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Poly-dialkyl phosphonates were synthesized by reacting methyl linoleate with dimethyl, diethyl, and di-n-butyl phosphites in the presence of free radical initiator and positively identified and cha...

Soy-based fatty acid methyl ester disulfide (FAME-S2) was synthesized in good yield by oxidation of polymercaptanized soybean oil fatty acid methyl ester (PM-FAME). The chemical structure of FAME-S2 is of interest because of its potential as a biobased multi-functional additive in lubricant formulations. Neat FAME-S2 and their blends (1–10% w/w) in polyalphaolefin (PAO-6) and high oleic sunflower oil (HOSuO) were characterized for its chemical, physical and tribological properties. Blends of FAME-S2 in HOSuO relative to similar blends of PM-FAME displayed higher oxidation onset temperature (> 15 °C) that remained constant with increasing concentration. Evaluation of FAME-S2 as an extreme pressure (EP) additive on a 4-ball tribometer showed increasing weld point (WP) with increasing concentration to a maximum of 220 and 180 kgf in HOSuO and PAO-6, respectively, at 10% w/w concentration. The results indicate that FAME-S2 has both anti-oxidant and EP properties and can be applied as a multi-functional biobased additive in lubricant formulation. This work demonstrates an encouraging progress towards the development of effective biobased lubricant additives.

Estolides are a relatively new class of biobased materials, and their properties are not thoroughly investigated. Since they have been recently commercialized as lubricants, a deeper investigation of their viscosity was warranted. Five 3-parameter viscosity models with theoretical derivations were found in the literature. Additionally, several empirical 2- and 3-parameter models, including one empirical 4-parameter model, used to describe the viscosity of lipids, were selected for investigation. These models were used to fit the experimental viscosity of 13 oleic estolide ester samples. The viscosity was measured at six temperatures between 20 and 100 °C. The jackknife procedure was used to estimate the uncertainty of the fitted parameters. For the theory-based models, correlations were derived between the fitted coefficients and the molecular weight of the sample. The results allowed for simple prediction of the viscosity of estolide esters as a function of the temperature, based only on number-average molecular weight (or on the estolide number). The best model required additional knowledge of the weight-average molecular weight.

The tribological properties of biobased and petroleum-based base oils in the entire lubrication regime were investigated. High oleic sunflower oil (HOSuO) and commercially available polyalphaolefin (PAO-6) were selected to represent biobased and petroleum-based base oils, respectively. These two oils had similar viscosity and pressure-viscosity coefficient at 40 °C, but differed in their chemical structures and many other properties. Tribological tests were conducted on a high frequency reciprocating rig tribometer at 40 and 75 °C, for 60 min, 1000 gf load, and variable combinations of frequency and stroke length. Lubrication regimes were quantified using the Hersey number (H) which was calculated from lubricant viscosity and test parameters (load, frequency, stroke length). The key tribological test outputs were coefficient of friction (COF); film thickness (h) expressed in % from contact resistance measurement; and ball wear scar diameter (WSD). Analysis of experimental data showed that the biobased HOSuO provided lower COF, thicker lubricant film, and lower WSD than the petroleum-based PAO-6, in all lubrication regimes and at both temperatures (40 and 75 °C). The difference in these properties between the two oils, [Δ(COF), Δ(WSD), Δ(h)], were the greatest in the boundary regimes (low H values) where the polar chemical structure of the biobased lubricant played a dominant role.

Ruthenium-catalyzed decarboxylation of 9-cis-octadecenoic is a path to produce biobased olefins. Here, a mechanistic study of this reaction was undertaken utilizing a closed reaction system and a pressure reactor. The proposed mechanism of an isomerization followed by a decarboxylation reaction was consistent with a mathematical kinetic model. That same model was able to accurately predict CO2 evolution. Additionally, computational chemistry was used to determine that the barrier of the oleic acid decarboxylation reaction is 249 kJ mol–1. Using the new information, the efficacy of the decarboxylation reaction was improved to an overall catalytic efficiency of 850 total turnovers.

