Hasil untuk "Paints, pigments, varnishes, etc."

M. Derrick, D. Stulik, J. M. Landry

محمد شیری, مجید حسین زاده, شهرزاد جوانشیر et al.

چارچوب‌های فلزی- آلی مواد متخلخلی هستند که به دلیل ویژگی‌های منحصربه‌فردی مانند قابلیت اصلاح‌پذیری، مساحت سطح زیاد، پایداری شیمیایی و مقاومت مکانیکی بالا ازجمله پیشتازترین جاذب‌ها در حوزه جذب و شناسایی آلاینده‌ها می‌باشند. یکی از مشکلات اساسی این ساختارها در فرایند جذب، جداسازی آن‌ها در انتهای فرایند جذب به دلیل ساختار پودری شکل آن‌ها می‌باشد. در این مطالعه برای حل این مشکل از هواژل و کامپوزیت ساختن آن با چارچوب فلزی- آلی سنتز شده استفاده شد. در این پژوهش کامپوزیت MOF-5/ هواژل سلولزی با استفاده از سلولز استخراج‌شده از گیاه پامپاس ساخته شد و اثر آن برای حذف ماده رنگزای آلی (متیلن بلو) از محیط‌های آبی بررسی شد. مشخصه یبلو کامپوزیت ساخته شده، به‌وسیله آنالیزهای تصویر میکروسکوپ الکترونی، پراش اشعه ایکس و IR بررسی گردید. میزان جذب آلاینده‌ (ماده رنگزای کاتیونی متیلن بلو) به‌وسیله دستگاه  UV- visنشان داد که میزان حذف ماده رنگزای کاتیونی در pH قلیایی مقدار 95 درصد در مدت ‌زمان 60 دقیقه است. همچنین اثر pH، زمان، غلظت مواد رنگزا بررسی گردید. استفاده مجدد از ماده جاذب مشخص نمود که بعد از 3 بار استفاده تنها 5 درصد از قدرت جاذب کاسته شد.

R. Wood

The subject areas of Coatings, Dyes and Interface Engineering are rarely seen together although there is potentially a huge synergy from embracing coatings-dyes-interface interactions. This allows an enabling science that aligns with global grand challenges such as net zero (batteries, renewal energy systems, low drag, antifouling and low friction interfaces, self-healing coatings, functionally graded, composite and multi-layered coatings sustainability of coatings, etc.), biomedical/health technologies, space and security. Coatings, dyes and interfaces engineering are used to optimize the functionality and to improve the entire function of materials and surfaces. Coatings have a wide range of forms, such as paints, adhesives, semiconductor thin films, hard facings and have a varied application route such as mechanical systems, solar cells, domestic appliances, photonics, smart coatings, microelectronics, offshore renewables, biomedical and photographic films. Several application and synthesis methods, such as sol–gel, spin, dip, physical and chemical vapour deposition, thermal spray, weld overlays, plasma electrolytic oxidation, atomic layer deposition, electroplating and so on, have been used for thin or thick hard and soft coatings and films. This article looks at recent state-of-the-art and related special issues and review papers to identify trends and future challenges for research in these areas. In scope for embracing coatings-dyesinterface interactions are thin and thick, composite, hard and soft coatings, coating structure and properties, processes for coating deposition, modification and characterization techniques, functional, smart, self-healing and sensing coatings, dyes, pigments and their intermediates. These in turn rely on fundamental mechanical and chemical as well as functional properties of surfaces and interfaces, theoretical and computational modelling of surfaces and interfaces as well as colloids, nanoparticles and large interfaces. The key to improved performance of coatings-dyesinterface engineering is understanding the manufacturer-composition-properties-performance interactions aligned to the service environment and operating conditions. Such research will be essential for energy research, photovoltaics, battery and electrochemical surfaces, biomedical applications, electronic applications of dyes and pigments, low friction, efficient machines and low drag, hydrophobic and nature inspired coatings. However, new understanding is needed for dynamic interfaces covering wear, corrosion, erosion for example. Modern measurement and imaging systems now allow in-situ and non-destructive monitoring of these interfaces. Miniaturisation of sensors and embedding sensors alongside or within interfaces is now possible which should provide a digital data stream for machine learning algorithms to allow smart interface management. Therefore, the challenges now lie around the synthesis and characterization of thin films andmultifunctional coatings and the use of novel interface characterization techniques (Special Issue, 2022) and Butt, M.A (Butt, 2022).

