Magnetic force microscopy investigation of domain structure and magnetic recording patterns in high-coercive garnet films with low Curie temperature

Authors present the investigation of domain structures and thermomagnetic recording patterns in iron garnet thin films by magnetic force microscopy. Iron garnet films with low Curie temperature and high coercivity were designed for recording process. Magnetic pattern of PC floppy disc was recorded in iron garnet film by contact printing method. Topography and magnetic structure of floppy disc and iron garnet film before and after thermomagnetic recording process are presented. Accuracy of thermomagnetic recording and parameters, which are influence on it, are discussed.The authors from V.I. Vernadsky Crimean Federal University acknowledge support by the RF Ministry of Education and Science (project no. 3.7126.2017)

Полимеризация стирола в присутствии кремнийорганических ПАВ различной природы

The characteristics of polymer suspensions received in the presence of different siliconorganic detergents were compared. The polymer suspensions have the narrow distribution of particles by size and contain the functional groups on their surface.Проведено сравнение свойств полимерных суспензий, полученных с использованием кремнийорганических ПАВ различного строения. Полученные полимерные суспензии характеризуются узким распределением по размерам и содержат на своей поверхности функциональные группы

Получение диагностических тест-систем на основе полимерных микросфер в присутствии поливинилпирролидона, модифицированного аминокислотой

Styrene-divinylbenzene particles (6 microns in diameter) with carboxyl groups on the surface have been synthesized by seed polymerization in the presence of an organosilicon carboxyl-containing surfactant soluble in the monomer phase. It has been shown that carboxyl groups on the microsphere surface are accessible for covalent immobilization of bioligands and alanine-modified polyvinylpyrrolidone. It was supposed that applying modified polyvinylpyrrolidone for obtaining diagnostic systems based on polymer microspheres is very perspective.етодом затравочной полимеризации в присутствии растворимого в мономерной фазе кремнийорганического карбоксилсодержащего ПАВ были синтезированы сополимерные стирол-дивинилбензольные микросферы диаметром 6 мкм с карбоксильными группами на поверхности. Было показано, что карбоксильные группы доступны для ковалентного связывания биолигандов и поливинилпирролидона, модифицированного аланином. Высказано предположение о перспективности применения поливинилпирролидона, модифицированного аланином, для получения диагностических систем на основе полимерных микросфер

Polymerization of styrene in the presence of different siliconorganic detergents.

The characteristics of polymer suspensions received in the presence of different siliconorganic detergents were compared. The polymer suspensions have the narrow distribution of particles by size and contain the functional groups on their surface

Identifying the Influence of the Polymer Matrix Type on the Structure Formation of Microcomposites When They Are Filled with Copper Particles

Studies were carried out to establish the mechanisms of structure formation during crystallization of polymer composites based on polyethylene, polypropylene or polycarbonate filled with copper microparticles. The researches were executed using a technique, the first stage of which consisted in the experimental determination of crystallization exotherms of composites, and the second – in the theoretical analysis based on the obtained exotherms of the structure formation characteristics. A complex of studies on determination of crystallization exotherms for investigated microcomposites was carried out. The regularities of the cooling rate influence of composites, the method of their production and the mass fraction of filler on the temperature level of the beginning and ending of crystallization, the maximum value of the reduced heat flux, etc. were established. It is shown that for the applied methods of obtaining composites the increase of their cooling rate causes the decrease of the indicated temperatures and heat flux. It is established that the value of the mass fraction of the filler has a less significant effect on the characteristics of the crystallization process.The regularities of structure formation of polymer composites at the initial stage of crystallization with the involvement of data on crystallization exotherms and nucleation equations are investigated. The presence of planar and three-dimensional mechanisms of structure formation at this stage has been established. It is shown that the ratio of these mechanisms is influenced by the type of polymer matrix and the method of obtaining composites.For the second stage of crystallization, which occurs in the entire volume of the composite, the results of experiments on crystallization exotherms were analyzed on the basis of the Kolmogorov-Avrami equation. It is shown that the structure formation of polyethylene-based composites occurs by the three-dimensional mechanism, and on the basis of polypropylene and polycarbonate – by the mechanism of the stressed matri

The synthesis diagnostic test systems on the basis of polymer microspheres in the presence of polyvinylpyrrolidone modified with an amino acid

Styrene-divinylbenzene particles (6 microns in diameter) with carboxyl groups on the surface have been synthesized by seed polymerization in the presence of an organosilicon carboxyl-containing surfactant soluble in the monomer phase. It has been shown that carboxyl groups on the microsphere surface are accessible for covalent immobilization of bioligands and alanine-modified polyvinylpyrrolidone. It was supposed that applying modified polyvinylpyrrolidone for obtaining diagnostic systems based on polymer microspheres is very perspective