Network structure and properties of polyurethanes from soybean oil

Vegetable oils are very heterogeneous materials with a wide distribution of triacylglycerol structures and double‐bond contents. The hydrogenation of epoxidized soybean oil (ESO) produces polyols having a functionality distribution related to that of soybean oil. Therefore, these polyols are convenient substances for studying the impact of structural heterogeneity on network formation and properties. Polyols of hydroxyl numbers ranging from 225 to 82 mg KOH/g and weight‐average functionalities ranging from 4.4 to 2.7 were obtained by the variation of the time of hydrogenation of ESO. An analysis of the functionality distribution in polyols shows that gel points with diisocyanates vary from 54 to 76% conversion. The molecular weights of the network chains of polyurethanes prepared from these polyols and diphenyl methane diisocyanate varied from 688 to 1993. Polyols with hydroxyl numbers above 200 mg KOH/g gave glassy polymers, whereas those below that value gave rubbers. The heterogeneity of polyols had a negative effect on the elastic properties only at low crosslinking densities. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Molecular Weight Distribution of Low Molecular Weight Polyols Derived from Fatty Acid Methyl Esters

A series of commercial polyether polyols with well-defined molecular weights (MW) was used along with propylene glycol and dipropylene glycol as gel permeation chromatography (GPC) calibration standards to determine the MW and oligomeric composition of the synthesized low MW fatty acid methyl ester (FAME) polyols, having an MW of lower than 600 Da. This GPC analysis was compared to the one calibrated against the commercially-available polystyrene (PS) standards and to the number-average molecular weight (M _n) obtained via vapor pressure osmometry (VPO) technique. The MW of FAME polyols obtained with GPC calibrated against polyether polyols were closer to the M _n values obtained via VPO than the MW obtained via GPC calibrated against PS standards. Using the reliable GPC calibration, the MW distribution and the hydroxyl functionality of FAME polyols were determined with greater confidence.     

Effect of tall oil fatty acids content on the properties of novel hyperbranched alkyd resins

Hyperbranched alkyd resins (HBRA) were synthesized by modification of hydroxylated hyperbranched polyester (HBP1‐4) with tall oil fatty acids (TOFA). The core is a hydroxylated hyperbranched polyester of fourth generation with OH groups in the periphery (18), which is endcapped with tall oil fatty acids. The occurrence of these reactions, HBP1‐4 and TOFA, was determined by making use of acid value, nuclear magnetic resonance, and hydroxyl values. The effects of TOFA and HBP1‐4 on properties of the HBRA resins were investigated by vapor pressure osmometry, differential scanning calorimetry, thermogravimetric analysis, friction resistance, and hardness. The resins with higher modification percentage (HBRA4) presented the best thermal and hydrolytic stability, but lower friction resistance and hardness. All HBRA resins presented amorphous characteristics, OH groups, and double bonds in the periphery. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Enzymatic methylation of canola oil deodorizer distillate

Methylation of canola oil deodorizer distillate catalyzed by a nonspecific lipase was investigated. The conversion of fatty acids to methyl esters has been optimized by using a statistical design. Up to 96.5% conversion of fatty acids to their methyl esters has been achieved without the aid of vacuum or any water-removing agent. The effects of temperature, ratio of the reactants (methanol: fatty acids in the deodorizer distillate) and enzyme concentration on the equilibrium conversion were studied. The temperature and ratio of the reactants showed a significant effect on the conversion of fatty acids to methyl esters and they exhibited a strong interactive effect. Enzyme concentration in the range of 2.7% to 4.3% did not show a significant effect on the equilibrium conversion of fatty acids. Greater than 95% conversion of fatty acids to methyl esters was achieved at temperatures around 50°C and at a ratio of the reactants between 1.8 and 2.0. The inhibitory effect of hydrophilic methanol on the enzyme activity was largely reduced by working at the lower temperature range (around 50°C).     

