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The macroporous synthetic poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels as 3D cellular scaffolds with specific internal morphology, so called dual pore size, were designed and studied. The morphological microstructure of hydrogels was characterized in the gel swollen state and the susceptibility of gels for stem cells was evaluated. The effect of specific chemical groups covalently bound in the hydrogel network by copolymerization on cell adhesion and growth, followed by effect of laminin coating were investigated. The evaluated gels contained either carboxyl groups of the methacrylic acid or quaternary ammonium groups brought by polymerizable ammonium salt or their combinations. The morphology of swollen gel was visualized using the laser scanning confocal microscopy. All hydrogels had very similar porous structures - their matrices contained large pores (up to 102 μm) surrounded with gel walls with small pores (100 μm). The total pore volume in hydrogels swollen in buffer solution ranged between 69 and 86 vol%. Prior to the seeding of the mouse embryonal stem cells, the gels were coated with laminin. The hydrogel with quaternary ammonium groups (with or without laminin) stimulated the cell growth the most. The laminin coating lead to a significant and quaternary ammonium groups. The gel chemical modification influenced also the topology of cell coverage that ranged from individual cell clusters to well dispersed multi cellular structures. Findings in this study point out the laser scanning confocal microscopy as an irreplaceable method for a precise and quick assessment of the hydrogel morphology. In addition, these findings help to optimize the chemical composition of the hydrogel scaffold through the combination of chemical and biological factors leading to intensive cell attachment and proliferation.

To determine whether PHEMA [poly(2-hydroxyethylmethacrylate)] is suitable for portal vein embolization in patients scheduled to right hepatectomy and whether it is as effective as the currently used agent (a histoacryl/lipiodol mixture). Two groups of nine patients each scheduled for extended right hepatectomy for primary or secondary hepatic tumor, had right portal vein embolization in an effort to induce future liver remnant (FLR) hypertrophy. One group had embolization with PHEMA, the other one with the histoacryl/lipiodol mixture. In all patients, embolization was performed using the right retrograde transhepatic access. Embolization was technically successful in all 18 patients, with no complication related to the embolization agent. Eight patients of either group developed FLR hypertrophy allowing extended right hepatectomy. Likewise, one patient in each group had recanalization of a portal vein branch. Histology showed that both embolization agents reach the periphery of portal vein branches, with PHEMA penetrating somewhat deeper into the periphery. PHEMA has been shown to be an agent suitable for embolization in the portal venous system comparable with existing embolization agent (histoacryl/lipiodol mixture).

An extensive study of various properties of gel electrolyte systems based on 2-ethoxyethyl methacrylate (EOEMA) was conducted with several experimental techniques in order to clarify the influence of varying composition of the samples. The addition of 3-(trimethoxysilyl) propyl methacrylate (SPMA), used here with the aim of decreasing flammability of the ether-oxygen rich system, was investigated in terms of resulting mechanical, thermal and electrochemical properties. Furthermore, changes in these properties based on the use of different cross-linker monomers, salt and its solvent were studied.

Currently, there is no effective strategy for the treatment of spinal cord injury (SCI). A suitable combination of modern hydrogel materials, modified to effectively bridge the lesion cavity, combined with appropriate stem cell therapy seems to be a promising approach to repair spinal cord damage. We demonstrate the synergic effect of porosity and surface modification of hydrogels on mesenchymal stem cell (MSC) adhesiveness in vitro and their in vivo survival in an experimental model of SCI. MSCs were seeded on four different hydrogels: hydroxypropylmethacrylate-RGD prepared by heterophase separation (HPMA-HS-RGD) and three other hydrogels polymerized in the presence of a solid porogen: HPMA-SP, HPMA-SP-RGD, and hydroxy ethyl methacrylate [2-(methacryloyloxy)ethyl] trimethylammonium chloride (HEMA-MOETACl). Their adhesion capability and cell survival were evaluated at 1, 7, and 14 days after the seeding of MSCs on the hydrogel scaffolds. The cell-polymer scaffolds were then implanted into hemisected rat spinal cord, and MSC survival in vivo and the ingrowth of endogenous tissue elements were evaluated 1 month after implantation. In vitro data demonstrated that HEMA-MOETACl and HPMA-SP-RGD hydrogels were superior in the number of cells attached. In vivo, the highest cell survival was found in the HEMA-MOETACl hydrogels; however, only a small ingrowth of blood vessels and axons was observed. Both HPMA-SP and HPMA-SP-RGD hydrogels showed better survival of MSCs compared with the HPMA-HS-RGD hydrogel. The RGD sequence attached to both types of HPMA hydrogels significantly influenced the number of blood vessels inside the implanted hydrogels. Further, the porous structure of HPMA-SP hydrogels promoted a statistically significant greater ingrowth of axons and less connective tissue elements into the implant. Our results demonstrate that the physical and chemical properties of the HPMA-SP-RGD hydrogel show the best combination for bridging a spinal cord lesion, while the HEMA-MOETACl hydrogel serves as the best carrier of MSCs.

