Amphoteric polymers based on chitosan, acrylamide and sodium acrylate with different content of the latter were synthesized using the radical copolymerization method in solution in the presence of 1.4 × 10–3 mol/L ammonium persulfate in an inert medium at 333 K. Terpolymers’ molecular weight characteristics, their structure, as well as the ability to flocculation and sorption of hydrogels based on them were investigated. The copolymers’ formation was proved by extraction, IR-spectroscopy, conductometric titration, differential scanning calorimetry, and statistical light scattering. The chitosan modification with acrylamide leads to an increasing of its molecular weight up to 5.2 × 105. The subsequent introduction of the sodium acrylate into the copolymer allows obtaining terpolymers with molecular weight from 7.7 × 105 to 18.5 × 105 depending on the amount of the introduced monomer. The maximum content of acid groups in the graft copolymers reached 26.8 wt

Abstract Binary TiO2-ZnO and TiO2 - nanoparticles (NPs) Cu in a chitosan stabilizer matrix were obtained and studied as photocatalysts at their content relative to the mass of the dry polymer of 10 wt.%. The effect of the mass ratio of TiO2:ZnO, TiO2:Cu NPs was revealed on the photocatalytic properties of materials in the decomposition reaction of methylene orange when exposed to UV and visible light. It is shown that the greatest depth of decomposition of the azo dye - 98% – in an aqueous solution is achieved in 60 minutes of light exposure using the system TiO2:ZnO with a mass ratio of 1:1 and 2:1 components. The same level of photocathaitic activity – a decrease in the concentration of methylene orange by 95-98 % is achieved when using the system TiO2: Cu NPs at a mass ratio of 10:1 and 5:1 components.

Gas transport and physico-mechanical properties of synthesized films based on modified starch and chitosan have been studied. The values of the permeability coefficients of pure gases included in the air for films based on modified chitosan and a copolymer based on modified starch and chitosan at a temperature of 23°C were determined. The oxygen permeability coefficient of the synthesized copolymer was compared with other polymers. A copolymer based on modified starch and chitosan was found to have medium oxygen barrier properties. The biodegradability of the samples under the action of the micromycete Aspergillus niger was studied by analyzing the degradation products by chromatography-mass spectrometry. The total biodegradation time of the samples was 4 weeks. These films are promising for use as packaging material.

Abstract The structure, tensile strength and thermo-physical properties of chitosan films reinforced by TiO2 nanoparticles and obtained from aqueous solutions of various acids - hydrochloric acid, acetic acid, and lactic acid - were investigated. The TiO2 nanoparticles concentration was from 0.5 to 10 wt.% relative to the chitosan weight. The tensile strengths of all chitosan films prepared from aqueous solutions of acetic acid and hydrochloric acid containing TiO2 nanoparticles were greater than 80 MPa, while this characteristic for initial chitosan was approximately 35 MPa. The highest tensile strength was 127 MPa with an elongation of 13% was found for samples with TiO2 concentration 0.5 wt.% and obtained using acetic acid. These effects can be attributed to changes in the film structure when TiO2 small amount was added to it which was confirmed by IR-spectroscopy, X-ray diffraction analysis, scanning electron microscopy and atomic force microscopy. A glass transition temperature increasing of the samples were determined in the TiO2 presence. Moreover, the films exhibited antibacterial activity against Staphylococcus aureus and were able to biodegrade.

The photocatalytic properties of poly(titanium oxide) (PTO) dispersed in optically transparent polymeric matrices of different natures under the action of both UV and visible light on aqueous solutions of azo dyes and phenols were investigated. PTO in materials forms clusters of mixed polymorphic modification—anatase and rutile—with an average size ~12 nm. With a one-electron transition Ti4+ + e− → Ti3+ accompanied by a reversible break of the Ti-O bond, the formation of electron-hole pairs and, consequently, active oxygen species occurs in PTO under UV irradiation. The PTO band gap in nanocomposites is 3.11–3.35 eV. Its doping with gold and silver nanoparticles with sizes from ~10 to ~30 nm reduces the PTO band gap by up to 2.11 eV, which leads to the operating wavelength range extension of the materials. It provides the enhancement of nanocomposites’ photocatalytic properties under UV irradiation and is the reason for their high activity under visible light action. It was found that azo dyes decompose by ~90% in this case. A phenol and para-nitrophenol conversion of 80–90% was proven at ~60 min upon their aqueous solutions’ visible-light irradiation at the nanocomposite concentration in a solution of 0.5 g/L.

