PSS Lubricants and Blends usty L. Blanski, Shawn H. Phillips, Joe Lichtenhan, Joe Schwab, Andre Lee, Justin Leland, and Patrick uth AFL/PSM 10 E. Saturn Blvd. Edwards AFB CA 93524 661-525-5391
Edwards AFL
PSS Lubricants Goal Develop a lubricant that can withstand high temperatures (>> 200 ºC) and flows at -40 ºC (20K centistoke) (High temp gas turbine engines: jets) Higher temperature lubes means more power: increase in thrust:weight ratio bjective Synthesize a PSS oil with an operating range of -40 ºC to >> 200 ºC Technical Challenges: Known PSS molecules decompose to sand Known PSS molecules are solids at room temperature
ther Applications: PSS Lubes -Any application where a lubricant is needed over a wide temperature range (gas turbines, other high temperature engines) -Some of the PSS lubricants have a very low volatility, making them suitable for space lubrication systems -Any application where high temperature stability is a must (high temperature mold releases)
Present AF Lubricants Technology The above polyol ester compounds are the main components of some AF turbine lubricants perating range of 40 ºC to 200 ºC In house calculations show that ester C- linkage breaks at 200 ºC C C Pentaerithritol Ester Trimethylopropane Ester C C C C Me C C C C C C C Pentaerithritol Dimer Ester
Pre-Hybrid PSS Synthesis Cl 3 + H 2 H H H H H H H = cyclopentyl cyclohexyl vinyl = cyclopentyl = cyclopentyl vinyl = cyclohexyl In PSS compounds, the C-C bonds are the weak link
PSS Lubes Project Synthesis of Vinyl 8 T 8 PSS Base Stock Cl 3 H 2, EtH 8 12 before: 20% yield (AFL) now: 80% yield (Hybrid Plastics) -Least expensive octafunctionalized PSS to date -Common starting point for octafunctional materials -CADA with Hybrid Plastics Further reduces Cost
PSS Cy 2 T 2 Tetrahydride Synthesis H H Me 2 H Me 2 H HMe 2 Cl NEt 3 H H Me 2 H Clear Liquid Me 2 H
PSS Synthesis: Hydrosilation ClMe 2 Me 2 Cl Me 2 Cl HMe 2 Cl, Platinum ClMe 2 ClMe 2 ClMe 2 Me 2 Cl Me 2 Cl
PSS Cross Metathesis/Hydrogenation Cl 2 u(=chph)(pcy 3 ) 2 Toluene/arene/alkene -C 2 H 4 Alkenyl-Arenyl PSS H 2 Pd/C Alkyl-Aryl PSS
PSS Lubricants/Blends Early work 1. HMe 2 Cl, Pt 8 12 2. ctylmgcl or HMe 2 ctyl, Pt 8 12 ctylme 2 = CH 2 CH 2 Me 2 ctyl IL AT T
PSS Lubricants/Blends T 8 [(CH 2 CH 2 )Me 2 ctyl] 8
PSS Lubricants/Blends Early work 1. HMe 2 Cl, Pt 8 12 2. ctylmgcl or HMe 2 ctyl, Pt 8 12 ctylme 2 = CH 2 CH 2 Me 2 ctyl IL AT T This class is NT suitable for High Temp Lubes (Tdec < 200 ºC), but could be used as a blendable
PSS Lubricants: T8 Class 8 12 1. cross metathesis 2. Hydrogenation 8 12 = alkyl, aryl, etc. ctaoctyl: Tm= 50 C, solid T8(ctyl)7Ethyl: Tm= 45C, grease Stable at 200 ºC (TGA) Not an oil, but a possible pathway to oil is shown: Adjust the organic side groups to disturb any possible order and give a flowable compound
PSS Lubricants: T8 Class ctyl 8 T 8 >>> ctyl 7 EthylT 8 >>
PSS Lubricants Chain Adjustment Lowers Viscosity 8 12 1. cross metathesis 2. Hydrogenation 8 12 Free flowing oil at room temperature Viscosity of 1650 centipoise at 0 ºC Freezes at -12 ºC Low volatility
PSS Lubricants Chain Adjustment Lowers Viscosity 8 12 ctyl 4.6 T 8 4-Methylpentyl 3.4
PSS Lubricants CyT 2 Class Me 2 H Me 2 H Me 2 Me 2 Hydrosilation Me 2 H Me 2 H Me 2 Me 2 = ctyl, liquid at T Flows even at VEY low temperatures (-60 ºC) Volatility problem at 200 ºC > Extend chain length
PSS Lubricants CyT 2 Class Me 2 H Me 2 H Me 2 Me 2 Hydrosilation Me 2 H Me 2 H Me 2 Me 2 = Decyl, Dodecyl, Tetradecyl, all liquids at T When =Decyl the viscosity at 40 ºC is 4000 cp!! Stable at 200 ºC with A/ present (TGA) When =Dodecyl, the freezing point is -12 ºC Higher temperature studies are underway
PSS Lubricants CyT 2 Class Me 2 Me 2 Me 2 Me 2 = Decyl
