Light-sensitive cross-linked polymeric structure (variations), method for preparation thereof, photoreactive component, their use, and a method for programming such a structure

FIELD: polymer materials.

SUBSTANCE: invention concerns amorphous light-sensitive cross-linked polymeric structure and provides structure including (i) amorphous cross-linked structure formed from matrix based on acrylate and/or methacrylate compound and cross-linking agent and (ii) photoreactive component capable of undergoing reversible photodimerization reaction. Cross-linked structures are characterized by good properties with shape-memory effect.

EFFECT: increased mechanical strength of material with desired property profile.

21 cl, 4 dwg, 2 tbl, 12 ex

 

This invention relates to a photosensitive polymer cross-linked structures, the light-sensitive components, are needed to obtain a photosensitive polymer cross-linked structures, and method of programming.

Polymeric reticulated structure are an important element in many fields of use, in which classic mesh structure, such as metals, ceramics and wood, due to their limited physical properties are no longer satisfactory. Polymeric reticulated structure has gained a broad scope, not least due to the fact that by varying the monomer of the polymer network elements you can change the properties of a mesh structure.

A particularly interesting class of polymeric mesh structures that have developed in recent times is the so-called polymers with shape memory effect (hereinafter also referred to as Shape Memory Polymere (polymers with memorizing forms), SMP or SMP materials), that is, a polymeric reticulated structure, which in addition to their actual, obvious forms can save one or even several forms of "memory", and these forms purposefully occur only under the influence of external factors, such as temperature changes. Through targeted change in the shape of these materials are great and the teres in many areas, in which, for example, preferably the resizing. This applies, for example, to medical implants, which at the point of use as possible should reach their full size, so that the introduction of these implants requires only a minimally invasive surgical intervention. Such materials are described, for example, in international patent applications WO-A-99-42528 and WO-A-99-42147.

Most are described in the literature polymers with shape memory effect are thermally driven. However, in some examples of the application of the temperature change is undesirable, so that other motivating factors, such as light, seem to be more suitable. For example, the introduction of a biologically compatible SMP in living organisms allow the temperature rise only a few degrees Celsius above the temperature of the body. High temperature harm the surrounding tissues. In most cases, the material is already exposed to natural temperature fluctuations. If the transition temperature of the SMP exceeds the norm, the shape memory effect can have undesirable effects.

A prerequisite for the solution of this problem is the use of photosensitive SMP. Known from the literature examples of light-sensitive polymers in most cases relate gels, which are under the influence of light is and change their degree of swelling (O. Pieroni, F. Ciardelli, Trends Polym. Sci. 3, 282 (1995); Y. Osada, J.-P. Gong, Adv. Mater. 10, 827 (1998); A. Suzuki, T. Tanaka, Nature 346, 345 (1990)). So, for example, can be carried out by the Sol/gel transition photosensitive gel by exposure to light (F.M. Andreopoulos, C.R. Deible, M.T. Stauffer, S.G. Weber, W.R. Wagner, E.J. Beckmann, A.J. Russel, J.Am. Chem. Soc. 118, 6235 (1996)). Another example is the permeability of the membrane of the light-sensitive hydrogel, adjustable by means of light (F.M. Andreopoulos, E.J. Beckmann, A.J. Russel, Biomaterials 19, 1343 (1998)).

This process is extremely three-dimensional, isotropic reversible volume change, which is not suitable to implement a certain shape change. In addition, gels, due to their low mechanical stability, and so is not suitable for many applications.

SMP described in applications WO-A-99-42528 and WO-A-99-42147, consist of segments. Their partially-crystalline morphology causes scattering of light on the surface and prevents photochemical reactions within the material. Due to these characteristics, such materials may not be stimulated by the action of light.

Therefore, the objective of this invention is to provide a polymeric reticulated structure, which does not have the disadvantages of the prior art, i.e. in particular not changed by a factor that is associated with temperature. In contrast to hydrogels material must be high the th mechanical strength. In addition, polymeric reticulated structure should provide the possibility of controlling the properties by simply changing the composition, so that may be obtained from the target material with the desired profile of properties.

This invention solves the problem by means of photosensitive polymeric reticulated structure, paragraph 1 of the claims. A preferred form of execution, shown in dependent clauses. First of all, these photosensitive polymeric reticulated structure are not the hydrogels.

In addition, this invention relates to light-sensitive components, suitable for the production of amorphous polymer cross-linked structures, for example, according to the given method.

In conclusion, this invention relates to a method of programming a photosensitive SMP. A preferred form of execution is also given in dependent clauses.