Oleic and linoleic acids are common fatty acids in commodity vegetable oils. Their modification into sulfur-containing molecules can be a route for producing biobased lubricants. We investigated modification of methyl oleate and methyl linoleate with thioacetic acid using UV-initiated thio-ene reaction to obtain methyl (acetylthio)stearates and methyl bis(acetylthio)stearates, respectively. Small amounts of acetyldithio derivatives were also detected. The products were characterized by Electron Impact Mass Spectrometry, High Resolution Mass Spectrometry, and 1- and 2-D NMR. The MS confirmed the anticipated molecular formulas. The fragmentation patterns can be explained with predominant breakage of carbon–sulfur bonds. The isomers of methyl bis(acetylthio)stearates were partially separated by chromatography, and some characteristic NMR peaks were identified and compared with the ones predicted by software. NMR showed distinct patterns of the quasi-meso- and quasi-rac- forms of the isomers. Most often thioacetates are used as protecting groups or intermediary of thiol groups.

Phosphonates were synthesized on a medium scale (~200 g) from three lipids—methyl linoleate (MeLin), high-oleic sunflower oil (HOSO) and soybean oil (SBO), and three dialkyl phosphites—methyl, ethyl and n-butyl, using a radical initiator. A staged addition of the lipid and the initiator was used to achieve good yields. Good results were observed with MeLin (94–99% conversions of the double bonds, as determined by NMR, and 83–99% isolated yields) and HOSO (99–100% NMR conversions, 87–96% isolated yields) using tert-butyl perbenzoate as the initiator. With SBO, benzoyl peroxide was used as the initiator, due to its capability to generate radicals at a higher rate at slightly lower temperatures, and thus to shorten the reaction time. Conversions of 91–93% (by NMR) and isolated yields of 80–94% were achieved. The progress of the reaction was monitored with GC–MS. The products were characterized using 1H, 13C and 31P NMR, IR and gel permeation chromatography. A prolonged reaction led to some transesterification between the carboxylic and phosphite ester groups. Conditions favoring higher reaction rates led to the formation of more oligomers and benzoate fatty ester byproducts. The benzoate fatty ester byproducts were formed by the attack of a benzoate radical on a double bond. The more double bonds that were present per lipid molecule, the more oligomers were formed: MeLin 2–8%, HOSO 3–9% and SBO 8–29%.

The addition of dialkyl phosphite (methyl, ethyl and n-butyl) to methyl linoleate (MeLin) double bonds was investigated. The reaction proved to be more challenging than the analogous reaction with methyl oleate (MeOl), due to inhibition of the radical reaction by the bis-allylic hydrogens of MeLin and the lower reactivity of MeLin double bonds. However, we demonstrated that this self-inhibition problem can be solved by simply keeping the MeLin reagent at low concentrations, while keeping the dialkyl phosphite at high concentrations. For optimization of the reaction, four different radical initiators were investigated: dilauroyl peroxide (LP), 2,2′-azobis(2-methylpropionitrile) (AIBN), tert-butyl perbenzoate (t-BP), and tert-butyl peroxide (TOOT). The initiators were used at temperatures that provided a half-life of 10 h: 64, 64, 104, and 125 °C respectively for LP, AIBN, t-BP, and TOOT. The tests showed the reaction to be faster at higher temperatures, but transesterification of the ester groups was also observed at elevated temperatures. t-BP was chosen as an optimal initiator for carrying the reaction. The apparent order of reactivity of the dimethyl, diethyl and di-n-butyl phosphites (Me >Et >n-Bu) towards MeLin was due to differences in their molar volumes. When the concentrations of dialkyl phosphite were kept the same, the order reversed (n-Bu > Et~Me). GC–MS spectra of the resulting phosphonates are reported and the main fragments assigned.

