KR100927243B1 - Manufacturing method of organic-inorganic shape memory polyurethane nanocomposite - Google Patents

Abstract

The present invention provides a sol-gel reaction of an inorganic particle having a specific functional group with an inorganic particle whose surface is modified to have a specific functional group, and a polyurethane bonded with a silane coupling agent having an amine group at a terminal thereof, thereby reacting the amine group with a functional group. The present invention relates to a method for preparing an organic-inorganic shape memory polyurethane nanocomposite having improved shape memory and resilience with thermal and mechanical properties through an organic-inorganic hybridization process in which inorganic particles are introduced into a polyurethane chain by chemical bonding.

Shape Memory Polymer, Composites, Silica, Polyurethane, Organic-Inorganic Hybridization

Description

Preparation method of organic-inorganic shape memory polyurethane nanocomposites {Preparation method of organic-inorganic shape memory polyurethane nanocomposite}

The present invention provides a sol-gel reaction between an inorganic particle having a modified particle surface and a polyurethane bonded to a silane coupling agent having an amine group at an end thereof with an inorganic particle having a specific functional group to chemically bond the amine group to a functional group. The present invention relates to a method for preparing an organic-inorganic shape memory polyurethane nanocomposite having improved shape memory ability and resilience with thermal and mechanical properties through an organic-inorganic hybridization process in which inorganic particles are introduced.

Shape memory polymers are light, easy to process, can be restored in large deformations, and various physical properties can be expressed through chemical composition and morphology control. In particular, polyurethane is widely used as a shape memory polymer because it is easy to adjust the transition temperature in a wide range depending on the raw material composition and structural design. Such shape memory polymers are used in tapes, actuators, information storage devices, temperature sensors, and medical, aircraft, automotive, and electronic industries.

However, since the shape memory polymer is an organic material, its use range is limited because of its low thermal stability and mechanical properties and low resilience as compared with shape memory alloys and ceramics. Therefore, attempts have been made to secure these shortcomings by organic-inorganic hybridization with inorganic materials such as nanoclays, glass fibers and silica particles.

In the case of forming a composite with a polymer using silica particles and clay, mechanical properties and thermal stability such as breaking strength and hardness are increased in both cases. The improvement of thermal stability was noticeable when the composite was formed using clay, because the plate-shaped clay can more effectively block heat transfer. In addition, not only physical dispersion but also clays modified to have ionic groups were attempted to disperse through ionic bonds with ionic groups in the polymer chain. This improved the reinforcement effect compared to the simple physical dispersion, but could not obtain the effect of improving the shape memory. Specifically, the addition of a small amount (less than 5% by weight) of the inorganic material was maintained as it is without the effect of improving or lowering, and when more inorganic materials were added, the results were rather reduced.

That is, in the case of the organic-inorganic composite formed by the above method, the thermal and mechanical properties were improved, but the shape memory capacity was maintained or decreased.

The present invention is to prepare a polyurethane in which inorganic material is introduced into the chain by chemical bonding by reacting the functional group and the polymer chain on the inorganic surface by sol-gel reaction to the polyurethane, as well as improving the thermal stability and mechanical properties as well as excellent shape memory and resilience An organic-inorganic shape memory polyurethane nanocomposite having

The present invention comprises the steps of preparing a prepolymer I by reacting the polyol 1 weight, aliphatic diisocyanate 1 to 1.1 weight ratio and dibutyl tin dilaurate in the range of 0.01 to 0.3 weight ratio; Preparing a prepolymer II by reacting 100 parts by weight of the prepared prepolymer I and 5.00 to 6.00 parts by weight of an epoxy compound; Preparing a polyurethane resin by mixing 100 parts by weight of the prepolymer II and 6.00 to 8.00 parts by weight of a silane coupling agent having an amine group at the terminal; And 1 to 5 parts by weight of the inorganic particles having a particle size in the range of 10 to 10 ³ nm with a sol-gel reaction at 50 to 80 ° C. and a pH of 8 to 14 parts by weight based on 100 parts by weight of the polyurethane resin. The manufacturing method of the organic-inorganic shape memory polyurethane nanocomposite comprising the step of preparing a composite is characterized by.

