Naslov
Polyolefine and Alkyl Methacrylate Graft Copolymers as Lubricating Oil Rheology Modifiers

Autori
Janović, Zvonimir ; Jukić, Ante ; Vidović, Elvira ; Romano, Jakov ; Barišić, Ankica ; Picek, Meri

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, pp prezentacija, znanstveni

Izvornik
Automotive and Industrial Lubrication / Bartz, J. Wilfried - Ostfildern : Stuttgart : Technische Akademie Esslingen (TAE), 2006, 36.1-13

Skup
15^th International Colloquium Tribology

Mjesto i datum
Stuttgart, Njemačka; Ostfildern, Njemačka, 17.01.2006. - 19.01.2006

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
polyolefine; alkyl methacrylate; graft copolymers; lubricating oil; rheology modifiers

Sažetak
Introduction. Poly(ethylene-co-propylene) (OCP) and poly(alkyl methacrylate) (PAMA) are the main class of viscosity improvers for lubricating mineral oils. Recently, inves-tigation and application of their mixtures has intensified as they show some complementary effect in the use properties. However, due to physical and chemical dif-ferences, their mixtures are not miscible and generate separate phases, particularly in concentrated solutions and at low temperatures. It is well established that such phase separation processes could be overcome by adding approriate compatibilisers, usually block or graft copolymers consisting of both polymer species [1]. In this work, the graft copolymers of OCP/PAMA were prepared and their solution rheology as base mineral oil additives has been examined. The obtained results in comparison to corresponding polymeric mixture additives [2] have been established and discussed. Results and discussion. Different composition graft copolymers are produced in solution copolymerization reaction using peroxide initiator. Molecular weight distribution are estimated by size exclusion chromatography (SEC). Graft copolymers were isolated by acetone extraction and their compositions were determined by infrared spectrometry (FT-IR). In addition, the influence of reaction parameters, such as temperature, monomers and initiator concentrations, on the extent of grafting were investigated and discussed. The rheological properties, such as viscosity, viscosity index, shear stability and pour point depression were established by standardized methods and correlated with the composition and some structural characteristic of the graft-copolymer mineral oil additives. It was find out that graft polymeric additives regarding OCP component show enhanced viscosity and shear stability whereas pour point of lubricants strongly depends on PAMA content. However, besides good blend compatibility the graft copolymer solutions showed no significant deviations of rheological properties from an poly(ethylene-co-propylene) / poly(alkyl methacrylate) mixture additive solutions. Conclusion. Polymeric additive based on OCP/PAMA graft copolymer show a complementary effect where is OCP considerably contributes to viscosity and shear stability increase, while PAMA contributes to VI increase and pour point temperature decrease. The obtained results are similar to the corresponding polymer mixtures. The advantage of using graft copolymers instead on OCP/PAMA mixture is reflected in their better compatibility (one-phase system forming) preventing a phase separation. Therefore graft copolymer could be used as a compatibilizer for corresponding polymer mixtures. References [1] Spiess, G.T., Johnston, J.E., Ver Strate, G., Procc. 5^th Int. Colloq., Additives for Lubricants and Operational Fluids, Technische Akademie Esslingen, Esslingen, 2 (1986) 8.10-1. [2] Jukic, A., Tomasek, LJ., Janovic, Z., Polyolefin and poly(alkyl methacrylate) mixed additives as mineral oil rheology modifiers, Lubrication Science, 17 (2005) 431-449.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

POVEZANOST RADA