A new versatile method of block-copolymer synthesis is based on classic radical polymerization with a multifunctional Si-organic chain transfer agent.

The article studies the effect of polynorbornene (PNB) in the composition of PNB with Norman 747 LV plasticizer (RC) on the curing characteristics of the rubber compound and the physico-mechanical, dynamic, dielectric properties and the thermal behavior of vulcanizates based on a combination of isoprene, α-methylstyrene-butadiene, and nitrile-butadiene rubbers. It is shown that vulcanizates containing PNB in the composition of the RC had lower conditional tensile strength, hardness, and tear resistance compared to the vulcanizate of the base version of the rubber compound. Studies of dynamic mechanical analysis indicate that an increase in the content of RC, and hence PNB, in the rubber compound contributes to an increase in the mechanical loss factor (tanδ) and a decrease in the storage modulus of vulcanizates. It was found that vulcanized rubber, containing 24.0 parts per hundred of rubber (phr) (8.98 wt. %) PNB as part of the RC, is characterized by stable physico-mechanical, improved vibration-absorbing properties, as well as increased dielectric parameters. This rubber compound can be used as a base for rail fasteners for railroad tracks.

Hydrogels based on chitosan derivatives, sodium alginate with acrylamide and acrylic acid were obtained by free radical solution copolymerization method in the presence of ammonium persulfate as initiator and urotropin and N,N methylene bisacrylamide as crosslinking agents. The formation of hydrogels was proved by extraction and IR spectroscopy. It is shown that hydrogels are able to fix the temporary form in iron (III) chloride solutions and reclaim it in solutions of ascorbic acid in less than 2 hours. Hydrogels based on sodium alginate have the best physical-mechanical characteristics compared with chitosan-based - the strength reaches 0.7 MPa and 0.11 MPa, the elasticity modulus is 1.02 MPa and 0.17 MPa at 65% deformation, correspondingly.

The article investigates the effect of polyisobutylene grades P-85 and P-200 on the vulcanization (rheometric) characteristics of a rubber mixture, physical-mechanical, operational, dielectric and dynamic properties of vulcanizates based on a combination of general-purpose rubbers. The investigated rubber mixture contained a combination of butadiene-methylstyrene SKMS30ARK, isoprene SKI-3 and butadiene SKD rubbers, sulfur, N-cyclohexyl-2-benzothiazole sulfenamide, tetramethylthiuram disulfide, zinc white, N-stearic acid, N-isopropyl-N'-phenyl-p-phenylenediamine, carbon black N 220, hollow corundum microspheres HCM-L and other ingredients. The rubber mixture was made on laboratory rolls LB 320 160/160. The first (basic) version of the rubber mixture was manufactured without the use of polyisobutylene. The second - the fourth version of it was prepared with the addition of polyisobutylene P-85, the fifth - seventh version polyisobutylene P-200. The rheometric characteristics of the rubber mixture were studied on an MDR 3000 Basic rheometer at 143 degrees C for 25 min. To determine the physical-mechanical properties of rubber, standard samples of all variants of the rubber mixture were vulcanized at a temperature of 143 degrees C for 25 min in a vulcanization press of the P-V-100-3RT-2-PCD type. Studies of the physical-mechanical, operational, dielectric properties of vulcanizates were carried out in accordance with the standards existing for the rubber industry. It is shown that an increase in the content of polyisobutylenes P-85 or P-200 in the rubber mixture leads to an improvement in the resistance of vulcanizates after 24 h thermal oxidative aging in air. According to dynamic mechanical analysis, it was found that rubbers containing 30.0 wt. including polyisobutylenes P-85 and P-200 per 100.0 phr including rubbers, have the largest maximum peak of the tangent of the angle of mechanical losses, the values of which are 0.611 and 0.639, respectively. Vulcanizate containing 30.0 phr including polyisobutylene P-200 per 100.0 phr including rubbers is characterized by stable elastic-strength characteristics, high dielectric and good vibration-clamping properties.

The copolymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) on chitosan (CTS) using ultrasonic irradiation was performed in the presence of ammonium persulfate (PSA) at a temperature of 343 K. The effect of the DMAEMA concentration in the reaction mixture on the copolymer yield, the degree and effectiveness of grafting, as well as on the physical–mechanical properties of films obtained on the basis of synthesized copolymers was studied. Copolymers formation was proven by extraction, FTIR spectroscopy, XRD analysis. CTS-graft-poly(DMAEMA) copolymers of various compositions were obtained. The DMAEMA grafting degree reached ~ 145 wt% and its grafting effectiveness was ~ 65 wt% with the ratio [DMAEMA]/[CTS] = 5 mol/(base-mol). The tensile strength (from 15.3 to 37.7 MPa) and deformation (from 68 to 612%) can be varied within a wide range by changing the composition of the copolymer and molecular weight of the grafted poly(DMAEMA) chains. Temperatures of physical transitions of the CTS-graft-poly(DMAEMA) copolymers were determined by the DSC and DMA methods; the resulting films are gas-permeable.

