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The product of the self-metathesis of soybean oil (MSBO) containing ∼80% of triacylglycerol (TAG) oligomers was easily transformed into polyols by a conventional one-pot epoxidation and hydroxylation reaction. The MSBO polyol inherited the oligomeric structure of its parent oil without significantly altering its functionality. The OH-value of the polyol from MSBO was easily customized by controlling the reaction conditions. Polyols having OH-values between 83 and 263 mg KOH/g were achieved and used to make polyurethane foams with controlled combinations of strength (stress at 10% deformation of 0.07–0.75 MPa) and flexibility (recovery from deep compression of 75–95%) suitable for versatile applications, particularly those requiring strength and resiliency. The large resistance to load and significant spring for recovery achieved by the polyurethane foams are attributable to the association of the high OH value and oligomeric structure of the MSBO polyols. More importantly, the self-metathesis is demonstrated to extend the range of the products derived from vegetable oils, particularly polyols and polyurethane foams. [ABSTRACT FROM AUTHOR]

A series of binary mixture additives made of a pour point depressant (PPD) and a vegetable oil based crystallization modifier (VOCM) have been used to substantially improve the cold flow performance of fatty acid methyl esters (FAME) of soybean oil (Soy1500). An apparatus improving on the ASTM methods was designed to measure the cloud point (CP) and pour point (PP). The mixtures dramatically altered Soy1500 crystallization from nucleation to aggregation, and delivered PP depressions reaching 30 °C. The effect was confirmed to be due to synergistic effects wherein the VOCM delays the nucleation by first combining with the saturated FAME of the biodiesel then growing structure specific crystal surfaces that effectively adsorb the PPD which provides barriers to agglomeration. The VOCM-PPD mixture constrains the biodiesel microstructure to very small crystals that are prevented from aggregating over an extended temperature range, leading to a significant depression in the PP. The most dramatic effects were achieved when the PPD is combined in optimal concentration with a VOCM having a structural element which initiates packing and another that prevents further crystallization. Importantly, the results and understanding gathered from the study can be used for the design of highly functional cold flow improver cocktail additives. [ABSTRACT FROM AUTHOR]

The derivatives of vegetable oils with specific chemical structures, such as TAG (triacylglycerols) having mixed straight and kinked moieties, have proven very effective in lowering the crystallization of biodiesel. SOO (1, 2-dioleoyl-3-stearoyl sn -glycerol)/MeS (methyl stearate) is part of a series of studies of TAG/FAME (fatty acid methyl ester) binary model systems conducted to establish structure–function relationships of lipid-based cold flow improvers in biodiesel with a particular attention to the effect of molecular symmetry in contrast with a previously published study of the OSO (1, 3-dioleoyl-2-stearoyl sn -glycerol)/MeS binary system. The phase behavior of several SOO/MeS mixtures were investigated at different length scales with XRD (X-ray diffraction), DSC (differential scanning calorimetry) and PLM (polarized light microscope). A complete phase diagram including the transformation lines, crystal structure and microstructure was constructed. The solubility behavior was discussed using a simple thermodynamic model based on the Hildebrand equation and pair interactions. The asymmetric position of the oleic moieties of SOO was shown to be crucial in modifying the thermal transformation behavior of MeS. The findings may be used to design effective crystallization modifiers of biodiesel based on particular structural determinants, and underscores the importance of symmetry in such designs. [ABSTRACT FROM AUTHOR]

The present study examines the phase behavior of a model binary system made of OPO (1,3-dioleoyl-2-palmitoyl glycerol); a TAG (triacylglycerol) highly effective in depressing onset of crystallization of biodiesel, and MeS (methyl stearate); a prevalent saturated FAMEs (fatty acid methyl esters) in biodiesel. The thermal behavior, crystal structure and microstructure of the OPO/MeS mixtures were investigated with DSC (differential scanning calorimetry), XRD (X-ray diffraction) and PLM (polarized light microscope). The OPO/MeS system presented a phase diagram with peritectic and eutectic transitions. A simple thermodynamic modeling of the liquidus line indicated a relatively complex mixing behavior, and highlighted the prevailing effect of the peritectic compound on solubility. Different types of microstructures that were more or less influenced by MeS, OPO or/and compound microstructures were observed in the mixtures. They are associated with the crystal phases and the thermal transitions. Furthermore, MeS, OPO and compound crystal structures (monoclinic, orthorhombic and triclinic, respectively) served as templates for the crystal forms of the coexisting phases. The singularities in the liquidus line are attributed to chain length mismatch between the palmitic acid and the FAME (fatty acid methyl ester). The phase diagram achieved for OPO/MeS system is complete and can help in designing additive formulations to improve the cold flow behavior of biodiesel. [ABSTRACT FROM AUTHOR]

