-healing elastomer exhibits self-healing properties under specific temperature conditions and can exhibit properties such as adhesiveness and coating properties.

Accordingly, the self-healing elastic body can be widely used in a variety of fields such as aerospace materials, building materials, medical materials, coating agents and adhesives.

Manufacturing method of self-healing elastomer

In another embodiment of the present invention, there is provided a process for the production of the self-healing elastomer described above. The process is very simple and useful for commercialization. The manufacturing method includes mixing a polyol compound and an isocyanate compound, and then polymerizing to form a polymer; And reacting the polymer with a disulfide compound to produce a self-healing elastomer; .

First, a polyol compound and an isocyanate compound are mixed and then polymerized to form a polymer.

At this time, 70 to 700 moles of the isocyanate compound may be mixed with 100 moles of the polyol compound. If they are mixed at less than 70 moles, mechanical performance such as tensile strength may be deteriorated. If they are mixed in excess of 700 moles, self-healing performance and ductility may be lowered.

In one embodiment, the polymerization can be run at 50 to 80 for 2-4 hours

Then, the polymer and the disulfide compound are reacted to prepare a self-healing elastic body.

In an exemplary embodiment, 5 to 100 moles of the disulfide compound may be reacted with 100 moles of the polymer. When the reaction is carried out at less than 5 moles, the self-healing performance may be deteriorated, and when it exceeds 100 moles, the ductility and mechanical performance may be lowered.

Self-healing composition and self-healing film

In another embodiment of the present invention there is provided a self-healing composition comprising the self-healing elastomer described above. The self-healing composition can exhibit excellent self-healing properties, including self-healing elastomers containing disulfide bonds.

In an exemplary embodiment, the self-healing composition may further comprise a self-healing elastomer comprising non-covalent bonds.

For example, the self-healing composition comprises a self-healing elastomer comprising a disulfide bond as set forth above in the main chain as a first self-healing elastomer and comprises a monomer having a hydroxyl group (-OH), wherein neighboring monomers are hydrogen The compound that forms the bond may be included as the second self-healing elastomer. In this case, the self-healing composition may include a first self-healing elastic material including a covalent bond and a second self-healing elastic material including a hydrogen bond (non-covalent bond) (see FIGS. 8A and 8B). In such a case, the self-healing performance can be further increased.

In an exemplary embodiment, the second self-healing elastomer may comprise a dopamine-based material (3,4-dihydroxyphenylamine) as a monomer.

Meanwhile, in another embodiment of the present invention, the self-healing composition can be dried to produce a self-healing film.

Specifically, the self-healing composition can be dried for 10 to 30 hours to produce a self-healing film. Since the self-healing film includes the above-mentioned self-healing elastic body, the self-healing film can exhibit excellent self-healing efficiency and excellent mechanical performance.

In an exemplary embodiment, the self-healing film may exhibit a self-healing efficiency of 80% or more at a temperature of 20 to 60 ° C.

In an exemplary embodiment, the self-healing film may exhibit a tensile stress of 15 to 23 MPa.

As described above, the self-healing elastic body of the present invention can exhibit self-recovery property and adhesive property repeatedly, and can exhibit thermo-reversible self-healing property under specific temperature conditions. In particular, the self-healing elastomer includes a disulfide bond. Since such a disulfide bond shows a self-value capability of a molecular unit through chain exchange with a neighboring sulfur atom at the time of damage, the self- The healing elastomer can exhibit excellent self-recovery properties (shape recovery rate).

In addition, it is possible to produce self-healing films by drying them. Such self-healing films can exhibit excellent self-healing efficiency, ductility and mechanical performance. Accordingly, it can be widely used in various fields such as aerospace material, building material, medical material, coating agent and adhesive.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for illustrating the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

[Experimental Example]

[Examples 1 to 3 (PMS1, PMS3 and PMS5)]

DMF (N, N-Dimethylmethanamide) as a solvent. First, a polycarbonate diol (PC-diol) (UH-300 manufactured by UBE Industries, Ltd. ETERNACOLL UH) and 4,4'-diphenylmethane diisocyanate (MDI) (Sigma Aldrich) were added to a 500 mL beaker type flask at 70 for 3 hours And polymerized to prepare a polymer. Then, 2-hydroxyethyl disulfide (2HEDS) (Sigma Aldrich) was reacted with the polymer to prepare a self-healing elastomer. At this time, the compositions according to Comparative Example 1 and Examples 1 to 3 were prepared by varying the input ratio of PC, MDI, and 2HEDS as shown in Table 1 below. Thereafter, the product was precipitated in methanol to prepare unreacted materials, completely dried in a vacuum oven for 24 hours, and then re-dissolved in DMF solvent to prepare a sample according to Examples 1 to 3, which is a film having a thickness of about 400 to 450 mm Respectively.