Other aspects of the invention defined in the claims and in the following description.

Figure 1 illustrates the principle of operation of the light-sensitive retinal patterns at the macroscopic and molecular level.

Figure 2 explains the photochemical reaction of cinnamic acid and cinemiracle.

The figure 3 shows the mechanical characteristics of the photosensitive mesh structures in cyclically the photomechanical tests.

The figure 4 shows the dependence of the properties of the shape memory effect on the content photoreactivation components.

Hereinafter the invention is described in detail.

The photosensitive polymer reticulate structure in the context of the invention includes a covalently crosslinked network polymer (amorphous lattice structure)with photoreactivation groups covalently associated with amorphous mesh structure or physically mixed with it), which give the material induced by the light properties of the shape memory effect. The polymer backbone does not absorb wavelengths required for photochemical reactions. In addition, a mesh structure is mainly amorphous, homogeneous and transparent.

The figure 1 shows the principle of operation of the light-sensitive retinal patterns at the macroscopic and molecular level. Along the "main chain" mesh patterns are substituents having at the ends of the groups capable of photochemical reactions. Under UV irradiation, these groups can form with each other covalent bonds. If the material is deformed and irradiated with light of suitable wavelength λ1the original mesh structure is additionally sewn (cross-bridges). Owing to cross-linking is achieved by a temporary fixing material in a deformable status is anii (programming). Because photochemical crosslinking is reversible, is made possible by renewed exposure to light with a different wavelength λ2again, to eliminate stitching and thereby re-call the original shape of the material (recovery). This photomechanical cycle can be repeated arbitrarily often.

Thus, the photosensitive polymeric reticulated structure according to the invention are characterized by the desired properties, i.e. for task the lattice structure must be largely transparent to radiation, referred to reshape. Usually this radiation is in the UV region, thus in particular possible to avoid actuation mechanism changes the shape of the visible light which is in all areas of life, it is difficult to completely eliminate. In addition, the proportion of UV radiation contained in most light sources are insufficient to cause a change of form in the material according to the invention. Thus, the preferred material of the present invention, transparent to UV radiation, particularly in the region from 200 to 400 nm, particularly preferably in the range from 250 to 350 nm.

The components of net structures

Matrix

The basis of a mesh structure is formed by using a matrix, which, as described above, transparent etc the respect to radiation, referred to invoke changes in the shape, that is, preferably the matrix is transparent to UV rays. Next, this matrix must be some degree of elasticity and flexibility (elastic properties). In addition, it is required that the matrix was amorphous. Finally, it is important that the matrix is crosslinked to provide a degree of mechanical strength, as well as the desired properties of the shape memory effect according to the invention. Fundamentally, in this sense, can be used according to the invention all polymerizable compounds, which give such a matrix, preferably these compounds should polymerization in mass.

According to the invention for the base mesh structure of this invention is the preferred matrix based on low molecular weight acrylates and methacrylates that can radically polymerization, in particular C1-C6-(meth)acrylates and hydroxy, with the preferred hydroxyethylacrylate, hydroxypropylmethacrylate, hydroxypropylamino, poly(ethylene glycol)methacrylate and n-butyl acrylate; preferably using n-butyl acrylate and hydroxyethylmethacrylate.

N-butyl acrylate, which is preferred as a component of the matrix, has the advantage, according to which its homopolymer is characterized by low temperatureincrease -55° With, so thanks to this component mesh structure with elastic properties. Comonomer, preferably hydroxyethylmethacrylate, is, if necessary, to regulate thermal and mechanical properties. Both of these compounds can cure any relationship, and if there is hydroxyethylmethacrylate (HEMA) (HEMA), n-butyl acrylate constitutes the major share. The preferred molar ratio of n-butyl acrylate to HEMA (HEMA), are in the range of 10:0.1 to 10:5, preferably 10:1 to 10:3 and in particular about 10:2.

2. A crosslinking agent

In addition to the material for the matrix polymer reticulate structure of the present invention contains the component that is responsible for the binding matrix. The chemical nature of this component, of course, depends on the nature of the matrix material. It also can be used in many compounds, consistent with the matrix material.

For the preferred mesh structure on the basis of the above as the preferred acrylate materials suitable cross-linking means is a bifunctional acrylate compounds which are suitable for reaction with the raw material matrix, so that they can together be subjected to transformation. Crosslinking means of this kind include short bifunctional staplers such as these is indiscreet, low-molecular bi - or polyfunctional staplers, oligomeric, linear diacrylate staplers, such as poly(oksietilenom)diacrylate or poly(oxypropylene)diacrylate, and branched oligomers or polymers with acrylate groups.