Preparation and morphological characterization of some novel hydrogels based on chitosan (CS) with porous structure tailored by ice-templating and porogen leaching are presented in the paper. Poly(methylmethacrylate) (PMMA), as fractionated particles, has been used as polymer porogen. The influence of the mesh of the fractionated PMMA particles, the weight ratio between CS and fractionated PMMA particles, and the speed of the crystallization, on the internal morphology of the hydrogels have been deeply investigated. The morphology of the obtained hydrogels was observed by scanning electron microscopy (SEM). As a function of the synthesis conditions, hydrogels with a heterogeneous morphology consisting of randomly and evenly distributed polyhedral pores, or with an oriented structure, which has microchanneled structures arranged along the freezing direction, were generated.

We describe the synthesis of new crosslinker N ′-{3-[2-(4-{2-[3-(methacryloylamino)propanoyl]hydrazono}cyclohexyliden)hydrazino]-3-oxopropyl}-2-methylacrylamide, which is stable at physiological pH, but is hydrolytically cleaved in acidic pH. Study of acid hydrolysis showed that the crosslinker is hydrolyzed into two N ′-(3-hydrazino-3-oxopropyl)-2-methylacrylamide molecules and one 1,4-cyclohexanedione molecule. Hydrogels based on poly[ N -(2-hydroxypropyl)methacrylamide] crosslinked with this crosslinker were prepared and their degradation rate was studied as a function of pH (in the range of pH 1.5–7.4). The hydrogel is cleaved within 8–27 days at pH between 1.5 and 6 and is stable at pH 7.4 making it promising for the construction of oesophageal stents.

Dependence of diffusion coefficients of spin-labeled poly(ethylene glycol)s (PEGs, Mw = 1500, 3000, and 6000) determined by One-Dimensional Electron Spin Resonance Imaging (1D ESRI) on the properties of hydrogel matrices prepared by photopolymerization of 2-hydroxyethyl methacrylate (HEMA) and 2-(2′-hydroxyethoxy)ethyl methacrylate (DEGMA) was studied. The hydrogels were characterized by degree of crosslinking, νgel, by hydrodynamic correlation length, ξgel, and by self-diffusion coefficient of water, D H 2 O . The tracer diffusion coefficients were analyzed in the frame of scaling reptation and hydrodynamic models. Molecular weight dependence of the tracer diffusion coefficients follow expression D ∼ Mwx with exponent x = −1.2 ± 0.1 which excludes contribution of reptation to the diffusion. Steep decrease of the tracer diffusion coefficients with increasing polymer concentration was observed. Decrease of the tracer diffusion coefficients with increasing ratio of the hydrodynamic radius of the tracer to the hydrodynamic correlation length of the hydrogel matrix, RH/ξgel, was well fitted with predicted stretched exponential expression. Dependence of the tracer diffusion coefficients on the degree of crosslinking νgel suggested as a new scaling variable was found to closely follow empiric stretched exponential dependence in the whole νgel range studied.

Macroporous hydrogels are artificial biomaterials commonly used in tissue engineering, including central nervous system (CNS) repair. Their physical properties may be modified to improve their adhesion properties and promote tissue regeneration. We implanted four types of hydrogels based on 2-hydroxyethyl methacrylate (HEMA) with different surface charges inside a spinal cord hemisection cavity at the Th8 level in rats. The spinal cords were processed 1 and 6 months after implantation and histologically evaluated. Connective tissue deposition was most abundant in the hydrogels with positively-charged functional groups. Axonal regeneration was promoted in hydrogels carrying charged functional groups; hydrogels with positively charged functional groups showed increased axonal ingrowth into the central parts of the implant. Few astrocytes grew into the hydrogels. Our study shows that HEMA-based hydrogels carrying charged functional groups improve axonal ingrowth inside the implants compared to implants without any charge. Further, positively charged functional groups promote connective tissue infiltration and extended axonal regeneration inside a hydrogel bridge.

