WO2013113593A1

WO2013113593A1 - Polar functionalized oligomers, polymer compound having blended polar functionalized oligomers, method for production thereof, and use thereof

Info

Publication number: WO2013113593A1
Application number: PCT/EP2013/051216
Authority: WO
Inventors: Hartmut Krüger; Björn KUSSMAUL; Guggi Kofod; Sebastian Risse
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2012-01-31
Filing date: 2013-01-23
Publication date: 2013-08-08
Also published as: DE102012001808A8; DE102012001808A1

Abstract

The invention relates to an oligomer having a polarizing functionality, to a polymer compound comprising, as minimum components, a matrix made of an elastomer or a blend of a plurality of elastomers and corresponding oligomers as filler, and to a method for the production thereof. The polymer compound can consist solely of said two components. The invention further relates to uses of the polymer compound according to the invention.

Description

Polar-functionalized oligomers, polymer compound with blended polar-functionalized oligomers, process for their preparation and

Use The present invention relates to an oligomer which has a polarizing

Functionality is equipped as well as a polymer compound containing as minimum constituents a matrix of an elastomer or a blend of several elastomers and corresponding oligomers as a filler and a process for their preparation. The polymer compound can also consist only of these two components. Furthermore, the invention relates

Uses of the polymer compound of the invention.

Dielectric Elastomer Actuators (DEA) are electroactive polymers that can strongly deform by the application of an activation voltage. Therefore, they are often referred to as "artificial muscles". These components are in the simplest case of an elastic dielectric with the thickness d, which is located between two expandable electrodes. This technology has many practical advantages over conventional actuators: - high specific electromechanical energy

Deformation-based movement and therefore continuous, smooth-running

deflection

noiseless

High efficiency due to the direct coupling to the voltage signal - Soft materials and therefore low sensitivity

shocks

In robotics, orthopedics and other fields, there is a need for electrically controllable "artificial muscles". The development of intelligent designs, such as minimal energy reactors or stack actuators with very small layer thicknesses, is required to get the best possible performance. There is a great deal of interest in electroactive polymer actuators that can convert electrical energy into linear mechanical motion. Although actuators have been developed that have been able to achieve deflections of more than 100%, however, reliable and repeatable relative expansions of 10-20% are the current state of the art. These relative strains also require an operating voltage of several thousand volts.

Because of these high operating voltages, which are impractical and unsafe, scientists are researching materials that can operate at lower voltages. The activity of an actuator can be improved by improving its ability to store electrical energy density. This corresponds to the increase of the permittivity ε> of the active material. Many approaches have resulted in reduced mechanical properties and reduced breakdown field strengths above which the material undergoes a catastrophic electrical breakdown.

Dielectric elastomers are useful as base materials for artificial muscles and actuator applications. As possible material classes, mainly polyurethane (PU) and polydimethylsiloxane (PDMS) elastomers are discussed. Due to the large number of base structures suitable for PU and PDMS synthesis, the mechanical properties of the polymers mentioned can be well adapted to the requirements of artificial muscles and actuator elements. However, the permittivity of said polymer structures is usually limited to values of up to three. As a result, switching voltages of generally> 1 kV result for artificial muscles and actuator elements made of these materials. These high switching voltages place narrow limitations on the applicability of this technology. Therefore, various technical proposals and solutions have been made which lead to a significant increase in permittivity. Thus, by blending the said polymers with nanoparticles of high-permeability inorganic materials, such as barium titanate, lead zirconate, titanium dioxide, etc., the permittivity of the elastomers can be significantly increased, so that lower switching voltages of a few hundred volts can be achieved. However, these solutions involve significant disadvantages, which in a substantial Deterioration of processing properties, in a change in the mechanical properties of the elastomers (stiffening) and in problems of homogeneous distribution of the nanoparticles in the elastomer matrix. Nanoparticles can aggregate, agglomerate and lead to problems in the formation of homogeneous elastomer films. Wetterhin nanoparticles of said inorganic materials are usually highly reactive due to their high inner surface and can thus lead to a destructuring or damage to the elastomer matrix. Furthermore, nanoparticle / elastomer matrix adhesion is a common, not easily solved problem in the use of nanoparticles to increase the permittivity of dielectric elastomers. Another application of these elastomers is so-called "energy harvesting". The principle of "energy harvesting" is to convert mechanical energy into electrical energy through the variability of the capacity of a DEA and relies on the strain-changing capacity C of a DEA. The principle is explained here by a simple illustrated cycle. Important here is the relationship in a capacitor between charge Q and voltage U, where: Q = CU.