The addition of self-MSBO (metathesized soybean oil) to biodiesel significantly depresses the onset temperature of crystallization (T on ). MSBO and self-MTO (metathesized triolein), used as model systems, were separated into their constituent “molecular families” using column chromatography and crystallization fractionation and tested as crystallization modifiers of biodiesel. The results indicate that cis- unsaturation combined with a straight chain moiety is a critical structural architecture for disrupting biodiesel crystallization. The data obtained with TAGs (triacylglycerols) propose that the most effective stereospecificity is when the two fatty acids in the cis- configuration are in the sn- 1 and sn -3 positions and a trans -/saturated fatty acid is at the sn- 2 position. The conversion of cis -double bonds to trans -double bonds by self-metathesis explains the lowering of T on of biodiesel. The fractionation of MSBO, leading to a liquid fraction enriched with molecules having cis- unsaturated fatty acids out-performed MSBO in lowering T on of biodiesel. This knowledge can be used for the design of economical and more functional materials from MSBO and other metathesized vegetable oils using selective and practical fractionation methods. The findings of the study suggest that the use of biodiesel with significant saturated methyl ester content can be extended in colder months of the year. [ABSTRACT FROM AUTHOR]

A model binary system made of methyl palmitate (MeP) and (E)-1-(1-(oleoyloxy)-3-(stearoyloxy)propan-2-yl) 18-(1-(oleoyloxy)-3-(stearoyloxy) propan-2-yl) octadec-9-enedioate (dimer, D), a structured triacylglycerol dimer, one of a series of fatty molecules that have been found to significantly reduce the crystallization temperature of biodiesel, was investigated with DSC (differential scanning calorimetry), XRD and PLM (polarized light microscopy). A complex and unusual phase behavior was uncovered for this system. The exclusive orthorhombic crystal packing that was detected by XRD was shown to be guided by the bulky D molecules. The findings are explained by the formation of dimer/methyl palmitate composite units in which the dimer associates with the MeP molecules at its fatty acid branches as well as bridges. This association was initiated in the liquid state where the mobility of MeP and free rotation of the fatty branches of D are favorable. The disruptive effect of D on the packing of the saturated FAME was effective only at low concentrations (<0.10) with the system presenting a eutectic at 5% of D, followed by three stepped transformation lines indicating three concentration regions of defined phases of increasing stability. The findings indicate that the dimer may be an effective cold flow improver of biodiesel but only at concentrations lower than 5%. [ABSTRACT FROM AUTHOR]

The phase behavior of a model binary system made of OSO (2-stearoyl diolein) and MeS (methyl stearate) was investigated with differential scanning calorimetry and X-ray diffraction. The study is part of a series of investigations of unconventional additives such as TAGs (triacylglycerols) and dimers of TAGs with a demonstrated potential to significantly alter the crystallization of biodiesel. The TAG (triacylglycerol) was found to be effective in depressing the crystallization onset of the FAME (fatty acid methyl ester) significantly even at low concentration. OSO was shown to affect the crystallization of the mixtures strongly, and to dramatically alter their polymorphism. The system's phase diagram involved marked transformation lines including eutectics and solid–solid transitions. The molecular interactions were evaluated using a simple thermodynamic model. A mechanism for disruption of crystallization was proposed to be dependent on the peculiar geometry of OSO: the “straight” stearic acid participates easily in the lamellar packing of the equally “straight” FAME, whilst its kinked oleic acids effectively halt additional saturated FAMEs from participating due to steric hindrances. The findings of the study indicate that judicious loadings of TAGs which would target biodiesel's saturated FAMEs will have a substantial beneficial effect on the low temperature performance of the fuel. [ABSTRACT FROM AUTHOR]

Abstract: The phase behavior of 1-palmitoyl-2,3-distearoyl-sn-glycerol (PSS)/tristearoylglycerol (SSS) binary system was investigated in terms of polymorphism, crystallization and melting behavior, microstructure and solid fat content (SFC) using widely different constant cooling rates. Kinetic phase diagrams were experimentally determined from the DSC heating thermograms and analyzed using a thermodynamic model to account for non-ideality of mixing. The kinetic phase diagram presented a typical eutectic behavior with a eutectic point at the 0.5PSS mixture with a probable precipitation line from 0.5PSS to 1.0PSS, regardless of the rate at which the sample was cooled. The eutectic temperature decreased only slightly with increasing cooling rate. PSS has a strong effect on the physical properties of the PSS–SSS mixtures. In fact, the overall phase behavior of the PSS–SSS binary system was determined, for a very large part, by the asymmetrical TAG. Moreover, PSS is a key driver of the high stability observed in crystal growth, polymorphism and phase development. Levels as low as 10% PSS, when cooled slowly, and 30% when cooled rapidly, were found to be sufficient to suppress the effect of thermal processing. [Copyright &y& Elsevier]

Abstract: Four pure jojoba wax-like esters (JLEs), having carbon chain length of 36, 40 (two isomers) and 44, were prepared by Steglish esterification of fatty acids (or acid chlorides) with fatty alcohols at room temperature. Calorimetric and diffraction data was used to elucidate the phase behavior of the esters. The primary thermal parameters (crystallization and melting temperatures) obtained from the DSC of the symmetrical molecules correspond well with the carbon numbers of the JLEs. However, the data also suggests that carbon number is not the only factor since the symmetry of the molecule also plays a significant role in the phase behavior. Overall, the JLEs show very little polymorphic activity at the experimental conditions used, suggesting that they are likely to transform the same way during melting as well as crystallization, a characteristic which may be useful in designing new waxes and lubricants. The XRD data clearly show that the solid phase in all samples consists of a mixture of a β-phase and a β′-phase; fully distinguishable by their characteristic diffraction peaks. Subtle differences between the subcell patterns and phase development of the samples were observed. Different layering of the samples was also observed, understandably because of the chain length differences between the compounds. The long spacings were perfectly linearly proportional to the number of carbon atoms. The length of the ester layers with n carbon atoms can be calculated by a formula similar to that used for the layers in linear alkane molecules. [Copyright &y& Elsevier]