The present study is bringing a comparison of surface morphology for various types of contact lenses. A novel method--scanning electron microscopy under aqueous conditions (cryo-SEM)--was tested for visualization of lenses at magnifications up to 2000x. For imaging lens surface on nanometre scale, we employed atomic force microscopy (AFM) in aqueous media. Various materials of lenses, based on silicone hydrogels or conventional hydrogels, were investigated. Total, 10 types of contact lenses from five manufacturers were selected and probed. We found that different methods of lens manufacture (lathe-cutting, cast-moulding, and spin casting) led to different values of surface roughness. In the swollen state, roughness values of lens surfaces lie between 4 and 140 nm. Lenses manufactured by lathe-cutting exhibit notable higher values, so that they could be easily distinguished from others. In cast-moulded lenses, the surface roughness decreased with increasing water content. Moreover, additional treatments of lenses introduced unique structural motifs onto surface. For instance, porous structure was found on lens surface finalized with plasma oxidation.

The goal was to electrospin 2-hydroxyethyl methacrylate — based biocompatible polymers and prepare submicron fibres (nanofibers) for biomedicinal applications. Syntheses of poly(2-hydroxyethyl methacrylate) (HEMA) and its copolymer with 2-ethoxyethyl methacrylate (EOEMA), and their characterization by viscometry and molecular weight are described. Their relation to electrospinning is discussed. Electrospinning of HEMA homopolymer from water-ethanol is successful for molecular weights 6.31 × 105 and 1.80 × 106 g/mol. Electrospinning of HEMA/EOEMA copolymers is feasible from ethanol.

Macroporous hydrogels based on 2-hydroxyethyl methacrylate, 2-ethoxyethyl methacrylate and N-(2-hydroxypropyl)methacrylamide, methacrylic acid and [2-(methacryloyloxy)ethyl]trimethylammonium chloride crosslinked with N,O-dimethacryloylhydroxylamine were prepared. Hydrogels were degraded in a buffer of pH 7.4. Completely water-soluble polymers were obtained over time periods ranging from 2 to 40 days. The process of degradation was followed gravimetrically and by optical and electron microscopy. In vivo biological tests with hydrogels based on copolymers of 2-ethoxyethyl methacrylate/N-(2-hydroxypropyl)methacrylamide were performed.

New poly(ethyl methacrylate) and poly(2-ethoxyethyl methacrylate) gel electrolytes containing immobilised lithium perchlorate solution in propylene carbonate were prepared by UV radical polymerisation. Materials exhibit high ionic conductivity up to 0.23 mS cm −1 and long-term stability of chemical and mechanical properties. Both materials keep their suitable conductivity above −20 °C. The effect of material composition, temperature, cross-linking agent and salt concentration on the electrochemical and mechanical properties were studied using impedance spectroscopy and cyclic voltammetry. The accessible electrochemical window of both polymer electrolytes was estimated from −2.1 to 1.5 V versus Cd/Cd 2+ . Impedance measurements showed almost one-order increase of conductivity when ethylene dimethacrylate was used as a cross-linking agent in comparison with the polymer electrolyte without agent.

The intermediate perfluoroalkylated diblock hydrophobic–hydrophilic secondary alcohols (9–11), which were prepared by the reaction of monomethyl ethers of oligomeric ethyleneglycols with 2-[(perfluoroalkyl)methyl]oxiranes (7 and 8), resulted in the formation of the title monomers (12–14) by the acylation with methacryloyl chloride. Copolymers of 12–14 with HEMA and DEGMA prepared under radical conditions display enhanced swelling properties.

A series of macroporous crosslinked copolymers of 2-hydroxyethyl methacrylate (HEMA) with methacrylic acid (MA) was prepared in the presence of fractionated particles of sodium chloride. The hydrogels were characterized by the number of pores in unit volume, the pore size, the water content in pores and diffusion parameters. The structure of the hydrogels was followed by confocal and scanning electron microscopy.