1. In the initial state A, the DEA is unencumbered by force and voltage, Ua = O. In this state, the DEA has an electrical capacitance of Ca, which has a relatively low value.

2. The DEA is expanded by an external force, which increases the capacity and reaches the value Cb. This condition is called 8 here.

3. The DEA is now being electrically charged by an amplifier.

Then the amplifier is again electrically disconnected. This loaded state is called C. In this state the capacitance is still Cb, the voltage is Vc and the charge is Qc. 4. Now the DEA is relieved of the force, so that it leans back to the initial strain. This condition is called D. In this case, the capacitance changes and goes from the relatively high value Cb back to the relatively low value Ca. The charge Qb is retained. Since voltage and charge are inversely proportional, the voltage increases to Vd. 5. The charges are now tapped by an external circuit and the DEA returns to the initial state A.

The charges Qc were thus brought from a low voltage Vc to a higher voltage Vd in this cycle. This electrical energy is obtained. This cycle is very simple but can be very complicated in practice,

The current disadvantages of these actuator systems are the high operating voltages of several thousand volts. For this reason, materials with high permittivity high breakdown field strength E _b and

low elastic modulus E sought to increase the maximum expansion s ₂ , and to lower the operating voltage U. Due to their functional principle, these dielectric elastomer converters can likewise be used in sensor technology and in so-called "energy harvesting". Both application fields have great potential. Especially in the sensor technology, there are many different applications that are ready for the market.

Actuators made of soft dielectric elastomers deform due to the Maxwell pressure induced by the electric field

and interacts with the mechanical properties of the material.

Here s _{2 are} the deformation in the z-direction, the electrostatic

Pressure from the electrodes, Y the elastic modulus of the material, the

Permittivity of the vacuum,

the relative permittivity of the material, E _b the breakdown field strength and the electromechanical sensitivity.

It can be seen from the above equation that in order to achieve large strains and low stresses, the relative permittivity must be increased and the modulus of elasticity must be reduced. The thickness of the electrical film can also be reduced, but is due to the technical Limited options. The currently smallest layer thickness was realized for Aktorikzwecken, is about 5 μιη.

Scientists have tried to date to modify existing elastomers by the addition of other components, such as filler particles. For this purpose, electrically non-conductive and conductive particles were used. The advantage of the ease of modification of existing elastomers has led to many different approaches in materials research.

For example, the use of electrically non-conductive particles has been proposed: As ceramic dielectric particles, TiO ₂ , BaTiO ₃ , PMN-PT (lead-magnesium niobate with lead titanate) or other materials may be used. These ceramics are known for their high permittivities, which are typically several orders of magnitude greater than the permittivity of the amorphous elastomer. The direct dispersion of the particles has led to unclear results. On the one hand, improvements and, on the other hand, improvements in the maximum actuator deflection were achieved. This is due to the relatively small increase in the permittivity of the composite and the simultaneous large increase in the modulus of elasticity due to the addition of particles. Another possibility of lowering the modulus of elasticity is the addition of plasticizers. The use of surfactants leads to an improved dispersion of the particles and prevents their agglomeration. Thus, also particles with a diameter of only 15 nm can be used. However, the poor nature of most composites meant that potential applications of these materials as actuators were not pursued. By modifying the surface of the nanoparticles with Siianen the properties of the composite actuators were significantly improved.

Electrically conductive particles were also used. In first experiments, dyes and conductive polymers were used. A later publication raised doubts about the increase in permittivity. The increase in permittivity in CuPc-PU composites (Cu phthalocyanine-polyurethane composites), for example, was the result of an incomplete chemical reaction. A work on the random Distribution of electrically conductive carbon black particles in a thermoplastic elastomer based, led to a strong increase in the permittivity but also at the same time to a greatly reduced breakdown field strength. In another work, a semiconducting polymer (poly (3-hexylthiophene)) was mixed with a chemically linking silicone. This resulted in an increase in permittivity and a reduction in the modulus of elasticity. In all cases mentioned above, in addition to the improvements achieved, the breakdown field strength was also greatly reduced. This limits very much the maximum Aktorauslenkung. A recent publication has shown that the addition of a conductive polymer to the backbone of the elastomer has very little impact on the breakdown field strength. This approach also resulted in a large increase in actuator characteristics, but also increased the dielectric losses to a small extent.

