CME/MSE 404G Dec 9 th 2010 lecture

1. CME/MSE 404GDec 9th 2010 lecture Vinod Kanniah Ph.D. candidate (Dr. Grulke’s Lab) Department of Chemical and Materials Engineering University of Kentucky, Lexington, KY Peng Wu Post doctoral student (Dr. Grulke’s Lab) Department of Chemical and Materials Engineering University of Kentucky, Lexington, KY

2. Purpose • Introduction to a real time polymer science project • Dr. Grulke’s lab (Astecc 215) • Research funded by Valvoline and US Army (TARDEC) • How to solve any industrial project? • Simple methods to analyze the problem (proof of concept) • Cost efficient to implement the solution • Recent work in Dr. Grulke’ lab • Phase behavior of a oligomer mixture • Other polymer science research (in brief) • Statistical distributions • How to fit/model raw data to statistical distributions in excel? Vinod Kanniah

3. Outline • Research project • Define overall objective • Understand the materials involved • Identify specific objective • Oligomer mixture - phase behavior • Cloud point curve • Quantitative analysis of oligomers • Size exclusion chromatography (SEC) • Mass spectrometry (MALDI TOFMS) • Fourier transformed infra red spectroscopy (FT-IR) • Partition coefficient • Conclusion • Other polymer science research in Dr. Grulke’s lab • Statistical distributions Vinod Kanniah

4. Research project • Overall objective - nanofluid for a specific application • Definition: nano-sized fillers suspended in base fluids • Product specifications expected • High heat transfer coefficient • Low temperature stability • Model system • Conventional base fluid • poly(α-olefin) oligomers • Additive • poly(dimethylsiloxane) oligomers • Base fluid mixture • poly(α-olefin) and poly(dimethyl siloxane) • Nanoparticle filler • graphite Vinod Kanniah

5. Materials • Oligomer mixture • poly(α-olefin), PAO • Chevron Phillips Chemical Company LP, USA • 1-decene monomer • common synthetic lubricant • poly(dimethylsiloxane), PDMS • GE Silicones, USA • Low viscosity index • Low pour point • Filler • Graphite • Graftech International, USA Vinod Kanniah

6. Material properties data chart Vinod Kanniah

7. Objective • Observations • At room temperature, the oligomer mixture (PAO and PDMS) were completely miscible. • Additive (PDMS) did have an effect, oligomer mixture did have lower pour points than the PAO base oil. • Phase separation of oligomers (PAO and PDMS) observed at temperatures less than 263 °K. • Top phase (PAO rich); Bottom phase (PDMS rich) • How to quantitate this composition? • Objective • To study the liquid-liquid demixing of two phase lubricant oligomer mixture Vinod Kanniah

8. Outline • Research project • Define overall objective • Understand the materials involved • Identify specific objective • Oligomer mixture - phase behavior • Cloud point curve • Quantitative analysis of oligomers • Size exclusion chromatography (SEC) • Mass spectrometry (MALDI TOFMS) • Fourier transformed infra red spectroscopy (FT-IR) • Partition coefficient • Conclusion • Other polymer science research in Dr. Grulke’s lab • Statistical distributions Vinod Kanniah

9. Oligomer mixture – phase behavior • Cloud point curve A plot indicating the temperature and composition variation in the appearance of the other phase is called CPC. • Phase volume ratio (r) measurements ratio of separated phase volumes, r = Vb / Va , a=top phase; b=bottom phase; V=volume; at r=0; T=cloud point temp. • Turbidity measurements heat the sample and record the appearance of turbidity with temperature. Vinod Kanniah

10. Quantitative analysis of oligomers • Size exclusion chromatography (SEC) • Requirements – special columns to detect the size range under study • Basis – Molecules in solution are separated by size. • Plot of intensity Vs retention time (or volume) • Mass spectrometry (MALDI TOFMS) • Requirements – Ionizable compound in sample • Basis – Ionizing chemical compounds to generate charged molecules or molecule fragments and measurement of their mass to charge ratio. • Plot of intensity Vs mass to charge ratio • Fourier transformed infra red spectrometry (FT-IR) • Basis – Characteristic Infra red spectrum of surface groups on the molecules. • Plot of absorbance Vs wave number Vinod Kanniah

11. Quantitative analysis issues • Only one of the component was detectable (PAO) in SEC • Why wasn’t PDMS detected? • Refractive index of solvent same as PDMS • How accurate is PAO data from SEC? • Not absolute but approximate (relative and consistent) • Use of linear oligomers as standards (polystyrene) Vs branched oligomer (PAO) • Only one of the component was detectable (PDMS) in MALDI TOFMS • Why wasn’t PAO detected? • PAO isn’t ionizable to be characterized through mass spectrometry Vinod Kanniah

12. Quantitative analysis issues (cont…) • PAO6 and PDMS overlapping at low M.W. • PAO4 is an alternative suggested to prevent phase separation Vinod Kanniah