Modification of TiO2 surface with silver nanoparticles is an urgent task in the light of the development of new types of photocatalysts for cleaning the environment from organic pollutants. For achieving this goal, it is required to obtain systems in which the deposition of silver nanoparticles on the titanium dioxide surface has been carried out by a nontrivial, simple, non-labor intensive method. The essence of the method is that at first stage formation of Ag nanoparticles from AgNO3 under UV-irradiation in a solution of a stabilizing polymer – chitosan occurs, than TiO2 particles disperse in the resulting colloidal solution, and subsequent enzymatic destruction of polysacharide. As a result, Ag nanoparticles, the size of which is 22.0 ± 0.25 nm, completely settle on the TiO2 surface. It was found that in the reactions of decomposition of methylene blue, methylene orange and congo red in an aqueous solution under UV irradiation, modified TiO2 is 2–2.5 times more photocatalytically active than the initial titanium dioxide.

Optically transparent organic-inorganic terpolymers containing nanostructured poly (titanium oxide) (PTO or (≡TiO)n) in polymeric matrixes of poly (hydroxiethylmethacrylate) (pHEMA) and its copolymers with acrylonitrile (AN), 2-ethylhexyleacrylate, buthylmethacrylate, vinylbuthyl ether and exhibiting UV-induced reversible surface hydrophilization had been subjected by climatic tests in the Q-SUN Xe-2 light weathering chamber, which simulates the exposure of the material under ambient conditions for 20 months of its operation. Adhesion, physical-mechanical and thermal-physical properties of PTO-containing materials had studied before and after climatic testing. The materials retain the capacity for the one-electron transition Ti4+ + e‾ ⇆ Ti3+ under UV-irradiation after environmental testing, resulting in both photochromic properties and reversible surface hydrophilization. The photocatalytic activity of materials in stearic acid decomposition at terpolymer's surface of composition [(≡TiO)n]: [HEMA]: [AN] = 1:5:1 had proven.

To increase the surface hydrophobicity of organic-inorganic copolymers containing nanostructured polytanoxide, they were modifified with flfluorine-containing monomers which were introduced into the composition of the monomer mixture, followed by polymerization-polycondensation. The flfluorinated monomers used were 2,2,3,3,4,4,5,5-octaflfluoropentylacrylate, 1,1,1,3,3,3-hex aflfluoroisopropylacrylate, 2,2,3,3-tetraflfluoropropylmethacrylate. The surfaces of the synthesized terpolymers were examined by X-ray flfluorescence analysis and atomic force microscopy. The inflfluence of the nature of the third monomer on the content of titanium and flfluorine atoms in the surface layer and in the chips of the samples as well as on the topography of their surface was determined. The difference in the elemental composition affects the initial hydrophobicity of the samples surface and their ability to hydrophilize the surface under UV exposure. Terpolymers with 1,1,1,3,3,3-hexaflfluoroisopropylacrylate links exhibit the highest wetting angle - 102° - in the absence of UV exposure. However, the "hydrophobicity-hydrophilicity" switching mode is most clearly seen in the terpolymers with 2,2,3,3,4,4,5,5-octaflfluoropentylacrylate links when the wetting angle can be reversibly changed from 86° to 10°.

Graft copolymers of collagen and polymethyl methacrylate were synthesized in a suspension of an acetic acid dispersion of fish collagen and methyl methacrylate in the presence of tributylborane. The copolymers were characterized by IR spectroscopy, gel permeation chromatography, and differential scanning calorimetry. The glass transition temperature is determined for the obtained copolymers. Changes in the synthesis temperature in a range of 25–60 °C did not significantly affect the fraction and molecular weight of the graft polymethyl methacrylate. Microphotographs obtained by scanning electron microscopy and atomic force microscopy indicate the destruction of the fibrillous structure of collagen in the copolymer at the synthesis temperature higher than 25 °C. The hydrophilicity and light transmission of films of the synthesized copolymer samples were studied.