Abstract: The kinetic phase behavior and phase transformation paths of purified tristearoylglycerol (SSS), 3-palmitoyl-1,2-distearoyl-sn-glycerol (PSS) and 1,2-dipalmitoyl-3-stearoyl-sn-glycerol (PPS) were investigated in terms of polymorphism, crystallization and melting. The details of the phase transformation paths were obtained using the heating cycles of two sets of experiments: (a) cooling rate was varied and heating rate fixed and (b) cooling rate was fixed and heating rate varied. Kinetic effects were manifest in all measured properties, underscoring the complexity of the phase transformation paths for each TAG, and the intricate thermodynamics–molecular relationships. For the first time, XRD data obtained for SSS, PSS and PPS TAGs, cooled at rates higher than 0.5°C/min, suggested the formation of a transient structure similar to the so-called α2-phase which has been observed in mixed saturated–unsaturated TAGs quenched from the melt. The more stable phases (β′ in PSS and PPS, and β in SSS) were only observed for cooling rates lower than 1.0°C/min. The kinetic and thermodynamic differences observed in the crystallization, structure and melting of SSS, PSS and PPS are proposed to be mainly due to the disturbances introduced at the “terrace” level via methyl-end group interactions, i.e., the missing of two or four CH2 groups compared to SSS. The symmetrical SSS with a relatively flat “terrace” crystallizes preferably in the most stable β-form. Two missing CH2 groups at the sn-1 position (PSS) introduces enough structural disturbances to promote the relative prevalence and persistence of the β′-phase, and four missing CH2 groups at the sn-1 and sn-2 positions (PPS) is relatively too large of a disturbance and therefore favors the α-form. [Copyright &y& Elsevier]

Abstract: A robust, well-defined and reproducible method to accurately measure the oil binding capacity (OBC) of structuring fats was developed. The method was validated using two oil/fat model systems, i.e., fully hydrogenated canola oil (FHCO) in canola oil (CO) (FHCO/CO) and fully hydrogenated soybean oil (FHSO) in CO (FHSO/CO). The mixtures were crystallized from the melt down to three different temperatures (15, 25 and 35°C) at constant rates of cooling and the OBC was measured after different periods of storage time. The critical concentration of hard fat at which the solid fat network is stable and effectively binds oil has been also measured for mixtures crystallized at temperatures close to room temperature, i.e., 25°C. Crystal structure, melting behavior, microstructure, and solid fat content of these binary systems have been investigated in relation to the OBC of the solid fat network using X-ray diffraction (XRD), differential scanning calorimetry (DSC), polarized light microscopy (PLM), and wide-line pulsed nuclear magnetic resonance (pNMR) techniques. The two model systems exhibited similar trends in OBC over time, a behavior attributed to their similar TAG composition and polymorphism. However, relatively smaller OBC values were achieved by the CO/FHSO compared to CO/FHCO samples, largely due to differences in their solid network structure. Four successive decreasing linear segments, identifying successive mechanisms of oil migration/binding, were observed in the experimental OBC versus fat weight fraction curves. The critical concentration of hard fat, at which the solid fat network is effective in binding oil, was also determined and found to be ∼6wt% for both systems. [ABSTRACT FROM AUTHOR]

Abstract: The binary phase behavior of purified 1,3-dilauroyl-2-stearoyl-sn-glycerol (LSL) and 1,2-dilauroyl-3-stearoyl-sn-glycerol (LLS) was investigated at a slow (0.1°C/min) and a relatively fast (3.0°C/min) cooling rate in terms of melting and crystallization, polymorphism, solid fat content (SFC), hardness and microstructure. Much of the behavior of the system is explained by its polymorphism and the influence of thermal processing. The α-form and the β′-form of a double chain length structure were detected in the mixtures cooled at 3.0°C/min, whereas only the β′-form was detected in those cooled at 0.1°C/min. X-ray diffraction data as well as thermodynamic data propose that the most stable phases are promoted by the symmetrical LSL. The measured trends in structural characteristics, thermal properties, SFC, relative hardness and microstructure delimit three groups of mixtures which imply a competition between the stabilizing effect of LSL and disordering introduced by kinetic effects: (a) LLS-rich mixtures with LSL molar fractions (X LSL) less than 0.3, (b) mixtures with X LSL clustered around 0.5 and (c) LSL-rich mixtures with X LSL ≥0.7. The balance between ordering and kinetic effects determines the polymorphism of the mixtures, which in turn determines the behavior of the LSL/LLS system. The kinetic phase diagram of the LSL/LLS binary system constructed using heating differential scanning calorimetry thermograms displayed a singularity at the 0.5LSL molar fraction which delimits two distinct behaviors: eutectic behavior in one region and monotectic behavior in the other. The molecular interactions, as depicted by a non-ideality parameter of mixing obtained from a thermodynamic model based on the Hildebrand equation, suggests an almost ideal mixing behavior and a moderate tendency to the formation of unlike-pairs in the liquid state. [Copyright &y& Elsevier]