L. Frolova, O. Sergeyeva

Recently, the interest of researchers in nanodispersed oxides of monovalent and bivalent copper, ferrum, cobalt, nickel, and chromium has significantly increased. At the same time, interest in their micro- and nanosized particles is due, first of all, to a wide range of possibilities for their practical application. Today it is possible to use Cu2O, CuO in the creation of new catalysts for various industrial processes, as a filler for varnishes and paints, antiseptics. Cu2O is used in the production of galvanic cells, other fields of technology, etc. [1]. At the same time, the characteristics and variants of their practical application largely depend on the method of preparation, which usually determines their structure, dimensions, physical and chemical properties, etc. [2]. Among the methods for obtaining micro- and nanoparticles, large groups form the methods of chemical, electrochemical, electropulse, and plasma-chemical synthesis, based on the processes of reduction or oxidation of metal ions in solutions, depending on the conditions. Each of these groups has its advantages and disadvantages, but the use of the plasma-electrochemical method (using the treatment of aqueous media with contact low-temperature non-equilibrium plasma (CNP) of reduced pressure) makes it possible to use the advantages of each of the groups [3-5]. However, in this case, it becomes necessary to establish the relationship between the synthesis parameters and the phase composition and morphology of the resulting particles. At the first stage, Pourbaix diagrams were constructed corresponding to the conditions of synthesis in a plasma reactor, and voltammograms were obtained, which made it possible to evaluate the effect of pH synthesis on the composition of products. The morphology of the particles was also studied depending on the current strength of the process at the same initial concentration of Сu2+ in an aqueous solution. The use of X-ray phase analysis and electron microscopy made it possible to evaluate the composition and dimensional characteristics of dry sediments. Thus, at the process current I=200-250 mA, particles were obtained, consisting of intergrowths of crystals, the size of which did not exceed 30 μm, at I=140-200 mA crystals up to 15 μm were obtained, at I=80-140 mA the average crystal size did not exceed 5 µm. The structure of the particles was also established: the largest particles were represented mainly by intergrowths of smaller crystals. It is obvious that the formation of numerous crystallization centers with the simultaneous intense evolution of hydrogen contributes to the fact that the rate of crystal growth at the cathode decreases. At higher current strength parameters, the growth of individual crystals is observed (mainly in the form of octahedrons and cuboctahedrons, the size of which reaches 10-15 μm. A decrease in the current strength leads to a decrease in the particle size - both individual crystals and their intergrowths, which in this case are predominantly octahedral structures, the largest of which are 1–2 µm, and the smaller ones are 100–200 nm. The results of X-ray diffraction analysis show that under the given conditions for the formation of a deposit, the surface of the formed particles consists mainly of Cu2O. On the basis of the conducted studies, it can be noted that the size of the precipitate particles obtained can vary within a fairly wide range. In this case, a change in the process parameters, especially a decrease in the process current, leads to a decrease in the size of the formed particles and an increase in the deposit uniformity, which is confirmed by the results of electron microscopic studies of the synthesized cathode deposits. This makes it possible to control the particle synthesis process by adjusting the parameters of the plasma-chemical processing process, which, due to its simple design, does not cause difficulties and, along with the possibility of using highly diluted solutions, is an advantage of this method.

مریم حیدری, مهرناز قراگوزلو, مهدی قهاری

چارچوب‌های‌‌ آلی-فلزی ترکیبات پلیمری کئوردیناسیونی هستند که از فلز به عنوان گره و لیگاندهای آلی به‌عنوان ارتباط‌دهنده تشکیل شده‌اند‌. این ترکیبات بلوری و متخلخل بوده و اندازه و شکل حفرات آنها را می‌‌‌توان مهندسی کرد. این ویژگی‌ها به همراه نسبت سطح به حجم بسیار بالا (در مواردی تا  m2/g 14600که این رقم نظری بوده و در حالت تجربی تفاوت دارد) آنها را برای کاربردهای مختلفی از جمله به‌عنوان کاتالیزور ناهمگن، جاذب، عامل جداسازی و ذخیره سازی گازها، حسگر، پیل سوختی، سل‌های خورشیدی و حذف آلاینده‌های‌‌ زیست محیطی مفید ساخته است. چارچوب‌های‌‌ آلی-فلزی خوراکی دسته‌ای از چارچوب‌های‌‌ آلی-فلزی هستند که لیگاند و فلز مرکزی زیست‌سازگار با بدن را دارا هستند. چارچوب‌های‌‌ آلی-فلزی خوراکی به روش‌های‌‌ گوناگون سنتز شده و مورد بررسی قرار می‌‌‌گیرند. چارچوب‌های‌‌ آلی-فلزی خوراکی به عنوان جاذب زیست‌سازگار و موثر برای انواع مواد رنگزا و حتی داروها، دارای انواع مختلفی هستند که بر اساس نوع لیگاند و فلز مرکزی دسته‌بندی می‌‌‌شوند. علاوه بر این، چارچوب‌های‌‌ آلی-فلزی خوراکی به دلیل داشتن تخلخل‌های‌‌ بسیار زیاد قادرند مواد رنگزا را در خود جذب و نگهداری کرده و باعث پاک‌سازی محیط‌زیست از آلاینده‌ها شوند. در این مقاله انواع لیگاندها و مراکز فلزی مورد استفاده در ساخت چارچوب‌های‌‌ آلی-فلزی خوراکی مورد بررسی قرار گرفته و دسته‌بندی شده‌اند‌.

