KR20240071292A - Isosorbide-based dynamic covalent polymer network and preparation method thereof, and recyclable composites prepared therefrom - Google Patents

Abstract

The present invention relates to an isosorbide-based reprocessed polymer for recycling composite materials and a method for manufacturing the same. Specifically, isosorbide (ISB)-based polyurethane and polythiourethane and a polymer composition containing a ZnDTC catalyst and the same. This is to implement the phenomenon of reprocessing and recycling.

Description

Isosorbide-based dynamic covalent polymer network and preparation method thereof, and recyclable composites prepared therefrom}

The present invention relates to isosorbide-based reprocessed polymers for use as composite materials and methods for manufacturing the same.

Among the polymer resins used in composite materials, thermoplastic polymer resins have advantages in formability and recyclability, but have the disadvantage of low thermal and mechanical properties and high resin viscosity, making the internal impregnation process of composite materials difficult. On the other hand, thermosetting polymer resins have high thermal, chemical and mechanical properties because the polymer chains are cross-linked in a network form, and are easy to manufacture through a solution phase process, so they have excellent characteristics with low raw material costs. However, it has the disadvantage of being difficult to reprocess and recycle due to the strong bonds between cross-linked molecules.

It is very difficult to separate the reinforcing fibers from the cured resin due to its molecular structure, and the used composite material is landfilled as industrial waste at the end of its lifespan, greatly affecting cost and environmental issues. Additionally, thermal decomposition and chemical decomposition methods for material recycling deteriorate the physical properties of composite materials.

Dynamically bonded crosslinked polymer (Covalent adaptable network, CAN) is defined as a crosslinked polymer that has both thermosetting and thermoplastic properties because the polymer chains are connected by dynamic crosslinking, which is a reversible exchange reaction. Because the chemical exchange reaction occurs within a covalent bond, it maintains high thermal and chemical stability and can provide easy processability and moldability. Reprocessing and recycling functions can be given through a simple thermal compression process, and research on recycling composite materials using this is actively underway.

In particular, among polymers, polyurethane is thermally stable and has excellent corrosion and chemical resistance, so it is used in various fields such as elastic fibers, paints, and adhesives. In addition, polythiourethane is a bonding state that can be created through a chemical reaction similar to urethane, and can maintain a chemical state as strong and stable as urethane, and dynamic covalent bonding is likely to occur under milder conditions. In addition, since the binding energy of thiourethane is relatively lower than that of urethane, a dissociation reaction is easy to occur, making it easy to recycle carbon fiber reinforced plastic.

The present applicant conducts research on dynamically bonded cross-linked polymer materials capable of the thiourethane exchange reaction, develops new polymer materials that satisfy high thermal and mechanical properties, and applies them to composite materials. We discovered that it is possible to recycle reinforcing fibers and cross-linked polymers at the same time by dissolving thermosetting polymers into a solution without harsh conditions and re-cross-linking them. By utilizing this, we developed a high-performance composite material using dynamically bonded cross-linked polymers. The invention was completed. The process of forming high molecular weight polyurethane oligomers using existing chain extenders has the limitation of being a complex synthesis process that requires 2 to 3 steps, and the synthesis method of this study forms a urethane prepolymer with Mn of 1000 or less in 1 step. It has the advantage of being crosslinked by adding a crosslinking agent without any separate separation process.

The existing known recycling method for composite materials uses polymer decomposition methods performed under harsh conditions such as thermal decomposition and chemical decomposition, so it is difficult to completely separate the carbon fibers, and even if the carbon fibers are successfully separated, the performance of the carbon fibers is reduced. It has the disadvantage of reduced strength. The introduction of dynamically bonded cross-linked polymers is expected to secure economic feasibility by effectively decomposing the polymer resin of composite materials under milder conditions and suggesting a recycling process that maintains the performance of carbon fiber.

While conducting research on reprocessed polymer materials capable of the above-mentioned thiourethane exchange reaction, the present applicant found that if the isosorbide material satisfies the polymer structure containing both urethane and thiourethane bonds, the dynamic covalent bond of thiourethane can be formed. It was suggested that possible reprocessing materials could be developed. Isosorbide and urethane have high thermal stability, so they can replace the thermosetting matrix of composite materials, and the present invention has been completed by providing reprocessing and recycling phenomena due to the dynamic covalent bonding of thiourethane.

Macromolecules, 2019, 52, 8207-8216. Molecules, 2019, 24, 1061.

The purpose of the present invention is as follows.

In one aspect, the aim is to provide a fiber reinforced urethane polymer that is dynamically crosslinkable and recyclable, using an isosorbide based urethane polymer as the polymer matrix.

In another aspect, there is provided a composition kit for making a dynamically crosslinkable and recyclable fiber reinforced urethane polymer.