Abstract: The phase behavior of a binary system constituted of purified 1,3-dicaproyl-2-stearoyl-sn-glycerol (CSC) and 1,2-dicaproyl-3-stearoyl-sn-glycerol (CCS) was investigated at a very slow (0.1°C/min) and a relatively fast (3.0°C/min) cooling rate using differential scanning calorimetry (DSC), low resolution NMR, X-ray diffraction (XRD), and polarized light microscopy (PLM). Related forms of the β′ polymorph were detected for all mixtures as well as a β form for CSC-rich mixtures. A double chain length (DCL) stacking of the non-mixed CCS–CCS and CSC–CSC phases and a triple chain length (TCL) stacking of mixed CCS–CSC structure were detected for the different β′ forms. The kinetic phase diagram demonstrated an apparent eutectic at the 0.5CSC composition when cooled at 0.1°C/min and at the 0.25CSC composition when cooled at 3.0°C/min. The application of a thermodynamic model based on the Hildebrand equation suggests that compounds CSC and CCS are not fully miscible. In addition, the miscibility changes according to the structure of the growing solid phase which is dependent on CSC molar ratio as well as on the kinetics. It was also shown that the miscibility is concentration dependent and that the solid phase, which is growing at conditions well away from equilibrium, is determined kinetically. The molecular interactions were found to be strong and to favor the formation of CSC–CCS pairs in the liquid state. CSC and CCS were also shown to be immiscible in the solid state. Depressions in solid fat content (SFC) were observed for both rates. Relatively complex networks made of needle-like, spherulitic and granular crystals were observed in the CSC/CCS system. A pure CSC phase was found to be instrumental in promoting a higher SFC, and more stable polymorphic forms. The microstructure was shown to be strongly dependent on the cooling rate and was linked to the different polymorphic forms observed by DSC and XRD. Correlations between SFC and the eutectic behavior have been observed for the 3.0°C/min cooling rate, but not directly in the case of the 0.1°C/min cooling rate, where slower kinetics which favors the metastable to stable phase conversion processes prevented the same shifts in behavior. [Copyright &y& Elsevier]

Abstract: The phase behavior of the 1,3 propanediol dicaprylate/1,3 propanediol distearate (CC/SS) and the 1,3 propanediol dicaprylate/1,3 propanediol dipalmitate (CC/PP) binary systems were investigated using different techniques. The two systems presented essentially the same overall features. XRD measurements detected CC–CC, PP–PP and SS–SS bilayers which crystallized in β forms but no mixed bilayers for all mixtures. The phase diagrams of both systems were comparable and displayed a monotectic behavior. As strongly evidenced by XRD data, both phase diagrams suggested that CC, PP and SS formed largely separate phases but were probably not completely immiscible. Avrami analysis of SFC vs. time indicated heterogeneous nucleation and spherulitic crystal development from sporadic nuclei. However, noticeable differences in the manifestation of the molecular interactions have been detected at all levels of structure and confirmed by the interchange coupling determined by the enthalpy of melt, the final SFC and the hardness data. This was obviously related to the difference in chain size between SS and PP molecules. The effect on texture was highlighted by drastic microstructural differences between the two systems. Furthermore, the differences in nucleation and crystal growth, the more pronounced tendency for phase separation in the CC/SS system compared to the CC/PP system, and the relatively better crystallization of the CC/PP mixtures, particularly visibly for x CC ≤0.3 compared to the CC/SS mixtures were associated with the chain length difference. [Copyright &y& Elsevier]

Abstract: Polymorphic influences on the phase behavior of two types of binary mixtures of saturated monoacid 1,3-propanediol esters (PADEs), dipalmitate/distearate (PP/SS) and dimyristate/distearate (MM/SS) were examined by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and by solid fat content (SFC), hardness and microscopy measurements. Three stacking modes have been found in the PP/SS binary system. Mixed SS–PP bilayers were detected in all mixtures, SS–SS bilayers in x PP =0.0–0.4 mixtures and PP–PP bilayers in x PP =0.6–0.1 mixtures. Two different but close β polymorphs and one β′ polymorph were detected for this system. β′ was only detected in x PP =0.5–0.9 mixtures for the mixed bilayers. For the MM/SS binary system, only MM–MM and SS–SS bilayers were detected and both solid phases crystallized in two different β forms. XRD data evidenced clearly that the MM and SS components were completely immiscible in the solid state. The phase diagrams constructed using DSC data, exhibited a typical eutectic-type phase boundary. The presence of eutectics, the shape of the solidus lines as well as the analysis of the individual enthalpies of melting indicated typical phase separation for both systems. A thermodynamic study based on the Hildebrand equation and using the Bragg–Williams approximation for non-ideality of mixing confirmed the phase separation in the solid phase and suggested that the PP and SS were miscible in the liquid phase and that SS formed an ideal mixing with MM. Avrami analysis of SFC vs. time curves indicated heterogeneous nucleation and spherulitic crystal development from sporadic nuclei, and suggested that the nucleation rate was higher for the mixture at the eutectic composition. The relative hardness was correlated with the enthalpies, the final SFC and the microscopy measurements. [Copyright &y& Elsevier]