A successful attempt to increase the permittivity of dielectric elastomers while lowering the E-Moduis was achieved by the chemical coupling of push-pul! Dipoles (see DE 10 2010 046 343). This achieves an advantageous modification at the molecular level, which does not have any disadvantageous properties, such as aggregation and disadvantageous

Influencing the mechanical properties shows more. However, the direct connection of the dipole to the elastomer causes an undesirable stiffening of the elastomer matrix and thus an adverse effect on the elastomeric properties.

It is therefore an object of the present invention to provide a polymer compound which is suitable, in particular, as an electrical elastomer actuator which has an excellent polerization behavior combined with good mechanical properties.

This object is achieved with regard to an oligomer which is suitable, for example, as a filler for elastomeric materials, with the features of patent claim 1, with regard to a method for producing the oligomer having the features of patent claim 6, with regard to a method for producing a polymer compound having the features of patent claim 13 , with respect to a polymer compound having the features of claim 8, as well as with respect to the uses of the polymer compound having the features of claim 14. The respective dependent claims represent advantageous developments.

Thus, according to the invention, an oligomer is provided which is suitable as a filler for elastomeric materials. The oligomer contains the repeat units k, I, m depicted below in the molar amounts given below or consists of:

wherein R is the same or different on each occurrence and has the definition given above, R ^{1 is the} same or different at each occurrence and is selected from the group consisting of hydrogen, linear or branched alkyl radicals having 1 to 8 carbon atoms and / or linear or branched Alkoxy radicals having 1 to 8 carbon atoms, n is 1 to 12, preferably 2, 3, 4, 5, 6, 7 or 8, and

the molar proportion of repeating units k, l, m im

Oligomer k 5 to 100 mol%, preferably 50 to 90 mol%, particularly preferably 65 to 75 mol%, I 0 to 95 mo! -%, preferably 0 to 45 mol%, more preferably 5 to 20 mol%, particularly preferably 7.5 to 12.5 mol%, and m is 0 to 95 mol%, preferably 0 to 50 mol%, more preferably 5 to 30 mol%, particularly preferably 17.5 to 22.5 mol%.

With regard to the termination of this oligomer of all other advantageous embodiments of this oligomer, reference is made to the remarks made earlier on the oligomers used in the polymer compound.

In addition, the present invention provides a process for the preparation of an oligomer described above, in which an oligomeric siloxane, alkylsiloxane or alkylhydrosiloxane, based on all repeating units, at least 5 mol% of a repeating unit o

having, with a compound of the general formulas given below!

in which

p is 0 to 10, preferably 1, 2, 3, 4, 5 or 6, and R and R ^{1 have} the abovementioned meaning, is reacted.

The vinyl-functional reagent described above is bound to the oligomeric siloxane, alkylsiloxane or alkylhydrosiloxane by hydrosilylation or hydrosilanization. In the case where the siloxane, alkylsiloxane or alkyhydrosiloxane is based 100% on repeating units o, by suitably selecting the proportion of the above-mentioned compound having the vinyl functionality, the content of the resulting functionalities k and l in the oligomer of the present invention can be adjusted.

In a variant of the process according to the invention for the preparation of the oligomer according to the invention, the reaction mixture, i. the oligomeric siloxane, alkylsiloxane or alkyhydrosiloxane having the repeating unit o and the compound of the general formula

a further Si-H-reactive compound is added, ie the reaction is carried out in the presence of a compound of the general formula shown below:

where p has the meaning given above.

This compound too is reacted by means of hydrosilanization or hydrosilylation with the Si-H functionality of the repeating unit o. From the above-described vinyl-functionalized silicon compound, the repeating unit m of the oligomer of the invention. By choosing the mixing ratio between the two vinyl-functionalized compounds, the resulting ratio between the repeat units k and m and k, I and m in the oligomer of the invention can be adjusted.

The hydrosilylation or hydrosilylation preferably proceeds catalysed transition metal, for this purpose, the catalysts known in the literature, in particular based on Pt can be used.