In another aspect, the aim is to provide a method for producing dynamically crosslinkable and recyclable fiber reinforced urethane polymers.

In another aspect, the aim is to provide a dynamically crosslinkable and recyclable urethane polymer.

In another aspect, the aim is to provide a method for producing a dynamically crosslinkable and recyclable urethane polymer.

In one aspect, the present invention

reinforcing fiber; It provides a recyclable fiber-reinforced urethane polymer, including an isosorbide-based urethane polymer crosslinked with a thiourethane bond containing a catalyst.

In another aspect, the present invention

A first component comprising a catalyst and a urethane prepolymer; a second component containing a cross-linking agent; and a third component containing reinforcing fibers. A composition kit for producing a recyclable fiber-reinforced urethane polymer is provided.

In another aspect, the present invention

Urethane prepolymer; catalyst; crosslinking agent; and reinforcing fibers; and providing a method for producing a recyclable fiber-reinforced urethane polymer, comprising the steps of preparing a composition containing a and performing a crosslinking reaction.

In another aspect, the present invention

It is an isosorbide-based urethane polymer crosslinked with a thiourethane bond containing a catalyst, providing a recyclable urethane polymer.

In another aspect, the present invention

Urethane prepolymer; catalyst; and cross-linking agents; A method for producing a recyclable urethane polymer is provided, which includes preparing a composition containing a and performing a crosslinking reaction.

The isosorbide-based urethane polymer according to the present invention has the advantage of maintaining a constant cross-linked structure and maintaining physical properties even after reprocessing and recycling processes because a dynamic exchange reaction occurs only in cross-linked thiourethane.

Since the reaction conditions for the isosorbide-based urethane polymer are optimized to proceed in a solution phase, it can be impregnated into the composite material after creating the final crosslinking solution, and the dynamic covalent properties make the stacking process of composite materials easier. There is.

The isosorbide-based urethane polymer is applied to carbon fiber reinforced plastic and shows that recycling of composite materials is possible using dynamic exchange reaction in thiourethane.

Ultimately, the polymer composition provided by the present invention can form a composite material using the dynamic cross-linked polymer characteristics of excellent thermal and mechanical properties and reprocessing and recycling performance, thereby solving the problems of high manufacturing costs and waste disposal in the industrial field. It can be solved.

Figure 1 is a FT-IR measurement graph for structural analysis of synthesized ISB-N.
Figure 2 is a thermal analysis graph through DSC and TGA measurements of ISB-N (HDI) by catalyst amount.
Figure 3 is a film photograph of ISB-N (HDI) containing 2 wt% ZnDTC.
Figure 4 is a thermal analysis graph through DSC and TGA measurements of ISB-N (HDI) by [NCO]/[OH] ratio.
Figure 5 is a graph of mechanical property measurement through UTM measurement of ISB-N film using HDI and IPDI.
Figure 6 is a photograph showing the reprocessed film of ISB-N (HDI).
Figure 7 is a photograph of the recycling process through dissolution and re-crosslinking of the ISB-N film.
Figure 8 is a graph comparing mechanical properties of recycled ISB-NR film through UTM measurement.
Figure 9 is a thermal analysis graph through DSC and TGA measurements of recycled ISB-NR film.
Figure 10 is a photograph showing the soluble decomposition phenomenon of ISB-N (HDI) through the use of alcohol.
Figure 11 graphically shows the recycling process by melting the polymer matrix of a carbon fiber composite material by adding an excess amount of PETMP.
Figure 12 is a photograph showing the surface condition of the carbon fiber before and after recovery and the surface condition of the composite material through SEM measurement.
Figure 13 is a graph showing the chemical weight change through TGA measurement before and after recovery of carbon fiber.
Figure 14 is a schematic diagram of the thiourethane exchange reaction performed in the present invention.

Hereinafter, the present invention will be described in detail.

Meanwhile, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Additionally, the embodiments of the present invention are provided to more completely explain the present invention to those with average knowledge in the relevant technical field.

Furthermore, “including” a certain element throughout the specification means that other elements may be further included rather than excluding other elements, unless specifically stated to the contrary.

As used herein, “ISB-N” refers to an isosorbide-based polymer network.

In this specification, “alkyl” refers to a monovalent radical as a substituent that is a fully saturated hydrocarbon and includes both straight-chain or branched-chain structural isomers. For example, when referring to C1 to C30 alkyl, it means that the number of carbons constituting the hydrocarbon is in the range of 1 to 30.

In this specification, “alkylene” means a divalent radical that is 2 substituted. For example, when referring to C1-C30 alkylene, it means that the number of carbons making up the hydrocarbon ranges from 1 to 30.

In this specification, “cycloalkylene” refers to a cyclic saturated hydrocarbon divalent radical substituted by two.

As used herein, “arylene” refers to a divalent radical in which an aromatic substituent is disubstituted.