In the present invention, the reinforcing effect is increased by introducing inorganic bonds into the chain as a chemical bond, rather than physically dispersing the polymer in the polymer, so that not only thermal and mechanical properties but also shape memory and resilience are significantly increased than physical dispersion. Since the criminal memory polymer nanocomposite having a chemical bond between organic and inorganic materials has a higher strength than the conventional shape memory polymer, its application range is not only for industrial use but also for medical applications such as various temperature sensors, self-resilient paints and coating materials, and IT component materials. It is expected to be able to widen.

The present invention is a chain extension is carried out by a silane kipling agent having an amine group at the end of the polyurethane production and at the same time the sol-gel reaction is easy when the inorganic particles are introduced, thereby forming a chemical bond of the polyurethane and inorganic particles, Composites prepared using inorganic particles as crosslinking points not only have excellent thermal stability and mechanical properties, but also improve shape fixability and shape restore ability.

Various methods of preparing a composite by mixing an inorganic material with an organic material such as a conventional polyurethane have been proposed. In particular, the inorganic surface was modified with organic materials of various lengths to attempt to evenly disperse the inorganic material by controlling the interfacial attraction with the polymer matrix. According to the present invention, the inorganic particles are directly introduced into the polyurethane resin by chemical bonding in a sol-gel reaction that induces chemical bonding, that is, the inorganic particles serve as a crosslinking agent. The sol-gel reaction can induce a reaction by easily controlling the reaction conditions compared to the reaction that induces other chemical bonds, and is effective in that the reaction occurs easily and has a strong bond compared to other methods. Since it has a raw material and a synthetic method, the silane coupling agent can be easily introduced. In particular, when using an inorganic material having a hydroxy group is a sol-gel reaction that does not need to undergo a separate reforming process is advantageous.

Looking at the organic-inorganic shape memory polyurethane nanocomposite of the present invention in more detail as follows.

First, prepolymer I is prepared by reacting a polyol in an amount of 1 to 1.1 weight ratio of aliphatic diisocyanate and 0.01 to 0.3 weight ratio of dibutyl tin dilaurate. The said reaction is made to react at 60-80 degreeC for 2 to 4 hours.

The polyol is generally used in the art, and is not particularly limited. Specifically, the polyol may be an ether or ester type having a polyol having a low molecular weight, or branched molecular weight of 1000 or less, preferably 300 to 1000. If the range exceeds 1000, it is preferable to maintain the above range because a polyol may form crystals and cause phase separation. Such polyols may specifically use polytetramethylenediol, polytetramethylene adipate glycol, polypropylenediol, polycaprolactone and the like.

The aliphatic diisocyanate is generally used in the art and is not particularly limited. Specifically, the diisocyanate is selected from 1,6-hexamethylene diisocyanate, 4,4-dicyclohexemethane diisocyanate and isophorone diisocyanate. Single compounds or mixtures of two or more may be used. In the present invention, in order to obtain a narrow glass transition section, it is more preferable to use isophorone diisocyanate having a polyol having a polyol component or a low molecular weight polyol, and having asymmetric structure of diisocyanate, which makes crystal formation difficult.

When the aliphatic diisocyanate is used in the range of 1 to 1.1 weight ratio with respect to 1 weight of polyol, when the amount is less than 1 weight ratio, the end of the isocyanate group is not formed, and when it exceeds 1.1 weight ratio, it does not satisfy the target molecular weight range. There is no problem. At this time, the target molecular weight range is 2800-3200.