Optically transparent organic-inorganic terpolymers based on poly (titanium oxide), hydroxyethyl methacrylate and organic monomers of the vinyl and (meth) acrylic series (acrylonitrile, butyl methacrylate, vinyl butyl ether, 2-ethylhexyl acrylate) were obained as a coating on silicate glass, polycarbonate, touch-up paint and metal. Materials’ light transmittance in the visible spectral range is 87 - 92% depending on the composition. The adhesion of terpolymers’ thin layers to substrates of various natures was investigated under shear deformations and by the lattice notch method according to ISO 15140. It was found that it is necessary to selectively excerpt composition of terpolymers in accordance with the nature of the substrate for creation adhesive durable coatings. The most durable coatings are formed on glass, polycarbonate and automotive enamel. It was revealed that the nature of the substrate and the composition of organic-inorganic terpolymers affect the hydrophobicity of the coatings and their ability to hydrophilize under the influence of UV-irradiation. The contact wetting angle of coatings with water, on average, reversibly varied within ~ 90 ° ↔ ~ 30 °.

The graft-polymerization of N, N-dimethylaminoethylmethacrylate (DMAEMA) on chitosan (CTS) was performed in the presence of ammonium persulfate (PSA) at a temperature of 323K. The effect of the DMAEM concentration in the reaction mixture on the copolymer yield, the degree and effectiveness of grafting, as well as on the physical-mechanical properties of films obtained on the basis of synthesized copolymers was studied. The copolymers formation was prooven by gravimetric method, extraction, and IR spectroscopy. Chitosan-graft-DMAEM copolymers of various compositions were obtained. The grafing degree reached ~ 350 wt. % with the ratio [DMAEMA]/[CTS] = 5 (mol/(base-mol), the grafting effectiveness was ~ 86 wt. % with the ratio [DMAEMA]/[CTS] = 1 (mol/(base-mol). It was established that the changing the copolymers composition lead to variation of tencile strength and deformation characteristics of films widely from 1.4 MPa to 25.7 MPa and from 34% to 413%, correspondingly.

Composite materials of various compositions based on chitosan and polylactide were obtained in the form of films or porous bulk samples. Preliminarily, poly-d,l-lactide was synthesized by ring-opening polymerization of lactide in the presence of Ti(OiPr)4. Polylactide obtained at components molar ratio [lactide]:[Ti(OiPr)4] = 3:1 had the best molecular weight characteristics at a high product yield. Film composition with the weight ratio chitosan-polylactide 50:50 wt. % was characterized by high mechanical properties. The value of the tensile strength of the film was 72 MPa with a deformation of 10% and an elastic modulus of 40 GPa, which is higher than the tensile strength of native chitosan by ~three times. The observed effect is a consequence of the fact that the chitosan-polylactide composite has an amorphous structure in contrast to the native chitosan, which is proved by X-ray phase analysis. An increase in the elastic modulus of the composite in the range of 20–60 °C in contrast to polylactide was found by dynamic mechanical analysis. The observed effect is apparently caused by the formation of hydrogen bonds between functional groups of chitosan and polylactide which is possible through an increase in polylactide segments mobility when its glass transition temperature is reached. The composite material is biocompatible and characterized by high cellular adhesion of fibroblasts (line hTERT BJ-5ta). Their growth on the composite surface was 2.4 times more active than on native chitosan. Bulk porous samples of the composition with the weight ratio chitosan-polylactide 50:50 wt. % were synthesized by original method in ammonium bicarbonate presence. Samples were characterized by a porosity of 82.4% and an average pore size of 100 microns. The biodegradability of such material and absence of inflammatory processes were proven in vivo by the blood parameters of experimental animals. Thus, materials with the weight ratio chitosan-polylactide 50:50 wt. % are promising for potential use in regenerative medicine.

The thermophysical properties of nanocompositions containing conducting nanoparticles of silver, gold, and fullerene C(60)( )in nonconductive polymer matrices of various natures - chitosan, poly(vinylpyrrolidone), poly (methyl methacrylate), poly(allyl methacrylate), organic-inorganic copolymers based on hydroxyethyl methacrylate and poly(titanium oxide) are considered in detail. Gold or silver nanoparticles in polymer matrices of various natures were formed in situ by UV reduction of the corresponding precursors - HAuCl4 or AgNO3. The average size of the nanoparticles did not exceed 20 nm. Fullerene C-60 was introduced either directly into the polymer matrix during the mixing process or on the synthesis of the polymer. The thermophysical properties of all polymer nanocomposites were studied by differential scanning calorimetry and dynamic mechanical analysis. In all cases, there is a significant decrease in the glass transition temperatures of the composites by an amount from 20 to 60 degrees C relative to the glass transition temperature of the polymer matrix.