A recyclable fiber-reinforced urethane polymer provided in one aspect of the present invention will be described.

Reinforcement fibers include carbon fiber, aramid fiber, and glass fiber. The reinforcing fiber includes carbon fiber as an embodiment of the present invention. The reinforcing fibers may be provided in the form of particles, rods with a high aspect ratio, or fabrics in which the fibers are woven.

In composite materials manufactured by impregnating reinforcing fibers, etc., the reinforcing fibers may be dispersed within the base (matrix). In terms of physical properties, reinforcing fibers are usually provided in the form of a bundle, and may be provided in the form of a fabric by weaving the reinforcing fibers provided in bundles. In this case, the polymer forming the base penetrates into the bundle or the inside of the fabric. A composite material impregnated with reinforcing fibers, etc. is manufactured.

In the fiber-reinforced urethane polymer that is recyclable as a composite material according to the present invention, the matrix is an isosorbide-based urethane polymer crosslinked with a thiourethane bond.

The crosslinked isosorbide-based urethane polymer according to the present invention is formed by crosslinking an isosorbide-based urethane prepolymer with a thiourethane bond, and a crosslinking agent having 3 or more thiol groups can be used to form a thiourethane crosslink. there is.

In this specification, urethane polymer or urethane prepolymer means containing a urethane bond of -NH-C(=O)-O-, and thiourethane bond means -NH-C(=O)-S-.

In the present invention, isosorbide (ISB) is represented by the following formula (1).

[Formula 1]

In the present invention, urethane prepolymer is synthesized using isosorbide in the form of a pentagonal ring with high thermal stability, and then prepared using pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) without any further purification process. By crosslinking the urethane prepolymer by adding a crosslinking agent, an isosorbide-based urethane polymer having thiourethane crosslinking can be prepared.

In one embodiment, the crosslinked urethane polymer is a three-dimensional polymer network structure by crosslinking a urethane prepolymer prepared by reacting the isosorbide as a monomer diol with a polyisocyanate monomer using a crosslinking agent having a thiol group of 3 or more -SH. It can be formed as

The crosslinking agent may be specifically represented by Formula 2 below.

[Formula 2]

In Formula 2,

A is C1 to C20 alkyl, m is an integer of 1 to 10, n is an integer of 2 to 10, or A is C2 to C10 alkyl, m is an integer of 1 to 5, and n is an integer of 3 to 6. The molecular weight of the crosslinking agent may be 100 to 3000. In one embodiment, the cross-linking agent may be PETMP.

The urethane prepolymer can be obtained by polymerizing isosorbide and polyisocyanate as monomers.

The number average molecular weight (Mn) of the urethane prepolymer may be 100 or more and 1000 or less, and may preferably be limited to a minimum of 480 to a maximum of 680.

The polyisocyanate may include two or more isocyanate groups, and in one embodiment, may be diisocyanate. In other words, the present invention presents the possibility of adjusting desired thermal and mechanical properties according to the structural effects of various diisocyanates.

The diisocyanate may be a material represented by the following formula (3).

[Formula 3]

The B is C1-C10 alkylene, and one or more carbons of the alkylene may be substituted with C3-C6 cycloalkylene or C6-C10 arylene, and the cycloalkylene or arylene may be substituted with one or more C1-C10 arylene. Can be substituted with alkyl.

In another embodiment, B is C2-C8 alkylene, and 1 to 2 carbons of the alkylene may be substituted with C3-C6 cycloalkylene or C6 arylene, and the cycloalkylene or arylene is 1 It may be substituted with 4 to 4 C1-C10 alkyl.

In another embodiment,

The B may be represented by one of those represented by the following formula (4).

[Formula 4]

One)

2)

3)

4)

In one embodiment, the molar ratio of isosorbide and polyisocyanate for preparing the prepolymer may be 1 to 5 or 1.5 to 4.

In one embodiment of the present invention, after preparing the prepolymer, crosslinking is performed by adding a crosslinking agent without separate purification. In order to form a thiourethane crosslinking by a crosslinking agent having a thiol group, the prepolymer has an isocyanate functional group at the terminal. It is desirable to have it. For this purpose, it may be preferable to use an excess amount of polyisocyanate relative to isosorbide for crosslinking. However, if the content of polyisocyanate is too excessive, the desired three-dimensional network may not be formed through crosslinking due to the presence of unreacted polyisocyanate monomers.

In one embodiment, the molar ratio may be selected in the range of 2.5 to 3.5 to form an appropriate network through crosslinking.

In the recyclable fiber-reinforced urethane polymer of the present invention, for smooth recycling of the urethane polymer and reinforcing fibers, the thiourethane bond includes a catalyst to enable dynamic crosslinking.

Dynamic crosslinking means that the carbon-sulfur bond of a covalent thiourethane bond can be reversibly broken and reconnected, and a new thiourethane bond is formed through an exchange reaction between the thiourethane bond and the surrounding thiol group. It means being formed.