The dibutyl tin dilaurate is used as a reaction catalyst, dibutyl tin dilaurate is used in the range of 0.01 to 0.3 weight ratio, 0.08 to 0.16 weight ratio with respect to 1 weight of the polyol, the reaction rate if the amount is less than 0.01 weight ratio When too slow and exceeds 0.3 weight ratio, since the reaction rate is too fast and the problem of viscosity control at the time of polymerization arises, it is preferable to maintain the said range.

Next, 100 parts by weight of the prepared prepolymer I and the hydroxyepoxide compound in the range of 5.00 to 6.00 parts by weight, preferably 5.00 to 5.25 parts by weight to prepare a prepolymer II having an epoxy terminal. The said reaction is made to react at 30-50 degreeC for 3 to 5 hours.

The epoxy hydroxide compound is generally used in the art, but is not particularly limited, and specifically, glycidol may be used.

If the amount of the epoxy hydroxide compound is less than 5.00 parts by weight, there is a problem in that the prepolymer II having an epoxy terminal is not completely produced, and thus the molecular weight cannot be sufficiently increased through chain extension in the next step. It is preferable to maintain the above range because problems may arise.

Next, a polyurethane resin is prepared by mixing 100 parts by weight of the prepolymer II and 6.00 to 8.00 parts by weight of a silane coupling agent having an amine group at the terminal, preferably 6.80 to 7.25 parts by weight. The reaction is carried out for 5 to 7 hours at 60 to 90 ℃ and under nitrogen environment to avoid contact with moisture as much as possible.

The silane coupling agent is generally used in the art, but is not particularly limited, and has a amine end group to induce a sol-gel reaction, specifically 3-aminopropyltrimethoxysilane, 3-aminopropylethoxysilane , A single compound or a mixture of two or more selected from N- (3- (trimethoxysilyl) propyl) ethylenediamine and 1- (3- (trimethoxysilyl) propyl) urea can be used.

If the amount of the silane coupling agent is less than 6.00 parts by weight, the chain length may not be sufficiently extended to decrease the molecular weight. If the amount of the silane coupling agent exceeds 8.00 parts by weight, the side reaction problem may occur due to the reaction between the silane coupling agents. Do.

Next, the organic-inorganic polyurethane nanocomposite is prepared by sol-gel reaction of the inorganic particles having a particle size in the range of 10 to 10 ³ nm with respect to 100 parts by weight of the polyurethane resin in the range of 1 to 5 parts by weight. The reaction is carried out for at least 12 hours, preferably 12 to 18 hours at 50 to 80 ℃, pH 8-14 conditions.

The inorganic particles are generally used in the art, but are not particularly limited, and the inorganic particles include silica particles having a functional group selected from hydroxy group, chloride, amine group and carbonyl group; Or nanoclay modified with a functional group selected from among hydroxy, amine and carbonyl groups. In this case, when the size of the inorganic particles is less than 10 nm, the reinforcing effect is not properly exhibited, and when the size of the inorganic particles exceeds 10 ³ nm, nano-size dispersion is difficult and the effect is poor, and when the dispersion is not properly performed, aggregation occurs. It is preferable to maintain the above range because is generated.

If the amount of the inorganic particles used is less than 1 part by weight, the reinforcing effect cannot be sufficiently obtained. If the amount of the inorganic particles is more than 5 parts by weight, evenly dispersed by the aggregation of inorganic materials, the dispersion is difficult, and thus the effect is lowered.

The inorganic particles contained above are subjected to a sol-gel reaction in a two-step reaction process of hydrolysis and condensation reaction, and introduced into the crosslinking point in the polymer chain.

In the above process, the polyurethane nanocomposite having the silica particles as the crosslinking point is formed. The polyurethane nanocomposite has an infinite molecular weight due to crosslinking, a glass transition temperature in the range of 45 to 61 ° C., a breaking strength in the range of 27 to 33 MPa, a shape fixing ability in a range of 99 to 100%, and a shape restoring ability of 96 It represents -100% of range.

Hereinafter, the present invention will be described in detail by the following examples, but the present invention is not limited by the following examples.