[Comparative Example 1 (PM)]

In Example 1, a self-healing elastomer was prepared by carrying out the same process except that the polymer was not reacted with 2-hydroxyethyl disulfide (2HEDS)

The molar ratios in Examples 1 to 3 and Comparative Example 1 are shown in Table 1 below.

Remarks PC (mol%) MDI (mol%) 2HEDS (mol%) Example 1
(PMS1) 25 50 25 Example 2
(PMS3) 12.5 50 37.5 Example 3
(PMS5) 8.5 50 41.5 Comparative Example 1
(PM) 33 67 0

(In Table 1, the molar ratio of PC to MDI: 2HEDS in PM is 1: 2: 0, the molar ratio of PC: MDI: 2HEDS of PMS1 is 1: 2: 1, : The molar ratio of 2HEDS is 1: 4: 3 and the molar ratio of PC: MDI: 2HEDS of PMS5 is 1: 6: 5. In PMS1 to PMS3, the molar ratio of the hard segment MDI and the soft segments PC and 2HEDS Are all 1: 1).

[Comparative Example 2 (PC)]

ETERNACOLL UH manufactured by UBE Industries (UH-300; MW: 3000) polycarbonate was used.

[Experimental Example 1: Synthesis of elastomer]

Experiments were carried out using FT-IR and Raman spectroscopy to confirm the chemical structure of the samples prepared according to Examples 1 to 3 and Comparative Example 1, which are shown in FIG. 1 and FIG.

Referring to FIG. 2, the samples according to Examples 1 to 3 are composed of repeating units derived from MD of a hard segment, repeating units derived from 2-hydroxyethyl disulfide, and repeating units derived from soft-segment poly Carbonate diol. As a result, it was confirmed that the elastomer synthesized in two segments having very different physical and chemical thermodynamic properties has a phase separation structure due to thermophilic incompatibility. In addition, the characteristic peaks of the NCO group at 2270 cm -1 disappear and at the same time, -NH stretching vibration (3500-3200 cm -1), δNH stretching vibration (1539-1531 cm -1), -C = O stretching vibration (1760- And that the linear elastic polyurethane elastomer was synthesized by confirming that a band of 1690 cm -1, CO stretching vibration of 1245 cm -1 and COC stretching vibration of 1162-1159 and 1046-1044 cm -1 were formed. However, it was confirmed that the sample according to Comparative Example 1 did not contain a repeating unit derived from 2-hydroxyethyl disulfide.

In addition, the C = O stretching vibration peaks of the urethane groups of FIG. 2 exhibit absorption bands at different positions depending on whether hydrogen bonding is present or not. In the rigid matrix having a peak of 1730 cm -1 corresponding to the carbonyl groups of the soft matrix, The phase separation can be calculated through the absorption peak at about 1690 cm -1 corresponding to the carbonyl group of the group. As a result, it was predicted that the degree of phase separation increased by inserting 2HED, a chain extender containing disulfide. This is probably because the interfacial area between the two phases decreases as the amount of the chain extender containing the disulfide participating in the phase separation increases and the molecules change from the isolated structure to the interconnected structure.

In addition, in FIG. 3, it was confirmed that a disulfide bond exists in the synthesized elastomer through 510 cm ^-1 peak corresponding to the disulfide bonding band ((SS) band).

[Experimental Example 2: DSC and TGA analysis]

Examples 1 to 3 and a T _g value of the sample prepared according to Comparative Example 1, DSC analysis, the pyrolysis temperature was confirmed by TGA analysis (Fig. 4a and 4b). As the content of isocyanate compound and disulfide compound increased, T _g value increased. Also, the disulfide bonds are easily cleaved from the chain due to the increase of the content, which is considered to be due to the fact that the decomposition temperature of the elastomer is advanced to inhibit the thermal stability. Therefore, it was confirmed that when disulfide compound of 37.5 mol% or more is contained in the self-healing polyurethane, it can be decomposed at a high temperature of about 200 ° C or more.

[Experimental Example 3: Mechanical Properties Analysis]

The intrinsic mechanical properties (tensile stress and tensile strain) of the samples prepared according to Examples 1 to 3 and Comparative Example 1 are shown in Fig. 5A, and their inherent mechanical properties are measured again after damage, . The values shown in Fig. 5A are shown in Table 2 below.