Abstract: A locally isolated (Perryvale, Alta., Canada) fungal genus, Mortierella ramanniana var. ramanniana, was evaluated as a potential industrial producer of γ-linolenic acid (GLA). Six growth variables (pH, temperature, carbon source, nitrogen source, and metal ions and oil supplementation) were systematically manipulated. The results indicated that the GLA production for this particular strain, could be maximized by using a basal growth medium consisting of 5% dextrose and 1% yeast extract, supplemented with 5mg/L Mn2+ with incubation at 20°C. The lipid yield under optimum conditions was 54.2% of the total dry biomass and consisted of 84.3% unsaturated fatty acids. The yield of GLA per gram biomass represented 13.3% of the total lipid content, slightly higher than that of the typical evening primrose oil GLA yield. The study establishes this variety as an effective intermediate fungal source of GLA. [Copyright &y& Elsevier]

• Self-metathesis is a platform for preparing competitive waxes from vegetable oils. • Self-metathesis of blends of common vegetable yield improved functional waxes. • Oligomerization compete with high unsaturation for crystallization and gelling. • Structure-function relationships relevant to wax applications established. The self-metathesis of vegetable oil blends was explored as a means for making functional and environmentally adapted waxes. Several mixtures of soybean oil (SBO) and palm oil (PO), the most readily available triacylglycerol (TAG) oils, were investigated as model unsaturated/ saturated systems to determine the advantages and limits of using such blends. The objective was to control the balance between unsaturation which tend to keep the material fluid at low temperature and saturation coupled with the self-metathesis induced oligomerization which promote crystallization and gelling for optimal wax applications. Five compositions of SBO and PO were metathesized and characterized for thermal transition behavior, solid fat content, microstructure, viscosity and hardness; parameters relevant to the functionality of waxes. The characteristic physical properties versus concentration presented peak-shaped curves with maxima at 15 %w/w SBO. This trend is explained by the modification to the molecular ensemble introduced by the self-metathesis, depleting the low melting species (liquid fraction) and enriching the high temperature melting species (solid fraction). The induced oligomerization combined with the pre-existing saturation which promote solidification are demonstrated to counterbalance the fluidization effect of unsaturation to a tipping point after which the unsaturation is overwhelming. The study shows that although limited in extent, appropriate blending can be an economical and effective tool to shift the crystallization toward room temperature of otherwise liquid TAG derivatives and improve their wax properties. [ABSTRACT FROM AUTHOR]

The hydrothermal degradation of a one-phase and a two-phase segmented thermoplastic poly(ester urethane) (TPEUs) made entirely from lipids was studied by accelerated ageing in water at 80 °C. Extensive alteration to the morphology, hydrogen bonding index and phase separation of the TPEUs were observed in one day of immersion in the water. The TPEU also achieved a tensile half-life of one day. The evolution of the physical properties of the TPEU such as the thermal decomposition, thermal transition and tensile characteristics was directly linked to the changes caused by hydrolysis to their phase morphology and microstructure. The degradation occurred in three stages depending on the degree of phase separation and hydrogen bond density. The formation of aliphatic carboxylic acid and amine degradation products following hydrolysis of both the soft and hard segments was identified by 1 H-NMR. The controlled life-cycle properties combined with the adequate thermal and mechanical properties of the materials demonstrate the viability of lipid derivatives as alternatives to petroleum for manufacturing TPEUs and credible potential in biomedical applications especially as bioresorbable implants or tissue scaffolds. [ABSTRACT FROM AUTHOR]

The cross-metathesis of vegetable oils containing a finite amount of unsaturation with small olefins such as ethylene or 1-butene results in the production of important platform chemicals. However, a largely unused portion of the original triacylglyceride molecule is left unused: a metathesis modified triacylglyceride or MTAG. The byproduct MTAGs are very interesting precursors for many materials; particularly for the synthesis of polyols and polyurethanes because of their shortened acyl chain and terminal double bond structure. The liquid-solid phase behavior of five metathesis modified triacylglycerols (MTAGS) produced when, for instance, canola, soy and palm oils are cross metathesized with ethylene or 1-butene; namely propane-1,2,3-triyl tris dec-9-enoate (DDD), 3-(stearoyloxy) propane-1, 2-diyl bis dec-9-enoate (DDS), 2-(stearoyloxy) propane-1, 3-diyl bis dec-9-enoate (DSD), 1,2-(stearoyloxy) propane-3-diyl bis dec-9-enoate (SSD) and 1,3-(stearoyloxy) propane-2-diyl bis dec-9-enoate (SDS), was comprehensively examined with DSC and XRD. The differences observed in the thermal transition behavior, melting temperatures and polymorphism between these MTAGs and their unmodified natural stearic-oleic TAG counterparts were well correlated with the number of terminal double bonds, number of shortened fatty acid chains, and number and positions of saturated fatty acid chains. The competition between the effects of unsaturation and position of the short moieties explained the distinctive phase trajectories of the MTAGs. The role of the large chain length mismatch (CLM) between the stearic and decenoic moieties was particularly highlighted in the chain length packing. The structure-function relationships established for MTAGs have never been reported before, and are important to the utilization of this feedstock which is growing in volume due to the commercial utilization of olefin cross metathesis of vegetable oils in the manufacture of oleochemicals. [ABSTRACT FROM AUTHOR]