As cross-linking means preferably use dimethacrylate, especially poly(propylene glycol)dimethacrylate with a molecular weight of from 300 to 1000 g/mol, preferably about 560 g/mol. A crosslinking agent is used in relatively low concentrations of approximately 0.3 to 3 mol.% in the calculation of the total number of materials that must be depolimerization with the formation of a mesh structure to form a flexible mesh structure. A large proportion of cross-linking means leads to less elastic, up to the fragile materials.

According to the invention, cross-linking agent is introduced into the mesh structure by simply mixing a binder with the source material for the matrix and subsequent polymerization, preferably in mass, with suitable initiators.

2. Photorealistically component

As other components of the net structure according to the invention includes photorealistically component (group), which are responsible for the initiation of directional controlled change form. This photoreactions the vulnerable group is the link, which is due to the excitation of a suitable light radiation, preferably UV radiation, capable of reversible reactions (with one of the two photoreactivation groups), which leads to the formation or destruction of covalent bonds. Preferred photoreactivation groups are those that are capable of reversible photodimerization.

Photorealistically component with suitable functionality may or radically copolymerizate directly with these monomers, or to form vzaimopronikayut part interpenetration mesh structure (interpenetrierenden Netzwerks) IPN.

Suitable photoreactivation components are those components that are characterized by the above properties and, in addition, or can be further copolymerizable with a mesh (for example, with a grid containing acrylates, with the introduction of photoreactivation groups in the acrylate monomer or oligomer), or by swelling or the like can be introduced into the already formed a network structure, for example, in the form of suitable functionalized polymers or oligomers.

As photoreactivation components in the photosensitive mesh structures according to the invention is suitable preferably different esters of cinnamic is islote (cinnamate, CA (CA)) and esters cinnamylalcohol acid (cinnamicacid, CAA (CAA).

It is known that cinnamic acid and its derivatives under the influence of UV radiation of about 300 nm timeresults education CYCLOBUTANE. The dimers may again split, if they are irradiated with UV radiation with a shorter wavelength of about 240 nm. The maximum absorption can be shifted by means of substituents in the phenyl ring, but always remains in the UV region. Other derivatives which may be photodimerization are 1,3-diphenyl-2-propen-1-he (Halcon), cannabinaceae acid, 4-methylcoumarin, various ortho-substituted cinnamic acid, cinnamoylcocaine (simple silloway ester of cinnamic alcohol).

For photodimerization cinnamic acid and similar derivatives we are talking about the [2+2] ticlopidine double bond with formation of a derivative of CYCLOBUTANE. As E-and Z-isomers can join in these reactions. Upon irradiation of E/Z-isomerization competes with cyclopentadiene. In the crystalline state, however, E/Z-isomerization is difficult. Due to the different capabilities of the ordering of the isomers of each other theoretically possible 11 different stereometric products (truxillo acid, taxinomie acid). Length of double bonds required for the reaction, two groups of cinnamic acid is approximately the 4 A. In Fig. 2 clearly explained photochemical reaction of cinnamic acid and cinemiracle.

Introduction photoreactivation components in the mesh structure according to the invention is, as described above, in two different ways. On the one hand, photoreactivation groups (components) can be further copolymerizable matrix of a mesh structure, so that the mesh structure as such becomes photoreactivation. This makes known a method of obtaining, as after a single polymerization can be obtained photosensitive lattice structure. If necessary, the required subsequent stages of the reaction concern then or only cleansing stage, or the stage of introduction of other optional components. At the same time thus can simply be governed by the properties of the mesh structure according to the invention, as this determines the polymerization mixture. The second alternative is that not the mesh structure as such provide photoreactivation groups, and they are by physical methods are mixed with a matrix of a mesh structure. A typical example of this is getting the IPN of the cross-linked polymer matrix (which may be as described above) with suitable functionalized second polymer is whether the oligomer, which contains photoreactivation group and can penetrate the mesh structure. The advantage of this variant lies in the fact that obtaining a polymeric matrix of a mesh structure is not as strictly limited as sensitive photoreactivation groups that interfere with a particular method of polymerization, are not present when receiving matrix mesh structure. Thus, for example, in this case, you can polimerizuet matrix mesh structure by initiating UV rays that the first alternative is impossible, since then photoreactivation group photoreactivation component can participate in polymerization unwanted way.

