Viscosimetric properties of polymeric additives of vegetable lubricant oils

Suvremeni izazovi vezani uz fosilna goriva i sirovine naglašavaju potrebu za prijelazom prema održivim alternativama, a upravo jedno od ključnih inovativnih rješenja leži u obnovljivim izvorima poput estera masnih kiselina (FAE). Maziva proizvedena iz FAE, uključujući metilne (FAME) i butilne (FABE) estere masnih kiselina, otvaraju vrata za perspektivnu proizvodnju visokoučinkovitih maziva. Navedeni esteri su dobiveni iz prirodnih resursa poput biljnih ulja te pokazuju manji ugljični otisak i štetni utjecaj na okoliš u usporedbi s konvencionalnim mazivima na bazi fosilnih sirovina, a u ovome radu sintetizirani su transesterifikacijom repičinog ulja. Maziva igraju ključnu ulogu u održavanju učinkovitosti strojeva, na način da smanjuju trenje i trošenje i time produžuju njihov vijek trajanja. Međutim, tradicionalna maziva proizvedena iz fosilnih sirovina često su povezana s negativnim utjecajem na okoliš i klimatskim promjenama. Stoga su istraživanja usmjerena na razvoj održivijih alternativa, a biljna maziva ulja iz estera masnih kiselina postaju obećavajuća opcija. Osim zadovoljavajuće mazivosti, prednosti ovih maziva ogledaju se u njihovoj ekološkoj prihvatljivosti, biorazgradivosti i manjoj toksičnosti. FAE se proizvode iz obnovljivih resursa, čime se smanjuje ovisnost o ograničenim zalihama fosilnih sirovina. Dodavanjem polimernih aditiva mazivim uljima možemo postići niz poboljšanja njihovih svojstava kao što su viskoznost, mazivost i niskotemperaturna svojstva. Upravo zbog te činjenice ovaj rad je usmjeren prema ispitivanju potencijalnih poboljšanja svojstava biljnih maziva, sintezom različitih polimernih aditiva u metilnom (FAME) i butilnom (FABE) esteru masnih kiselina. U tu svrhu su korišteni metakrilatni monomeri dodecil-metakrilat (DDMA), oktadecil-metakrilat (ODMA) te metil-metakrilat (MMA) u različitim ukupnim koncentracijama u biljnom esteru uz dodatak peroksidnog inicijatora. Radi ispitivanja primjenskih svojstava i karakterizacije sintetiziranih uzoraka te otkrića mogućih poboljšanja, primijenjen je niz analitičkih metoda. Ove metode uključuju nuklearnu magnetsku rezonancu, diferencijalnu pretražnu kalorimetriju, reološka ispitivanja i kromatografiju na propusnom gelu, čiji su rezultati i usporedbe prikazani u radu.Contemporary challenges related to fossil fuels underscore the need for a transition towards sustainable alternatives, and one of the key innovative solutions lies in renewable energy sources such as fatty acid esters (FAE). Lubricants produced from FAE, including methyl (FAME) and butyl (FABE) fatty acid esters, open the door to prospective high-performance lubricant production. These esters are derived from natural resources such as vegetable oils and exhibit a smaller carbon footprint and less harmful environmental impact compared to conventional lubricants based on fossil resources. In this study, they were synthesized through the transesterification of rapeseed oil. Lubricants play a crucial role in maintaining the efficiency of machinery by reducing friction and wear, thereby extending their lifespan. However, traditional lubricants derived from fossil fuels are often associated with negative environmental impacts and climate change. Hence, research is directed towards developing more sustainable alternatives, and plant-based lubricating oils from fatty acid esters are becoming a promising option. In addition to satisfactory lubricity, the advantages of these lubricants include their environmental friendliness, biodegradability, and lower toxicity. FAEs are produced from renewable resources, reducing dependence on finite fossil fuel reserves and emissions of harmful gases, thus promoting energy sustainability and supporting the global transition to cleaner energy sources. The addition of polymeric additives to lubricating oils can yield a range of improvements in their properties. Among other things, these additives can enhance lubricity, low-temperature properties, and further extend the equipment's lifespan. This study is focused on investigating potential property enhancements of plant-based lubricants through the synthesis of various polymeric additives obtained via radical polymerization within fatty acid esters. For this purpose, methacrylic monomers DDMA (dodecyl methacrylate), ODMA (octadecyl methacrylate), and MMA (methyl methacrylate) were used in different ratios with the addition of a peroxide initiator. To assess the performance properties of the synthesized samples, such as viscosity, friction coefficient, pour point, lubricity, and other characteristics, a series of analytical methods were employed. These methods include nuclear magnetic resonance, differential scanning calorimetry, rheological testing, and gel permeation chromatography, the results and comparisons of which will be presented in the following sections of the paper