A Study of Interactions between Viscosity Index Improvers and Wax by Fluorescence Kiarash Gholami Solmaz Pirouz, Sheng Jiang, Jean Duhamel Department of Chemistry University of Waterloo IPR Symposium, May 4, Confidential and Proprietary pursuant to Research Agreement # between Afton Chemical Corporation and University of Waterloo, Canada - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corp © Afton Chemical Corp., all Rights Reserved

Introduction Role: Oils are vital to the proper operation of engines. Deficiency: Oils are too thin and too viscous at high and low temperatures, respectively. Solution: Viscosity index improvers (VII) can mitigate the sudden drop or rise in viscosity caused by temperature changes. V h (low Temp.) V h (High Temp.) 2 ~ Confidential and Proprietary pursuant to Research Agreement # between Afton Chemical Corporation and University of Waterloo, Canada - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corp © Afton Chemical Corp., all Rights Reserved

( __ ) 0.01 g.L -1 Py-EP, 10 g.L -1 EP, and 10 g.L -1 wax ( ···· ) 0.01 g.L -1 Py-EP and 10 g.L -1 EP (- - -) 10 g.L -1 wax. Steady-state fluorescence spectra & () ratio Steady-state fluorescence spectra & (I E /I M ) ratio Fluorescence spectra of above-mentioned compositions, (Solvent: toluene, λ ex =344 nm) Low Concentration Py Py* High Concentration Py Py* Py SS fluorescence spectra of wax (10 g.L -1 ) as a function of temperature. -30 o C 25 o C (Solvent: toluene λ ex =344 nm) Confidential and Proprietary pursuant to Research Agreement # between Afton Chemical Corporation and University of Waterloo, Canada - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corp © Afton Chemical Corp., all Rights Reserved 3

4 f inter representing the intermolecular interactions between Py-EP copolymers and wax Initial copolymer labeled copolymer Temp ( o C) -30 to -10 Temp ( o C) -5 to 25 Temp ( o C) -30 to -10 Temp ( o C) -5 to 25 Without WaxWith Wax EP(AM)Py(108)-EP(60-1)0.28± ±0.01 EP(SM)Py(116)-EP(78-1)0.56± ± ± ±0.01 Py(108)-EP(60-1) Py(116)-EP(78-1) Plots of I E /I M -vs-T for the mixtures of ( ) Py-EP (10 g.L -1 ) and wax (10 g.L -1 ) and (  ) Py-EP (0.01 g.L -1 ), EP (10 g.L -1 ), and wax (10 g.L -1 ). A) Py(108)-EP(60-1) C) Py(116)-EP(78-1) f inter calculated from the ratio I E ( nm)/I M ( nm) (×) without wax. f inter calculated from the ratio I E ( nm)/I M ( nm) (●) without wax and (○) with 10 g.L  1 wax. Confidential and Proprietary pursuant to Research Agreement # between Afton Chemical Corporation and University of Waterloo, Canada - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corp © Afton Chemical Corp., all Rights Reserved

The presence of wax in the EP solutions seemed to increase intermolecular associations between EP copolymers in toluene, since it interacts strongly with long ethylene sequences along the EP copolymers. Above T C : EP(AM) and EP(SM) copolymers interact strongly with wax which results in increased intermolecular interactions between the EP copolymers. Below T C : EP(SM): The formation of microcrystals by these copolymers leads to the release of wax from them and they show little-to-no difference in behaviour with or without wax. EP(AM): Due to the inability of the EP(AM) copolymers to form crystalline microdomains in solution, they behave in the same manner below or above T C showing increased interactions. A procedure based on pyrene excimer fluorescence was developed to determine f inter for amorphous and semicrystalline EP copolymers with wax in toluene. Conclusions Confidential and Proprietary pursuant to Research Agreement # between Afton Chemical Corporation and University of Waterloo, Canada - not to be copied, shared, or reproduced in any media without the express written permission of Afton Chemical Corp © Afton Chemical Corp., all Rights Reserved 5

Acknowledgments 6