Films are prepared from an aqueous solution of polyvinyl alcohol (PVA) and silver nitrate AgNO3 under ultraviolet irradiation (UV). The effect the filler has on their physicochemical and relaxation properties is studied via relaxation spectrometry. The resulting spectra are characterized by two local temperature peaks of dissipative losses, regardless of the state of silver in the PVA structure. With PVA–Ag+ chelates, the intensity of the peak responsible for vibrations of OH-groups falls and is partially restored after irradiating samples with UV light. Shear modulus G(T) for the original PVA matrix is higher than the one for the filled system (PVA–AgNO3). The temperature of the glass transition in the region where the α peak appears is reduced in filled systems.

Путем сравнительного анализа спектров внутреннего трения исследован диссипативный α-процесс релаксации в пленках поливинилового спирта (ПВС) и в супрамолекулярной композитной структуре, образующейся при формировании упорядоченных областей в системе ПВС–I2–KI. Показано, что структурные изменения в образцах поливинилового спирта, происходящие при введении йода, вызывают увеличение релаксационной микронеоднородности всей системы в области температур α-процесса релаксации.

The dissipative α-relaxation process in poly(vinyl alcohol) (PVA) films and in a supramolecular composite structure resulting from the formation of ordered regions in a PVA–I2–KI system has been studied by the comparative analysis of internal friction spectra. It has been shown that structural changes that occur in poly(vinyl alcohol) samples upon the incorporation of iodine enhance the relaxation microinhomogeneity of the entire system in the temperature region of the α-relaxation process.

The dissipative α-relaxation process in PVA films and in the supramolecular composite structure formed during the formation of ordered regions in the PVA–I2–KI system is studied by a comparative analysis of internal friction spectra. It is shown that the structural changes in the samples of polyvinyl alcohol that occur with introduction of iodine increases the relaxation microuniformity of the entire system in the temperature range of the α-relaxation process.

The effect of ionizing radiation on the segmental mobility of chains of polyvinyl alcohol (PVA) macromolecules has been studied by relaxation spectrometry. It has been shown that depending on the electron beam radiation dose, the degree of relaxational microinhomogeneity of the α-relaxation process increases significantly due to the scission of macromolecule chains or their crosslinking and structural rearrangement. No significant changes in the mechanical properties of PVA depending on the γ-radiation dose at absorbed doses in the range from 700 to 1500 kGy have been revealed.

The polyvinyl alcohol–chitosan composite system at a 1 : 1 ratio between the components is studied. The internal friction spectra are recorded, and the temperature dependences of the frequency of the free damped torsional vibrations excited in the system are investigated. The physicomechanical and physicochemical characteristics of α-relaxation are calculated and a theoretical analysis is made of the use of the Kohlrausch function to describe the relaxation microheterogeneity of structural-kinetic elements, the mobility of which gives rise to this dissipative process.

The effect of electron irradiation (doses up to 53 kGy) on the relaxation properties and segmental mobility in polyvinyl alcohol molecules has been studied using relaxation spectrometry. It has been shown that radiolysis leads to the formation of radicals that do not cause crosslinking of polymer chains. Irradiation with electrons causes a linear increase in the relaxation microheterogeneity of the alpha-process in the internal friction spectrum; this change manifests itself in broadening of the corresponding loss peak.

Методом свободно затухающих крутильных колебаний получены и проанализированы спектры внутреннего трения в системе хитозан поливиниловый спирт в широком температурном интервале. По температурно-частотным зависимостям, определены времена релаксации в областях релаксационных переходов. Установлено, что полученный в виде пленки композитный материал хитозан поливиниловый спирт, имеющий соотношение компонентов 1:1, представляет собой однородную (дисперсную) систему, в которой выявлено заметное влияние поливинилового спирта на релаксационные характеристики хитозана. By the method of freely damping torsional vibrations, the internal friction spectra were obtained and analyzed in the chitosan polyvinyl alcohol system over a wide temperature range. From the temperaturefrequency dependences, relaxation times in the regions of relaxation transitions are determined. It was found that the composite material obtained in the form of a fi lm, chitosan polyvinyl alcohol, having a component ratio of 1:1, is a homogeneous (dispersed) system, in which a noticeable effect of polyvinyl alcohol on the relaxation characteristics of chitosan was revealed.