Field ionization mass spectrometry of long chain fatty methyl esters

Mass spectrometry is particularly useful for identifying lipid materials. One primary factor in the interpretation of mass spectra is the recording of the molecular ion peak giving the molecular weight of the compound. Regrettably many compounds, including hydroxy compounds, do not give significant molecular ion peaks; consequently their identification is difficult. A mass spectrometer equipped with a field ionization source produces a greatly different mass spectrum consisting almost entirely of the molecular ion peak. This new source was used to measure the mass spectra of methyl esters of saturated, unsaturated and hydroxy fatty acids. Saturated esters gave the molecular ion peak almost exclusively; unsaturated esters yielded molecular plus metastable ion peaks; whereas the hydroxy esters had molecular, M-18, meaastable and fragment ion peaks. Presented at the AOCS Meeting, Chicago, October 1967. No. Mktg. and Nutr. Res. Div., ARS, USDA.     

The influence of trace components on the melting point of methyl soyate

The objective of this study was to determine the effect of various amounts of unsaponifiables and bound glycerol on the crystallization temperatures of methyl soyate used as biodiesel. The preparation of methyl esters did not affect the amount of unsaponifiable matter in biodiesel. A synthetic unsaponifiable mixture added to distilled methyl soyate and blends of methyl soyate and No. 1 diesel fuel (20:80, vol/vol) did not affect the crystallization onset temperature, cloud point, or pour point at concentrations up to 3% by weight. The amounts of monoglycerides and diglycerides in methyl soyate decreased from 2.60 and 9.87%, respectively, to 0% as the methanol/soybean oil ratio increased from 90 to 200% of the theoretical requirement. Transesterification reactions conducted with less than 130% of the theoretical amount of methanol resulted in methyl soyate with a higher cloud point because of the presence of saturated mono- and diglycerides. Pure mono- and diglycerides added to distilled methyl soyate at 0 to 1.0% did not change the pour point of the esters, but the cloud point of esters increased with increasing amount of saturated mono- or diglyceride. Pure saturated mono- or diglyceride presented in concentrations as low as 0.1% increased the cloud point of methyl soyate. Similar results were obtained with mono- and diglyceride mixtures present in incompletely converted methyl soyate.     

Novel biobased dual-cure coating system

Sucrose esters consisting of acetoacetates and fatty acids were invented as novel biobased amine-cured and autoxidation dual-cure coating systems, in the presence of diamine crosslinker and metal salt driers. Acetoacetylated sucrose soyate (ASS) was an intramolecular system containing both acetoacetates and fatty acids in the same molecule. Miscible bicomponent blends, made of ASS and partially enamine alkyl substituted acetoacetylated sucrose (p-EAS), was an intermolecular curing system. Compatibility between the two components was achieved by reacting acetoacetylated sucrose (AS) with alkyl amines, in which the compatibility could be adjusted by either the alkyl chain length or the degree of enamine alkyl substitution, DES. Sucrose esters were characterized by gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and differential scanning calorimetry (DSC). The properties and drying times of coatings cured through autoxidation, amine-acetoacetate reactions, and by dual-curing were studied. It was found that acetoacetate chemistry improved the attributes of sucrose ester of fatty acids in ambient curing conditions, as well as providing dual-cure coatings having a good balance of properties.     

Analysis of hydroxylated fatty acids from plant oils

A novel process has been described recently for the preparation of hydroxylated fatty acids (HOFA) and HOFA methyl esters from plant oils. HOFA methyl esters prepared from conventional and alternative plant oils were characterized by various chromatographic methods (thin-layer chromatography, high-performance liquid chromatography, and gas chromatography) and gas chromatography-mass spectrometry as well as¹H and¹³C nuclear magnetic resonance spectroscopy. HOFA methyl esters obtained fromEuphorbia lathyris seed oil, low-erucic acid rapeseed oil, and sunflower oil contain as major constituents methylthreo-9,10-dihydroxy octadecanoate (derived from oleic acid) and methyl dihydroxy tetrahydrofuran octadecanoates, e.g., methyl 9,12-dihydroxy-10,13-epoxy octadecanoates and methyl 10,13-dihydroxy-9,12-epoxy octadecanoates (derived from linoleic acid). Other constituents detected in the products include methyl esters of saturated fatty acids (not epoxidized/derivatized) and traces of methyl esters of epoxy fatty acids (not hydrolyzed). The products that contain high levels of monomeric HOFA may find wide application in a variety of technical products.     

