The surface treatment of the cardboard in the wet condition by biomodified starch

Поверхностная проклейка бумаги придает ей гидрофобные свойства с одновременным повышением физико-механических и печатных показателей. Крахмал является одним из старейших и наиболее распространенных связующих веществ, используемых в производстве бумаги и картона. Однако в настоящее время вместо нативного крахмала в качестве связующего чаще используются модифицированные крахмалы различного вида. Такие амилолитические ферменты, как амилаза, изоамилаза и пуллуланаза, вызывают энзиматическую модификацию крахмала. Показано, что обработка амилолитическими ферментами крахмала перед поверхностной пропиткой картона заметно улучшает его упругие и деформационные характеристики, поскольку ферментативная модификация крахмала влияет на характер связей, образующихся между крахмалом и волокнами целлюлозы, от чего зависит, какое количество крахмала проникнет между волокнами целлюлозы, а сколько останется на поверхности в виде пленки. От этого соотношения зависит, насколько сильно изменится способность получаемого композитного материала сопротивляться прилагаемой нагрузке. Пропитка картона биомодифицированным крахмалом приводит к увеличению количества водородных связей между волокнами целлюлозы и гидроксильными группами крахмала, что обеспечивает повышенную жесткость при растяжении уже на начальном участке деформирования. При этом повышение физико-механических показателей зависит от вида ферментного препарата и, соответственно, от механизма гидролиза связей в крахмале. Установлено, что обработка картона при 50 сухости амилолитическими ферментами амилазой, изоамилазой или пуллуланазой приводит к значимому увеличению упругости картона после кратковременного увлажнения, но не оказывает значимого положительного эффекта на прочностные характеристики картона при сухости 50 . Paper surface impregnation imparts it hydrophobic properties with a simultaneous increasing in physical-mechanical and printed properties. Starch is one of the oldest and most accepted binders used in the production of paper and cardboard. However, at present time various kinds of modified starch are more often used as a binders instead of native starch. Such amylolytic enzymes as amylase, isoamylase and pullulanase cause enzymatic modification of starch. It has been shown that treated with amylolytic enzymes starch before surface impregnation significantly improves elastic and deformation characteristicsof cardboard, since the enzymatic modification of starch affects the nature of the bonds formed between starch and fibers and determines which part of starch penetrates between the cellulose fibers and which part of starch remains on the surface in the form of a film. It depends the ability of the resulting composite material to resist the applied load. Cardboard impregnation with biomodified starch leads to an increasing in the number of hydrogen bonds between the cellulose fibers and the hydroxyl groups of starch, which provides increased rigidity in tension already at the initial part of the deformation. At the same time, an increasing in physicmechanical parameters depends on the type of enzyme and, accordingly, on the mechanism of hydrolysis of bonds in starch. It has been established that impregnation of cardboard with 50 dryness with amylolytic enzymes amylase, isoamylase or pullulanase leads to a significant increasing in the elasticity of the cardboard after a short-term wetting, but does not have a significant positive effect on the strength characteristics of cardboard with 50 dryness.

Modifying of the Surface of Products from Cast Iron as the Element of Production Modernization

The way of solving the problem of surface wear of products from cast iron due to development of technological processes of its strengthening treatment is offered in this article. Receiving the hardened skins is reached by purposeful formation of the set structural condition of metal by methods of surface impregnation, i.e., modifying. Results of researches on thermochemical treatment of cast irons of grades EN-GJL-250, EN-JS1060 are presented The micro-structural analysis showed that with rising the saturation temperature and increasing the process duration the layer depth cartbonitration increases. Studying the samples for wear resistance carried out on stand ММ 295 showed that for grade EN-GJL-250 it increased 2,2 times, and for grade EN-JS1060 – 3 times as compared to the initial (non-modified) state. Experimental-industrial tests of products of cast iron (model accessory, parts of homogenizing pumps) after carbonitration permitted to state 2-4 times of its surface.

Perfluorinated Ammonium and Phosphonium Ionic Liquids

Ammonium and phosphonium ionic liquids with perfluorinated side chains were prepared as hybrid materials for surface impregnation. Melting points of the triflimide salts range up to 95 °C. The key feature of this investigation are relatively short perfluorohexyl residues as the fluorinated part of the cations, making the target compounds beneficial alternatives to established products because of their enhanced degradability and therefore lower bioaccumulativity. In the ammonium series, pyrrolidinium, piperidinium, morpholinium triflimides as well as the dication derived from DABCO were prepared. Mono-phosphonium triflimides were obtained from triphenyl- and diphenylphosphane. Diphosphonium bistriflimides were obtained from bis(diphenylphosphano)alkanes, Ph2P(CH2)nPPh2 with n = 2–5. As alkylating reagents, n-C6F13CH2CH2OTf and n-C6F13CH2CH2I were applied.