Dynamic crosslinking through the exchange reaction of thiourethane bonds can be conceptually explained as shown in Chemical Formula 5 below.

[Formula 5]

In the present invention, the bond energy of thiourethane has a lower value than the bond energy of urethane, so the catalyst for dynamic crosslinking in the present invention mediates dynamic crosslinking through the exchange reaction of thiourethane bonds.

In the present invention, catalyst refers to a substance that mediates the dynamic binding of thiourethane bonds. The catalyst may be added in the step of forming the urethane prepolymer in the manufacturing process, and may be added in the subsequent crosslinking step.

The catalyst may be a catalyst belonging to the ZnDTC group represented by the following formula (6).

[Formula 6]

Here, R1 to R4 are each independently C1 to C10 alkyl. In one embodiment, the catalyst may be ZnDTC, where R1 to R4 are C2 in the above formula.

The catalyst may be a catalyst belonging to the TBD group represented by the following formula (7).

[Formula 7]

Here, R5 is H or C1 to C10 straight or branched chain alkyl. The catalyst may be TBD, where R5 is H in the above formula.

The catalyst may be DBU represented by the following formula (8).

[Formula 8]

The catalyst may be a catalyst belonging to the DBTDL group represented by the following formula (9).

[Formula 9]

Here, R6 is C1 to C20 alkyl, and R7 is C1 to C10 alkyl, but R6 has the same number of carbon atoms or is larger than R7. The catalyst may be DBTDL, in which R6 is C11 straight-chain alkyl and R7 is C4 straight-chain alkyl in the above formula.

The weight ratio of the catalyst to the total weight of isosorbide, diisocyanate, PETMP, and catalyst may be 0.6 to 4 mass% (wt%), preferably 1.5 to 3 mass% (wt%).

In another aspect, the present invention provides a kit for manufacturing a recyclable fiber-reinforced urethane polymer, and describes the same.

In the present invention, the kit consists of components for producing recyclable fiber-reinforced urethane polymer. The kit for manufacturing a recyclable fiber-reinforced urethane polymer refers to a composition kit for manufacturing the aforementioned fiber-reinforced urethane polymer.

The kit is

A first component containing a urethane prepolymer containing isosorbide and a catalyst for dynamic crosslinking of thiourethane;

A second component containing a cross-linking agent having 3 or more thiol groups; and

It includes a third component containing reinforcing fibers.

The second component may be provided as a composition included in the first component.

Here, the urethane prepolymer, crosslinking agent, reinforcing fiber, catalyst, isosorbide, and polyisocyanate are as described above for the fiber-reinforced urethane polymer.

In another aspect, the present invention provides a method for manufacturing a recyclable fiber-reinforced urethane polymer, and describes the same.

The manufacturing method includes preparing a composition including a urethane prepolymer, a crosslinking agent, a catalyst, and reinforcing fibers; and performing a crosslinking reaction.

Here, the urethane prepolymer, crosslinking agent, catalyst, and reinforcing fiber are as described above for the fiber-reinforced urethane polymer.

In another aspect, the present invention provides and describes a recyclable urethane polymer.

The recyclable urethane polymer refers to a urethane polymer as a base that does not contain reinforcing fibers in the above-described recyclable fiber-reinforced urethane polymer. Here, the urethane prepolymer, crosslinking agent, catalyst, and reinforcing fiber are as described above for the fiber-reinforced urethane polymer.

In another aspect, the present invention provides a method for producing a recyclable urethane polymer and is described.

The recyclable urethane polymer manufacturing method refers to a urethane polymer manufacturing method as a base that does not include reinforcing fibers in the recyclable fiber-reinforced urethane polymer manufacturing method described above. Here, the urethane prepolymer, crosslinking agent, and catalyst are as described above for fiber-reinforced urethane polymer.

Hereinafter, it will be described through examples and experimental examples.

<General experiment method>

1. Thermogravimetric analysis (TGA)

TA instruments' Q500 was used, and it was performed in a temperature range of 25 to 800 ^°C in N ₂ atmosphere at a temperature increase rate of 10 ^°C /min.

2. Differential scanning calorimetry (DSC)

TA Instruments DSC Q2000 was used, and the study was performed in a temperature range of -40 to 200 ^°C in N ₂ atmosphere at a temperature increase rate of 10 ^°C /min.

3. Tensile test (Universal testing machine, UTM)

The tensile test of the ISB-N film was performed using Lloyd instruments' Instron LR5K universal testing machine (UTM), and a bar-shaped specimen measuring 5 mm * 50 mm * 0.25 mm (width * length * thickness) was preloaded at 5 mm/min. It was performed until fracture under the conditions of 0.1 N and a gauge length of 20 mm.

