Studies on Wool Wax III: Effect of Wool Wax and Certain Wool Wax Derivatives on the Rheological Behaviour of Vaseline

Wool wax and certain wool wax derivatives are investigated as regards their effect on the rheological behaviour of a hydrocarbon ointment base (vaseline). The rheological parameters considered are: flow pattern, structural viscosity, yield value, plastic viscosity, coefficients B and M of thixotropic breakdown and structural recovery. Evidence is provided for marked changes of the rheological characteristics of the system in presence of any of the investigated materials. A discussion of the different effects is presented.     

Sustainable synthesis of cyclic carbonates from bio‐based polyether polyol: the structure characterization,rheological behaviour and thermal properties

The cycloaddition of CO₂ to epoxides represents a green efficient method to form bis(cyclic carbonate)s. The main purpose of the work reported in this paper was to examine the effect of the gas flow rate (20, 40, 60 and 100 mL min^–1) during carbonation on the conversion yield, chemical structure, rheological behaviour and thermal properties of the prepared compounds. A series of new bis(cyclic carbonate)s was obtained from bio‐based polyether polyol. The syntheses were performed in the absence of toxic solvents and the process did not require the use of elevated pressure. The progressive structural changes and the presence of characteristic chemical groups were monitored by attenuated total reflection Fourier transform infrared spectroscopy. The characterization of the structure by ¹H NMR and ¹³C NMR also confirmed the formation of cyclic carbonate moieties. The non‐Newtonian behaviour and the optimal mathematical model (Herschel–Bulkley) were verified by rheological measurements. The materials obtained could be used as a chemical intermediate to synthesize advanced materials based upon polyurethanes without using isocyanates. © 2019 Society of Chemical Industry     

Rheological characteristics of proanthocyanidin polymers from Pinus radiata. II. Viscoelastic properties of sequential alkaline extracts based on phenolic acid fraction

Steady and dynamic oscillatory rheometry were used to characterize two members of the plant polyphenols from Pinus radiata bark, water-soluble proanthocyanidin polymers, and phenolic acids. The viscosity-controlling factor of the extracts could be revealed by examining the various extracts under different chemical and rheological environments. Water extracted (100°C) bark was successively extracted with aqueous NaOH solutions of increasing alkalinity at 100°C and the rheological characteristics of the each fraction were examined in detail. The significant viscoelasticity of the 100°C aqueous NaOH sequential extracts suggests that this fraction can have a critical impact on the flow characteristics of overall extracts and arises from a major contribution of colloidal interactions involving the carbohydrate component. © 1995 John Wiley & Sons, Inc.     

Rheological properties of montmorillonitic clay suspensions: Effect of firing and interlayer cations

The effect of a prior firing of three montmorillonite clays, exhibiting different nature of interlayer cations, on the rheological behaviour of related aqueous suspensions (5 and 10 mass% of solid content) was examined. Calcinations were performed at 150 °C, 250 °C, 300 °C or 450 °C for 30 min. The rheological properties were characterized at 25 °C in the flow mode using the Herschel–Bulkley model.The alkaline interlayer cation (Na) tended to increase the yield stress of montmorillonite suspensions in comparison with earth-alkaline ones (Ca, Mg). As expected, increasing solid content led to increasing yield stress.For calcinations until 200 °C, the relevant suspensions exhibited an increasing yield stress due to a gel-like behaviour in relation with a card-house-like structure. Furthermore, calcination above 300 °C favoured the decrease of the corresponding yield stress. This behaviour seemed to be related to the modification of the surface properties of the clay platelets, more precisely to the beginning of clay dehydroxylation.     

Physikalisch-chemische Eigenschaften von Braunkohlenextrakten und abgetrennten Wachs- und Harzstoffen

Physico-chemical Properties of Brown-Coal Extracts and Separated Wax and Resin Substances The component composition and the physico-chemical properties of the raw montane wax Romonta as well as of three samples of the toluene extracts from the mine Turów, obtained at different extraction temperatures, were determined. The wax and resin substances were separated from the raw montane wax Romonta and from the toluene extract of brown-coal from the mine Turów, obtained at 100°C, and then characterized. The rheological properties of the extracts, the separated components and the four selected processing products of the raw montane waxes Romonta (means of hydrophobation Romonta 55, acid wax R, ester wax K-60, partly saponified ester wax REW II) were determined by the rotation viscosity metre Rheotest 2. The viscosity measurements were carried out at higher temperatures than the dropping point of the investigated substance, in case of extracts rich on resin also at lower temperatures. A significant influence of the sort of coal and the extraction temperature on the component composition of the obtained extracts as well as on the properties of the separated wax and resin substances was established. Furthermore a different rheological behaviour of the wax substances and wax containing extracts in comparison to the resin components of brown-coal bitumen was observed. Concerning the extracts of brown-coal from the mine Turów it was found out that the viscosity slowly increases in case of an increase of the resin content up to 50%, but at higher resin content it increases very quickly.     