Sample name Tensile strain (%) Tensile Stress (MPa) Tensile modulus (MPa) Comparative Example 1 372.59 ± 21.1 12.5 ± 0.76 6.78 + - 0.39 Example 1 553.3 ± 73.8 21.5 ± 1.73 6.97 + - 0.75 Example 2 385.1 + - 12.64 22.56 ± 0.19 9.35 + 0.18 Example 3 252.62 + - 9.53 18.03 + - 0.35 11.96 ± 0.28

As a result, tensile modulus increased and tensile strain decreased, while tensile stress tended to increase with increasing disulfide bond content.

 [Experimental Example 4: Examination of self-recovery property]

(1) First, self-healing efficiency of samples according to Examples 1 to 3 and Comparative Example 1 was measured. The self-healing efficiency was calculated by the following equation. The results are shown in FIG. 6 Respectively.

[Equation 1]

Self-healing efficiency (%) = [(tensile strain or tensile stress of self-restored elastomer) / (tensile strain or tensile stress of original elastomer)] X100

In Examples 1-3, tensile strain of 30-70% and tensile stress of 40-70% were shown, respectively, indicating high self-healing efficiency.

(2) as well as the samples according to Examples 1 to 3 and Comparative Example 1 were subjected to physical damage of not less than 150 mm with a sharp knife, and then the two cut surfaces were brought into contact again, The surface was photographed after heat treatment for 5 minutes and is shown in Fig.

Referring to FIG. 7, it can be seen that the samples according to Examples 1 to 3 have excellent self-healing properties as compared with the sample according to Comparative Example 1. In particular, it was confirmed that the sample according to Example 2 was excellent in self-healing property and partly stuck again.

6 and 7, it can be seen that the samples according to Examples 1 to 3 exhibit excellent self-recovery characteristics, and particularly excellent self-recovery characteristics at temperatures of 40 to 60 ° C.

The embodiments of the present invention described above should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art will be able to modify the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the scope of protection of the present invention as long as it is obvious to those skilled in the art.

Claims (12)

A repeating unit derived from a polyol compound; A repeating unit derived from an isocyanate compound; And a repeating unit derived from a disulfide compound,
Self-healing elastomers containing disulfide bonds in the main chain or branching chain.
The method according to claim 1,
The self-
A repeating unit derived from 1 to 40 mol% of a polyol compound;
A repeating unit derived from 30 to 70 mol% of an isocyanate compound; And
And a repeating unit derived from 5 to 30 mol% of a disulfide compound.
The method according to claim 1,
Wherein the disulfide bond is comprised between 5 and 20 mole%.
The method according to claim 1,
Wherein the polyol compound is selected from the group consisting of polyalkylene ether glycols, polyester polyols, e-caprolactone polyols, polyethylene glycols, polypropylene glycols, polyester polyols, polycaprolactone diols, polycarbonate diols and polytetramethylene ether glycols Self-healing elastomer comprising at least one.
The method according to claim 1,
Wherein the isocyanate compound comprises at least one member selected from the group consisting of toluene diisocyanate, methylenediphenyl diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.
The method according to claim 1,
The disulfide compound may be selected from the group consisting of 2-hydroxyl disulfide, 3,3'-dithiodipropionic acid, 2,2 '- (dithiodiethylene) '- (Dithodimethylene) difuran, 4-aminophenyl disulfide, 2,2'-Diaminodiethyl disulfide dihydrochloride and 3,3'-di Wherein the self-healing elastomer comprises at least one selected from the group consisting of 3,3'-Dihydroxydiphenyl disulfide.
A self-healing film comprising a dried self-healing composition comprising a self-healing elastomer according to any one of claims 1 to 6.
8. The method of claim 7,
The self-healing film has a self-healing efficiency (%) of 80% or more at a temperature of 20 to 60 ° C.
8. The method of claim 7,
The self-healing film has a tensile stress of 15 to 23 MPa.
A self-healing elastic body,
Mixing a polyol compound and an isocyanate compound and then polymerizing to form a polymer; And
Preparing a self-healing elastomer by reacting the polymer with a disulfide compound; Lt; / RTI >
Wherein the self-healing elastomer comprises a disulfide bond in the main chain or the branch chain.
11. The method of claim 10,
With respect to 100 moles of the polyol compound
Wherein 70 to 700 moles of the isocyanate compound are mixed.
11. The method of claim 10,
Reacting the disulfide compound with 5 to 100 moles of the disulfide compound per 100 moles of the polymer.

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