Topicality and demand of the theme of dissertation. One of the actual problems of modern physical chemistry and macromolecular chemistry is the study on the development of the fundamentals of synthesis of functional polymers with ion-exchange and complexing properties.
Anion exchange and complexing compounds based fibrous materials have a high specific surface area, which provides a high possibility of sorption and desorption processes. They arc especially effective in removing toxic substances, even at very low content of the latter from the air and water pollution. Of particular interest is the acrylic fiber "Nitron", which is produced by JSC "Navoiazot" (Uzbekistan).
In the Academy of Sciences of the Republic of Uzbekistan, Tashkent Institute of Textile and Light Industry conducted research on the development of fibrous ion exchange materials based on acrylic fiber "Nitron" but they have not been brought to its logical end. In addition, when these studies neglected the study of the physicochemical aspects of the preparation of these materials.
In developing the fundamentals of ion exchange materials obtaining a lot of attention paid to the study of physical and chemical aspects of the synthesis and properties of these high-molecular compounds. These studies due to the fact that they allow you to adjust the processes of synthesis and, therefore, necessary to obtain polymers with required composition and with complex specific properties.
As noted above, to date, no attention was paid to the study of the physicochemical foundations of anion exchangers and polycomplcxons, due to applied research conducted to date in this field of research. In this regard, the study of physical and chemical principles of bases of creation, and the properties of anion exchangers and polycomplcxons based on acrylic fiber "Nitron" arc actual both from a theoretical and practical point of view.
Demand perform of the dissertation is characterized by the fact that modern worldwide technology for extraction of non-ferrous and precious metals can not be realized without the use of ion-exchange materials. These techniques use mostly granular sorbents, while fibrous sorbents comprise just 2-3 % of the ion exchange materials used . Using technology employing ion exchange material from algae and natural brine deposits of oil and gas recovered to 90% of iodine and bromine, lodinc-containing sorbents arc used for disinfection of drinking water from microorganisms and extraction of mercury from wastewater and gas emissions. They can be used for concentrating the processing solutions and biologically active substances in the preparation of catalyst systems nanoparticles metals. It should also be noted that Uzbekistan hitherto not been established as industrial manufacture granular and fibrous sorbents, although such polymers arc widely used in industry.
The purpose of this study is to identify the physico- chemical characteristics of the formation and properties of anion exchangers polycomplcxons based on acrylic fiber " Nitron ".
Scientific novelty of disscrtational research consists in the following:
in the first time studied the kinetics of the interaction of acrylic fiber "Nitron" with nitrogen-containing bases in aqueous and organic media;
shown that due to the high surface area fibers arc modifiable , the reaction rate depends on the concentration of the nitrile groups of the polymer being in the solid surface;
proved previously identified mechanism of the catalytic action of small amounts of hydroxylaminc on the process of modifying of fiber " Nitron " with nitrogen-containing bases;
in the first lime developed a method for producing anion exchangers branched structure by sequential treatment of acrylic fiber " Nitron " with cthylcncdiaminc and dichlorocthanc;
found that the interaction of PAN - fibers with hcxamcthylcnc- and ethylene diamines formed anion exchange fibrous materials having in its composition as a weakly basic and strongly basic functional groups ;
in the first time obtained new polycomplcxons with ampholytic properties by reacting maleic anhydride with amine -modified polyacrylonitrile fiber " Nitron " or by hydrolysis of residual of the nitrile groups modified with diamines of acrylic fiber "Nitron";
established values of the thermodynamic equilibrium constants of adsorption of ions Cr (VI), Си (II), halogens, Arsenazo (III) by synthesized anion exchangers and polycomplcxons and alteration in thermodynamic functions of the process testify to high sorption capacity of these ion-exchange materials with respect to the sorption ions;
Conclusion
1. Values degree reaction of the nitrile group and a nitrogenous base, the activation energy of the process shows that the process of modifying fiber " Nitron " nitrogen-containing bases subject to the usual regularities observed in homogeneous reactions. This effect is due to a high fiber surface area to be modified, allowing the reactants to facilitate access to the nitrile groups of the polymer. (Physical chemistry, High molecular compounds).
2. Kinetic studies of the reaction of acrylic fiber " Nitron " with diamine (hexamethylene and ethylenediamine) showed that the change of physical and chemical parameters of the modification process can be controlled sorption properties, chemical resistance and the strength of the anion exchangers due to network structure of the polymer. It has been established that this modification "Nitron" produces strongly basic anion character especially in organic media. Strongly basic anion exchangers possibility of obtaining a high sorption capacity with graft polycthylcnpolyaminc chain reactions revealed in fiber modification "Nitron " ethylenediamine in the presence of dichloroethane. (High molecular compounds, Physical chemistry ).
3. IR - spectroscopic and analytical determination of the formation of intermediate amidoxime groups in the polymer chains and free hydroxylaminc after substitution reaction proved previously proposed mechanism of the catalytic action of hydroxylaminc on the process of chemical modification of acrylic fiber " Nitron " nitrogen-containing bases . ( Physical Chemistry).
4. Developed conditions of synthesis polycomplcxons reacting maleic anhydride with modified by hcxamcthylcncdiaminc acrylic fiber "Nitron" and with of hydrolysis of residual nitrile groups modified by hcxamcthylcnc- and cthylcncdiamin of acrylic fibers . (High molecular compounds, Physical Chemistry).