For evidence of photochemical reactions (cycloaddition) can be involved in various spectroscopic methods. By means of UV spectroscopy to observe the weakening of the maximum absorption at 275 nm due to the elimination of conjugation π-electrons of the benzene ring with alkene-carbonyl group.

3.1 Additional copolymerization photoreactivation component.

The opportunity to introduce photoreactivation component in the mesh structure is joining photoreactivation groups for source material matrix of a mesh structure. For the preferred net art is occur on the basis of acrylates at the same time, for example, it becomes possible to atrificial the cinnamic acid anhydrides or cinnamylalcohol acid hydroxyethylacrylate or-methacrylates. So are photoreactivation esters, which may simply be radically copolymerizable with other monomers. Suitable hydroxyacrylates and-methacrylates for the esterification with cinnamic acid (CA) (CA) or cinnamylalcohol acid (CAC) (CAA) are: hydroxyethylmethacrylate (HEMA) (HEMA), hydroxyethylacrylate (HEA) (HEA), hydroxypropylmethacrylate (HPMA) (HPMA), hydroxypropionitrile (HPA) (HPA), poly(ethylene glycol)methacrylate (PEGMA) (PEGMA). The esterification takes place under conditions known in the art from the prior art (the Method of Schotten's-Baumann. Hydroxyethylacrylate or-methacrylate dissolved in diethyl ether and mixed first with the acid chloride cinnamic acid, and then with triethylamine).

Radical polymerization of the above components with the formation of a mesh structure is preferably in the mass adding of heat-sensitive initiator. Suitable initiators are peroxides, such as benzoyl peroxide, di-tert.-butylperoxide, and azo compounds, such as azobisisobutyronitrile (ABN) (AiBN). Preferably use ABBN in a concentration of from 0.1 to 1 wt.%.

The number photoreactivation the component is usually from 1 to 30 mol.% calculated on the total mixture of components 1 to 3, preferably from 2 to 20 mol.%, more preferably from 4 to 12 mol.%.

Additional copolymerization leads to static allocation photoreactivation component in the polymer reticulate structure, as could be shown by spectroscopic studies. This ensures that the properties of the shape memory effect, as only with a uniform distribution photoreactivation component in the entire mesh structure, you can expect a consistent, reproducible, and reliable properties of the shape memory effect.

3.2 Additional loading (physical mixture)

Another possibility to enter in the mesh structure photoreactivation group is more physical loading defunctionalizing mesh structure. Loading mesh structure is that it is subjected to swelling in solution photoreactivation component and then dried. Photorealistically component is thus distributed over the entire mesh structure. If you loaded the mesh structure is then irradiated with UV light, photoreactivation group timeresults with reversible transformation of a mesh structure in constant mesh structure. Occurs vzaimopronikayut (interpenetration) lattice structure (IPN).

Defunctionalization behold the striated structure of this form of execution preferably corresponds to the amorphous mesh structure, which was described above and includes a component matrix and a crosslinking agent. A preferred form of execution of the above in this regard, there are also preferred.

So in General could be formed reversible mesh structure, it is necessary to photoreactivation components contained at least three photoreactivation group capable of forming a grid on the molecule. For loading constant mesh structure, thus suitable in particular star-shaped, branched polymers or oligomers, or Greene or podobrannye (stabartige) grafted polymers or oligomers. Preferably use the star macromonomer with one photoreactivation group at each end of the chain ("branch"). The "branches" are preferably of links alkalophiles.

Macromonomer can come out of the star-shaped molecules with terminal OH-groups, which are subjected to esterification with one of the above photoreactivation acid chlorides of the acids. Preferably use a "beam" poly(ethylene glycol) with a molecular weight of from 400 to 1000 g/mol, preferably about 560 g/mol, which is commercially available. When this molecular weight and the number of "branches" are not decisive. However, this requires, at m is re, three "branches". The esterification takes place under conditions known from the literature.

Loading mesh structure photoreactivation component is carried out by swelling the grid in the solution photoreactivation component. For the preferred mesh structure on the basis of acrylates, loaded the preferred four-pointed star photoreactivation component, the loading is preferably from 5 to 45 wt.% in the calculation of the entire mixture, more preferably 15-35 wt.% and, in particular, 25-35 wt.%, most preferably about 30 wt.%.

Also for the preferred IPN according to the invention photoreactivation components mainly distributed homogeneously in the net structure, which, as described above, provides the properties of the shape memory effect.