4. Infrared spectroscopy (IR)

Infrared spectroscopy (IR) was performed using Agilent's 4100 Exoscan FTIR spectrometer with attenuated total reflectance (ATR) equipment.

5. Scanning electron microscope (SEM) surface analysis

Carl Zeiss (Sigma HD) was used, and pre-coating with Quorum 150T (Pt coating_120sec) was performed under an acceleration voltage of 3 kV.

6. Gel fraction measurement

Gel fraction measurement was calculated by impregnating a 0.1 g film piece in 20 ml of DMF for 24 hours, removing the solvent, drying the film, and comparing the weight before and after measurement. The formula used for calculation is as follows.

(One)

Wa is the weight of the dried film after measurement, and Wb is the weight of the dry film before measurement.

<Experimental materials>

Isosorbide (ISB, Alfa asear), hexylenediisocyanate (1,6-hexylenediis℃yanate, 1,6-HDI, Sigma-Aldrich), Zinc diethyldithiocarbamate, ZnDTC, Sigma-Aldrich), 4,4'-Methylenebis(cyclohexyl is℃yanate), HMDI, Sigma-Aldrich), Tetramethylxylylene diisocyanate yanate, TMXDI, Sigma-Aldrich), Isophorone diisocyanate (IPDI, Sigma-Aldrich), Dimethylformaldehyde (DMF > 99.9%, Samchun Pure Pharmaceutical Industry) and hexanol (98%, Samchun) pure medicine industry) was prepared and used. All other reagents and solvents were used as received from standard suppliers.

<Example 1> Preparation of crosslinked ISB-based urethane polymer according to catalyst amount

A urethane prepolymer was prepared as shown in Scheme 1 below, and then a crosslinked ISB-based urethane polymer was prepared as shown in Scheme 2.

[Scheme 1]

[Scheme 2]

To make the prepolymer first, the conversion rate for controlling the amount of catalyst was checked. The NCO ratio was arbitrarily set to 3, and the reaction time was terminated based on the point at which all OH groups of ISB, the starting material, disappeared.

First, ISB (1 eq), 1,6-hexylene diisocyanate (3 eq), ZnDTC, and DMF (4 wt%) were placed in a 50 ml vial with a magnetic stirring bar and stirred at 80 degrees. The reaction time was based on the time at which the -OH peak of ISB, the starting material, disappears by collecting the mixture in the vial every hour. The reaction rate according to the amount of catalyst was performed according to Table 1, and then the solvent was added to a concentration of 3 w/v%, and PETMP (1 eq) as a cross-linking agent was added and reacted at 80°C for 3 hours (Scheme 1) reference). The stirred mixed solution is cast in 35 ml each into an 8 x 3 x 2 cm Teflon mold and dried at 50°C for 48 h and 80°C for 24 h. The dried film was separated and dried in a vacuum oven at 150°C for 24 h to obtain an ISB-N film (see Scheme 2). The synthesized film was analyzed through ATR analysis to confirm whether the peaks of the functional groups of the starting material disappeared, and whether the NH peak of urethane and thiourethane was generated at 3400 cm ^-1 , which is shown in Figure 1. there is.

Table 1 below presents conditions for producing a cross-linked polymer network using HDI (hexylene diisocyanate) according to catalyst capacity.

R = [NCO]/[OH] Isosorbide 1,6-HDI ZnDTC Solvent
(4w/v%) R1 time PETMP Solvent
(3w/v%) Example 1-1 3 700.0mg
(4.8 mmol) 2417.0mg
(14.4 mmol) 31.2mg
(0.6 wt%) DMF
(136.4ml) 5h 2341.0mg
(4.8 mmol) DMF
(+45.5ml) Example 1-2 3 700.0mg
(4.8 mmol) 2417.0mg
(14.4 mmol) 62.3 mg
(1.1 wt%) DMF
(136.4ml) 5h 2341.0mg
(4.8 mmol) DMF
(+45.5ml) Example 1-3 3 700.0mg
(4.8 mmol) 2417.0 mg
(14.4 mmol) 109.2mg
(2.0 wt%) DMF
(136.4ml) 5h 2341.0mg
(4.8 mmol) DMF
(+45.5ml) Example 1-4 3 350.0mg
(2.4 mmol) 1208.0mg
(7.2 mmol) 109.2 mg
(4.0 wt%) DMF
(68.2ml) 3h 1170.0mg
(2.4 mmol) DMF
(+22.7 ml)

In this specification, wt% of catalyst refers to the weight percent of the catalyst relative to the total weight of isosorbide, diisocyanate, PETMP, and catalyst.

<Experimental Example 1> Analysis of crosslinked urethane polymer according to Example 1

Analysis was performed on the crosslinked urethane polymer prepared in Example 1.