Bilanz der Schnellpyrolyse des Rohmontanwachses

Rapid Pyrolysis of Raw Montana Wax Raw montana wax from Slovakian Lignite was subjected to rapid pyrolysis at a temperature of 600° and 700° C. The products of pyrolysis were segregated into a solid, a liquid and highly volatile fraction. The products of pyrolysis were determined in each fraction. Both the pyrolysis products as well as the original wax were fractionated by column chromatography. The individual eluates were analyzed by gas chromatography and mass spectrometry.     

Compositional and structural variations of bitumen and its interactions with mineral matters during Huadian oil shale pyrolysis

Thermal bitumen is an important intermediate derived from kerogen decomposition during oil shale pyrolysis. In this study, free bitumen (FB) and bound bitumen (BB) were obtained by extracting oil shale chars (300–550 °C) before and after demineralization, and then analyzed by liquid chromatography fractionation, Fourier transform infrared spectroscopy, and gas chromatography/mass spectrometry. The FB yield first increased and then decreased with increasing temperature, and the maximum value was 2.10% at 400 °C. The decarboxylation of acids and decomposition of esters at 350–450 °C decreased the content of these compounds. Meanwhile, the intense cracking reactions of aliphatic compounds and alkyl chains at 400–450 °C decreased the carbon chain lengths and molecular weights of these compounds. From the analytical results obtained for the BB fractions, we suggest that some carboxylic acids or carboxyl group-containing compounds may be trapped on carbonate particles by the formation of Ca₂₊COO_? bonds, whereas other oxygenated compounds (e.g., esters and phenols) can be adsorbed preferentially by clay minerals through Lewis acid-base interactions.     

Enhancement of rheological and mechanical properties of bitumen using styrene acrylonitrile copolymer

In this research, styrene acrylonitrile copolymer as a novel additive is used to modify rheological, mechanical and thermal properties of the base bitumen 70 penetration grade. Styrene acrylonitrile copolymer combines the rigidity of polystyrene with the hardness and thermal resistance of polyacrylonitrile to enhance viscoelastic property of the bitumen. To investigate the performance of the proposed mixture, shear complex module, phase angle, penetration, softening point, and reversibility of prepared samples are measured at different additive content and compared with the base bitumen. The results show that softening point of the base and modified samples are 49–86°C, respectively. The rheological properties of the base bitumen and modified samples are measured by a dynamic shear rheometer (DSR). The phase angle as elasticity measure decreases from 55° to 35° in the modified bitumen compared to the base bitumen. Generally, the experimental results showed that styrene acrylonitrile copolymer makes bitumen to be more stable at high temperatures and more flexible at low temperatures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41875.     

The effect of bitumen molecular fractions on diffusivity and rheology of bitumen under high-temperature conditions: Molecular dynamics (MD) simulation study

Heavy oil and bitumen play an incredible role in Canada's energy resources. The main processes that have already been applied to produce heavy oil and bitumen are in-situ thermal methods. The primary mechanism of production in these reservoirs is a reduction in heavy oil and bitumen viscosities via heat transfer. Having deep knowledge about the rheological behaviour of heavy oil and bitumen is crucial to designing a more accurate and efficient in-situ thermal recovery method. In this work, molecular dynamics (MD) simulation was used to model the rheological behaviour of bitumen under different temperatures. According to MD outputs, the highest diffusion coefficient between bitumen fractions belongs to saturate fractions. On the other hand, the lowest diffusion coefficient belongs to asphaltene fractions. The size of asphaltene, its polarity, and the polarity of a resin fraction affect the diffusion coefficient of asphaltene in a bitumen sample and its rheological behaviour. The MD simulation aims to provide molecular insights and essential information about the rheological trend of bitumen under different thermodynamic conditions. The results of the current work provide essential information about the effect of bitumen fractions on its rheological behaviour.     