Seven lipoate esters were synthesized by esterification of lipoic acid with different structures of alcohols in the presence of a solid acid catalyst and without solvent. The esters were obtained in good yield, characterized using 1H NMR and GPC; and their physical properties investigated. Four of the seven lipoate esters, with good solubility in high oleic sunflower oil (HOSuO) and polyalphaolefin (PAO6) base oils, were further investigated for their lubricant additive property. Additive properties were investigated in HOSuO base oil by varying the additive concentrations in the range 0–20 (w/w %). Properties investigated include: density; kinematic and dynamic viscosity; viscosity index (VI); oxidation stability from onset and peak oxidation temperatures on a PDSC; 4-ball antiwear (AW); and 4-ball extreme pressure (EP). Neat lipoate esters displayed high oxidation stability and high VI. As additives to HOSuO base oil, lipoate esters displayed good viscosity index improver (VII), good antioxidant, good e...

Production of an effective industrial lubricant additive from vegetable oils is a high profile and difficult undertaking. One candidate is alkyl 9(10)-dibutylphosphonostearate, which has been made through a radical transformation of alkyl 9-cis-octadecanoate. It is effective, but still suffers from drawbacks. In this report, that synthesis is combined with a ruthenium based isomerization process to create not just one, but an entire series of new chemical compounds. A low level of [Ru(CO)2(EtCO2)]n is first used for the isomerization of the starting material, then radical chemistry is employed. A series of methyl dibutylphosphonooctadecanoates was made. In an analogous fashion, trans-7-tetradecene was also isomerized and then polymerized. As in the phosphonate case, the follow-up chemistry could be performed in the presence of the residual isomerization catalyst. The alkane:alkene ratio, observed by 1H NMR, was found to change from 14:1 in the isomerized starting material to a value of 41:1 in the polymer...

Polymercaptanized soybean oil (PMSO) was investigated for its chemical, physical and tribological properties relative to soybean oil (SO) and also as a potential multi-functional lubricant additive in high oleic sunflower oil (HOSuO). Analytical investigations showed that PMSO is obtained by conversion of 76% of double bonds in SO into thiol (–SH) and sulfide (R–S–R′) groups. PMSO product mixture comprised 70% monomer and 30% oligomers, versus 99.6 and 0.4%, respectively, for SO. Relative to SO, PMSO displayed higher density, viscosity and oxidation stability; similar cold flow properties; and lower viscosity index. PMSO displayed good solubility in HOSuO (>10% w/w), but poor solubility in polyalpha olefin-6 (

Reactions of epoxidized alkyl soyate with four different alcohols: ethanol, isopropyl alcohol, 2-ethylhexanol, benzyl alcohol, in the presence of Bronsted acid catalyst, were investigated. Products, not reported in prior studies of similar reactions, were found. These were furan fatty acid alkyl esters (FFE, mixture of alkyl 8-(5-hexyl-2-furyl) octanoate and alkyl 9-(5-pentyl-2-furyl)nonanoate) which were unambiguously identified by means of GC–MS and two-dimensional NMR. Evidence suggests that the FFE are formed by an acid-catalyzed rearrangement of the epoxidized linoleates. The FFE were formed in presence of all four alcohols tested and in the presence of either sulfuric acid or Amberlyst 15 catalyst. Yields of up to 13 %, as quantified by GC and NMR spectroscopies, were observed.

Heat-bodied oils were prepared by thermal treatment of soybean oil under inert atmosphere. Different viscosity grades of heat-bodied oils synthesized by varying the reaction time were investigated for various properties including viscosity, viscosity index, elastohydrodynamic film thickness, and pressure–viscosity coefficient. Heat-bodied oils displayed elastohydrodynamic film thickness characteristics typical of lubricating oils. The film thickness of heat-bodied oils increased with increasing entrainment speed and viscosity, decreased with increasing temperature, and was unchanged with varying load. Pressure–viscosity coefficients of heat-bodied oils were estimated from film thickness as well as from physical property data. The pressure–viscosity coefficient values of heat-bodied oils increased with increasing viscosity and decreasing temperature and were in the range displayed by such oils as polyol esters, poly-α-olefins, and petroleum-based base oils. Heat-bodied oils provide access to a wide viscosi...