Предложен способ управления смачиваемостью поверхности фторированного материала и контроля биообрастания за счет внедрения в структуру модифицированного наноалмаза. На примере сенсора молекулярного кислорода с помощью комплекса методов определены оптимальные условия модифицирования, не приводящие к изменению прочих функциональных свойств материала, таких как градуировочная зависимость и время отклика. Испытания in vitro показали, что небольшое количество аминированных наноалмазов придает поверхности бактерицидные свойства, но при большом содержании, напротив, наблюдается улучшенная адгезия биоматериала за счет уменьшения гидрофобности. Длительные испытания in situ в условиях, симулирующих биореактор с активно растущей биомассой, продемонстрировали практически полное отсутствие биологического обрастания у модифицированного материала и значительное обрастание сенсора из традиционно применяемого полистирола.

The internal friction spectra λ = f ( T ) were obtained experimentally and the frequency of the free damped vibrational process v = f (T) was determined for an excited polyvinyl alcohol-chitosan system on the temperature interval of –150-250°C. Theoretically analyzed is the possibility of using the Maxwell function to describe the local dissipative processes observable on different temperature ranges of dynamic studies. The physical and chemical characteristics of various local dissipative relaxation processes are calculated for the spectra of individual components and of the composite as a whole.

Phase equilibria in the mixtures of polyvinyl alcohol (PVA) and chitosan were revealed. Structures of the phases were identified. The temperature and concentration dependences for the chitosan—PVA and chitosan—PVA—water systems were determined. The phase state diagram was built. It is shown that the polymer mixtures are characterized by a complex supramolecular organization, which corresponds to their phase diagram.

The internal friction spectra λ = f(T) and the temperature dependence ν = f(T) of the frequency of free damping in the temperature range from –150°C to 120°C of microwave-irradiated and nonirradiated samples of polyvinyl alcohol were obtained. A theoretical analysis of nature of the peak located on the ascending branch of the α-peak of relaxation losses on the internal friction spectrum is carried out, and its disappearance after the microwave irradiation is explained. A comparison of changes in the continuous spectrum of relaxation times in the region of glass-transition temperature is performed. It is established that microwave irradiation expands the spectrum of relaxation time, and, consequently, increases the relaxation microinhomogeneity of the α-relaxation process.

The spectra of internal friction and temperature variation in the frequency of free damped torsional vibrations excited in a polyvinyl alcohol (PVA) sample in the temperature range from –150 to 0°C were investigated. Several local dissipative processes of low intensity were detected in the spectrum in the temperature range from –150 to –90°C and one more intense dissipative process in the temperature range from –70 to 0°C. According to these processes, deviations from the linear change in frequency of the vibration process were observed in the temperature-frequency relations in these temperature ranges. The mechanisms of internal friction for each of the dissipative processes are considered, and their probable structural interpretation is proposed. The defects of shear modulus arising in these processes are determined, and their contribution to the shear modulus of the entire PVA system is evaluated.

Inner friction spectra are obtained and analyzed for various chemical structures of chitosan—temperature dependence of logarithmic damping factor of free torsion motion λ = f(Т) and temperature change of their frequency ν = f(Т) within the range from –150°С to 300°С. In basic and salt forms of chitosan, three intense local dissipative phenomena are revealed. It was found that each local dissipative process has correspondent characteristic change of frequency of oscillating process, stimulated in chitosan samples. This fact allowed one to reveal and theoretically analyze the change of shear modulus defect both for local temperature ranges and for the entire chitosan system as a whole.