Five wax ester oligomers of oleyl oleate (monomer to pentamer) produced from the self-metathesis of oleyl oleate derived from soybean oil were separated from the crude metathesis product by column chromatography. The purified compounds contained trans - and cis - configurations with a trans/cis ratio ranging from 3.6 for the monomer to 6.6 for the pentamer. The thermal transition behaviour of the oligomers as revealed by DSC was directly related to their trans - and cis - composition. Although odd/even effects presented predictable deviations, the crystallization and melting characteristics such as temperature and enthalpy scaled predictably with molecular size, and demonstrated a diminishing effect of incremental increases in monomer units. As determined by TGA, and except for the monomer which started to evaporate at ∼200 °C, the oligomers presented excellent thermal stability with onsets of degradation higher than 360 °C. The thermal transition characteristics of the monoester oligomers are comparable to commercial waxes and show potential for their use in a large range of wax applications ranging from viscous fluids to hard brittle solids. Furthermore, the thermal transitions occurred over narrow temperature spans, a feature that is useful for applications requiring collimated melting and crystallization ranges. [ABSTRACT FROM AUTHOR]

Adiabatic compressed air energy storage is an emerging energy storage technology with excellent power and storage capacities. Currently, efficiencies are approximately 70%, in part due to the issue of heat loss during the compression stage. An exergy analysis is presented on a novel adiabatic compressed air energy storage system design utilizing a cascade of PCMs (phase change materials) for waste heat storage and recovery. The melting temperatures and enthalpies of the PCMs were optimized for this system and were shown to be dependent on the number of PCMs, the number of compression stages, and the maximum compression ratio. Efficiencies of storage and recovery using this approach are predicted to be as high as 85%, a 15% increase over current designs which do not incorporate PCMs. [ABSTRACT FROM AUTHOR]

High molecular weight, thermoplastic poly(ester urethane) (TPEU) elastomers were synthesized from oleic-acid derived polyester diols (PED)s and 1,7 heptamethylene diisocyanate (HPMDI). Functional group stoichiometry and polymerization time were used to control molecular weight and optimize thermal and mechanical properties. A targeted range of PEDs with controlled molecular weights and consistent dispersity were obtained in high yields using an induced stoichiometric imbalance method. The PEDs were reacted with HPMDI with different NCO:OH ratios (1.1–2.1) and polymerization times (2–24 h) to obtain high molecular weight TPEUs. Solvent-resistant TPEUs, displaying polyethylene-like behavior were obtained and characterized by GPC, FTIR, DSC, XRD, TGA, DMA and tensile tests in order to reveal the structure-property relationships. Melting temperatures, tensile strength and maximum strain scaled with molecular weight approaching saturation values, demonstrating a plateau effect of molecular weight on physical properties. The entirely lipid-derived TPEUs exhibited thermal and mechanical properties comparable to commercial, petroleum-based analogues. [ABSTRACT FROM AUTHOR]

Metathesized palm oils are now a major source of fine chemicals; in particular due to the commercial production of 1-decene and 3,4-dodecene by cross metathesis of 1-butene and palm oil. This process results in the generation of a modified palm oil triacylglycerol (PMTAG) by-product, which has not been sufficiently studied. In this communication, the compositional analysis of PMTAG produced at a commercial scale is reported for the first time, and reveals that a percentage of the unsaturated fatty acids were shortened at the location of the double bond, producing a lower molecular mass TAG oil with terminal double bonds, and less steric hindrance compared to the natural oil. Furthermore, although PMTAG presented physical properties close to highly unsaturated vegetable oils, it retained a two-portion composition similar to palm oil, making its fractionation feasible with existing industrial methods. The epoxidation followed by hydroxylation of PMTAG resulted in a polyol comprising non-functional structures inherited from PMTAG and structures with diols, tetrols and hexols in which 50% of the hydroxyl groups were in terminal positions. The OH value (155 mg KOH/g), thermal stability (∼370 °C), melting profile (offset temperature ∼45 °C) and viscosity characteristics qualify the PMTAG polyol as a suitable substrate for the manufacture of a variety of materials including waxes, cosmetics and polyurethanes. [ABSTRACT FROM AUTHOR]

Palm oil metathesized triacylglycerol (PMTAG), the product of 1-butene cross-metathesis of palm oil stripped from it olefins, was fractionated using dry and solvent mediated crystallization. The fractionation yielded solid and liquid fractions (LF-PMTAG and SF-PMTAG, respectively) reminiscent of the stearin and olein portions of the natural palm oil. The polyol which was synthesized from LF-PMTAG (LF-Polyol) comprised ∼30% more hydroxyl groups (diols, tetrols and hexols) and more short chain moieties than the polyol from SF-PMTAG (SF-Polyol). As a result, LF-Polyol presented a much higher OH value (184 mg KOH/g) than SF-Polyol (136 mg KOH/g) and more advantageous thermal and viscosity properties than SF-Polyol. The LF-Polyol was demonstrated to make improved rigid and flexible foams compared the polyol from PMTAG (PMTAG-Polyol) or from the natural palm oil. The rigid foam (RF) obtained with LF-Polyol presented compressive strength which was 1.5 times higher than the RF prepared with PMTAG-Polyol, indicating that the removal of stearin-like components can significantly increase the rigidity. The study demonstrate that controlled fractionation of PMTAG can produce customized functional feedstocks for enhanced polyurethane foams. [ABSTRACT FROM AUTHOR]