Hydrogel implants for urinary incontinence treatment based on HEMA supplemented with 10% methacrylic acid have been developed. The swelling properties of implants were tested in vitro and in vivo after implantation to laboratory mice. Biocompatibility has been determined by incubation of implants in tissue culture, by histological examination of adjacent tissues after subcutaneous application of implants to laboratory mouse in a long-term experiment, and by flow cytometry examination of blood cells. The swelling of hydrogel implants was completed in 6-24 h. There was no effect on in vitro growth of cells incubated with implants. In mice, implants were well tolerated without any sign of inflammatory reaction. The material allows an elastic compression of urethra compensating a damaged sphincter after trans-urethral sub-mucosal implantation of hydrogel cylinders.

This study compares subcutaneous and intracerebral biocompatibilty of two hydrogels: copolymer of 2-hydroxyethyl methacrylate with 2-(methylsulfanyl)ethyl methacrylate and poly(2-hydroxyethyl methacrylate) as reference polymer. The experimental copolymer was more biologically inert than poly(2-hydroxyethyl methacrylate) in both the studied parameters, hence the former material is a suitable candidate for biomedical application.

A comparative evaluation of the morphological and swelling properties corresponding to the porous poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels and to the chitosan (CS) hydrogels was developed in this paper. The porous structure of hydrogels based on PHEMA or CS was tailored by ice-templating process and porogen leaching. Poly(methylmethacrylate) (PMMA), as fractionated particles, was used as polymer porogen. The influence of the average size of the fractionated PMMA particles on the internal morphology and swelling properties of the hydrogels was followed. The average pore diameter of PHEMA cryogels increased from 10 ± 2 μm up to 22 ± 5 μm with the increase of the size of the fractionated PMMA particles from below 32 μm up to 50–90 μm. On the other hand, in the case of CS cryogels prepared in the presence of the PMMA particles with different sizes, pores with an average size of 74 ± 6 μm, irrespective of the size of PMMA particles were formed, strong changes being observed in the morphology of the pore walls, these being less compact and, therefore, more accessible for the diffusion of low molecular weight species. Hydrogels based on PHEMA or CS with microchanneled structures arranged along the freezing direction, were generated by unidirectional freezing. The swelling measurements showed that the cryogels prepared in the presence of PMMA particles attained the equilibrium swelling much faster than those prepared without PMMA.

The structural properties of microfiber meshes made from poly(2-hydroxyethyl methacrylate) (PHEMA) were found to significantly depend on the chemical composition and subsequent cross-linking and nebulization processes. PHEMA microfibres showed promise as scaffolds for chondrocyte seeding and proliferation. Moreover, the peak liposome adhesion to PHEMA microfiber scaffolds observed in our study resulted in the development of a simple drug anchoring system. Attached foetal bovine serum-loaded liposomes significantly improved both chondrocyte adhesion and proliferation. In conclusion, fibrous scaffolds from PHEMA are promising materials for tissue engineering and, in combination with liposomes, can serve as a simple drug delivery tool.

The interaction of substituted poly(N-phenylmaleimides) with low- and high-molecular-weight amines were studied. Colourless chloroform solutions of polymers, which carry electron-attracting substituents in benzene rings, turn intensively red on addition of amines in neutral or basic media depending on the nucleophilicity and accesibility of amino groups. Absorption spectra of the solutions in the visible range suggest that the formation of colour complexes consists in an interaction of free electron pairs of amines with adjacent carbonyl groups of the polyimides.

Five methods of preparation of macroporous hydrogels are described and compared: precipitation polymerization, polymerization in presence of salt, polymerization in presence of gas-releasing compound, lyophilization and electrospinning. Crosslinked copolymers based on 2-hydroxyethyl methacrylate were selected as model hydrogels. Hydrogels were characterized by SEM microscopy, porosity, communicating/non-communicating pore ratio, pore sizes and their distributions. The advantages and drawbacks of the methods of preparation, modification of hydrogel properties, reproducibility and issues related to their preparation are discussed. The most convenient method was preparation in presence of salts. One type of porous hydrogel was based on a hydrogel matrix composed of nanofibers prepared by electrospinning method. The nanofibers have shown unique properties due to their large specific surface. The least suitable method seems to be the preparation of porous hydrogels by polymerization using gas (nitrogen) releasing initiator, 2,2´-azobisisobutyronitrile. The use of prepared porous hydrogels is intended especially for scaffolds in tissue engineering.