According to the invention, a polymer compound is additionally provided, comprising or consisting of a) a matrix containing or consisting of at least one elastomer or a blend of several elastomers and also admixed b) at least one oligomeric filler having an oligomeric skeleton, to which at least one or a plurality of polarizing Functionalities R, selected from the group consisting of nitrile, imine, cyanate, isocyanate, thiocyanate, isothiocyanate, amidine, carboxylic acid, carboxylate, carboxylic acid ester, thiol acid, thiol acid ester, thionic acid, thionic acid ester, Dithiosäure, Dithosäureester-, Nitoso-, Nitro-, Sulfinyl-, Suifonyl-, Sulfonsäureester-, Carbonsäureamid-, Carbonperoxosäure-, Carbonperoxosäureester-, oxime, ether, thioether, halide, phthalide, silatran-, anhydride and / or lactone functionalities, covalently or via a spacer are attached.

In contrast to DE 10 2010 046 343, in which the polyelastomer used itself was functionalized by covalent attachment of a dipole, the present invention proposes to blend an elastomeric matrix with an oligomer having a polarizing functionality. The polarizing functionality R is selected from the groups indicated above and can be covalently attached directly to the oligomer skeleton or via a spacer. A spacer is understood as meaning a functional group which comprises at least one atom and over which the Functionality R is covalently linked to the oligomeric backbone, ie the backbone of the oligomer.

The polymer compound of the present invention combines excellent polerization performance with good properties required of the electrical elastomer actuators because the oligomeric filler simultaneously acts as a plasticizer of the elastomer matrix. The oligomeric filler can thus be referred to as a "smart filier".

With the present solution, disadvantageous effects which are caused by the direct dipole connection to the elastomer, such as stiffening, limited choice of dipoles and limited amount of dipoles which can be coupled, can be avoided. The incorporation of a specially adapted oligomer of widely varying structure and content of the polar groups significantly reduces the existing limiting factors of the preceding patent application. So z. B. the oligomer to be introduced already as a plasticizer, so that a stiffening of the elastomer matrix can be avoided.

A preferred embodiment provides that the oligomer skeleton is derived from oligomeric siloxanes, oligomeric alkylsiloxanes, oligomeric alkylhydro siloxanes, oligomeric dialkylsiloxanes, oligomeric urethane, oligomeric (meth) acrylic acids or oligomeric (meth) acrylic esters. Preferably, in this case, the chemical nature of the skeleton of the oligomer can be matched to the elastomer matrix, i. if the elastomer is based on a polydiazolysis compound, the oligomeric filler used may also be an oligomeric alkylsiloxane; The same applies to the aforementioned oligomers or elastomeric materials. However, it is also possible to use an oligomer whose backbone has a different chemical nature to the elastomer, for example, as an oligomeric filler to add an oligomeric dialkylsiloxane a polyurethane elastomer.

Particularly preferred oligomeric fillers have at least the. Repeat unit k shown below Repeat units k, 1, m, wherein preferred molar ratios of these repeat units to each other are given below:

In the formulas given above

R is the same or different on each occurrence and has the definition given above,

R ^{1 is} identical or different on each occurrence and is selected from the group consisting of hydrogen, linear or branched alkyl radicals having 1 to 8 carbon atoms and / or linear or branched alkoxy radicals having 1 to 8 carbon atoms, n 2 to 12, preferably 2, 3, 4, 5, 6, 7 or 8.

The molar fraction of repeating units k, i, m in the oligomer for k is 5 to 100 mol%, preferably 50 to 90 mol%, particularly preferably 65 to 75 mol%,

I is 0 to 95 mol%, preferably 0 to 45 mol%, more preferably 5 to 20 mol%, particularly preferably 7.5 to 12.5 mol%, and m is 0 to 95 mol%, preferably 0 to 50 mol%, more preferably 5 to 30 mol%, particularly preferably 17.5 mol% to 22.5 mol%. in particularly preferred radical R ¹ is methyl. These preferred oligomeric fillers have, of course, at the Si terminus and at the O-terminus corresponding to the oligomer-terminating groups. Preferred terminating groups at the Si terminus are, for example, selected from R ¹ (as defined above), -OR ¹ -Si (R ¹ ) ₃ and / or -OSi (R ¹ ) ₃ . Preferred terminating groups at the O-terminus may be, for example, -R ¹ , -OR ¹ and / or -Si (R ¹ ) ₃ .