TGA and DSC measurements were performed to confirm the thermal properties of the synthesized ISB-based network polymer, which are presented in Figure 2. For catalyst amount conditions of 2 wt% or less, there was no difference in reaction time with respect to Scheme 1, and under 4 wt% conditions, the reaction time could be reduced to 3 hours, but there was a tendency for Tg to decrease.

Table 2 below presents the results of thermal analysis of the crosslinked urethane polymer according to Example 1, that is, Tg, gel fraction, etc.

ZnDTC gel fraction T _g T _i T _d5% Example
1-1 31.2mg
(0.6 wt%) 96% 56℃ 198℃ 285℃ Example
1-2 62.3 mg
(1.1 wt%) 96% 57℃ 217℃ 285℃ Example
1-3 109.2 mg
(2.0 wt%) 98% 57℃ 222℃ 278℃ Example
1-4 109.2 mg
(4.0 wt%) 96% 54℃ 224℃ 268℃

Therefore, the network film containing 2 wt% (Example 1-3) was judged to be superior in terms of gel fraction and thermal properties, and the catalyst content was fixed at 2 wt% in subsequent examples, and Example 1- A photograph of the ISB-N (HDI) film of 3 is shown in Figure 3.

<Example 2> Preparation of crosslinked ISB-based urethane polymer according to [NCO]/[OH] molar ratio

To compare the thermal properties according to the ISB ratio within the ISB-based network polymer (ISB-N), synthesis was performed according to the ratio R = [NCO]/[OH], and this synthesis was similar to the synthesis process carried out in Example 1. Proceeded in the same way. Table 3 below presents conditions for preparing cross-linked polymer networks according to R values.

R = [NCO]/[OH] Isosorbide 1,6-HDI ZnDTC Solvent
(4w/v%) R1 time PETMP Solvent
(3w/v%) Example
2-1 4 100mg
(0.7 mmol) 460mg
(2.7 mmol) 21.2 mg
(2wt%) DMF
(26.5ml) 5h 502mg
(1.1 mmol) DMF
(+8.9 ml) Example
2-2 3 350mg
(2.4 mmol) 1209mg
(7.21 mmol) 54.6mg
(2wt%) DMF
(68.2ml) 5h 1170mg
(2.4 mmol) DMF
(+22.7 ml) Example
2-3 1.5 300mg
(2.1 mmol) 518mg
(3.1 mmol) 21.4mg
(2wt%) DMF
(26.7ml) 5h 251mg
(0.5 mmol) DMF
(+8.9 ml)

<Experimental Example 2> Analysis of crosslinked urethane polymer according to Example 2

The ISB content ratio according to each R value is 10%, 12%, and 28%. The increase in thermal properties as the ISB content increases was measured through DSC and TGA, and the results are presented in Figure 4 and Table 4. there is. That is, Table 4 presents the results of thermal analysis of the crosslinked urethane polymer according to Example 2. As the content of ISB increases, the thermal properties increase, but the film tends to become brittle, brittle, and opaque.

In this specification, an additional experiment, Example 3, was conducted by adopting the R=3 condition, which is relatively excellent in terms of physical properties.

R = [NCO]/[OH] gel fraction T _g T _i T _d5% Example
2-1 4 96% 42℃ 196℃ 277℃ Example
2-2 3 98% 51℃ 220℃ 273℃ Example
2-3 1.5 95% 62℃ 173℃ 281℃

<Example 3> Preparation of crosslinked ISB-based urethane polymer according to various diisocyanates

ISB-based networks can be synthesized by introducing various diisocyanates based on the previously optimized ISB-N synthesis conditions (see Schemes 3 and 4).

[Scheme 3]

[Scheme 4]

The ISB-N includes, in addition to hexamethylene diisocyanate (HDI), 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI), tetramethylxylene diisocyanate (TMXDI), and isophorone diisocyanate (IPDI). . The synthesis was performed by fixing the value of R = [NCO]/[OH] at 3, the reaction time of Scheme 1 for each diisocyanate was investigated, and the synthesis was performed in the same manner as the experimental procedure in Table 1. The reaction conditions for this, that is, the conditions for preparing the cross-linked polymer network for each diisocyanate, are presented in Table 5.

Isosorbide Isocyanate (3 eq) ZnDTC Solvent
(4w/v%) R1 time PETMP Solvent
(3w/v%) Example
3-1 700mg
(4.8 mmol) HDI
(14.4 mmol) 109.2mg
(2.0 wt%) DMF
(136.4ml) 5h 2341.0mg
(4.8 mmol) DMF
(+45.5ml) Example
3-2 600mg
(4.1 mmol) HMDI
(12.3 mmol) 116.8 mg
(2.0 wt%) DMF
(145.9ml) 7h 2006.3mg
(4.1 mmol) DMF
(+48.6 ml) Example
3-3 600mg
(4.1 mmol) TMXDI
(12.3 mmol) 112.3mg
(2.0 wt%) DMF
(140.4ml) 7h 2006.3mg
(4.1 mmol) DMF
(+46.8 ml) Example 3-4 600mg
(4.1 mmol) IPDI
(12.3 mmol) 106.9 mg
(2.0 wt%) DMF
(133.6ml) 5h 2006.3mg
(4.1 mmol) DMF
(+44.5ml)

<Experimental Example 3> Analysis of crosslinked urethane polymer according to Example 3

All thermal analyzes were performed on the final curled film after solution casting, and the values, that is, the thermal analysis results of the crosslinked urethal polymer according to Example 3, are shown in Table 6.