Photosensitive lattice structure

Simple mesh structure

By radical copolymerization of an ester of cinnamic acid, as described above, with acrylates or methacrylates as described above, it is possible to get photoreactivation mesh structure, as, for example, should be explained a second series of cross-linked structures. In the first series one ester of cinnamic acid was copolymerization with two components (n-butyl acrylate and poly(propylene glycol)dimethacrylate), in the second series and with three components (additional hydroxyethylmethacrylate HEMA). The concentration of the ester of cinnamic acid was varied within the same range. Content photoreactivation component in the mixture was between 0,075 and of 1.27 mmol/g

The amount of gel content in the resulting mesh structure, i.e. the proportion of not extractable components, is often above 90%, in most cases, even above 95%, which corresponds to a high degree of conversion. Therefore, we may assume that the monomer mixture and the corresponding lattice structure are characterized by the same structure.

IPN

For the physical loading of the photosensitive components (macromonomers) suitable mesh structure is preferably of n-butyl acrylate and poly(propylene glycol)dimethacrylate. The mesh structure is subjected to swelling in the solution of macromonomer in THF and then dried. The degree of loading can be adjusted by the concentration of the solution. After drying, the impregnated samples can be set increase the weight by approximately 30%if the solution contained 10 wt.% macromonomer. This corresponds to the content photoreactivation groups in the network structure 0.32 mmol/g (0.32 mmol/g × 85% functionalized end groups = 0.27 mmol/g).

These photosensitive mesh structure of the present invention are characterized by the following properties.

All mesh with the touch are transparent, that speaks of a homogeneous, amorphous morphology. An exception is the lattice structure 10A-C; it is slightly muddy.

Mesh patterns are characterized by low glass transition temperature. For mesh structures of a number without HEMA it is between -46,1 and -10,9° (DSC), with HEMA - between -11,9 and 16.1°C. There is a tendency of increase of glass transition temperature with increase in the content photoreactivation component.

Above the glass transition temperature lattice structure is elastic. At room temperature the stress at break (Reiβbalancing) for most mesh structures without HEMA is 20-45%, for net structures with HEMA - up to 60%. E-modulus tends to increase with increase in photoreactivation of co monomer in the net structure by up to 4.2 MPa (mesh without HEMA) or up to 120 MPa (HEMA), that is, the elasticity decreases. Interpenetrating net structure can be stretched to more than 100%, not torn.

Through photochemical reactions change the mechanical properties of the material. UV-irradiation with λ1causes covalent crosslinking photoreactivation groups and may increase E-module by approximately 18% (example IPN). Upon irradiation with UV light with a different characteristic wavelength λ2the stitching is eliminated, and the E-module again on yaetsya.

High elasticity mesh structures before irradiation enables easy transformation of the material when programming a temporary form. In General, amorphous mesh structure of the present invention are good SMP-materials (materials with shape memory effect), with a high degree of return, i.e. the original form again receive when conducting multiple cycles of deformation with a high percentage, usually above 90%. This also has not been any negative losses in the values of mechanical properties.

Properties of shape memory effect materials of this invention are briefly defined below.

Polymers with shape memory effect in the context of the invention are materials which due to their chemical and physical structure are able to make meaningful changes form. The materials have, in addition to its original continuous form, another form, which can be temporarily acquired material. Such materials are characterized by two features. They include the so-called photoreactivation groups that can use light to move in an excited transition state. In addition, these materials contain covalently crosslinked places that are responsible for the so-called permanent form. This constant is I the form is characterized by a three-dimensional grid structure. These places are joining the network structure according to the invention are covalent in nature and in the preferred form of the present invention are formed by polymerization of acrylate or methacrylate groups. Photoreactivation group, passing under the action of light induced in the transition state (change of form), in this invention, the preferred forms of execution are cinnamate groups or cinnamaldehyde groups.

Photomechanical cycle consists of stages: the elongation of the sample, irradiation λ1(recording, programming), stress relief sample, irradiation λ2(recovery). By suitable experiments of a number of strains (Zug-Dehnungs) may be shown a shape memory effect. As an example of a number of strains in Fig. 3 shows the mechanical behavior of photosensitive retinal patterns when passing three photomechanical cycles.

In Fig. 3 film SMP stretched by 10% (from ε1to εmand 90 minutes were irradiated wavelength λ1>250 nm (45 min each side). The accuracy with which can be fixed provisional form, was identified as the fixation index of the form Rf. The terminals are then returned to the original length (εuand (now bent) film free from nab is agenia condition was again irradiated for 90 minutes a wavelength of λ 2<250 nm. When this film again is compressed (shape memory effect), and in the first cycle, just not achieved its original length, and the material remains a small residual tensile (εp) (balance in the first cycle). The accuracy with which again receive the original form was defined as the ratio of return Rr.