Lipoyl glycerides were synthesized by enzymatic transesterification of lipoic acid with high-oleic sunflower oil in 2-methyl-2-butanol solvent. The synthesis gave a crude product mixture comprising unreacted lipoic acid, free fatty acids, and several lipoyl glyceride structures of varying lipoic acid substitution. A more purified product mixture, devoid of unreacted lipoic acid and free fatty acids, was obtained in 61% yield. The crude and purified product mixtures were thoroughly characterized and their components positively identified. The tribological properties of the product mixtures were further investigated using a variety of methods. The product mixtures displayed significantly improved oxidation stability, cold-flow, and extreme pressure properties over those of the parent high-oleic sunflower oil. The extreme pressure results for the neat products showed a higher weld point for the crude than for the purified mixture. This was attributed to differences in the chemical properties of the components in the two product mixtures.

Vegetable oils containing thioether groups have been synthesized and used to effectively remove heavy metal ions from aqueous solution. The use of thioether-functionalized corn oil (TF-corn oil) an...

Three phosphonate derivatives of methyl oleate (MeO) were chemically synthesized in a radical chain reaction and their physical and tribological properties investigated. The phosphonates differed from each other in the structure of the alkoxy groups attached to the phosphorous, which were as follows: methoxy, ethoxy, and n-butoxy. Phosphonylation eliminated the unsaturation in MeO and also introduced branching. The phosphonate oils had higher density and viscosity than MeO, which was attributed to the contribution of the heavier phosphorus atom in their structures, and to their higher molecular weights, respectively. The phosphonates also displayed improved oxidation stability and cold flow properties, which were attributed to the elimination of the double bond and the introduction of branching in their molecular structures, respectively. Tribological investigations were conducted using 4-Ball anti-wear (AW) and extreme pressure (EP) methods. Neat phosphonates displayed lower AW coefficients of friction and wear scar diameters than MeO. The improved AW results were attributed to the higher viscosity of the phosphonates, since the AW test is conducted in the mixed film regime. The phosphonates had no effect on EP weld point (WP) as neat oils or as 5 % additives in petroleum-based oils. In soy base oil, 5 % phosphonate additives displayed smaller improvement in WP than zinc dialkyl dithiophosphate (ZDDP). It is proposed that this lack of EP characteristics could be due to the high dissociation energy of C–P bonds in the phosphonates, compared to, for example, S–P bonds in ZDDP.

The pressure viscosity coefficient (PVC) of ten vegetable oils from commodity and new crops, and two petroleum-based oils [polyalphaolefin (PAO) and hexadecane], were investigated. PVC was estimated using two different methods: from analysis of oil physical properties (viscosity and density); and from analysis of elastohydrodynamic (EHD) film thickness data. Estimated PVC of vegetable and petroleum-based oils decreased with increasing temperature, which was expected. PVC values derived from physical properties were generally much higher than the values from the literature or those derived from EHD film thickness. PVC values increased with increasing viscosity of the tested oils. Based on further examination of PVC data for a wide range of oils from the literature and this work, it is proposed that lubricating oils can be roughly divided into three structural categories, each with defined range of PVC values: low PVC oils ( 20 GPa−1) with predominantly entangled molecular structures, and intermediate PVC oils (10–20 GPa−1) with negligible layering or entangling molecular structures. It is proposed that vegetable oils, along with PAO and hexadecane, have flexible hydrocarbon chain structures, with little or no branching or layering, and, hence, belong to the intermediate PVC category.

Using a catalytic system, methyl oleate is transformed into long-chain keto and diketo derivatives via an epoxide route. Methyl 9(10)-oxooctadecanoate and methyl 9,10-dioxooctadecanoate were made by a ring-opening reaction of epoxidized methyl oleate using bismuth(III) trifluoromethanesulfonate (bismuth triflate) catalyst. Lower reaction temperatures favor the ketone, whereas higher temperatures are required to produce the diketone. The second synthesis also requires the use of dimethylsulfoxide to serve as an oxygen atom donor and that reagent also is needed to keep the catalyst in its active form. The ketone was also evaluated as a lubricity additive in soybean oil, where it was found that it had a minimal effect in reducing wear and did not improve oxidative stability. This drawback, while not good in lubricant formulations, is desirable in many applications such as paint and linoleum production. Also, the structure of the ketone could make it a desirable dielectric fluid, where the water sequestering ...