Isocyanate gel fraction T _g T _i T _d5% Example
3-1 HDI 98% 57℃ 222℃ 278℃ Example
3-2 HMDI 96% 112℃ 172℃ 262℃ Example
3-3 TMXDI 96% 105℃ 152℃ 250℃ Example 3-4 IPDI 96% 117℃ 167℃ 269℃

There were differences in thermal properties due to structural differences in diisocyanate, and each film was produced in a different state after solution casting. In the case of HMDI, it was impossible to control the thickness of the film due to gelation during the drying process after solution casting. Additionally, in the case of TMXDI, it was impossible to measure mechanical properties because the final curled film showed very high brittleness and was completely broken. Therefore, the mechanical properties of ISB-N network films containing HDI and IPDI were compared, and the corresponding UTM data is shown in Figure 5. The maximum stress of the ISB-N film of HDI and IPDI was 47 MPa and 49 MPa, respectively, and the strain values were 5.7% and 3.3%, showing a brittle state due to the structural effect of IPDI. This can also be explained by the difference in Young's modulus, which is 1.1 GPa for ISB-N (HDI) and 1.9 GPa for ISB-N (IPDI). Structural differences were seen in not only mechanical properties but also significant differences in thermal properties, Tg.

<Example 4> Preparation of cross-linked ISB-based recycled urethane polymer

The following experiment was performed to verify the dynamic covalent bonding ability between thiourethane of the prepared ISB-N (HDI) polymer film. After cutting the produced film into small pieces, place it in a sus 40 mm (L) This was performed to reform the film. Figure 6 shows a photograph of the reprocessed film.

In order to verify the recycling characteristics of the prepared ISB-N (HDI) polymer film, the bonds of the synthesized polymers were dissociated, cross-linked again, and the thermal and mechanical properties were compared. For this purpose, an excess amount of PETMP (1 eq, 234 mg) and DMF (16.7 ml, 3 w/v%) were added to the produced film (556 mg), stirred at 150°C for 24 h, and the bonds of the cross-linked polymer were mixed. Dissociate to obtain a cleared solution. It is assumed that the solution is in the form of an oligomer with a low cross-linking density whose terminal is -SH. Afterwards, the ISB-urethane prepolymer was added in an equivalent ratio (stoichiometry) to the previously added PETMP and re-crosslinked for 3 h at a temperature of 80°C. The re-crosslinked ISB network polymer solution was cast in a Teflon mold and dried in the same manner as in Table 1. In this way, a re-crosslinked ISB-NR (HDI) film was obtained, and the recycling process and final film are shown in Figure 7.

<Experimental Example 4> Analysis of thermal and mechanical properties of urethane polymer before and after recycling

Thermal and mechanical analyzes of the recycled film (ISB-NR) are shown in Figures 8, 9, and Table 7. Compared to the existing film ISB-N, the thermal and mechanical properties were slightly reduced, but the decomposition temperature and stress did not deviate significantly.

Thickness T _g T _i T _d5% Stress Strain Young’s modulus gel fraction Example 4-1 ~350 μm 57℃ 220℃ 273℃ 47.6 MPa 5.7% 1.1 GPa 98% Example 4-2 ~230 μm 44℃ 212℃ 267℃ 38.1 MPa 5.0% 1.5 GPa 96%

<Experimental Example 5> Observation of solvolysis effect of crosslinked ISB-based urethane polymer

The results are shown in Figure 10. Hexanol, which has a boiling point similar to DMF, was used as the alcohol solvent, and the mixed solvent was prepared in a 1:1 ratio. For a smooth solvation process, adjust the concentration of DMF:hexanol (1:1) (10 ml, 1.5 w/v%) based on 155 mg of ISB-N (HDI) polymer film. Afterwards, the vial containing the relevant reagents was heated at 150°C for 18 h, and it was confirmed that more than 99% had been dissociated. Due to the effective dissociation reaction of thiourethane, the dissolution effect of the polymer film could be observed even in alcohol solvents. This showed that cross-linked polymer films can be effectively dissociated under environmentally friendly conditions.