Polyols derived from 1-butene cross metathesized palm oil (PMTAG polyol) were used to prepare improved rigid and flexible foams. The chemical structure, thermal degradation, thermal transition behavior and compressive strength of the foams were determined using FTIR (Fourier Transform Infrared Spectroscopy), TGA (Thermogravimetric analysis), DSC (Differential Scanning Calorimetry) and texture analyzer, respectively. Their cellular structure was investigated by SEM (Scanning Electron Microscopy). Both the rigid and the flexible foams from the metathesized palm oil polyol displayed high thermal stability ( T on of degradation of ∼253 °C) comparable to commercial and other vegetable oil polyol foams. The rigid foams from the polyol of PMTAG presented compressive strengths as high as 2.6 MPa, a value higher than similar foams prepared from palm oil polyol or highly unsaturated vegetable oils such soybean and canola oil based polyols. The flexible foams from the metathesized palm oil polyol displayed excellent flexibility with more than 90% recovery in thickness after compression. [ABSTRACT FROM AUTHOR]

The thermal behavior, microstructure and crystal structure of 1,3-dioleoyl-2-palmitoyl glycerol (OPO); an additive demonstrated to improve the cold flow behavior of biodiesel, and methyl palmitate (MeP); a saturated FAME (Fatty acid methyl ester) implicated in the high melting temperature of common biodiesel, were investigated by DSC (Differential Scanning Calorimetry), PLM (polarized light microscopy) and XRD, respectively. Very complex and rich concentration dependent phase behavior was revealed attributed to specific intermolecular interactions between OPO and MeP. OPO delayed crystallization effectively and disrupted nucleation and growth altering crystal structure and microstructure profoundly. A steep drop in melting temperature accompanied a dramatic decrease of crystal size upon addition of OPO. A complete pseudo-equilibrium phase diagram of OPO/MeP including the thermal transitions below the liquidus line, polymorphism and microstructure development has been achieved. The study provides a comprehensive fundamental understanding that can help optimize the formulation of bio-sourced structured additives that would suppress crystallization and reduce crystal size of biodiesel effectively. [ABSTRACT FROM AUTHOR]

High molecular weight semi crystalline thermoplastic poly(ester urethanes), TPEUs, were prepared from a vegetable oil-based diisocyanate, aliphatic diol chain extenders and poly(ethylene adipate) macro diol using one-shot, pre-polymer and multi-stage polyaddition methods. The optimized polymerization reaction achieved ultra-high molecular weight TPEUs (>2 million as determined by GPC) in a short time, indicating a very high HPMDI – diol reactivity. TPEUs with very well controlled hard segment (HS) and soft segment (SS) blocks were prepared and characterized with DSC, TGA, tensile analysis, and WAXD in order to reveal structure–property relationships. A confinement effect that imparts elastomeric properties to otherwise thermoplastic TPEUs was revealed. The confinement extent was found to vary predictably with structure indicating that one can custom engineer tougher polyurethane elastomers by “tuning” soft segment crystallinity with suitable HS block structure. Generally, the HPMDI-based TPEUs exhibited thermal stability and mechanical properties comparable to entirely petroleum-based TPEUs. [ABSTRACT FROM AUTHOR]

Saturated aliphatic diesters sourced from vegetable oils present phase change properties particularly suitable for latent heat thermal energy storage (LHTES). However, inherent ester group flexibility, weak intermolecular attractions and intramolecular steric repulsions between the electronic clouds of the two ester groups, which lead to degraded packing and polymorphism, prevent these molecules from achieving optimal functionality as phase change materials (PCM). The present work demonstrates that the incorporation of a planar benzene ring between the two ester groups restricts intramolecular steric repulsion, increases the intermolecular attractions and effectively limits molecular flexibility, leading to the formation of stable monomorphs and enhancement of the thermal properties. The terephthalate diesters prepared in this work crystallized in the most stable triclinic β -polymorph regardless of cooling rate, demonstrated melting temperatures up to 86 °C and enthalpies up to 260J/g as well as higher thermal stabilities than corresponding aliphatic diol and diacid diesters. The enhanced thermal properties are mainly attributed to the π-π intermolecular attractions established between planar benzene rings inherent quadrupole moment and resonance effect from the delocalization of π-electrons within the extended conjugated π-system formed between the benzene ring and ester groups. The π-π intermolecular attractions and resonance stabilized ester group contributed to a higher energy barrier for rotation to occur at the center molecules and resulted in the stiffening of the fatty chains, facilitating periodic crystal packing. [Display omitted] • Terephthalates are excellent PCMs for medium temperature thermal energy storage. • High melting point (86 °C) and thermal energy storage density (260J/g) achieved. • Rapidly store/release heat via sharp phase transitions with low supercooling. • Planar ring, π-π interaction and resonance effect instrumental performance. • Molecular packing constrained into the most stable monomorph regardless of kinetics. [ABSTRACT FROM AUTHOR]