The viscosity, density, and elastohydrodynamic film thicknesses of oil-soluble polyalkyl glycols (PAG), high oleic sunflower oil (HOSuO), and their 50/50 (wt.%) blends were investigated. The viscosity and density of the blends were found to be predictable from the corresponding neat oil properties using simple mixing rules. Pressure–viscosity coefficients (PVC) of HOSuO, the two PAGs, and the two 50 wt% HOSuO/50 wt% PAG blends were calculated from measured film thickness data using the Hamrock-Dowson method and compared to values estimated from literature data. Literature pressure-density and viscosity-temperature data for oils with high-oleic acid group content were analyzed using the Tait and Casalini et al. models. Viscosity versus pressure data obtained from these analyses was used to calculate PVC using the Barus and Bair et al. models. The PVC values calculated from the literature data following this procedure showed reasonable agreement with that from film thickness data from this work.

The film thickness in elastohydrodynamic (EHD) conditions for soybean oil (SBO), oleic estolide ester (EST) and their binary blends with polyalphaolefins (PAO2 or PAO40) were studied at 30 and 100 °C. Changes with time, for up to 200 min, were monitored. SBO and its blends with the lower viscosity PAO2 showed initially good agreement with the Hamrock–Dowson (H–D) equation down to 1–3 nm film thickness. 60 min or more after the start of the measurements, boundary layers with thickness up to 4.7 nm were observed. The blend of SBO with the more viscous PAO40 showed initially a good agreement with H–D at 100 °C. Negative deviations in film thickness were observed 15 min after the start of the measurements. At extended periods of time, up to 200 min, they were less pronounced but still detectable. EST–PAO2 blend showed initially formation of boundary layers with thickness around 2 nm. The boundary layer at 30 °C did not change for 200 min, while at 100 °C showed a decrease in thickness and/or viscosity with time. The EST and the EST–PAO40 blends showed good agreement with the H–D equation and did not display a boundary or fractionation layer within 200 min.

Corn, canola, and castor-lauric estolide oils were chemically modified by photochemical direct reaction of butanethiol with the double bonds on the hydrocarbon chains. The effect of chemical modifications on viscosity, viscosity index (VI), pour point (PP), cloud point (CP), oxidation stability (RPVOT), 4-ball anti-wear (AW), and extreme pressure (EP) were investigated. The sulfide modified (SM) corn and canola oils showed increased viscosity, increased RPVOT time (more than one order of magnitude), reduced PP (9–18 °C), and reduced VI. The SM estolide displayed similar trends in VI and RPVOT but showed no change in viscosity or cold flow. The SM oils, along with commercial mono- and polysulfide additives were also investigated as additives, at 0.6% (w/w) S concentration, in corn and polyalphaolefin (PAO) base fluids. In both fluids, the additives resulted in minor changes of PP, CP, coefficient of friction, wear scar diameter (WSD), and weld point (WP). Only the commercial polysulfide EP additive displayed large WP increases in the fluids. The additives resulted in no change of oxidation stability of corn oil, but displayed big improvement in the oxidation stability of PAO (8 to 16-fold increase in RPVOT time). The difference in the effect of the additives on the oxidation stability of PAO versus corn oil was attributed to the difference in the reactive hydrogen contents in the two base fluids relative to those in the additives. An empirical equation, for correlating change in RPVOT time with change in bond dissociation energy of reactive protons before and after chemical modification, is proposed.

