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 ACES  Vol.12 No.2 , April 2022
Compositionally Driven Viscometric Behaviors of Poly (Alkyl Methacrylates) in Lubricating Oils
Abstract: Viscosity index (VI) and shear stability index (SSI) are standard methods used in the lubricant industry to determine temperature-viscosity dependency and resistance to product degradation, respectively. A variety of oil-soluble polymers, including poly(alkyl methacrylates) (PAMAs) are routinely used to control these properties in fully-formulated liquid lubricants. In this report, we use reversible addition-fragmentation chain transfer (RAFT) polymerization to precisely target identical degrees of polymerization in a family of PAMAs with varying lauryl, hexyl, butyl, ethyl, and methyl groups. Then, expanding on previous methodology reported in the literature, we establish structure property relationships for these PAMAs, specifically looking at how intrinsic viscosity [η] and Martin interaction parameters KM relate to VI and SSI characteristics. While the intrinsic viscosity [η] is associated with the volume of macromolecules at infinite dilution, the parameter KM reflects the hydrodynamic interactions of polymer chains at actual polymer concentrations in lubricating oils. In this paper, we show that the dependence of VI on the non-dimensional concentration c/c* (or c[η]) can be presented in a form of master curve with shift factors proportional to KM that decreases with increasing size of alkyl groups. This finding implies that even in the dilute regime, the coil-expansion theory used to explain the effect of macromolecules on VI should be complemented with the idea of hydrodynamic interactions between polymer molecules that can be controlled by the choice of alkyl chains in the family of PAMAs.
Cite this paper: Patterson, R. , Kabb, C. , Nickerson, D. and Pashkovski, E. (2022) Compositionally Driven Viscometric Behaviors of Poly (Alkyl Methacrylates) in Lubricating Oils. Advances in Chemical Engineering and Science, 12, 65-86. doi: 10.4236/aces.2022.122006.
References

[1]   Stribeck, R. (1901) Kugellager für beliebige Belastungen [Ball Bearings for Any Stress]. Zeitschrift des Vereins Deutscher Ingenieure, 45.

[2]   Hersey, M.D. (1914) The Laws of Lubrication of Horizontal Journal Bearings. Journal of the Washington Academy of Sciences, 4, 542-552.

[3]   Umamori, N. and Kugimiya, T. (2003) Study of Viscosity Index Improver for Fuel Economy ATF. SAE Technical Paper 2003-01-3256.
https://doi.org/10.4271/2003-01-3256

[4]   Vickerman, R., Streck, K., Schiferl, E., and Gajanayake, A. (2010) The Effect of Viscosity Index on the Efficiency of Transmission Lubricants. SAE International Journal of Fuels and Lubricants, 2, 20-26.
https://doi.org/10.4271/2009-01-2632

[5]   Lauterwasser, F., Bartels, T., Smolenski, D., and Seemann, M. (2016) Megatrend Fuel Economy: How to Optimize Viscosity with VI Improvers. SAE Technical Paper 2016-28-0030.
https://doi.org/10.4271/2016-28-0030

[6]   Clevenger, J., Carlson, D., and Kleiser, W. (1984) The Effects of Engine Oil Viscosity and Composition on Fuel Efficiency. SAE Technical Paper 841389.
https://doi.org/10.4271/841389

[7]   Selby, T.W. (1958) The Non-Newtonian Characteristics of Lubricating Oils. ASLE Transactions, 1, 68-81.
https://doi.org/10.1080/05698195808972315

[8]   Dean, E.W. and Davis, G.H.B. (1929) Viscosity Variation of Oils with Temperature. Chemical and Metallurgical Engineering, 36, 618-619.

[9]   Walther, C. (1933) Evaluating Lubricating Oils. Oel und Kohle, 1, 71-74.

[10]   Covitch, M.J. and Trickett, K.J. (2015) How Polymers Behave as Viscosity Index Improvers in Lubricating Oils. Advances in Chemical Engineering and Science, 5, 134-151.
https://doi.org/10.4236/aces.2015.52015

[11]   Rubinstein, M and Colby, R. (2003) Polymer Physics. Oxford University Press, Oxford.

[12]   Kulicke, W.M. and Clasen, C. (2004) Determination of the Polymer Coil Dimensions from the Intrinsic Viscosity. In: Kulicke, W.M. and Clasen, C., Eds., Viscosimetry of Polymers and Polyelectrolytes, Springer, Berlin, 91-94.
https://doi.org/10.1007/978-3-662-10796-6_7

[13]   Lutz, J.F., Weichenhan, K., Akdemir, O. and Hoth, A. (2007) About the Phase Transitions in Aqueous Solutions of Thermoresponsive Copolymers and Hydrogels Based on 2-(2-Methoxyethoxy)ethyl Methacrylate and Oligo(Ethylene Gylcol) Methacrylate. Macromolecules, 40, 2503-2508.