<Example 5> Preparation of cross-linked ISB-based fiber reinforced urethane polymer

Based on the previously confirmed reprocessing and recycling performance of ISB-N, a carbon fiber composite material ISB-N sheet (CF-ISB-N) containing ISB-N as a matrix resin was produced. The weight of the polymer matrix resin contained in the manufactured CF-ISB-N sheet is 922 mg, and an excess amount of 0.387 g of PETMP equivalent to the weight of PETMP contained in the polymer resin is dissolved in DMF (30.1 ml, 3 w/v%) to create a PETMP solution. After preparing, add CF-ISB-N and react at 150°C for 24 hours. After 24 hours, all thiourethane functional groups in the polymer resin dissociate due to the excess thiol functional groups, and the color of the solution turns yellow due to the excess thiol groups. Remove the carbon fiber sheet (CF sheet) from the dissociated polymer solution, wash it with DMF, and dry it in a vacuum oven at 150°C for 6 hours to dry all of the impregnated DMF solution. Through this process, the CF sheet was able to be recovered, and then additional ISB-PP material (30.1 ml, 3 w/v%) was synthesized and added to the solution remaining after separating the CF sheet in accordance with the thiol equivalent ratio. Afterwards, the recycling process using the method of manufacturing the carbon fiber composite material ISB-N sheet (CF-ISB-N) is shown in Figure 11.

<Experimental Example 6> Physical property analysis of cross-linked ISB-based fiber reinforced urethane polymer

Scanning electron microscopy was measured to confirm the surface area of carbon fiber (CF) separated from the carbon fiber composite material, and the photo is shown in Figure 12. Compared to the original CF before recycling, it was confirmed that the CF after recycling was also in a clean carbon fiber state. This means that effective carbon fiber peeling is possible due to the dissolving effect of thiourethane. Compared to scanning electron microscope images of carbon fibers before and after recovery, it can be observed that the surface of the CF-ISB-N composite material is impregnated with a polymer matrix between the carbon fibers. Through TGA thermal analysis of the recovered carbon fiber, a weight change similar to that of CF before recycling was observed, indicating that the polymer matrix was cleanly removed. Experimental data on weight change is shown in Figure 13.

Claims (11)

reinforcing fiber; and
It includes an isosorbide-based urethane polymer crosslinked with a thiourethane bond,
The urethane polymer contains a catalyst for dynamic crosslinking of thiourethane bonds,
Recyclable fiber-reinforced urethane polymer. The method of claim 1, wherein the crosslinked isosorbide-based urethane polymer is a urethane prepolymer containing isosorbide crosslinked by a crosslinking agent having 3 or more thiol groups.
Recyclable fiber-reinforced urethane polymer. The method of claim 1, wherein the catalyst is a ZnDTC group defined by [Formula 6], a TBD group defined by [Formula 7], a DBU defined by [Formula 8], and a DBTDL group catalyst defined by [Formula 9] A recyclable fiber-reinforced urethane polymer selected from .
[Formula 6]

(However, here R1 to R4 are each independently C1 to C10 alkyl)
[Formula 7]

(However, here R5 is H or C1 to C10 alkyl)
[Formula 8]

[Formula 9]

(However, here R6 is C1 to C20 alkyl, and R7 is C1 to C10 alkyl, but R6 has the same or greater carbon number than R7.) The method of claim 2, wherein the urethane prepolymer is obtained by reacting isosorbide and polyisocyanate.
Recyclable fiber-reinforced urethane polymer. The method of claim 4, wherein the polyisocyanate is diisocyanate,
Recyclable fiber-reinforced urethane polymer. The method of claim 2, wherein the number average molecular weight of the urethane prepolymer is 100 to 1000,
Recyclable fiber-reinforced urethane polymer. The method of claim 1, wherein the reinforcing fiber is carbon fiber, aramid fiber, or glass fiber.
Recyclable fiber-reinforced urethane polymer. A first component containing a urethane prepolymer containing isosorbide and a catalyst for dynamic crosslinking of thiourethane;
A second component containing a cross-linking agent having 3 or more thiol groups; and
Containing a third component containing reinforcing fibers,
Kit for manufacturing recyclable fiber-reinforced urethane polymer. Preparing a composition including a urethane prepolymer containing isosorbide, a crosslinking agent having 3 or more thiol groups, a catalyst for thiourethane bonding, and reinforcing fibers; and
Including the step of performing a crosslinking reaction,
Method for manufacturing recyclable fiber-reinforced urethane polymer. It is an isosorbide-based urethane polymer crosslinked with thiourethane bonds.
The urethane polymer contains a catalyst for dynamic crosslinking of thiourethane bonds,
Recyclable urethane polymer. Preparing a composition including a urethane prepolymer containing isosorbide, a crosslinking agent having 3 or more thiol groups, and a catalyst for thiourethane bonding; and
Including the step of performing a crosslinking reaction,
Method for manufacturing recyclable urethane polymer.