Rfand Rrcalculated by: (a) Rfum×100

(b) Rr(N)=(εmp(N)/εmp(N-1)×100

where N is the cycle number.

The extended exposure of the sample can be conducted or regulated by the length (length constant of the sample), or the regulated voltage (DC voltage). If during irradiation maintain a constant tension, the tension increase. When constantly supported the voltage is usually set clenching of the sample. Fig. 4 clarifies that the variant of the method has only a minor influence on the properties of the shape memory effect. Properties of shape memory effect depends on the concentration photoreactivation groups in the network structure, as further shown in Fig. 4. Rrand Rf(estimated at 5-second cycle) reach at a concentration of about 18% boundary values.

Photosensitive polymeric reticulated structure according to the invention characterized is described, however, that first created functional materials with shape memory effect, which can switch motive other than temperature. Thus, this invention opens up a new type of materials with shape memory effect and a new way of using such materials in areas where materials with shape memory effect, adjustable temperature, cannot be used. The preferred mesh structure of the present invention may also be regulated by UV-light in a narrowly limited area of the wavelength region which is not problematic for many applications, as is already present in the corresponding radiation source, and this wavelength region for other materials, without prejudice.

Amorphous mesh structure of the present invention may contain, in addition to the above essential components, other substances, if they do not disturb the function of the mesh structure. Such additional materials can be, for example, dyes, fillers or additional polymeric materials that can be used for different purposes. In particular amorphous mesh structure of the present invention, used for medical purposes, may contain medical biologically active substances and diagnostics, as contrast media. They are also what may be put into a mesh structure by known methods.

The following examples explain the invention.

Getting a star photosensitive macromonomer

Star-shaped poly(ethylene glycol) with 4 integral processes (molecular weight 2000 g/mol) dissolved in dried THF and triethylamine. To this is slowly added dropwise to cinnamylpiperazine dissolved in dried THF. The reaction mixture is stirred for 12 hours at room temperature, then for 3 days at 50°C. the Precipitated salt is filtered off, the filtrate is concentrated and the obtained product is washed with diethyl ether. Measurements H NMR give a conversion of 85%. By UV spectroscopy macromonomer before photochemical reaction is characterized by a maximum absorption at 310 nm, after photochemical reactions at 254 nm.

Getting a mesh structure

10 mmol of n-butyl acrylate (BA) (BA), ester of cinnamic acid (0.1 to 3 mmol) and, if necessary, 2 mmol of hydroxyethylmethacrylate (HEMA) (HEMA) are mixed in a glass flask. To the mixture was added 1 mol.% ABN and 0.3 mol.% poly(propylene glycol)dimethylacrylate (Mn=560). The mixture with a syringe fill in the form of two similarbank slides between which is Teflon sealing ring with a thickness of 0.5 mm, the Polymerization mixture occurs within 18 hours at 80°C.

The form in which occur the it education grid corresponds to a permanent form. The mixture may also be crosslinked in any other form.

After polymerization, the mesh structure is taken out of the form and cover 150 ml of hexane fraction. Then gradually add the chloroform. This mixture of solvents within 24 hours several times changed to separate low molecular weight and unstitched components. Then the mesh structure of the purified fraction of hexane and dried under vacuum at 30°With during the night. The weight of the extracted sample with respect to the former weight corresponds to the content of the gel. The two subsequent tables show the number of monomers and swelling of the mesh structure in chloroform, and its content.

-
No.The content of monomers in the mixture (mmol)G (%)
BAHEMA-CAHEA-CAHPMA-CAHPA-CAPEGMA-CAQ (%)
1A100,25----72097,2
1B100,5----55094,9
1C101----400to 91.6
2A10-0,1---62089,0
2B10-0,25---90096,2
2C10-0,5---68095,7
2D10-1---132096,5
2E10-2---132096,5
3A10--0,25--95098,7
3B10--0,5--650for 93.4
3C10--1--45098,4
4A10--0,25-83095,9
4B10---0,5-70098,1
4C10---1-55094,3
5A10----0,25600of 98.2
5B10----0,555097,3
5C10----153092,4

In the next series of binary polymer systems add additional share of 2 mmol of hydroxyethylmethacrylate (HEMA), as with this co monomer can expect further opportunities for control of mechanical properties of polymeric reticulated structure.