The viscosity and elastohydrodynamic (EHD) film thickness properties of binary blends of castor oil with polyol esters were determined experimentally. Predicted blend viscosities were calculated from the viscosities of the pure blend components. Measured viscosity values were closer to the values predicted using the Lederer model than the Arrhenius model. EHD film thickness data were mostly in agreement with the predictions of the Hamrock–Dowson model. Observed deviations of EHD film thickness were attributed to boundary film formation and thermal effects. Calculated effective pressure–viscosity coefficients, α, displayed a complex relationship with blend viscosity. At 40°C, the addition of 10% polyol esters resulted in a 12–17% drop in α of castor oil. Higher concentrations of polyol esters resulted in an increase of α. At 70 and 100°C, α displayed an almost linear dependence on blend composition. Copyright © 2011 John Wiley & Sons, Ltd.

The effect of sulfide-modified corn oil (SMCO) and ditertiary dodecyl pentasulfide (PS) additives on the oxidative stability of corn oil (CO) and polyalphaolefin oil (PAO) was investigated using pressurized differential scanning calorimetry in dynamic (DDSC) and isothermal (IDSC) modes. DDSC showed a weak pro-oxidant effect of SMCO and PS in CO, and antioxidant behavior in PAO. Analysis of the IDSC data showed the existence of isokinetic temperature in both oils. Below the isokinetic temperature the sulfides behaved as antioxidants while above it they behaved as pro-oxidants. The isokinetic temperature was found to depend on the chemical structure of the oils. For the highly unsaturated CO, the isokinetic temperature was 100–135 ◦ C, while for the fully saturated PAO it was above 200 ◦ C. The existence of isokinetic temperature provides consistent explanation to our and literature data for oxidation behaviors of sulfide additives in oils, which appears to be contradictory (pro-oxidant vs. antioxidant) depending on experimental conditions. The isokinetic temperature suggests that accelerated oxidation test methods at elevated temperatures are poor predictors of the low-temperature performance of sulfide-containing

The elastohydrodynamic traction coefficient (tc) properties of nine seed oils of varying chemical structures, polyalphaolefin oil (PAO) and hexadecane, were investigated using a ball-on-disk traction apparatus. The seed oils were castor oil, a triglyceride with hydroxyl functional group; jojoba, a monoglyceride; and seven triglyceride seed oils with varying fatty acid compositions. Two types of experiments were conducted at constant temperature (40 or 100°C) and constant load (10, 20, 30, or 40 N): tc as a function of slide-to-roll ratio (srr) at 1 m/s entrainment speed (u); and tc as a function of u at 50% srr. In both types of experiments, tc increased with decreasing temperature, increasing load, and increasing srr. All u vs. tc experiments gave the familiar Stribeck-type profiles. A maximum in tc values was observed in some srr vs. tc experiments. Regression analysis showed excellent agreement between limiting tc (tc at 1 m/s u and 50% srr) values from these two types of experiments. Hexadecane and PA...

Polymercaptanized soybean oil (PMSO), the product of a thiol-ene reaction between soybean oil and hydrogen sulfide, is a material of interest as a lubricant additive and polymer precursor. We investigated with gel permeation chromatography, nuclear magnetic resonance (one-dimensional and two-dimensional), gas chromatography–mass spectrometry, and viscometry the changes that occur with PMSO upon heating or ultraviolet irradiation. The observed changes were due to a further thiol-ene reaction between the thiol groups and the residual unsaturation. The formation of oligomers was a result of new sulfide bridges. Additionally, tetrahydrothiophene moieties were detected. An almost linear increase of the average molecular weight (MW) and the polydispersity index (PDI) was observed upon heat treatment [number-average MW (Mn)=1180 Da, PDI=1.32 for PMSO, Mn =1720 Da, PDI=2.17 for PMSO that was heated for 1000 h at 130 8C]. PDI correlated best with the z-average MW. The Mn was the best predictor of the viscosity. For samples with close Mn, the higher PDI corresponded to a higher viscosity index.