Šárka Msallamová, M. Kouřil, K. C. Strachotová et al.

Historical museums and depositories contain collections with a number of lead objects or historical documents with lead seals. Lead is a metal which has good corrosion resistance under atmospheric conditions. On the other hand, lead corrodes in an activity in an environment which contains volatile organic compounds (mainly acetic acid and formic acid). In a depository environment, sources of volatile compounds can be the historical documents themselves, wood, plastics (those made from cellulose acetate), polyvinyl acetate adhesives, varnishes, oil or emulsion paints, etc. The aim of this work was to compare the efficiency of commercial adsorbents (activated carbon, activated alumina, zeolite, and bentonite) in the acetic acid vapours. The lead corrosion rates were determined by using lead resistometric probes. Activated alumina and activated carbon were found to be the most effective adsorbents of acetic acid vapours. On the other hand, the available zeolite had the worst sorption ability compared with the other tested substances.

مهری مقصودی, شاهین خامنه اضل

سالانه مواد رنگزا‌‌‌‌‌‌‌‌ زیست تجزیه‌‌‌‌ناپذیر موجود در صنایع نساجی، چرم‌‌‌‌، کاغذ، غذایی، سل‌‌‌‌های فوتوالکتروشیمیایی به جریانات طبیعی آب تخلیه می‌‌‌‌شود. آرایه‌‌‌‌های نانولوله‌‌‌‌ای بسیار منظم TiO2 تهیه شده با آندایزینگ تیتانیم، به‌دلیل سطح ویژه بزرگ، توانایی اکسیدکنندگی قوی و عملکرد عالی انتقال بار، در سال‌‌‌‌های اخیر به طور گسترده به عنوان فوتوکاتالیست برای تجزیه مواد رنگزا‌‌‌‌‌‌‌‌ به کار می‌‌‌‌رود. با این وجود، معایب TiO2 گاف انرژی وسیع (eV 2/3-3) و نرخ بالای بازترکیب الکترون- حفره حاصل از نور است که کاربرد نانولوله‌‌‌‌های TiO2 را در استفاده از نور مرئی برای تجزیه آلودگی‌‌‌‌های آلی محدود می‌‌‌‌کند. به ‌‌‌‌این منظور در سال‌‌‌‌های اخیر تلاش‌‌‌‌های بسیاری برای اصلاح نانولوله‌‌‌‌های TiO2، برای افزایش جذب نور تا محدوده نور مرئی، محدود نمودن گاف انرژی، افزایش مساحت سطح و جلوگیری از بازترکیب حامل‌‌‌‌های بار، صورت گرفته است. برای غلبه بر این محدودیت‌‌‌‌ها و افزایش فعالیت فوتوکاتالیستی نانولوله‌‌‌‌ها روش‌‌‌‌های مختلفی بررسی شده است که عبارتند از: آرایش با ذرات فلزات نجیب، آلایش با عناصر فلزی، اصلاح با نیمه‌‌‌‌رسانا و آلایش با عناصر غیرفلزی.

Camille Simon Chane, M. Thoury, A. Tournie et al.

F. Gresta, A. D. Luca, A. Strano et al.

Guar ( Cyamopsis tetragonoloba L.) is a spring-summer legume with a high drought tolerance, grown mainly in India, Pakistan, United States and South Africa, whose seeds contain galactomannans. These can be used as an emollient, softening or thickening agent, a flocculant, as well as in hydraulic fracturing, and as a stabiliser in a wide range of other industrial activities: the production of cosmetics, paper, textiles, paints and varnishes, detergents, in construction, and in food products (jams, jellies, yogurt, mayonnaise, ketchup, diet foods, foods for coeliacs, etc .). In the light of a growing industrial demand for guar flour, in May 2012 a trial was carried out in southern Italy. Seeds from South Africa were sown in large plots on two farms with different soil characteristics. The crop showed yields varying between 1.8 and 2.2 t ha –1 . Agronomic results were then used to conduct an integrated sustainability analysis using the production cost analysis and the life cycle assessment, in order to assess, respectively, the cost-effectiveness and the environmental impact of the production process of guar in a Mediterranean environment. Compared to other competitive crops, guar, with less than 3000 kg of CO 2 eq. emissions, can be considered as a low-emission crop. Given the above-mentioned yield, guar growing is economically sustainable when the purchase price of seeds is not less than 0.96 € kg –1 .

L. Prinsloo, A. Tournie, P. Colomban et al.