Synthesis and evaluation of comb-type copolymers prepared via atom transfer radical polymerization as possible cold flow improvers in GTL diesel fuels
Journal of Applied Polymer Science
Laboratory of Polymer Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands; Sasol Technology R and D, 1 Klasie Havenga Street, Sasolburg, South Africa; Department of Polymer Science and Chemistry, University of Stellenbosch, Matieland, South Africa
Statistical comb-type copolymers of styrene (Sty) and stearyl methacrylate (C18 MA) with varying [styrene]:[C18MA] ratios were synthesized by a controlled/living radical polymerization technique called atom transfer radical polymerization. The polymeric materials were evaluated in selected SASOL Fischer Tropsch gas-to-liquid diesels as possible cold flow improvers. Crystallization studies revealed that as the styrene content of the copolymer increased, a crystal growth inhibition mechanism was exhibited. With an increase in styrene content of the copolymer, differential scanning calorimetry and the cloud filter plugging point (CFPP) revealed a delay in onset of crystallization and lowered CFPP, respectively, whereas low-temperature microscopy indicated modifications and size reduction of wax crystals. However, there appeared to be a styrene content, beyond which the additive's efficiency decreased. Homopolymer and copolymers with the highest styrene content led to long unfavorable needle-shaped crystals. © 2011 Wiley Periodicals, Inc.
Cold filter plugging point; Cold flow improver; cold flow properties; Comb-type copolymer; Controlled/living radical polymerization; Crystal growth inhibition; Filter plugging; Fischer Tropsch; GTL diesel; Low temperatures; Size reductions; Stearyl methacrylate; Wax crystals; Copolymers; Crystal growth; Diesel fuels; Differential scanning calorimetry; Polymerization; Styrene; Atom transfer radical polymerization