2
No.The content of monomers in the mixture (mmol)Q (%)G (%)
BA HEMAHEMA-CAHEA-CAHPMA-CAHPA-CAPEGMA-CA
6A1021----37095,5
6B1022----35099,2
6C1023----42096,8
7A102-1---39098,5
7B102-2---30092,8
7C102-3---25096,4
8A102----24094,4
8B102----31092,3
8C102--3--31092,9
9A102---1-45094,7
9B102---2-36082,7
9C102---3-380an 80.2
10A102----11300of 83.4
10B102----21450is 83.8
10C102----3215084,8

Getting vzaimopronikayut mesh structure IPN

n-butyl Acrylate is subjected to crosslinking with 3 wt.% (0.6 mol.%) poly(profiling icol)dimethacrylate (molecular weight of 560 g/mol) in the presence of 0.1 wt.% ABBN, as explained above. Then the film is subjected to swelling in THF, to separate the unused monomer, and then again dried. Then the film may be subjected to a swelling in the solution Torx photoreactivation of macromonomer in THF (10 wt.%) and then again dried. Loading mesh structure photoreactivation component comprises about 30 wt.%.

Polymer amorphous mesh patterns are examined with respect to their thermal and mechanical properties. The results of these studies are summarized in the following table.

No.Tg,< / br>
(°C)
E-module E< / br>
when CT1< / br>
(MPa)
Stress at break σr< / br>
when CT1(MPA)
Elongation εr< / br>
when CT1(%)
1A-40,80,540,2445
1B-34,51,100,2115
1C-21,21,770,2410
2A-46,10,291,0020
2B-40,30,220,15 20
2C-35,60,940,1820
2D-19,91,690,4220
2E-10,94,220,1235
3A-30,60,560,1530
3B-22,80,900,3135
3C-18,62,390,4425
4A-40,50,540,1835
4B-34,91,040,2425
1-CT room temperature

No.Tg,< / br>
(°C)
E-module E with CT (MPa)Stress at break σrat RT (MPA)Elongation εrwhen CT (%)
4C-24,91,880,3525
5A-38,80,360,0820
5B-36,51.44 0,1015
5C-29,61,410,226
6A-10,01,800,3425
6B2,2to 11.522,4835
6C16,1120,699,6615

14,04
No.Tg,< / br>
(°C)
E-module E with CT (MPa)Stress at break σrat RT (MPA)Elongation εrwhen CT (%)
7A-11,4to 2.670,5125
7B7,39,71of 2.2630
7C12,639,785,2825
8A-11,92,350,8345
8B6,625,025,1750
8C10,4139,913,0615
9A3,51,530,5350
9B8,54,5560
9C13,932,426.42 per50
10A-27,4 25,71,400,2930
10B-23,6 of 52.82,410,6725
10C-20,0 56,64,740,9625
11*-46,50,15>1,60>2000

No.Tg,< / br>
(°C)
E-module E with CT (MPa)Stress at break σrat RT (MPA)Elongation εrwhen CT (%)
12**before irradiation-45,00,171,0-1,5300-500
12**after irradiation-40,00,200,5-0,930-100
*-lattice structure of n-butyl acrylate and 0.3 mol.% cross-linking means, without photoreactivation component

**-IPN, 0.6 mol.% cross-linking means, the physical loading photoreactivation component.

Properties effect saponin is of the form defined in cyclic mechanical testing. This used the cut handleeasy sample film thickness of 0.5 mm with a length of 10 mm and a width of 3 mm

If necessary the material before photomechanical cycles pre-treated with irradiation λ2this split may present cyclobutanone rings, and there may be a larger number of all photoreactivation groups of the monomer. The elongation of the sample occurs at a rate of 10 mm/min To fix the temporary shape, the samples were stretched by 30% and were irradiated at a constant voltage. For actuation of the shape memory effect samples, not under tension, again irradiated.

The irradiation of the samples is by using a UV lamp. Using a filter, select the desired wavelength region.

Normal lattice structure with CA: λ1=>250 nm, λ2=<250 nm,

IPN with CAA: λ1=>300 nm, λ2=254 nm,

The distance to the sample is 10 cm, if the lamp 200 watt (>300 nm), or 3 cm, if was used lamp 4 watt (254 nm), or 10 cm, if the lamp 40 watt (> and <250 nm).

The optimal duration of exposure depends, among other things, how great is the distance from the lamp to the sample, and a high intensity lamp. For normal retinal structure of sufficient length is zlecenia 30 min on each side, in order to achieve the maximum possible values for Rfand Rr. In the case of IPN maximum value for Rf21% after 4 hours of exposure.