Recent advances in the preparation of nanofibre layers, especially using the Nanospider™ technology, allow prepare a sufficiently large area of nanofibrous layer of reproducible thickness and structure. Subsequently, it is possible to employ these layers as cell carriers and evaluate their efficiency in laboratory bioreactors. The construction of the functional hepatal bioreactor is particularly given by the positive response of hepatocyte cells to the used carrier layer as well as by the cell morphology, their viability and biological activity in certain period of time. We compared cell growth on collagen with nanofibres electrospun from selected copolymers of methacrylic esters (HEMA/EOEMA) and from differently prepared polycaprolactone (PCL) layers. The morphology was evaluated using Phaloidin/DAPI staining. On the nanofibres based on methacrylates, the cells survived and showed a common morphology comparing with cells grown on collagen (controls). On the PCL nanofibres, the cells attached well and showed a better growth than cells grown on collagen (controls). The results obtained in laboratory bioreactor proved the biochemical functionality of the studied system.

Chronic spinal cord injury (SCI) is characterized by tissue loss and a stable functional deficit. While several experimental therapies have proven to be partly successful for the treatment of acute SCI, treatment of chronic SCI is still challenging. We studied whether we can bridge a chronic spinal cord lesion by implantation of our newly developed hydrogel based on 2-hydroxypropyl methacrylamide, either alone or seeded with mesenchymal stem cells (MSCs), and whether this treatment leads to functional improvement. A balloon-induced compression lesion was performed in adult 2-month-old male Wistar rats. Five weeks after injury, HPMA-RGD hydrogels [N-(2-hydroxypropyl)-methacrylamide with attached amino acid sequences--Arg-Gly-Asp] were implanted into the lesion, either with or without seeded MSCs. Animals with chronic SCI served as controls. The animals were behaviorally tested using the Basso–Beattie-Breshnahan (BBB) (motor) and plantar (sensory) tests once a week for 6 months. Behavioral analysis showed a statistically significant improvement in rats with combined treatment, hydrogel and MSCs, compared with the control group (P < 0.05). Although a tendency toward improvement was found in rats treated with hydrogel only, this was not significant. Subsequently, the animals were sacrificed 6 months after SCI, and the spinal cord lesions evaluated histologically. The combined therapy (hydrogel with MSCs) prevented tissue atrophy (P < 0.05), and the hydrogels were infiltrated with axons myelinated with Schwann cells. Blood vessels and astrocytes also grew inside the implant. MSCs were present in the hydrogels even 5 months after implantation. We conclude that 5 weeks after injury, HPMA-RGD hydrogels seeded with MSCs can successfully bridge a spinal cord cavity and provide a scaffold for tissue regeneration. This treatment leads to functional improvement even in chronic SCI.

Copolymers of acrylic acid and butyl acrylate crosslinked with 4,4′-bis(methacryloylamino)-azobenzene were synthesized by radical copolymerization with different amounts of acrylic acid and crosslinker. They were characterized by equilibrium degree of swelling, modulus of elasticity in compression at pH 2 and 7, and effective network density. The acido-basic properties of crosslinked copolymers were compared with linear (soluble) ones of the same composition. The study of the dependence of the apparent dissociation constant (pKapp) on the degree of dissociation has shown that conformational transition from the compact to the random conformation of the polymeric chains occurs only in crosslinked copolymers. The high values of pKapp obtained indicate that strong Donnan effects and low polarity of environment of carboxy groups are operative in acido-basic equilibria.

The potentiometric behaviour of two polyampholytes, poly[(methacrylic acid)-co-(2-dimethyl-aminoethyl metharylate)] and poly{(methacrylic acid)-co-[2-(methacryloyloxy)ethyltrimethyl-ammonium iodide]} is described. The dissociation constants of low-molecular-weight compounds modelling the structural units and diads of polyampholytes are reported, and effects of adjacentgroups on the potentiometric behaviour of the copolymers are discussed.

Infrared attenuated total reflection spectroscopy was used for in situ observation of the deposition of collagen I on poly(2-hydroxyethyl methacrylate-co-methacrylic acid, 2.9%) hydrogels and subsequent attachment of laminin or fibronectin on the collagen surface. While there was no adsorption of collagen dissolved in an acid solution on the hydrogel surface, it deposited on the surface at pH 6.5. The collagen layers with attached laminin or fibronectin were stable on hydrogel surface in physiological solution. The modification with collagen and particularly with collagen and laminin or fibronectin allowed the adhesion and growth of mesenchymal stromal cells and astrocytes on the hydrogel surface.