The film thickness of seven seed oils and two petroleum-based oils of varying chemical structure was investigated by the method of optical interferometry. The measured film thickness (hmeas) was then compared to that calculated using the Hamrock–Dowson (H-D) equation. The result showed that the H-D equation adequately and without exception predicted hmeas in the high entrainment speed region but not in the low entrainment speed region. In order to understand these deviations further, the chemical structural variabilities of the oils were quantified using empirical parameters, and its effect on film thickness in the low entrainment speed region was examined. The result of this examination indicated that, in the low entrainment speed region, the film thickness of seed oils (i) rarely correlates with viscosity as proposed by the H-D equation, (ii) increases with decreasing polarity of the oil, and (iii) increases with decreasing degree of unsaturation of the oils. Published in 2008 by John Wiley and Sons, Ltd.

Two polyalphaolefins, of higher and lower viscosity than vegetable oils, were used to make binary blends of varying compositions with soy bean and canola oils. The pure oils and the blends were used in viscosity and film thickness investigations. The effects of composition and temperature on viscosity were found to agree well with the theoretical predictions of a simple mixing law. The film thicknesses of the various blends under elastohydrodynamic conditions were measured at 20 N load, and varying entrainment speeds and temperatures. From the data, pressure–viscosity coefficients, α, as a function composition and temperature were obtained. The resulting α values were compared with theoretical predictions. Experimental values of α as a function of composition showed a slight negative or no deviation from the values predicted by an ideal mixing model. On the other hand, experimental values of α displayed a mild decrease with increasing temperature, while the model predicted a sharp decrease with increasing temperature. Published in 2008 by John Wiley & Sons, Ltd.

Limonene was chemically modified by reacting it with dialkyl phosphites of varying alkyl structures under inert atmosphere in the presence of free radical initiators. The reaction gave a mixture of mono- and di-adduct products and was optimized to produce only the di-adduct product limonene bisphosphonate by forcing both limonene double bonds to react completely. The product mixture was carefully characterized using a combination of gas chromatography–mass spectroscopy, infrared spectroscopy, and nuclear magnetic resonance spectroscopy (1H, 13C, 31P). The bisphosphonates were investigated for their physical and tribological properties. The alkyl bisphosphonates displayed density and viscosity that was a function of the alkyl structure (methyl, ethyl, n-butyl) and much higher than the values for the unreacted limonene. They also displayed improved oxidation stability but lower viscosity index and solubility in polyalphaolefin (PAO6) and high-oleic sunflower oil (HOSuO) base oils. Tribological characterization of the neat modified oils on a four-ball tribometer showed improved extreme-pressure weld point by all three di-adducts and improved anti-wear coefficient of friction (COF) and wear scar diameter (WSD) by the n-butyl di-adduct only. The limonene bisphosphonates also displayed improved COF and WSD as additives in PAO6 and HOSuO base oils at low concentrations. The effects of chemical modifications on physical and tribological properties can be explained in terms of increased polarity of the modified products, insertion of heavy atoms (from PO3) into the limonene structure, and complete absence of unsaturation in the modified products.

We report the nanoscale structural changes associated with the interfacial gelation of adsorbed beta-casein layers as a function of aging time. Adsorbed layers were transferred to solid supports and imaged by atomic force microscopy. The aging of the layer was accompanied by the formation of distinct disk-shaped protein nanoparticles ( approximately 20 nm in diameter). Under conditions where a gelled layer was expected (from previous interfacial rheology experiments), we observed ordering of the particles and the formation of elongated aggregates or linear rows. Brewster angle microscopy images were also obtained during the adsorption and gelation processes and during the degradation of the protein layer following addition of the surfactant sodium dodecyl sulfate (SDS). If SDS was added prior to interfacial protein gelation, the layer developed a foamlike morphology consistent with a fluid interfacial protein layer. However, if SDS was added after gelation, the protein layer was observed to fracture, consistent with the behavior of a solid phase.

A magnetic rod interfacial shear rheometer was used to measure the properties of β-casein adsorbed at the air/solution interface as a function of aging time. Over a wide range of concentrations (1 × 10-6 to 2 × 10-2 wt % β-casein) the initial rheology of the adsorbed surface layer is dominated by a viscous response of the interface. For solutions in the range 5 × 10-3 to 2 × 10-2 wt %, interfacial gelation is observed after ∼15 h of aging, long after the surface tension has stabilized. In particular, although both components of the complex interfacial shear modulus (i.e., the storage and loss moduli) gradually increase with aging time, the ratio of the loss to the storage modulusthe loss tangentdecreases and drops below unity. The frequency dependence of the shear modulus is consistent with sol−gel transitions observed in bulk systems and described within the context of percolation theory.