Abstract: Three lipid-based Polyester Amides (PEAs) with varying ratios of ester and amide linkages were synthesized. Oleic acid was used as the starting material to produce the intermediates, characterized by MS and NMR, used for polymerization. PEAs were characterized by FTIR and GPC. The PEAs were constrained to have similar number average molecular weights, in the 2 × 104 range, thereby enabling comparison of their physical properties from a structural perspective. The thermal behavior of the polymers was assessed by DSC, DMA and TGA. Thermal degradation was not affected by ester/amide ratios, but T g increased non-linearly with decreasing ester/amide ratios and correlated with hydrogen-bond density and repeating unit chain length. Crystallinity was studied by XRD and DSC. Degree of crystallization and multiple melting behavior as a function of cooling kinetics were explained well by hydrogen-bond density, repeating unit chain length and density of ester moieties. Mechanical properties were investigated by DMA and Tensile Analysis, with a non-linear increase of storage and tensile moduli recorded as a function of decreasing ester/amide ratios. The findings suggest how approaches to the synthesis of lipid-based PEAs can be targeted to the delivery of specific physical properties. [Copyright &y& Elsevier]

The solid-liquid phase behavior of three saturated aliphatic symmetrical sulfones (n-SO 2 -n) were assessed for potential use as Phase Change Materials (PCM) using TGA, DSC and XRD. The compounds were synthesized in high yield and purity via the simple solvent-free oxidation reaction of the fatty sulfides. The sulfones demonstrated properties suitable for medium temperature thermal energy storage applications. TGA measurements confirmed that the sulfones commences weight loss with onset temperatures up to 283 °C. The crystal structure and the thermal transition parameters of the sulfones were not significantly affected by cooling rate. 18-SO 2 -18 and 12-SO 2 -12 crystallized in the thermodynamically stable β -form and 10-SO 2 -10 crystallized in the γ -form, and all adopted single-molecular layer stacking configurations along the plane normal. DSC indicated that these compounds can rapidly store and release large amounts of thermal energy (>200 J/g) as latent heat between 89-109 °C with minimal supercooling. The sulfones presented higher melting temperatures compared to analogous monofunctional lipid-based counterparts such as fatty acids, fatty alcohols, ethers, monoesters, diesters, monoamides and alkanes attributed to the added strong sulfonyl-sulfonyl attraction between the highly polar sulfonyl groups. Importantly, this work shows that linear saturated lipid-based sulfones can extend the available range of the current available organic, lipid-based PCMs. Image 1 • Lipid-based monosulfones synthesized solvent-free in high purity and yield. • Monosulfones are thermally stable with onset of degradation up to 283 °C. • Monosulfones change phase rapidly over a narrow range at up to 109 °C. • Phase change enthalpies of monosulfones are higher than 200 J/g. • Lipid-based Monosulfones ideal for latent heat thermal energy storage. [ABSTRACT FROM AUTHOR]

A series of five linear aliphatic diamides were synthesised via facile direct coupling of stearic acid (C18) with diamines of varying carbon number (18- n -18, n = 2, 4, 6, 8 and 10) in a catalyst-free neat reaction. The compounds were investigated as potential renewable phase change materials (PCMs) for latent heat thermal energy storage. The thermal properties of the diamides were predictably related to the diamine chain length. TGA measurements indicated that the diamides evaporated before decomposition, with evaporation onsets increasing from 325 °C for 18- 2 -18 to plateau at 337 °C for the longer-chain diamides. The diamides display negligible supercooling and melt and crystallize at 140 °C–150 °C within a narrow transition span (<5 °C). Notably, both their melting and crystallization temperatures versus n present a maximum at n = 4, explained by peak hydrogen bonding and chain length considerations. As the distance between the amide groups increases, the transition temperatures decrease exponentially owing to the subsequent decrease in intermolecular hydrogen bond strength. The latent heat of the diamides presented a sharp increase from 165 J/g for 18- 2 -18 to plateau at ~210 J/g for the other amides (n ≥ 4). XRD measurements support the thermal transition behaviour; it shows that all the diamides crystallize from the melt into the β-phase, except for 18- 2 -18 in which the β-phase co-existed with the less stable β′-phase. Overall, the study shows that the diamides are suitable alternatives to classical petrochemical derived PCMs, expanding the currently limited library of organic PCMs. Image 1 • Renewable lipid derived organic PCMs for applications at > 100 °C. • High phase transition temperatures (~150 °C) and thermal storage density (~220 J/g). • Hydrogen bonding of the amide groups influenced by diamine chain length. • Melting and crystallization affected primarily by hydrogen bonding of amide groups. • Latent heat primarily dependent on dispersive forces of the fatty acid moieties. [ABSTRACT FROM AUTHOR]

Abstract: Four aliphatic thermoplastic poly(ester-urethane)s (PEUs) with similar molecular weights but varying polyesters molecular weight (534–1488 g/mol) were prepared from polyester diols, obtained by melt condensation of Azelaic acid and 1,9-Nonanediol, and 1,7-heptamethylene di-isocyanate (HPMDI) all sourced from vegetable oil feedstock. The thermal, and mechanical properties, and crystal structure of PEUs were investigated using DSC, TGA, DMA, tensile analysis and WAXD. For sufficiently long polyester chain, WAXD data indicated no hydrogen bonds polyethylene (PE)-like crystalline packing and for short polyester chains, small crystal domains with significant H-bonded polyamide (PA)-like packing. Crystallinity decreased with decreasing polyester molecular weights. The polymorphism of PEUs and consequently their melting characteristics were found to be largely controlled by polyester segment length. TGA of the PEUs indicated improved thermal stability with decreasing polyester chain length, suggesting a stabilization effect by urethane groups. Mechanical properties investigated by DMA and tensile analysis were found to scale predictably with the overall crystallinity of PEUs. [Copyright &y& Elsevier]