Highly functional biobased polyols and their use in melamine–formaldehyde coatings

Highly functional sucrose soyate polyol (SSP) resins were synthesized by ring-opening epoxidized sucrose soyate with methanol or ethanol and were subsequently crosslinked with a melamine–formaldehyde (MF) resin in the presence of an acid catalyst or blocked acid catalyst. The biobased polyols were characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, proton nuclear magnetic resonance spectroscopy, Brookfield viscosity, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The thermal properties of the biobased MF coatings were studied using differential scanning calorimetry and dynamic mechanical analysis. As controls, a soybean oil polyol (SBOP) with lower functionality and a commercial polyester polyol were studied for comparison. Overall, MF coatings formulated with SSPs showed superior properties to coatings formulated with SBOP and comparable properties to the commercial polyester which was attributed to the high hydroxyl functionality.     

Low-temperature properties of alkyl esters of tallow and grease

The low-temperature properties of mono-alkyl esters derived from tallow and recycled greases were determined for neat esters and 20% ester blends in No. 2 low-sulfur diesel fuel. Properties studied included cloud point, pour point, cold filter plugging point, low-temperature flow test, crystallization onset temperature, and kinematic viscosity. Compositional properties of the alkyl esters determined included water, residual free fatty acids, and free glycerol content. In general, the secondary alkyl esters of tallow showed significantly improved cold-temperature properties over the normal tallow alkyl ester derivatives. The low-temperature flow test did not show a 1:1 correlation with cloud point as previously observed with methyl soyate and methyl tallowate. For the homologous series methyl to n-butyl tallowate, ethyl tallowate had the best broad-spectrum low-temperature properties, both neat and when blended in diesel fuel. For the greases studied, both the normal and branched alkyl ester derivatives showed improved properties over corresponding tallow esters, especially with neat esters.     

Oligomeric Composition of Polyols From Fatty Acid Methyl Ester: The Effect of Ring‐Opening Reactants of Epoxide Groups

Commercial availability of fatty acid methyl ester (FAME) from palm oil targeted for biodiesel offers a good feedstock for the production of structurally well‐defined polyols for polyurethane applications. The effect of molecular weight (MW), odd and even carbon numbers, and the linear and branched structure reactants used in the ring‐opening reaction of epoxidized fatty acid methyl ester (E‐FAME) on the properties of polyols was investigated. Conversions of E‐FAME to PolyFAME polyols were confirmed by Fourier transform infrared analysis, oxirane oxygen content, and hydroxyl number. Gel permeation chromatography (GPC) calibrated against polyether polyols as a standard and vapor pressure osmometry were used for MW determination. GPC chromatograms of PolyFAME polyols clearly demonstrated the formation of oligomers during ring‐opening reactions. MW, and odd and even carbon numbers in a structure of linear diols and branched diol used in the syntheses of PolyFAME polyols did not have an effect on crystallinity, glass transition, or melt temperatures measured using Differential scanning calorimetry (DSC). PolyFAME polyols ring‐opened with water, methanol, and 1,2‐propanediol contained secondary hydroxyl groups, whereas PolyFAME polyols ring‐opened with linear diols contained a mixture of primary and secondary hydroxyl groups. It was found that the concentration of primary hydroxyl groups increased significantly by increasing the number of carbons from C2 to C3 in the linear diols. The viscosity of PolyFAME polyols also increased with the MW of linear diols used in the E‐FAME ring‐opening reaction. These findings would be beneficial for formulators in choosing the most cost effective polyols for polyurethane formulations.     

Production of polyols and waterborne polyurethane dispersions from biodiesel‐derived crude glycerol

This study investigated the preparation of polyols and waterborne polyurethane dispersions (CG‐WPUDs) from biodiesel‐derived crude glycerol. The polyols were produced from biodiesel‐derived crude glycerol via a thermochemical conversion process, which converted crude glycerol components such as glycerol, free fatty acids, and methyl esters of fatty acids (FAMEs) into polyols under optimized reaction conditions. CG‐WPUDs with different hard segments (41.0% to 63.2 wt %) were prepared from the crude glycerol‐based polyols produced. PU coating films cast from CG‐WPUDs showed increasing glass transition temperatures (T_g) from 63°C to 81°C when hard segment content increased from 41.0% to 63.2% and had good thermal stability up to 240°C. CG‐WPUD‐based coatings showed excellent adhesion to steel panel surfaces, pencil hardness as high as F, but relatively low flexibility. This study demonstrated the potential of biodiesel‐derived crude glycerol for the production of bio‐based polyols and WPUDs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41425.     

