Hydrogels Based on Polyvinylpyrrolidone Copolymers

The role of polyvinylpyrrolidone (PVP) complex formation with water-soluble 2-hydroxyalkyl methacrylates is described. The impact of the complexation on both the polymerization kinetics and the formation of a copolymer structure initiated by radical initiators has been studied. The activating effect of iron(II) and iron(III) sulfates has been revealed for the initiator-free polymerization of the formulation. An analytical approach to determining the molecular weight of the chain fragments located between two neighboring cross-linking nodes in the polymer network (Mn) has been developed depending on the values of the stability constant (Кst) for the charge-transfer complexes. The basic regularities of hydrogels obtaining based on PVP copolymers with high sorption capacity and diffusion characteristics are presented. The main directions of practical application of synthesized hydrogels are considered

Термогравіметричні дослідження композитів на основі сумішей поліпропілену та модифікованого поліаміду

We established in the present work the regularities for obtaining homogeneous nanocomposites based on the mixture of PP/PA-6 with montmorillonite modified using PVP. In these nanocomposites, PA-6 and MMT contribute to the increase in thermal resistance of the material, while PVP improves compatibility between polar PA-6 and hydrophobic PP.The goal of the present work was to investigate by applying the methods of thermogravimetric analysis a correlation between thermal characteristics of the newly-created nanocomposites based on the mixture of PE/PA-6 with montmorillonite, modified using PVP, and to determine the optimal composition of a nanocomposite with enhanced thermal resistance and a wide temperature interval of the viscous-fluid state.On the basis of experimental data, it was found that the mixtures of polypropylene with polyamide modified by the montmorillonite-polyvinylpyrrolidone mixture are distinguished by the higher thermal resistance compared with the starting PP. It is established that at a content of the modified polyamide in the mixtures with polypropylene within 30 % by weight, samples of the composite are characterized by the highest thermal resistance ‒ weight loss of such composites in a temperature range of 218‒322 ºC is only 7.1 %, temperature of the onset of thermo-oxidation destruction is 300 ºC. It is shown that the developed nanocomposites have wider temperature intervals of the viscous-fluid state – 126–300 ºC. This makes it possible, by changing the modes of processing, to influence the structure and properties of products, especially taking into account the difference in crystallization of the material depending on the conditions and the method of processing. It is established that the most suitable for application and processing is the mixture of polypropylene with modified polyamide in the ratio 70:30 % by weight, respectivelyМетодами дифференциально-термического, термогравиметрического и дифференциально-термогравиметрического анализов исследованы композиты на основе смесей полипропилена с полиамидом, который предварительно модифицирован монтмориллонитом, интеркалированным поливинилпирролидоном. Показано, что смеси полипропилена с модифицированным монтмориллонит-поливинилпиролидоновой смесью полиамидом отличаются повышенной термостойкостью. Установлено, что при содержании модифицированного полиамида в смесях с полипропиленом в пределах 30 % масс. образцы композита характеризуются найвысшой термостойкостьюМетодами диференційно-термічного, термогравіметричного та диференційно-термогравіметричного аналізів досліджено композити на основі сумішей поліпропілену з поліамідом, котрий попередньо модифікований монтморилонітом, інтеркальованим полівінілпіролідоном. Показано, що суміші поліпропілену з модифікованим монтморилоніт-полівінілпіролідоновою сумішшю поліамідом відзначаються підвищеною термостійкістю. Встановлено, що за вмісту модифікованого поліаміду в сумішах з поліпропіленом в межах 30 % мас. зразки композиту характеризуються найвищою термостійкіст

Rheological Properties of Compositions Based on Modified Polyvinyl Alcohol

The paper is dedicated to development of a method for producing structured waterproof films based on polyvinyl alcohol (PVA) and montmorillonite-polyvinylpyrrolidone mixture (MPM) to research the impact of borax, pH-environment and MPM content on the rheological properties PVA solutions and water absorption capacity of films based on them. By experimental studies have been established that the montmorillonite- polyvinylpyrrolidone mixture significantly affects on viscosity the characteristics of the solution polyvinyl alcohol provided their mixing in the ultrasonic field. Composition of traces of sodium tetraborate in the aqueous solution eminent by the highest rates of viscosity. Also, designed compositions considerable influence pH at the viscosity, particularly compositions obtained in weakly alkaline environment with higher values of relative viscosity than compositions obtained in neutral and acidic environments. Simultaneously, is the best water resistance and mechanical properties of films obtained in an acidic environment. The optimum from the standpoint of durability and water resistance is a composition of PVA:MPM = 12:1 and because, depending on the contents of the MPM and pH characteristics films based on PVA can be adjusted over a wide range, which would expand the scope