Decomposition of Lubricants Selected TGA Data for PSS Lubes eagent mp C iso temp C 10% wt loss % lost 9 hrs Grade 4 Base stock Liq rt 219.5 30 min 90 T 8 (octyl) 8 50 218 60 min 27 T 8 (octyl) 7 (ethyl) 1 45 216 225 11 T 8 (octyl) 4.5 (4-methylpentyl) 3.5-10 215 391 min 11.6 Cy 2 T 2 (Me 2 ctyl) 4 < -40 219 evaporated 100 (evap) Cy 2 T 2 (Me 2 Decyl) 4 w/a < -40 205 N/A 1 (4 hours)
Viscosity of Lubricants Selected Data for PSS Lubes eagent mp F Viscosity cp (T 1 F) Viscosity cp (T 2 F) Viscosity cp (T 3 F) T 8 (octyl) 4.5 (4-methylpentyl) 3.5 14 1650 (32) 11 (230) 1 (410) Cy 2 T 2 (Me 2 ctyl) 4 < -76 28000(-76) 2600 (-40)
Conclusions: PSS Lubes -By adjusting organic side groups, PSS oils can be made to flow at low temperature and are stable at higher temperature (Both thet 2 s and the larger T 8 s) - Addition of Antioxidant to T2 tetraalkyl derivatives slows down decomposition at 200 ºC
PSS Blendables
Why Use Blendables? Easier to tailor the organic side groups of the PSS molecule to give a polymer-soluble species mple blending techniques can be used instead of copolymerization with reactive PSS monomers Potential Drop-in molecular modifier without requiring expensive replacement of processing equipment
Pre Hybrid Plastics PSS Synthesis Cl 3 + H 2 H H H = cyclopentyl vinyl = cyclopentyl = cyclopentyl vinyl H H H Cl 3 THF, NEt 3 -NEt 3.HCl = cyclopentyl = cyclopentyl
PSS Synthesis Styrenyl and Phenethyl PSS Ph Ph Ph Cl 2 u(=chph)(pcy 3 ) 2 Ph Toluene/Styrene -C 2 H 4 Ph Ph Styrenyl PSS Ph Ph H 2 Pd/C Ph Ph Ph Ph Ph Ph Ph Phenethyl PSS Ph
Preparation of Styrene-PSS Blends TEM Method Dissolve the Styrene and PSS in THF Cast very thin film by slow solvent evaporation Traditional Processing Place Polystyrene in Extruder Add PSS Blend 2-5 Minutes
Preparation of Polymer-PSS Blends Traditional Processing: Brabender Mixer Place Polystyrene in Mixer at temperature Add PSS Blend 5-10 Minutes Grind Press into disks/extrude/ injection mold
PSS Blends - Crystal Formation 50 wt % Cp 8 T 8 in 2 million mol. wt. Polystyrene = cyclopentyl Cp 8 T 8 1 µm TEM image clearly shows formation of immiscible PSS crystallites (20-50k molecules)
PSS Blends - Crystal Formation 50 wt % Vi 8 T 8 in 2 million mol. wt. Polystyrene Vi 8 T 8 1 µm TEM image clearly shows immiscibility in polymer system
PSS Blends - Increased Solubility 50 wt % Cp 7 T 8 Styryl in 2 million mol. wt. Polystyrene = cyclopentyl 1 µm TEM image shows significant decrease in size of crystallites
PSS Blends - Miscibility 50 wt % Styrenyl 8 T 8 in 2 million mol. wt. Polystyrene = Styrenyl White domains represent pure polystyrene (process issue) Grey domains represent miscible PSS/polystyrene Black dots are PSS crystallites (<100 PSS molecules) 30% increase in surface hardness of the material
PSS Blends - Miscibility 50 wt % Phenethyl 8 T 8 in 2 million mol. wt. Polystyrene = Phenethyl 1 µm Demonstrated Complete Miscibility!! Grey domains represent miscible PSS/polystyrene Black dots are PSS crystallites (<100 PSS molecules)
Examples of Polymer-PSS Blends (not exhaustive) rganic de group on PSS Methyl Ethyl Isobutyl Phenethyl Styrenyl, Epoxystyryl ctyl Polymer i-pp, HDPE i-pp HDPE, syn-pp PS,PC,SB ptically Clear EPN 828, other epoxies HDPE
Conclusions For PSS Blends The organic side groups on the PSS molecule are extremely important in determining the solubility of the PSS in polystyrene The addition of the more soluble styrenyl PSS into styrene leads to an increase in surface hardness without adversely affecting polymer properties PSS can be thought of as functionalized silicas with the side groups acting as solubility enhancers PSS can be blended and dispersed into many polymers
Acknowledgements AFL Propulsion Directorate Mr. Paul Jones (Analytical) Dr. Charles Lee, AFS (Funding) Hybrid Plastics (materials)