5. Alkalinity obtained anion exchange resins depends on the nature of their functional groups. Strongly basic anion exchangers have in their composition cyclic amidine groups and they arc formed by the reaction of polyacrylonitrile fiber with a diamine. The specific surface area obtained fibrous sorbents exceeds by two orders of known surface area granular ion exchange resins, and their crosslinking rate is up to 100 nodes per macromolecule polymer. ( Physical Chemistry )
6. Kinetics and thermodynamics of the sorption of various inorganic and organic ions obtained polycomplcxons sorbents showed that ions of Cr (VI), Arsenazo (111) can be sorbed strongly basic anion exchangers only, and the process of sorption of copper (II) with polycomplcxons occurs not only due to the ion exchange, but also due to chelation. ( Physical Chemistry ).
7. Developed the conditions obtaining bromide complexes of polymers and kinetics, thermodynamics of the sorption halogen anion in synthesized materials was studied. It is shown that the lower the stability of the ion [Bn]’ for ion [J3]'than the ability to form such molecular chlorine ions leads to the fact that almost no molecular chlorine is adsorption, and molecular bromine is absorbed to a lesser extent than the molecular iodine. (Physical Chemistry ).
8. Combined developed iodinated anion exchange materials based on acrylic fiber " Nitron " and chitosan. Insertion of the iodinc-containing chitosan materials, leads to an increase of absorbent capacity. Combined antibacterial dressings have a pronounced anti-inflammatory and antibacterial effect, arc effective for the treatment of necrotic soft tissue diseases. (High molecular compounds, Physical Chemistry).
Mazkur maqolada nuqtadan tekislikka parallel to‘g‘ri chiziq o‘tkazishni talabalarga nazariy va amaliy bog‘liqligida bilim berish orqali fazoviy tasavvurini oshirish ko‘rsatilgan.
In the struggle for the well-being of mankind and their environment, the habitat is green, human beings create poisonous drugs to destroy pests. Until recently, in the mid 20th century, chemicals were called poisons to control pests of agricultural crops, and today in our time they are called such pesticides.
Pesticides (Latin pestis - infection and caedo - kill). They are compounds that have a special place among living organisms that are alien to living organisms - compounds called xenobiotics. More than 4 million pesticides are used against pests worldwide, of which only 1% is effective. The development of hygienic standards for pesticides is of particular importance to prevent the negative effects of pesticides on the human body and the environment. The resistance of Seller's insecticide to soil, its movement through layers, accumulation, the degree of transfer of plants to the surface, the level of atmospheric air pollution at the workplace and atmospheric air when processing crops were evaluated.
Pesticides inevitably lead to profound changes in ecosystems, as they have a wide range of toxic effects on all living organisms. The names "Fungicide", "Acaricide", "Herbicide" and others, which are included in them, are to some extent conditional.
Chemical treatment of any pesticide can always give unexpected results i.e. it can cause a destructive effect, including for plants trying to protect. Often the plants are weakened and defeated by pests
Мақолада минерал ўғитларга теримк ишлов бериш орқали қуритиш жараёни ва унда қўлланиладиган қурилмаларнинг тахлили, жараёндаги мавжуд муаммолар ва уларнинг мақбул ечимлари ҳамда барабанли қуритгичнинг гидродинамик режимлари тадқиқ қилинган. Қурилманинг умумий гидравлик қаршилиги ва контакт элементнинг қаршилик коэффициентини аниқловчи тенглама тавсия этилган.
Maqolada kontakt elementi uyurmali oqim xosil qiluvchi ho‘l usulda chang ushlovchi va gaz tozalovchi qurilmaning gidrodinamik qarshiliklari aniqlash rejimlari tavsiya etilgan.
Ushbu maqola topografik chizmachilik fanini o‘qitishda grafik dasturlardan foydalanilgan holda talabalarning fazoviy tasavvurini hamda ko‘nikma va malakalarini oshirishga qaratilgan. Topografik chizmachilikning nazariy qonun-qoidalarini bilish talabalarning topografik chizmachilik fanidan yanada chuqurroq bilimga ega bo‘lishlariga yordam beradi.
Для подогрева сырья в нефтеперегонной установке используются горячие технологические потоки, выходящие из ректификационной колонны - дистилляты топливных фракций и мазута [1-4]. Для подогрева углеводородного сырья на НПЗ в основном применяют трубчатые теплообменные аппараты [2;4;5;6].
Simblefaron is a scar fusion of the posterior conjunctival surface of the eyelid with the eyeball. It often develops as a complication of thermal burns of the eyes. Eye burns are severe damage to the organ of vision and occupy a significant share (6.9-30.5%) in the structure of eye injuries. The results of the study showed that the stage-by-stage surgical plastic surgery of the anterior segment of the eye performed by us, which consists in a combination of plastics of the fornix with flaps from the automucosal cavity of the mouth (lips) and transplantation of the amniotic membrane onto the surface of the cornea and conjunctiva with the capture of the limbal zone, allows you to eliminate the defect of the cornea and maintain its transparency and also contributes to the restoration of the conjunctival arches, which can significantly reduce the likelihood of developing complications of burn injury and shorten the rehabilitation period, improve the functional results of treatment.
Одним из способов декорирования фарфоровых изделий является украшение декоративными глазурями и цветными массами. Цветные массы употребляют в виде пластичного теста для формования и лепки. Использование для декорирования готовых цветных масс дает возможность упростить сложные процессы нанесения различных по цвету керамических красок на поверхность художественно-декоративных изделий.
Резорбция костной ткани после удаления зуба более выражена со стороны вестибулярной кортикальной пластинки, которая резорбируется как по высоте, так и по ширине. В исследовании Pietrikovski показано, что редукция ширины со стороны вестибулярной кортикальной пластинки более выражена в связи с тем, что формируется уплощенная поверхность, которая соединяет альвеолы соседних зубов.