The oligomers used according to the invention thus have at least the repeating unit k, but may also have further and other repeating units in addition. It is preferred that the oligomeric filler has at least 2 repeating units k and I, k and m or all three repeating units k, l and m defined above, wherein the repeating units can be linked randomly, alternately or to form a block copolymer.

In the event that the oligomers according to the invention have only 2 of the 3 repeat units depicted above, these are preferably contained in oligomers in the ranges indicated below. I = 0: k of 5-100 mol%, preferably 50-90 mol%, particularly preferably 65-

75 mol%

m of 0-95 mol%, preferably 10-50 mol%, particularly preferably 25- 35 mol% m = 0 k of 5-100 mol%, preferably 50-90 mol%, particularly preferably 65-

75 mol%

I from 0-95 mol%, preferably 10-50 mol%, particularly preferably 25- 35 mol%

The repeating entity k present according to the invention in this case contains the polarizing functionality R, which imparts the properties of an electrical dipole to the oligomer.

The possibly further present functionality m includes a silyl functionality which makes the oligomer of the invention more compatible, ie miscible with the E! Astomer matrix, especially in the case where the elastomer matrix itself is a poly (alkyl) stloxane, such as PDMS

In particular, the oligomeric filler consists of repeating units k and 1, k and m or k, I and m (wherein the oligomeric fillers in addition to

Of course, the repeating units also have the terminating functionalities, as defined, for example, above at the respective end of the oligomer).

An especially usable oligomeric filler has or consists of the repeating units k, I, m shown below.

Here is

R is the same or different at each occurrence and is selected from the group consisting of nitrile, cyanate, isocyanate, thiocyanate, isothiocyanate, nitro, and / or sulfonic acid ester functionalities, where R ¹ , n or the molar proportions of repeating units k, I and m in the oligomer as defined above.

The oligomeric filler preferably has a number-average molecular weight M _{n of} from 500 to 100,000 g / mol, preferably from 1,000 to 20,000 g / mol, in particular from 2,000 to 10,000 g / mol. The content of the oligomeric filler is preferably, based on the matrix, from 1 to 75% by weight, preferably from 2 to 50% by weight, in particular from 3 to 30% by weight.

Suitable elastomers of the elastomer compound are, in particular, uncrosslinked or crosslinked elastomers. Particularly preferred

these elastomers selected from the group consisting of polysiloxanes, polyalkylsiloxanes, polyalkylhydrosiloxanes, polyalkyl siloxanes, polyurethanes, rubbers, natural rubbers, nitrile rubbers, chloroprene rubbers, fluoroalcohols, poly (meth) acrylic acids, poly (meth) acrylates and mixtures or blends thereof. Particular preference is given here to polydimethylsiloxanes (PDMS).

In a further advantageous embodiment, the matrix may contain further additives, preferably nanoscale additives, in particular nanoscale additives selected from the group consisting of ferroelectric ceramics, metal oxides, metal mixed oxides and combinations or mixtures thereof, in particular titanium dioxide, barium titanate and / or lead zirconium titanate. The use of ferroelectric materials can further increase the polerability of the entire polymer compound.

The invention likewise provides a process for preparing a polymer compound according to the invention in which at least one oligomer according to the invention is admixed with an elastomer or a blend of a plurality of elastomers or b) is mixed with at least one elastomer precursor and subsequently at least one elastomer precursor is converted to the elastomer.

Further possible additives, like the oligomer, can be introduced into the polymer compound, ie already finished polymerized elastomers or be added before preparation of the elastomer to the reaction mixture containing the elastomer precursors, whereupon the elastomers are polymerized or cured only in a subsequent step.

In accordance with the invention, uses of the polymer compound are also indicated, preferred uses being elastic dielectrics, dielectric actuators, artificial muscles, dielectrics for flexible electronic components, in particular capacitors, e.g. soft capacitors, for energy harvesting, for strain, pressure and bending sensors, for haptic interfaces, for integrated pumps in microfluidics, for medical and diagnostic applications, for active optics and / or as or for motors, in particular soft motors. The present invention will be further described with reference to the following embodiments, without limiting the invention to the illustrated and described parameters.

According to the invention, the objective of high-performance elastomers on PU, natural rubber, nitrile rubber, chloroprene rubber, fluororubber, acrylates and PDMS base can be achieved by a blend with "smart filler" components. Suitable "smart filing" components are oligomers which, on the one hand, carry organic dipoles to achieve a high permittivity and furthermore carry those chemical groups which have a high compatibility with the elastomer matrix. This achieves a homogeneous distribution of the "smart fil! Er" component in the elastomer matrix. In this case, at least one dipole and at least one compatibility-promoting group can be installed side by side in the "smart filier". In addition to a high permittivity, a reduction of the modulus of elasticity is simultaneously achieved by the soft-maker effect of the "smart filler".