Fuel properties and emissions of soybean oil esters as diesel fuel

The effects of using blends of methyl and isopropyl esters of soybean oil with No. 2 diesel fuel were studied at several steady-state operating conditions in a four-cylinder turbocharged diesel engine. Fuel blends that contained 20, 50, and 70% methyl soyate and 20 and 50% isopropyl soyate were tested. Fuel properties, such as cetane number, also were investigated. Both methyl and isopropyl esters provided significant reductions in particulate emissions compared with No. 2 diesel fuel. A blend of 50% methyl ester and 50% No. 2 diesel fuel provided a reduction of 37% in the carbon portion of the particulates and 25% in the total particulates. The 50% blend of isopropyl ester and 50% No. 2 diesel fuel gave a 55% reduction in carbon and a 28% reduction in total particulate emissions. Emissions of carbon monoxide and unburned hydrocarbons also were reduced significantly. Oxides of nitrogen increased by 12%.     

Characteristic properties of cutting fluid additives derived from the reaction products of hydroxyl fatty acids with some acid anhydrides

Several adducts were prepared from the thermal reaction of hydroxyl fatty acids (ricinoleic acid oligomers, 12-hydroxystearic acid oligomers, oleyl alcohol, dehydrated castor oil fatty acids, and dimer acid) with maleic anhydride and screened as water-soluble cutting fluids. For example, aqueous solutions of triethanolamine salts with the products of ricinoleic acid oligomers, 12-hydroxystearic acid dimer, and 12-hydroxysteric acid hexamer showed good antirust properties for waterbased cutting fluids. Various half esters of hydroxyl fatty compounds with acid anhydrides were prepared. Aqueous solutions of triethanolamine salts of half esters of maleic anhydride and succinic anhydride and phthalic anhydride with hydroxyl fatty acids gave good antirust and antiwear properties for waterbased cutting fluids.     

Gaschromatographische und dünnschichtchromatographische Untersuchung von Fettsäuren: Die Anwendung von gepackten Glaskapillarsäulen zur Trennung von cis- und trans-ungesättigten Fettsäuren

Gas Chromatographic and Thin-Layer Chromatographic Studies on Fatty Acids: The Application of Packed Glass Capillary Columns for Separation of cis- and trans-Unsaturated Fatty Acids from Saturated Fatty Acids Packed glass capillary columns were used for the quantitative determination of trans- and cis-unsaturated fatty acids in the presence of saturated fatty acids by gas chromatography. The fatty acids were analyzed as methyl esters after interesterification of the triglyceride samples. The conversion of glyceryl esters of fatty acids into methyl esters could be followed using short GC columns and by thin-layer chromatography.     

Antioxidant effect of mono‐ and dihydroxyphenols in sunflower oil with different levels of naturally present tocopherols