The cell/tissue engineering therapy of extensive or chronic skin wounds is a highly topical task of the contemporary medicine. One of possible therapeutic approaches is grafting of in vitro cultured keratinocytes directly to the wound bed, where the cells colonize the wound, proliferate and improve the re-epithelization process. Because the successful cultivation of keratinocytes needs an application of feeder cells, the exclusion of these cells from the cultivation system is highly required. In this study we show a positive influence of 2-ethoxyethyl methacrylate as a component of cultivation support on growth of keratinocytes without feeder cells. Keratinocytes cultured on these surfaces are able to migrate to the model wound bed in vitro, where they form distinct colonies and have a normal differentiation potential.

Perfluoroalkylated methacrylates 7a – c bearing sulfinyl group within a straight-chain ester group, i.e. CH 2 =C(CH 3 )CO 2 CH 2 CH 2 S(O)–CH 2 CH 2 CF 2 (CF 2 CF 2 ) n CF 3 ( n = 1–3) were prepared by two alternative synthetic sequences from 2-[(polyfluoroalkyl)sulfanyl]ethanols HOCH 2 CH 2 SCH 2 CH 2 CF 2 (CF 2 CF 2 ) n CF 3 ( n = 1–3) in overall yields of 88–91%. Copolymers of 7a – c with diethylene glycol methacrylate (DEGMA) prepared in bulk under radical conditions display high transparency, increased water content and good oxygen permeability properties, which are advantageous for their application in ophthalmology and as prosthetic materials.

The implantation of non-resorbable biocompatible polymer hydrogels into defects in the central nervous system can reduce glial scar formation, bridge the lesion and lead to tissue regeneration within the hydrogel. We implanted hydrogels based on crosslinked poly hydroxyethyl-methacrylate (pHEMA) and poly N-(2-hydroxypropyl)-methacrylamide (pHPMA) into the rat cortex and evaluated the cellular invasion into the hydrogels by means of immunohistochemical methods and tetramethylammonium diffusion measurements. Astrocytes and NF160-positive axons grew similarly into both types of hydrogels. We found no cell types other than astrocytes in the pHEMA hydrogels. In the pHPMA hydrogels, we found a massive ingrowth of connective tissue elements. These changes were accompanied by corresponding changes in the extracellular space volume fraction and tortuosity of the hydrogels.

The synthesis is reported of copolymers of styrene with methacrylic acid and of methyl methacrylate with methacrylic acid by radical copolymerization, of copolymers of methyl methacrylate with methacrylic acid by partial alkaline hydrolysis of poly(methyl methacrylate), and of block copolymers of styrene with methacrylic acid. Modified titration curves of all these copolymers were recorded in water and water-ethanol solutions. In a solution containing 50 mass.% ethanol, only small differences could be observed between the potentiometric behaviour of the individual copolymers and polymethacrylic acid. Also, there were no essential differences in any of the solvents used between the potentiometric behaviour of block copolymers of styrene with methacrylic acid, on the one hand, and polymethacrylic acid, on the other. On the contrary, maxima and minima were always observed on the modified titration curves of statistical copolymers with a higher content of the hydrophobic comonomer in solutions with a high water content. Thus, using the modified titration curves, it is possible to decide whether a given copolymer is of the block or statistical type.

From the products of hydrolysis of dimethyl 2-methoxymethyl-2, 4-dimethylglutarate, the pure stereoisomers of 2-methoxymethyl-2,4-dimethylglutaric acid and their anhydrides have been prepared. Alkaline hydrolysis of the stereoisomeric anhydrides yields the corresponding pure stereoisomeric acids which can be transformed to the corresponding pure threo- and erythrodimethyl esters by means of diazomethane. The configuration of the stereoisomeric anhydrides was determined by analysis of1H-NMR spectra, the configuration of the other compounds was derived from the anhydride structures based on the preparative procedure controlled by1H-NMR spectra.

By analysis of infrared, Raman and 13C NMR spectra of 2,2-dimethyl-1-methoxypropane and of the methyl ester of 3-methoxy-2,2-dimethylpropanoic acid, the formation of conformers generated by rotation about the CH2-OCH3 and C-CH2 bonds was studied. It was found that in both molecules, only the form with trans orientation of the C-CH2-O-CH3 bonds is present. The conformational structure of the major form of the methyl ester of 3-methoxy-2,2-dimethylpropanoic acid was proposed.