These experiments demonstrate the superior properties of amorphous cross-linked structures of the present invention. Mesh patterns are characterized by good values of the ratio of total return, characterizing the properties of the SMP, after 5 cycles, as shown by the following table. The materials of the prior art often show here values less than 80%.

Through a simple structural element mesh structures according to the invention, moreover, ensured ease of synthesis. By varying the composition, as was shown above, can be obtained defined polymeric materials, which are characterized by a desirable combination of properties.

The materials of this invention are particularly suitable as materials for medical areas, as implants for targeted, receptive to the initiation of the release of biologically active substances, for the increment of the ligaments, as a substitute of intervertebral discs. In addition, the materials of the amorphous cross-linked structures transparent above the glass transition temperature, which is an advantage for certain applications.

1. The photosensitive polymer reticulate structure, including AMO is fnuu mesh structure, formed from a matrix and a cross-linking agent, and photorealistically component, and the component matrix derived from acrylate and/or methacrylate compounds, and photorealistically component capable of reversible reactions photodimerization.

2. The photosensitive polymer reticulate structure, transparent to radiation that initiates photoreaction comprising covalently linked amorphous network structure and photorealistically component, and photorealistically component capable, under the action of a suitable light radiation, to a reversible reaction with the second photoreactivation component, leading to the formation or destruction of covalent bonds.

3. The photosensitive polymer reticulate structure according to claim 1, and an amorphous lattice structure contains a matrix and a crosslinking agent.

4. Photosensitive mesh structure according to claim 3, and photorealistically component copolymerization with amorphous mesh structure.

5. The photosensitive polymer reticulate structure according to claim 2, and photorealistically component is not copolymerization with amorphous mesh structure.

6. The photosensitive polymer reticulate structure according to claim 5, whereby the polymer reticulate structure includes an amorphous network structure and physically mixed with the her photorealistically component.

7. The photosensitive polymer reticulate structure on one of the aforementioned items, and the component matrix is an acrylate and/or methacrylate material and a crosslinking agent is diacrylates connection and/or dimethacrylates connection.

8. The photosensitive polymer reticulate structure according to claim 1, and photorealistically component capable of reversible reactions photodimerization.

9. The photosensitive polymer reticulate structure of claim 8, and photorealistically component is a compound ester of cinnamic acid or a compound of the ether cinnamomi acid.

10. The photosensitive polymer reticulate structure according to claim 1, and photorealistically component in the form of acrylate compounds copolymerizate mesh with amorphous structure or photorealistically component in the form of a polymer or oligomer, at least three photoreactivation groups physically mixed with amorphous mesh structure.

11. A method of obtaining a photosensitive polymer reticulate structure on one of the aforementioned items, and or component of the matrix polimerizuet with a crosslinking agent and photoreactivation component or component of the matrix polimerizuet with cross-linking agent with the formation of amorphous cross-linked structures which, then photorealistically component is physically mixed with amorphous mesh structure.

12. The use of photosensitive polymeric reticulated structure on one of the aforementioned items as a medical material, particularly for the transport and targeted release of biologically active substances or diagnostic tools.

13. Photorealistically component photosensitive polymeric reticulated structure according to claim 1, comprising oligomeric or polymeric backbone, at least three ends of the chain, each end of the chain has photoreactivation group.

14. Photorealistically component 13, and photoreactivation group is a group capable of reversible reactions photodimerization.

15. Photorealistically component 14, and photoreactivation group is a compound ester of cinnamic acid or a compound of the ether cinnamomi acid.

16. Photorealistically component according to one of p-15, and the frame is a star skeleton with three to six, preferably four branches (end of chain).

17. Photorealistically component according to item 16, and the frame is the skeleton of polyalkyleneglycol, preferably the backbone of the polyethylene glycol.

18. The use of photoreaction nesposobnogo component according to one of p-17 to obtain a photosensitive polymer reticulate structure.

19. The method of programming the photosensitive polymeric reticulated structure according to claim 1, comprising the following stages: preparation of the sample light-sensitive polymeric reticulated structure, and photoreactivation groups are photodimerizable form, the deformation of the sample, the irradiation of a sample with light of a wavelength that causes photodimerization photoreactivation component, the relief pattern.

20. The method of programming the photosensitive polymeric reticulated structure according to claim 19, and photorealistically component is a compound ester of cinnamic acid or a compound of the ether cinnamomi acid.

21. The method of programming the photosensitive polymeric reticulated structure according to claim 19 or 20, and the light is UV radiation with a wavelength in the region of >250 nm.



 

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