Rheological examination of temperature dependence of conventional and polymer‐modified road bitumens

Rheological characterization of two types of road bitumens, conventional and polymer‐modified, has been examined in the temperature range between 20°C and 140°C. Tests were carried out before and after ageing following a thin‐film oven test. Polymer‐modified bitumens exhibit non‐Newtonian behaviour up to the 120°C due to a complex secondary structure formed by added polymers. For conventional bitumens, Newtonian behaviour was observed above 60°C. Special attention was paid to measurements and to analysis of the dynamic data of oscillatory shear. The mechanical spectra in a wide frequency range have been obtained using the WLF time‐temperature superposition principle. The analysis of viscoelastic data clearly showed the differences between the two types of bitumen. Conventional bitumens were more sensitive to temperature and to the ageing effects. For polymer modified bitumens, the elastic contribution to viscoelastic response was more pronounced, and independent of temperature and ageing.     

Effect of particle size on the rheology of Athabasca clay suspensions

The success of the separation process conventionally used in Alberta for oil sands extraction is highly influenced by the rheology of the oil sands slurry. In the gravity separation vessel, high slurry viscosities can hinder the rise of aerated bitumen and reduce the efficiency of the recovery process. In this study, the effect of particle size on the viscosity of oil sands slurries is investigated. Solids from mature fine tails (MFT) obtained from tailings pond were fractionated into three fractions of different particle size distributions and their rheological properties were studied. The solids in each fraction were characterized by XRD analysis which showed the presence of different types of clays in each fraction. For the rheological measurements, dispersions of the three fractions were prepared in the supernatant water decanted from centrifuged MFT to maintain the solution chemistry of the solids. Suspensions of each fraction showed a non‐Newtonian shear thinning behaviour as well as yield stress that is characteristic of structure formation within the suspensions. For all solids fractions, increasing solids concentration led to higher viscosities and higher yield stress values. Viscoelastic properties of the suspensions showed stronger solid‐like behaviour at higher particle concentrations. Among the three fractions numbered from 1 to 3, solids in fraction 3 were coated with organic matters, exhibiting the highest suspension viscosities. Also for fraction 3, higher gelling potency was observed at much lower weight fractions of solids as compared to the other fractions.     

Pyrolysis of peat: Product yield and characterization

Pyrolysis of peat obtained from Yeniça?a, Bolu, Turkey was conducted in a fixed-bed tube furnace under various conditions, and variations in the structure of the char, tar and gas products were examined. The chars produced were studied by proximate and ultimate analyses. The maximum tar yield of 20.41% was obtained at a heating rate of 20 °C/min, a temperature of 450 °C, a sweeping gas flow rate of 100 ml/min and a 0.5–2.0 mm size range. The chemical composition of the tar was examined by elemental analysis, FTIR spectroscopy, ¹H-NMR spectroscopy and column chromatography. The chemical composition of the tar with dense aliphatic structure was established to be CH_1.22O_0.25N_0.02. The composition of the gases obtained at a heating rate of 20 °C/min for the 0.5–2.0 mm size range was examined by gas chromatography.     

Polymer‐modified bitumen of recycled LDPE and maleated bitumen

Maleated bitumen was prepared by the reaction of penetration grade bitumen (80/100) with maleic anhydride at 150°C for 2 h under nitrogen atmosphere. The effectiveness of maleation was assessed in bitumen–recycled low‐density polyethylene (LDPE) blends in terms of their softening point and elastic recovery. It was observed that the softening point and elastic recovery of the blends increased after maleation of the base bitumen owing to the formation of an asphaltene‐linked‐LDPE system. To obtain the desired elasticity, a recoverable composition was worked out with the help of maleated bitumen, recycled LDPE and styrene–butadiene–styrene. The storage stability of the blends was assessed in terms of their difference in softening points, rheological parameters, and microstructure of the top and bottom portions of test tube samples. The difference in softening point of the recoverable maleated bitumen blend was 5°C as compared to 60°C for the base bitumen blend. The phase angle was also reduced to 7.4° at 70°C compared with the 44.30° for the base bitumen blend. Scanning electron micrographs indicate that polymers existed in both the top and the bottom portions of the aged test tube maleated blend samples. The stability of the blend was further improved when LDPE is colloidal milled with maleic anhydride in the blend preparation. Roofing bitumen was also made with maleated bitumen containing 9 wt % recycled LDPE content. Based on the rheological data, it was found that the maleated bitumen–LDPE blend exhibited superior time‐/temperature‐dependent response and higher creep recovery compared with the base bitumen blend. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013     