The paper deals with the quaternization reaction of isotactic and atactic poly(2-dimethylaminoethyl methacrylate) with methyl iodide in three water-ethanol solutions at different temperatures. Using the temperature dependence of the rate constants extrapolated to zero conversion, the activation quantities at the beginning of the reaction were calculated (activation energy, enthalpy, entropy, free enthalpy, and the frequency factor). The reactivities of the two polymers are compared with each other and then also with that of a low-molecular weight model compound, 2-dimethylaminoethyl pivalate (DAEP). Reactivity of all compounds under investigation increases with increasing water content in the solvent: that of DAEP due to the decreasing negative activation entropy, that of the two polymers as a result of decreasing activation energy. Using the measured activation energies and entropies, polarity of the transient state of the polymers is discussed in comparison with the low-molecular weight model, along with polymeric effects which may become operative in the quaternization reaction.

The paper deals with kinetics phenomena occurring in the quaternization of some polymeric amines, such as poly[2-(dimethylamino)ethyl methacrylate], poly{N-[3-(dimethylamino)propyl]-acrylamide}, and poly[2-(dimethylamino)ethyl methacrylate-co-2-hydroxyethyl methacrylate], with alkyl halides. The accelerating and slowing-down effects which take place in the alkylation reactions are discussed on the basis of the reaction course, i.e. of the dependence of differential rate constants on the conversion fraction of the reaction. Accelaration of the reaction is affected by the increasing polarity of microsurroundings of the reacting groups, while electrostatic and steric hindrances of the reacted groups slow down the reaction. Conformational effects, chemical and solvation interactions in the polymer-solvent-alkylating agent system and tacticity of the polymer are also operative.

Raman, infrared, and 1H and 13C NMR spectra of 2-(dimethylamino)ethyl pivalate, 2-(pivaloyloxy)ethyltrimethylammonium iodide, poly[2-(dimethylamino)ethyl methacrylate] and of its quaternary iodide were measured. Spectral analysis revealed that in crystalline 2-(dimethylamino)ethyl pivalate and in its quaternary salt, the 2-(dimethylamino)ethyl group exists in the g conformational state. In the liquid state, these compounds also contain a smaller amount of the t conformational structure of the 2-(dimethylamino)ethyl group. In poly[2-(dimethylamino)ethyl methacrylate] and in its quaternary iodide in solution, the population of the g and t conformational structures are similar to those found in 2-(dimethylamino)ethyl pivalate and in its quaternary iodide.

Quaternization reactions of poly(2-dimethylaminoethyl methacrylate) using methyl iodide were carried out up to 50% conversion in 18 chemically different solvents. Copolymers which contain moderate hydrophilic 2-dimethylaminoethoxycarbonyl groups and strongly hydrophilic 2-trimethylammoniumethoxycarbonyl iodide groups were obtained. Potentiometric titration showed that in some solvents the reaction proceeds by the zip mechanism, i.e. copolymers with a predominantly block structure are formed, while in other solvents the reaction proceeds along the macromolecular chain randomly, that is, giving rise to statistical copolymers.

The potentiometric behaviour of poly(methacrylic acid) (PMA), poly(2-dimethylaminoethyl methacrylate) (PDAEM), and low-molecular-weight compounds modelling the structural diad of these polymers, 2,2,4,4-tetramethylglutaric acid (TMGA) and its 2-dimethylaminoethyl ester (ETMG), is reported. The dissociation constants of these compounds to the 1st and 2nd degree were measured and compared with the values for polymers. It appears that TMGA adequately models the behaviour of PMA up to the conformational transition compact coil (stage “a”) — random coil (stage “b”) at higher ionic strength values of the titrated solution. On the contrary, ETMG behaves as a typical low-molecular-weight compound with properties differing from those of PDAEM.

By analysis of fully coupled 13C NMR spectra and of 1H NMR spectra of dimethylaminoethanol, its methyl ether, and of the corresponding trimethylammonium iodides, populations of isomers generated by rotation about the bonds N-CH2, CH2-CH2, and CH2-O in these compounds in solution were determined. By analysis of Raman and infrared spectra of these compounds in the solid and liquid states it was found that in the crystalline state these compounds form structures with parallel N-CH3 and O-CH2 bonds, which are also preferred in the liquid state.