13. Quantitative analysis of PAO6 oligomers • Size exclusion chromatography (SEC) • Relative intensity curves of top and bottom phases • Top phase - less of low M.W. PAO and more of high M.W PAO • Bottom phase - less of high M.W. PAO and more of low M.W PAO Vinod Kanniah

14. Quantitative analysis of PAO6 oligomers • Forced deconvolution of PAO oligomers • To determine %area (or %mass) contribution of each n-mer chain length in the top and bottom phases Vinod Kanniah

15. Quantitative analysis of PDMS oligomers • Mass spectrometry (MALDI TOFMS) • Cumulative frequency curves of top and bottom phases • Top phase – less of high M.W oligomers • Bottom phase – more of high M.W oligomers Vinod Kanniah

16. Oligomer mixture – phase behavior • Fourier transformed infra red spectroscopy (FT-IR) quantitation • Peaks were selected with a high response for the target molecule and a low or non-changing baseline of the other type of molecule. • PAO specific surface group - 1462 cm-1 (bending vibration of –CH2- groups) • PDMS specific surface group - 1257 cm-1 (asymmetric C-Si-O stretching) Vinod Kanniah

17. Oligomer mixture – phase behavior • Partition coefficient (K) • Ratio of concentration of materials in two phases of a binary mixture a = top phase; b = bottom phase; 1 = component (PAO or PDMS); Φ = volume fraction • Effect of temperature and n-mer chain length on partition coefficient Vinod Kanniah

18. Oligomer mixture – phase behavior • Conclusion • Partition coefficients of PAO components increased with increasing oligomer components and were relatively independent of temperature. • Partition coefficients of PDMS components decreased with increasing oligomer components. • The partition coefficient data can be used to develop oligomers with different distribution of component n-mer chain lengths that would have different cloud points. • Alternative solutions • Controlling oligomer chain lengths during polymerization, fractionating existing commercial materials, adding monodisperse components or via combinations of these methods. Vinod Kanniah

19. Outline • Research project • Define overall objective • Understand the materials involved • Identify specific objective • Oligomer mixture - phase behavior • Cloud point curve • Quantitative analysis of oligomers • Size exclusion chromatography (SEC) • Mass spectrometry (MALDI TOFMS) • Fourier transformed infra red spectroscopy (FT-IR) • Partition coefficient • Conclusion • Other polymer science research in Dr. Grulke’s lab • Statistical distributions Vinod Kanniah

20. Other works in Dr. Grulke’s lab • Graphite dispersion in PAO-PDMS oligomer mixture. • Selective graphite functionalization • Uniform dispersion in a two phase binary mixture (PAO and PDMS oligomers) • Through coupling reactions between the graphite surface and silanes (silanization) • Qualitative and quantitative characterization of graphite • Morphology (SEM); • Surface group (FT-IR); • Amount of surface groups and coating thickness (TGA-MS) • Stability or partitioning (dispersion images) Vinod Kanniah

21. Other works in Dr. Grulke’s lab (cont…) • Graphite dispersion in PAO-PDMS oligomer mixture. • 50:50 (PAO:PDMS) oligomer mixture with functionalized graphite • a) at room temperature; b) at -15 °C. • Figure a) indicates one phase at room temperatures. • Figure b) indicates the success of selective functionalization of graphite Vinod Kanniah

22. Outline • Research project • Define overall objective • Understand the materials involved • Identify specific objective • Oligomer mixture - phase behavior • Cloud point curve • Quantitative analysis of oligomers • Size exclusion chromatography (SEC) • Mass spectrometry (MALDI TOFMS) • Fourier transformed infra red spectroscopy (FT-IR) • Partition coefficient • Conclusion • Other polymer science research in Dr. Grulke’s lab • Statistical distributions Vinod Kanniah

23. Statistical distributions • Commercial cerium oxide (ceria) nanoparticles have broad size distribution Analysis of particle size distribution TEM image Vinod Kanniah

24. Statistical distributions (cont…) • How to fit particle size data using lognormal distribution in Excel ? • Calculation of log of particle size: log (size) • 2.Calculation of mean and std. dev of log (size) • Generate model data set using LOGNORMDIST function: • LOGNORMDIST (particle size, $[mean of log (size)], $[std. dev. of log (size) ]) • 4.Calculation of sum of squared error (model and data): (cumulative frequency - lognormdist)^ 2 • 5.Sum all the errors: error • 6. Using ‘solver’ function, set ‘sum of error’ to ‘minimum’ by changing the parameter of ‘mean of log (size)’ and ‘std. dev. of log(size)’ • 7. Obtain the lognormal distribution model. Vinod Kanniah

25. Statistical distributions (cont…) Vinod Kanniah

26. Questions ??? REMINDER: 2 questions will be asked in final based on the content of this presentation  Vinod Kanniah