[14]   Kayaman, N., Gurek, E.E., Baysal, B.M., and Karasz, F.E. (2000) Coil to Globule Transition Behaviour of Poly(Methyl Methacrylate) in Isoamyl Acetate. Polymer, 41, 1461-1468.
https://doi.org/10.1016/S0032-3861(99)00316-X

[15]   Stickler, M., Panke, D., and Wunderlich, W. (2003) Solution Properties of Poly(Methyl Methacrylate) in Methyl Methacrylate. Viscosities from the Dilute to the Concentrated Solution Regime. Die Makromolekulare Chemie, 188, 2651-2664.
https://doi.org/10.1002/macp.1987.021881116

[16]   Hernandez-Fuentes, I., et al. (1982) Limits of the Dilute Regime for the Solution Viscosity of PMMA in Good and in Poor Solvents. European Polymer Journal, 18, 29-35.
https://doi.org/10.1016/0014-3057(82)90128-8

[17]   Lenka, S., Nayak, P.L., and Dash, M. (1983) Solution Properties of Poly(Methyl Methacrylate) by Viscometric Measurements in Organic Solvents. I. Journal of Macromolecular Science: Part A—Chemistry, 20, 469-486.
https://doi.org/10.1080/00222338308060795

[18]   Chinai, S.N., Matlack, J.D., Resnick, A.L. and Samuels, R.J. (1955) Polymethyl Methacrylate: Dilute Solution Properties by Viscosity and Light Scattering. Journal of Polymer Science, 17, 391-401.
https://doi.org/10.1002/pol.1955.120178507

[19]   Lal, J. and Green, R. (1956) Intrinsic Viscosities and Polymerization Speeds in Methacrylic Ester-Alkyl Polymethacrylate Systems. Journal of Polymer Science, 20, 387-396.
https://doi.org/10.1002/pol.1956.120209514

[20]   Ramasamy, U.S., Lichter, S., and Martini, A. (2016) Effect of Molecular-Scale Features on the Polymer Coil Size of Model Viscosity Index Improvers. Tribology Letters, 62, 1-7.

[21]   Willett, E., DeVore, A., and Vargo, D. (2019) Viscometric and Low Temperature Behavior of Lubricants with Blended VI Improvers. NLGI Spokesman, 83, 6-21.

[22]   Chiefari, Y.K., et al. (1998) Living Free-Radical Polymerization by Reversible Addition-Fragmentation Chain Transfer: The RAFT Process. Macromolecules, 31, 5559-5562.

[23]   Crow Polymer Science. Polymer Properties Database.
https://polymerdatabase.com/polymer%20physics/C%20Table%20.html

[24]   Mays, J.W. and Hadjichristidis, N. (1988) Characteristic Ratios of Polymethacrylates. Journal of Macromolecular Science, Part C, 28, 371-401.
https://doi.org/10.1080/15583728808085380

[25]   ASTM D445-21 (2021) Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity). ASTM International, West Conshohocken, PA.
https://www.astm.org/

[26]   API 1509-19 (2019) API 1509 Annex E-API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils.
https://www.api.org/~/media/Files/Certification/Engine-Oil-Diesel/Publications/AnnE-REV-09-20-19.pdf

[27]   Spearot, J.A. (Ed.) (1989) High-Temperature, High-Shear (HTHS) Oil Viscosity: Measurement and Relationship to Engine Operation. American Society for Testing and Materials, STP1068-EB.
https://doi.org/10.1520/STP1068-EB

[28]   Rhodes, R.B. (Ed.) (1992) Low Temperature Lubricant Rheology Measurement and Relevance to Engine Operation. American Society for Testing and Materials, STP1143-EB.
https://doi.org/10.1520/STP1143-EB

[29]   ASTM D2270-10 (2016) Standard Practice for Calculating Viscosity Index from Kinematic Viscosity at 40°C and 100°C. ASTM International, West Conshohocken, PA.
https://www.astm.org/

[30]   Covitch, M.J. (2018) An Improved Method for Calculating Viscosity Index (VI) of Low Viscosity Base Oils. Journal of Testing and Evaluation, 46, 820-825.
https://doi.org/10.1520/JTE20150242

[31]   Wright, W.A. (1964) A Proposed Modification of the ASTM Viscosity Index. Proceedings of the American Petroleum Institute, 44, 535-541.

[32]   Zakarian, J.A. (2012) The Limitations of the Viscosity Index and Proposals for Other Methods to Rate Viscosity-Temperature Behavior of Lubricating Oils. SAE International Journal of Fuels and Lubricants, 5, No. 3, 1123-1131.

[33]   Zakarian, J.A (2013) V.I. Too Resistant to Change? Lubes ‘n’ Greases, 54-62.

[34]   Graessley, W.W. (1980) Polymer Chain Dimensions and the Dependence of Viscoelastic Properties on the Concentration, Molecular Weight and Solvent Power. Polymer, 21, 258-262.
https://doi.org/10.1016/0032-3861(80)90266-9

[35]   Einstein, A. (1911) Eine Neue Bestimmung der Molekuldimantionen. Annalen der Physik, 339, 591-592.
https://doi.org/10.1002/andp.19113390313

[36]   Kumar, A. and Gupta, R.K. (1998) Fundamentals of Polymers. McGraw-Hill, New York.

[37]   CEC L-45-A-99 (1999) Viscosity Shear Stability of Transmission Lubricants (Taper Roller Bearing Rig). Brussels.

[38]   Matsuoka, S. and Cowman, M.K. (2002) Equation of State for Polymer Solution. Polymer, 43, 3447-3453.
https://doi.org/10.1016/S0032-3861(02)00157-X

 
 
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