A method is described for the calculation of differential rate constants using an empirical description of the time dependence of the product of integral rate constant and time or of conversion. The method has been verified for quaternization reactions of poly(2-dimethylaminoethyl methacrylate), poly(4-dimethylaminomethylstyrene), poly[N-(3-dimethylaminopropyl)acrylamide], poly(4-vinylpyridine), poly(iminoethylene), and [4-bis(2-hydroxyethyl)aminomethylstyrene] as a function of conversion of the reaction. The calculations were carried out using reported data on the dependence of conversion on time.

Analysis of 13C NMR spectra of methylethers of the type CH3OCH2R, with R = CH3 (I), CH2CH3 (II), CH(CH3)2 (III) and C(CH3)3 (IV) has shown that the trans form strongly predominates on the OCH, bond, the gauche forms appearing only in those cases where close contact between methyl groups can be avoided. Analysis of both 1H and 13C NMR spectra indicates that all staggered forms are populated on the CH2R bond. In vibrational spectra, the strong Raman bands near 800 cm−1 were found to be very sensitive to conformational structure. For I, III and IV, the bands of various conformers in this range are separated, permitting ΔH to be determined.

The conformational structure of the dimethyl esters of 2,2,4-trimethylglutaric acid, and of the erythro- and threo-isomers of 2-methoxymethyl-2,2,4-dimethylglutaric acids was studied by NMR and vibrational spectroscopic methods. Conformational structure generated by rotation about skeletal bonds was determined by analysis of vicinal coupling in 1H and 13C NMR spectra. The results are discussed in relation to the conformational structure of PMMA.

The dissociation constants of partially ionized isotactic and atactic poly(2-dimethylaminoethyl methacrylate) in water/ethanol solutions were measured. The strong dependence of the apparent dissociation constant on the degree of ionization of the macromolecule is discussed using viscometric data and compared with the properties of low-molecular-weight model compounds. The values of the internal dissociation constants at various ionic strength in various water/ethanol solutions were obtained by extrapolation of the apparent dissociation constants to zero ionization degree of the macromolecule. The conformational structures of macromolecules in solution are discussed.

Interactions between the carbonyl and amino groups in copolymers of 2-dimethylaminoethyl methacrylate with N-phenylmaleimide are reported. The existence of interactions ensues from potentiometric measurements and UV-VIS spectra. Interactions in these copolymers result in the formation of energetically very advantageous chromophores, reflected in an intense red colour of the substances obtained.

The study concerns the potentiometric behaviour of statistical copolymers of 2-dimethylaminoethyl methacrylate with 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, 2-methacryloyloxyethyltrimethylammonium methylsulfate, and of copolymers arising by the partial quaternization of poly(2-dimethylaminoethyl methacrylate) with methyl iodide in various water-ethanolic solutions. The potentiometric properties of poly(4-dimethylaminobutyl methacrylate) and poly(6-dimethylaminohexyl methacrylate) are also reported. The course of modified titration curves and the differences between pK0 values of copolymers and pK values of low-molecular weight model compounds are discussed. Side chains of copolymers of 2-dimethylaminoethyl methacrylate have a cyclic conformation (similarly to the homopolymer); the carbonyl and amine group interact with each other. Copolymers formed by the partial quaternization of poly(2-dimethylaminoethyl methacrylate) with methyl iodide in a water-ethanolic medium (Menshutkin's reaction) have a block structure, which suggests a zip mechanism of the quaternization reaction.

The study deals with the kinetic behaviour of atactic and isotactic poly[2-(dimethylamino)-ethyl methacrylate] (PDAEM) and of low-molecular-weight tertiary amines in the quaternization by low-molecular-weight alkyl iodides (Mentschutkin's reaction) in water/ethanol solution at 60°C. Unlike quaternization of PDAEM with methyl iodide and 2-iodoethanol, in the cases of the other alkyl iodides the rate constant of quaternization depends on the initial concentration of the alkyl iodide. The rate constant decreases with increasing concentration of the alkyl iodides. The effect becomes more pronounced in a reaction medium containing 43 wt.-% of water in a mixture with ethanol as compared to azeotropic ethanol. Such behaviour is attributed to the fact that in solution of a water/ethanolic mixture the tertiary amines investigated in this study are preferentially solvated by water.