For covalent incorporation into the "smart filier", the simple dipoles described above can be functionalized, for example, with vinyl or allyl groups (for example for attachment to oligomeric siloxanes) or with hydroxyl or amino groups (for example for attachment to oligomeric urethanes). At the same time, the "smart filier" can be equipped with additional groups which ensure high compatibility with the respective elastomer matrix. This can be in the case of a PDMS matrix z. B. trialkylsilyl groups.

The content "smart filier" in the respective elastomer matrix can be varied between 1 and 75 Ma%.

The following examples describe the preparation of high-permeability elastomer films:

Example of Use 1: Synthesis of the "Smart Filler" 1

3.4 g of the poly-methylhydrosiloxane HMS-993 (Geiest, M = 2100-2400, J = 36.92, 55.79 mmol reactive SiH), and 2.6 mL allyltrimethylsilane (16.36 mmol) and 4.0 mL (49.49 mmol) allyl cyanide were dissolved in 100 mL toluene , 0.1 mL of a platinum catalyst solution (2.1-2.4 wt% in Xylol) was added and the mixture was heated at 90 ° C. for 22 h with stirring in an argon atmosphere. During the reaction, an insoluble product formed, which was filtered off after the reaction. Subsequently, the solvent, as well as unreacted Ailylcyanid and allyltrimethylsilane from the filtrate mitteis rotary evaporator were removed. The residue was dried in vacuo overnight.

7.41 g of a yellowish oil are obtained as product. In the ¹ H-NMR spectrum, the molar ratio k: l: m = 0.7: 0.1: 0.2 was found. The product can thus be represented by the following formula, wherein the repeating units k, I, m are statistically distributed.

Application Example 2: Synthesis of the "smart filler" 2

2 g of the poly-methylhydrosiloxane HMS-993 (32.73 mmol reactive SiH), and 1.5 mL allyltrimethylsilane (9.51 mmol) and 3.0 mL (28.55 mmol}

Allylmethylsulfone was dissolved in 100 mL of toluene. 0.1 mL of a platinum catalyst solution (2.1-2.4 wt% in xylene) was added and the mixture was heated at 90 ° C for 22 hours with stirring in an argon atmosphere. Afterwards, the batch was filtered and the solvent and unreacted starting materials were removed from the filtrate by means of a rotary evaporator. The residue was over

Dried overnight in vacuo.

Comparative Example 1: Unmodified Matrix The unmodified matrix is a two-component system. The

Base material consists of a vinyl-terminated PDMS, which has a molecular weight of M = 62700 g-mol ^-1 . In component A, the matrix is introduced together with the catalyst and in component B the partially hydride-functionalized crosslinker, which connects via a hydrosilation reaction with the network. As a solvent

Chloroform used. The components A and B are mixed in the ratio 4: 0.5 ml and crosslink after evaporation at room temperature.

Anwendungsbeispiei 3: General rule for film production with "smart filier":

For integration into the polymer network, the "smart filier" is dissolved in chloroform; the resulting solution is referred to below as component C. For high-permeability films, solutions A and B from comparative example with component C in the volume ratio A: B: C = 4: 0.5: X (X.

= 0-8) mixed together. After evaporation of the solvent, the network is filmed for 30 minutes at a temperature of 120 ° C. The overview of mechanical and dielectric properties:

The addition of the oligomers according to the invention (% by weight) to the elastomer blend significantly improves its actuator characteristics. The permittivity is significantly increased with increasing content of oligomers and can be almost doubled by the addition of 13.8 wt% of the oligomer of the invention from 2.93 to 5.40. At the same time, as the content of the oligomer according to the invention increases, the Young's modulus of the elastomer blend decreases in parallel to 25% of its initial value. Both effects thus act synergistically on the highest possible actuator sensitivity, which can be increased by the factor 6 by adding 13.8 wt% of the filler, so that the switching voltage can be correspondingly reduced for the same actuator performance.

FIG. 1 shows a model of a polymer compound according to the invention, which shows an oligomer according to the invention carrying dipolar groups marked with +/- in an elastomer-compounded form. In this case, the elastomer matrix is formed of PDMS.