Antioxidant properties of mono‐ and dihydroxyphenolic acids and their alkyl esters were examined, with emphasis on the relationship between their molecular structure and antioxidant activity. Test media with different tocopherol level were used for determining the oxidative stability: original refined sunflower oil (total tocopherols 149.0 mg/kg), partially tocopherol‐stripped sunflower oil (total tocopherols 8.7 mg/kg) and distilled fatty acid methyl esters (FAME) as a tocopherol‐free medium. The chemical reaction of tocopherols with diazomethane tested for the purpose to eliminate their antioxidant activity failed due to the negligible degree of methylation of hydroxyl group in the tocopherol molecule. Caffeic acid and protocatechuic acid (3,4‐dihydroxyphenolic acids) and their alkyl esters were found to be more active antioxidants than monohydroxyphenolic acid (p‐hydroxybenzoic acid), 2,5‐dihydroxyphenolic acid (gentisic acid), 3‐methoxy‐4‐hydroxyphenolic acids (vanillic and ferulic acids) and their corresponding alkyl esters. Naturally present tocopherols in refined sunflower oil proved to have a synergistic effect on gentisic acid but not on its alkyl esters. In contrast, tocopherols showed an antagonistic effect on alkyl esters of caffeic acid, because their protection factors decreased with increasing level of tocopherols in the test medium. Moreover, the antioxidant activity of these alkyl esters decreased with increasing length of their alkyl chain in conformity with the polar paradox hypothesis. Practical applications: Tocopherols as naturally present antioxidants influence considerably the antioxidant activity of other antioxidants added to plant oils used as a test medium. Distilled fatty acid methyl esters prepared from refined sunflower oil may serve as an optimal tocopherol‐free test medium. Some alkyl esters of phenolic acids were evaluated to be applicable as natural more lipophilic antioxidants in comparison with phenolic acids.     

Polyurethane foams from hydroxymethylated fatty diethanolamides

Satisfactory rigid polyurethane foams were prepared from diethanolamides of hydroxymethylated oleate, linseed oil, safflower oil and their methyl esters. These foams were improved when the fatty polyols were blended with a commercial, low molecular weight polyol. National Flaxseed Processors Association Fellow. ARS, USDA.     

Aromatic Products from Reaction of Lignin Model Compounds with UV-Alkaline Peroxide

A series of guaiacyl and syringyl lignin model compounds and their methylated analogues were reacted with alkaline hydrogen peroxide while irradiating with UV light at 254 nm. The aromatic products obtained were investigated by gas chromatography-mass spectrometry (GC-MS). Guaiacol, syringol and veratrol gave no detectable aromatic products. However, syringol methyl ether gave small amounts of aromatic products, resulting from ring substitution and methoxyl displacement by hydroxyl radicals. Reaction of vanillin and syringaldehyde gave the Dakin reaction products, methoxy-1,4-hydroquinones, while reaction of their methyl ethers yielded benzoic acids. Acetoguaiacone, acetosyringone and their methyl ethers afforded several hydroxylated aromatic products, but no aromatic products were identified in the reaction mixtures from guaiacylpropane and syringylpropane. In contrast, veratrylpropane gave a mixture from which 17 aromatic hydroxylated compounds were identified. It is concluded that for phenolic lignin model compounds, particularly those possessing electron-donating aromatic ring substituents, ring-cleavage reactions involving superoxide radical anions are dominant, whereas for non-phenolic lignin models, hydroxylation reactions through attack of hydroxyl radicals prevail.     

Synthesis of Fatty Acid Esters of Selected Higher Polyols Over Homogeneous Metallic Catalysts

Studies on the synthesis of esters of natural origin fatty acids (oleic acid) and a branched synthetic isostearic acid derived from oleic acid with commercially available selected higher polyols in the presence of homogeneous metallic catalysts have been carried out. The effects of the synthesis temperature, molar ratio and the catalysts amount have also been studied. It was shown that higher fatty acid conversion and selectivity to tri‐ and tetraesters were obtained for organotin catalyst Fascat 2003, which was used as the esterification catalyst. Anti‐wear test confirmed good tribological properties of the obtained esters.     

Isocyanate-modified dehydrated castor oil

Esters of dehydrated castor oil fatty acids with polyhydric alcohols like ethylene glycol, propylene glycol, glycerol, pentaerythritol and sorbitol have been prepared. The esters, having hydroxyl value ranging from 78.5 to 167, were reacted with toluene diisocyanate. The scratch hardness and other film properties of the resulting urethanes have been studied. Urethanes obtained from various mixtures of the above esters also have been studied. The best results have been obtained when a mixture of ethylene glycol ester and plenaerythritol ester of dehydrated castor oil fatty acids in the ratio of 4:1 are reacted with one equivalent of toluene diisocyanate. One equivalent of glycerol ester (hydroxyl value 78.5), ethylene glycol ester (hydroxyl value 167), or propylene glycol ester (hydroxyl value 159.4) of DCO fatty acids when reacted with 1.25 equivalent of toluene diisocyanate also gave satisfactory products.