Example 1

A 500 mL round four-necked flask equipped with a thermometer and a stirrer was reacted with polytetramethylenediol and isophorone diisocyanate shown in the following Table 1 at 60 ° C. for 4 hours at a ratio of 1: 1.04 by weight while injecting nitrogen for 4 hours at an isocyanate terminal prepolymer. I was synthesized. At this time, dibutyl dilaurate was used in the range of 0.12 weight ratio based on polytetramethylene diol as a catalyst. Thereafter, 10 parts by weight of glycidol was added to 100 parts by weight of prepolymer I, and reacted at 40 ° C. for 4 hours to prepare an epoxy terminal prepolymer II. Next, a polyurethane resin was synthesized by chain extension by adding 7.10 parts by weight of 3-aminopropyltriethoxy silane to 100 parts by weight of the prepolymer II prepared above. Next, after dispersing 2 parts by weight of Aerosil 200 (Deggusa), which is a 12 nm size silica particle, in 100 parts by weight of the polyurethane resin prepared, sol-gel reaction was performed at 60 ° C. under a condition of pH 8 Inorganic polyurethane composites were prepared.

Example 2

In the same manner as in Example 1, an organic-inorganic polyurethane composite was prepared using 4 parts by weight of Aerosil 200 (Deggusa), which is a silica particle of 12 nm size.

Example 3

In the same manner as in Example 1, an organic-inorganic polyurethane composite was prepared using 6 parts by weight of Aerosil 200 (Deggusa), which is a silica particle of 12 nm size.

Comparative Example 1

A polyurethane resin was prepared in the same manner as in Example 1, but without performing a sol-gel reaction with silica particles.

Comparative Example 2

An organic-inorganic polyurethane composite was prepared in the same manner as in Example 1, but using a simple physical dispersion in which a pure inorganic material was added and mixed instead of a sol-gel reaction by silica particles.

The specific components used in the polyurethane resins prepared in Examples 1 to 3 and Comparative Examples 1 to 2 are summarized in Table 1 below.

Category (g) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Prepolymer II 100 100 100 100 100 3-aminopropyltriethoxy silane 7.10 7.10 7.10 - - Butylamine - - - 2.49 2.49 Silica particles 12 nm in size (Aerosil 200, manufactured by Deggusa) 2 4 6 0 2

Experimental Example

Mechanical properties and shape memory performance of the polyurethane composites prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were measured, and the results are shown in Table 2 below. At this time, UTM (Tinius Olsen 1000) was used to measure the breaking strength, and a specimen of 25 mm (length) × 5 mm (width) × 1 mm (thickness) was prepared by a film casting method.

For shape memory, a UTM (Tinius Olsen 1000) equipped with a temperature control chamber was used. Detailed measurement methods for shape fixation and restoring ability are as follows.

First, the specimen is heated to a glass transition temperature (Tl) or more and then strained to a predetermined ε _m as shown in FIG. While maintaining this deformation, the specimen is quenched to below the glass transition temperature (Tu) and then the force holding the deformation is removed. When the force is removed, a momentary contraction (ε _m -ε _u ) occurs and then maintains the deformed shape (ε _u ). When it is heated again above the glass transition temperature Tl, it contracts to ε _p .

[Equation 1]

Shape Fixed Performance (%) = ε _u / ε _m × 100

[Equation 2]

Shape resilience (%) = (ε _m -ε _u ) / ε _m × 100

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Breaking strength (MPa) 27.32 32.12 32.56 23.55 26.03 Shape Fixed Performance (%) 99.95 99.00 99.75 95.05 87.90 Shape Restoration (%) 99.70 96.00 96.85 55.00 62.20 Glass transition temperature (℃) 59.69 60.54 57.44 45.38 49.06 Rubber Modular (dyne / cm ² ) 1.75 × 10 ⁷ 2.15 × 10 ⁷ 2.6 × 10 ⁷ 5.85 × 10 ⁶ 1.08 × 10 ⁶ Stress relaxation time (s) > 3,000 > 3,000 > 3,000 2.62 12.84

