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Title: Probing the molecular design of hyper-branched aryl polyesters towards lubricant applications

We report novel polymeric materials that may be used as viscosity index improvers (VII) for lubricant applications. Our efforts included probing the comb-burst hyper-branched aryl polyester architecture for beneficial viscosity and friction behavior when utilized as an additive in a group I oil. The monomer was designed as to undergo polymerization via polycondensation within the architectural construct (AB2), typical of hyperbranched polymers. The monomer design was comprised of aliphatic arms (12 or 16 methylenes) to provide the necessary lipophilicity to achieve solubility in a non-polar medium. Once polymerized, via catalyst and heat, the surface alcohols were functionalized with fatty acids (lauric and palmitic). Controlling the aliphatic nature of the internal arms and peripheral end-groups provided four unique flexible polymer designs. Changing the reaction time and concentration provided opportunities to investigate the influence of molecular weight and branching density on oil-solubility, viscosity, and friction. Oil-solubility was found to decrease with fewer internal carbons, but the number of internal carbons appears to have little influence on the bulk solution viscosity. Increased branching and degree of polymerization, and thus molecular weight, were found to reduce the solubility of these systems in the base oil. At concentrations of 2 wt % in a groupmore » I base oil, these polymer additives demonstrated improved viscosity index and reduced friction coefficient, validating the basic approach.« less
 [1] ;  [2] ;  [1] ;  [3] ;  [2] ;  [1] ;  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2045-2322; VT0604000; CEVT240
Grant/Contract Number:
AC05-00OR22725; AC05-76RL01830; AC02-06CH11357
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2045-2322
Nature Publishing Group
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Lubricant additive; viscosity modifier; viscosity index; friction modifier; hyperbranched polymer; 36 MATERIALS SCIENCE; mechanical properties; polymer synthesis; lubricant additive
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1249365; OSTI ID: 1251125; OSTI ID: 1341006