IMPROVING THE WEAR RESISTANCE OF PAINT AND VARNISH MATERIALS FOR ROAD MARKINGS BY INTRODUCING HIGHLY DISPERSED ADDITIVES

Возможность управления качеством продукции, улучшение эксплуатационных характеристик, адгезии, износостойкости являются приоритетными направлениями в лакокрасочной промышленности. Один из способов влияния на качество лакокрасочных материалов (ЛКМ) – введение высокодисперсных добавок (ВДД) в полимерную основу. В работе осуществлялся подбор ВДД и способ их введения в краску с целью улучшения ее износостойкости, что важно при использовании, например, для дорожной разметки. Было изучено влияние трех типов ВДД: электровзрывного оксида алюминия, ультрадисперсных алмазов детонационного синтеза и оксида алюминия – глинозема (техногенные отходы Ачинского глиноземного комбината). Наибольший интерес в качестве высокодисперсной добавки для улучшения износостойкости полученных композитов представляет электровзрывной оксид алюминия. Установлено, что введение 0,05 масс. % взрывного Al2O3 позволяет увеличить износостойкость в лабораторных условиях на 25 % при сохранении других эксплуатационных характеристик в пределах требования нормативных документов. The ability to manage product quality, improve performance, adhesion, and wear resistance are priorities in the paint and varnish industry. One of the ways to influence the quality of paint and varnish materials (LCM) is the introduction of highly dispersed additives (HDA) into the polymer base. In the work, the selection of HDA and the method of its introduction into the paint was carried out in order to improve its wear resistance, which is important when used, for example, for road markings. The influence of three types of HDA was studied: electroexplosive aluminum oxide, ultrafine diamonds of detonation synthesis, and aluminum oxide-alumina (technogenic waste of the Achinsk alumina combine). Electroexplosive aluminum oxide is of the greatest interest as a highly dispersed additive for improving the wear resistance of the obtained composites. It was found that the introduction of 0.05 wt. % explosive Al2O3 allows you to increase the wear resistance in the laboratory by 30% while maintaining other properties.

EXCESSIVE ENERGY OF DETONATION NANODIAMONDS

Алмазы детонационного синтеза (ДНА) отличаются набором уникальных свойств, связанных с существенно неравновесными условиями их получения. Исследование их свойств продолжает оставаться актуальным в последние годы. Наноалмазы находят применение в полировальных составах, при модификации каучуков, резин, полимеров, металлов, создании новых композиционных материалов, в качестве добавок к топливу, адсорбентов и катализаторов, в биологии и в медицине. Интерес представляет энергетическая насыщенность наноалмазов. В данной работе проведено теоретическое и экспериментальное исследование избыточной энергии алмазов детонационного синтеза. Доказано, что ДНА обладают избыточной энергией по сравнению с природными и синтетическими алмазами. Рассмотрены возможные источники возникновения избыточной энергии. Исследованы образцы ДНА, полученные в различных условиях синтеза. На основе данных по термогравиметрическому анализу образцов ДНА представлены результаты анализа избыточной энергии образцов и ее зависимости от площади удельной поверхности частиц. Площадь удельной поверхности порошков получена методом БЭТ. Установлено, что чем больше поверхность частиц, тем больше тепла затрачено на её получение и выделилось при сжигании. Однако зависимость избыточной энергии от площади удельной поверхности частиц обратная. Экспериментально полученные нами величины плотности избыточной энергии на 1-2 порядка выше теоретически полученных значений для природных алмазов и для наноалмазов, что подтверждает наличие большой избыточной энергии ДНА. Такое свойство детонационных наноалмазов может найти применение в новых технологиях, в частности, при использовании наноалмазов в роли сорбентов. Detonation synthesis diamonds (DNDs) are distinguished by a set of unique properties associated with substantially nonequilibrium conditions for their production. The study of their properties continues to be relevant in recent years. Nanodiamonds are used in polishing compositions, in the modification of rubbers, polymers, metals, the creation of new composite materials, as additives to fuel, adsorbents and catalysts, in biology and medicine. The energy saturation of nanodiamonds is of interest. In this work, a theoretical and experimental study of the excessive energy of detonation synthesis diamonds is carried out. It has been proven that DNDs have excessive energy in comparison with natural and synthetic diamonds. Possible sources of excess energy are considered. Samples of DND obtained under various synthesis conditions have been investigated. Based on the data on thermogravimetric analysis of DND samples, the results of the analysis of the excessive energy of the samples and their dependence on the specific surface area of ​​the particles are presented. The specific surface area of ​​the powders was obtained by the BET method. It was found that the larger the surface of the particles, the more heat is spent on its production and released during combustion. However, the dependence of the excessive energy on the specific surface area of ​​the particles is inverse. The experimentally obtained values ​​of the excessive energy density are 1–2 orders of magnitude higher than the theoretically obtained values ​​for natural diamonds and for nanodiamonds, which confirms the presence of a large excess excessive of DND. This property of detonation nanodiamonds can find application in new technologies, in particular, when nanodiamonds are used as sorbents.

Synthesis of Oxide Ceramics in Detonating Atmosphere

A detonation process based on 2,4,6 trinitrotoluene (TNT), used as an energetic reagent, was successfully implemented in the synthesis of a series of metal oxide ceramics. TNT offers better physicochemical and mechanical properties than the energetic compounds traditionally used in such processes, thus offering safer handling and transport conditions. The experimental procedure, which consisted to of mixing the energetic molecule with a ceramic salt, was simple to perform. The detonation products were characterized by X-ray diffraction, scanning and transmission electron microscopies, energy dispersive X-ray spectroscopy and nitrogen physisorption. The as-synthesized ceramic powders (CeO2, HfO2, Nb2O5, and In2O3) were crystalline and made of nano-sized quasi-spherical particles. This investigation provides an enhanced detonation synthesis process for elaborating ceramics. The majority of the oxide materials mentioned in this study had never previously been prepared by the detonation process.

Several Aspects of Application of Nanodiamonds as Reinforcements for Metal Matrix Composites

After detonation synthesis, primary nanodiamond particles are around 4–6 nm in size. However, they join into agglomerates with larger parameters and weak bonds between particles. The introduction of agglomerates into a metal matrix can lead to the weakness of composites. This paper demonstrates the possibility of obtaining a non-agglomerated distribution of nanodiamonds inside a metal matrix. The fabrication method was based on mechanical alloying to create additional stresses and deformations by phase transformations during treatment in a planetary mill. According to the findings, the starting temperature of the reaction between the non-agglomerated nanodiamonds and aluminium matrix reduces to 450 °C. Furthermore, the paper shows that existing methods (annealing for the transformation of a diamond structure into graphitic material and cleaning from this graphitic material) cannot reduce the sizes of nanodiamonds in the agglomerated state. Agglomerated nanodiamonds transform into carbon onions (graphitic material) during annealing in a vacuum in the following way: the nanodiamonds located in the surface layers of the agglomerate are the first to undergo the complete transformation followed by the transformation of nanoparticles in its deeper layers. In the intermediate state, the agglomerate has a graphitic surface layer and a core from nanodiamonds: cleaning from graphite cannot reduce nanodiamond particle size.