As shown in Table 2, it can be seen that the breakdown strength of the organic-inorganic polyurethane nanocomposites prepared in Examples 1 to 3 according to the present invention was significantly increased compared to Comparative Examples 1 to 2. In particular, when comparing Example 1 containing silica particles with a sol-gel reaction and Comparative Example 2 by simple physical mixing, the same amount of silica particles was used, but Example 1 in which inorganic substances were introduced into the chain through chemical bonding. It was confirmed that this is more effective. This is because the crosslinking is formed by chemical bonding due to the introduction of silica particles, and the effect is further improved. As a result, the formation of crosslinking can be confirmed from the result of FT-IR of FIG. 3. It confirmed that the peak of 955 cm <^-1> disappears. In addition, in both Examples and Comparative Examples, silica particles were introduced to increase the glass transition temperature and the rubber modulus, and the modulus was maintained up to a high temperature, and the effect was more effective when introduced through chemical bonding.

In addition, as a result of the shape memory test based on the glass transition temperature near 60 ℃, the organic-inorganic polyurethane nanocomposites prepared in Examples 1 to 3 significantly increased the shape fixing performance and the restoring ability compared to Comparative Examples 1 to 2. In particular, in the case of Example 1, it is noteworthy that the shape fixing ability and the restoring ability are close to 100%. This can be confirmed through the stress relaxation experiment that the large difference in stress relaxation time. Compared with the stress relaxation time of several tens of seconds in Comparative Examples 1-2, the stress relaxation time of 3000 seconds or more was shown in Examples 1-3.

Figure 1 shows briefly a method of manufacturing the shape memory organic-inorganic polyurethane nanocomposite of Example 1 according to the present invention.

Figure 2 shows the shape memory test schematic diagram of the polyurethane nanocomposite.

Figure 3 shows the FT-IR photograph of the shape memory organic-inorganic polyurethane nanocomposite of Example 1 according to the present invention.

Claims (6)

Single compound or mixture of two or more selected from aliphatic diisocyanates consisting of 1 weight of ether or ester type polyol, 1,6-hexamethylene diisocyanate, 4,4-dicyclohexemethane diisocyanate and isophorone diisocyanate 1 to 1.1 Preparing a prepolymer I by reacting in a weight ratio of 0.01 to 0.3 weight ratio of dibutyl tin dilaurate; Preparing prepolymer II by reacting 100 parts by weight of the prepared prepolymer I with 5.00 to 6.00 parts by weight of glycidol; Preparing a polyurethane resin by mixing 100 parts by weight of the prepolymer II and 6.00 to 8.00 parts by weight of a silane coupling agent having an amine group at the terminal; And 100 parts by weight of the polyurethane resin, selected from silica particles having a functional group selected from hydroxy group, chloride, amine group and carbonyl group, or nanoclay modified with a functional group selected from hydroxy group, amine group and carbonyl group, particle size of 10 to 10 Preparing an organic-inorganic polyurethane nanocomposite by sol-gel reaction at 1 to 5 parts by weight of inorganic particles having a range of ³ nm at 50 to 80 ° C. and a pH of 8 to 14; Method for producing an organic-inorganic shape memory polyurethane nanocomposite comprising a. delete delete The silane coupling agent of claim 1, wherein the silane coupling agent is 3-aminopropyltrimethoxysilane, 3-aminopropylethoxysilane, N- (3- (trimethoxysilyl) propyl) ethylenediamine and 1- (3- ( Trimethoxysilyl) propyl) urea is a single compound or a mixture of two or more selected. delete The method according to claim 1, wherein the polyurethane nanocomposite has a glass transition temperature of 30 to 50 ℃ range, breaking strength of 27 to 33 MPa range, shape fixing ability is 99 to 100% range, shape restoring ability is 96 ~ Manufacturing method, characterized in that 100% range.

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