Usage of Mathematical Modeling and Optimization in Development of Hydrogel Medical Dressings Production

In connection with the significant complication of research objects of technological systems and the considerable increase in expenses for carrying out experimental research, improving the mathematical modeling methods of these systems is a current problem. By using the means of mathematical modeling and optimization, the calculation of the main technological parameters of the formation method of film hydrogel products based on silver-filled copolymers of 2-hydroxyethylmethacrylate with polyvinylpyrrolidone was performed. The technological parameters of the polymerization processes, chemical reduction of silver ions, and centrifugal formation of the film cloth were substantiated. These are the components of the technological process, which occurs in one stage in the form of a centrifugal unit. By using the obtained results, silver-filled films were obtained, which are characterized by unique properties and can be used in the treatment of trophic ulcers of lower limbs

Effect of Nature and Amount of Polypropylene Composite Filler on the Productivity of Extruder with the Cylinder Equipped with Grooves

The effect of grooves number in the feed section and screw length as well as filler nature and content on the productivity of single-screw extruder has been examined. Compositions based on polypropylene with glass fibers, talc and chalk were used for research. It is established that the number of grooves in the feed section and the length of the screw differently affect the productivity of a single screw extruder depending on the nature and content of the filler. This effect is shown to be most significant for polypropylene compositions with mineral powders (talc and chalk)

Thermogravimetric Research Into Composites Based on the Mixtures of Polypropylene and Modified Polyamide

We established in the present work the regularities for obtaining homogeneous nanocomposites based on the mixture of PP/PA-6 with montmorillonite modified using PVP. In these nanocomposites, PA-6 and MMT contribute to the increase in thermal resistance of the material, while PVP improves compatibility between polar PA-6 and hydrophobic PP.The goal of the present work was to investigate by applying the methods of thermogravimetric analysis a correlation between thermal characteristics of the newly-created nanocomposites based on the mixture of PE/PA-6 with montmorillonite, modified using PVP, and to determine the optimal composition of a nanocomposite with enhanced thermal resistance and a wide temperature interval of the viscous-fluid state.On the basis of experimental data, it was found that the mixtures of polypropylene with polyamide modified by the montmorillonite-polyvinylpyrrolidone mixture are distinguished by the higher thermal resistance compared with the starting PP. It is established that at a content of the modified polyamide in the mixtures with polypropylene within 30 % by weight, samples of the composite are characterized by the highest thermal resistance ‒ weight loss of such composites in a temperature range of 218‒322 ºC is only 7.1 %, temperature of the onset of thermo-oxidation destruction is 300 ºC. It is shown that the developed nanocomposites have wider temperature intervals of the viscous-fluid state – 126–300 ºC. This makes it possible, by changing the modes of processing, to influence the structure and properties of products, especially taking into account the difference in crystallization of the material depending on the conditions and the method of processing. It is established that the most suitable for application and processing is the mixture of polypropylene with modified polyamide in the ratio 70:30 % by weight, respectivel

EFFECT OF SMALL ADDITIVES OF POLYAMIDE MODIFIED BY POLYVINYLPYRROLIDONE AND MONTMORILLONITE ON POLYPROPYLENE TECHNOLOGICAL PROPERTIES AND HEAT RESISTANCE

The effect of small polyamide additives modified with polyvinylpyrrolidone and montmorillonite on polypropylene technological properties and heat resistance has been researched in the work. It has been determined that the melt flow index of the obtained composites increases by more than 2 times in comparing with pure PP. It has been shown that adding to polypropylene a small amount of polyamide which is modified by montmorillonite-polyvinylprolidone mixture significantly increases the heat resistance of the material. The displacement of the beginning of thermal-oxidation destruction and burning samples into the range of higher temperatures on 114-123 oC dependently on the modified polyamide content has been observed

Nanocomposites Based on Polyamide and Montmorillonite Obtained from a Solution

This work deals with the development of a method for obtaining polyamide and montmorillonite based nanocomposite, which was modified with polyvinylpyrrolidone by mixing in a formic acid solution. The structure and thermophysical properties of the obtained nanocomposites were investigated by means of the X-ray, differentialthermal, thermogravimetric and IR spectroscopic analyses. It was found that nanomodified polycaproamide has a higher crystallinity and higher thermal stability than the original PA-6, and is characterized by considerably higher melt fluidity. The presence of polyvinylpyrrolidone and exfoliated montmorillonite in the nanocomposite structure was confirmed experimentally