Claims

PATENT CLAIMS 1. Oligomer comprising repeating units k, I,

contains or consists of, where

R is the same or different at each occurrence and is selected from the group consisting of nitrile, imine, cyanate, isocyanate, thiocyanate, isothiocyanate, amidine, carboxylic acid, carboxylate, carboxylic acid, thiol, thiol , Thionic, thionic, dithioic, dithoic, nito, nitro, sulfinyl, sulfone, sulfonic acid,

Carboxylic acid amide, carboxylic peroxyacid, carboxylic peroxyacid ester, oxime, ether, thioether, halide, phthalide, sifatran, anhydride or lactone functionalities,

R ^{1 is the} same or different at each occurrence and is selected from the group consisting of hydrogen, linear or branched alkyl radicals having 1 to 8 carbon atoms or linear or branched alkoxy radicals having 1 to 8 carbon atoms,

n 1 to 12, and

the molar fraction of repeating units k, I, m in the oligomer k is 5 to 100 mol%,

I 0 to 95 mol%, and m is 0 to 95 mol%,

having a number average molecular weight M _n of 500 to 100,000 g / mol,

2. Oligomer according to claim 1, characterized in that n is 2, 3, 4, 5, 6, 7 or 8.

3. Oligomer according to one of the preceding claims, characterized in that it has at least 2 repeating units k and I, k and m or k, I and m, wherein the repeating units are linked randomly, alternately or to a Biockcopolymer.

4. Oligomer according to one of the preceding claims, characterized in that it repeats the units k, I, m

contains or consists of, where

R is the same or different at each occurrence and is selected from the group consisting of nitrile, cyanate, isocyanate, thiocyanate, isothiocyanate, nitro or sulfonic acid ester functionalities.

5. Oligomer according to one of the preceding claims, characterized by a number average molecular weight M _n of from 1,000 to 20,000 g / mol.

6. A process for the preparation of an oligomer according to the preceding claim, wherein an oligomeric siloxane, alkylsiloxane or

Aikylhydrosiloxan, based on all repeating units at least 5 mol% of a repeat unit o

comprising, with a compound of the general formula given below

in which

p is 0 to 10, preferably 1, 2, 3, 4, 5 or 6, and

R and R ^{1 have} the meaning given in claim 1, is reacted.

7. The method according to the preceding claim, characterized in that the reaction in the presence of a compound of the general formula shown below) ₃

where p has the meaning given above, is performed.

8. Polymer compound containing or consisting of a) a matrix containing or consisting of at least one elastomer or a blend of several elastomers, as well as dazzled

b) at least one oligomer according to any one of claims 1 to 5.

9. Polymer compound according to the preceding claim, characterized in that the content of the oligomeric filler, based on the matrix, of 1 to 75 wt .-% is.

10. A polymer compound according to any one of claims 8 to 9, characterized in that the at least one elastomer is an uncrosslinked or crosslinked elastomer.

11. A polymer compound according to the preceding claim, characterized in that the at least one elastomer is selected from the group consisting of polysiloxanes, polyalkylsiloxanes, polyalkyl hydrosiloxanes, polydialkylsiloxanes, polyurethanes, rubbers, natural rubbers, nitrile rubbers, chloroprene rubbers, fluororubbers, poly (meth) acrylic acids, poly (meth) acrylates and mixtures or blends thereof.

12. Polymer compound according to one of claims 8 to 11, characterized in that the matrix contains further additives.

13. A process for preparing a polymer compound according to any one of claims 8 to 12, characterized in that at least one oligomer according to any one of claims 1 to 5

a) an elastomer or a blend of several elastomers is dazzled or

b) is mixed with at least one elastomer precursor and, subsequently, the at least one elastomer precursor is converted to the elastomer.

14. Use of a polymer compound according to any one of claims 8 to 12 as a dielectric, as an elastic dielectric in the actuator system, as an elastic dielectric for soft actuators, for the construction of Aktuato for artificial muscles, as a dielectric for flexible electronic components, as a dielectric for flexible capacitors, as a dielectric for soft capacitors, for energy harvesting, for strain, pressure and bending sensors, for haptic interfaces, for integrated pumps in microfluidics, for medical and diagnostic

Applications, for active optics, as or for motors, as or for soft motors.