This chapter is a short introduction to the thiol-ene reaction and includes the thiol-ene reaction as a click chemistry reaction, radical chain reactions, basic mechanisms and kinetics, the use of the thiol-ene reaction for the synthesis of novel bio-based materials (polymers, lubricants and coatings), addition of H-phosphonates to double bonds, some reaction information and bio-based products, and possible applications of the products (lubricants, plasticizers and anti-microbial agents).

In this work we study experimentally the lifetime of oil droplets pressed by buoyancy against a large oil/water interface, in a system containing protein (bovine serum albumin). The stability of the drops depends strongly on their size, which can be explained with the hydrodynamics of thinning of the gap region. Two distinct size intervals with different thinning regimes may be discerned: (i) Very small drops (below ∼20 μm). They remain practically nondeformed up to coalescence; in this case the lifetime diminishes with increase of the drop radius. The latter trend may be described qualitatively in terms of the Taylor law (or mixed Stokes−Taylor law) for viscous resistance. (ii) Large drops. They form films, and the lifetime rises with the increase of the size, which complies with the Reynolds law for the friction in the gap. The overall dependence of the lifetime on the drop radius passes through a shallow and broad minimumhere for the first time this is proved by direct measurement in a real system: o...

Dimethyl, diethyl, and di-n-butyl phosphites were reacted with methyl or ethyl oleates using thermally initiated radical reactions. Reactions were conducted with or without the presence of a dilauroyl peroxide initiator. The reactions gave mixture of isomers with the phosphorus attached at the 9 or 10 carbon of the stearates. High yields (94-97%) and high purity products (98-99% by GC) were obtained in the presence of the initiator, while without initiator, the reaction was very slow resulting in very low conversions (50% after 6 days). The phosphonostearate products were positively identified and thoroughly characterized using GC with EI-MS, FTIR, and (1)H-, (13)C-, and (31)P NMR spectra. GC achieved only partial resolution of the positional isomers. Principal component analysis was applied to successfully separate the MS-EI spectra of fractions from the 9- and 10-isomers. A mechanism to explain the observed MS fragmentation pattern and the relative abundances is proposed. 2D-NMR data analysis was applied to assign values of (13)C- and (1)H NMR shifts as well as P-C and P-H splitting constants. The molecular volume and the refractive indices of the phosphonostearates were determined experimentally and were found to be in agreement with the computationally predicted values using the PM3 semi-empirical method and the group-contribution method of Bondi.

A none-washing technique for layer-by-layer deposition of polyelectrolyte on colloids based on careful monitoring of colloid recharging is elaborated. It allows applying the technique for colloid systems in larger scale than laboratory, and avoiding the expensive washing procedure with centrifugation or filtration. The colloidal aggregation process depends on the cycle of sequential polycation/polyanion deposition and molecular weight of the polyelectrolytes used. The aggregation can be reversed by the addition of the next polyelectrolyte layer.

Butanethiol was used in ultraviolet-initiated thiol-ene reaction with canola and corn oils to produce sulfide-modified vegetable oils (SMVO). The crude SMVO product was successfully purified by solvent extraction, vacuum evaporation, and silica gel chromatography. The SMVO products were characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. Further product characterization and analysis was conducted using GC and GC-MS on the fatty acid methyl esters obtained by the transesterification of the SMVO products. Investigation of the effect of reaction conditions showed that high yield and high conversion of double bonds into thiol were favored at low reaction temperatures and high butanethiol/vegetable oil ratios. Canola and corn oils gave similar double-bond conversions and yields of the desired SMVO product even though they have big differences in the relative numbers of single and multiple double bonds in their structures. Under best reaction conditions, up to 97% of double-bond conversion and 61% isolated yields of the purified SMVO products were attained.