Phase behaviour of CO2 -bitumen fractions

The phase behaviour of Cold Lake bitumen and its five fractions (or “cuts”) saturated with carbon dioxide is examined. The two lightest fractions (bp < 510°C) were clear liquids, whereas the third and fourth fractions were dark and viscous, i.e. much like the whole bitumen. The fifth fraction was a glass-like solid, with a softening temperature of approximately 100°C. The vapour-liquid equilibrium (VLE) data for the bitumen and bitumen fractions saturated with CO₂ were collected at temperatures from 25 to 150°C and pressures up to 10 MPa. Experiments were also performed at conditions under which pure CO₂ exists as a liquid. The VLE and LLE data were correlated with the Peng-Robinson equation of state by modeling each bitumen fraction as one pseudocomponent whose critical properties and acentric factor were estimated from correlations available in the literature. The CO₂-solubility and density data were used to develop generalized correlations for the critical pressure and the binary interaction parameter (k_ij) in terms of molar mass and critical temperature. The model was subsequently used to predict the solubility of CO₂ in the whole bitumen which was represented as a 5-component mixture. A correlation for Cut i-Cut j binary interaction parameter (k_ij) was developed in terms of temperature and the difference in hydrocarbon molar masses. The average deviation in the predicted and experimental CO₂-solubility in the whole Cold Lake bitumen was less than 7%.     

Cooling rate and dilution affect the nanostructure and microstructure differently in model fats

The effects of cooling rate and solid mass fraction on the polymorphism, nano and microstructure, thermal and rheological properties of binary mixtures of fully hydrogenated canola oil and canola oil at 20°C have been studied. The β‐polymorph was observed in fully hydrogenated canola oil (FHCO) when crystallized at slow cooling rates (0.1C°/min), however crystallization at higher cooling rates (0.7 and 10°C/min) resulted in the formation of the α form. The β‐polymorph was detected in all the binary mixtures of FHCO/canola oil and was not affected by crystallization at different cooling rates. Melting thermograms obtained from 100% FHCO displayed three melting peaks, associated with the development of the β‐polymorph via α→ β′→ β‐polymorphic transition in the DSC pan. Some solubilization of solid FHCO into canola oil was observed and the solubility was proportionally higher with increasing liquid oil fraction. The strong influence of the matrix concentration on micro/nanoscale structure was demonstrated by characterization of crystal size using cryogenic transmission electron (Cryo‐TEM) and polarized light microscopy (PLM). Crystallization under higher cooling rates lead to formation of smaller nano and meso‐structural elements. Furthermore, oscillatory rheology showed the influence of structural elements' size and polymorphism on material strength. The shear storage modulus (G′) of the mixtures was higher when crystallized at fast cooling rates (10°C/min). In contrast, for pure FHCO, G′ increased by lowering the cooling rate and the highest storage modulus was observed after crystallization at 0.1°C/min.     

Novel combustion synthesis of La3+-substituted MnFe2O4

La³⁺-substituted MnFe₂O₄ compounds have been prepared by using a novel combustion synthesis method. This process was found to yield homogeneous, finely crystalline powders without intermediate decomposition and/or calcination steps. Combustion-synthesized powders were sintered at 1000°C, and structural features of thus prepared materials were characterized by XRD analysis and FT-IR spectroscopy. The dc electrical conductivity of synthesized materials has been measured as a function of temperature up to 1000°C. The materials have shown semiconducting behavior at elevated temperatures. The ac electrical conductivity of synthesized samples was found to increase with increasing applied frequency. The dielectric constant and dielectric loss tangent have also been characterized. The article is published in the original.     

Effect of low-temperature oxidation on the composition of Athabasca bitumen

The effect of low temperature oxidation on the composition of Athabasca bitumen was examined. Oxidation temperatures in the range 125–135 °C and extents of oxidation up to 100mg $\text{O}{}_2\text{g}$ bitumen were investigated. The aromatics concentration was observed to decline steadily and the concentration of asphaltenes to increase, during oxidation. The saturates were unaffected by low-temperature oxidation. The resins concentration displayed a strange behaviour, first dropping and then increasing to a maximum and again dropping as oxidation proceeded.     

Experimental study on the effect of molecular weight and chemical composition distribution on the mechanical response of high-density polyethylene

This article aims to appraise the effect of microstructure comprising molecular weight distribution and chemical composition distribution on the mechanical properties of high-density polyethylene (HDPE). HDPE resins were synthesized using several titanium–magnesium-supported Ziegler–Natta catalysts in the industrial gas phase reactor under the same polymerization condition. Gel permeation chromatography and crystallization elution fractionation (CEF) were conducted on the resins to characterize the molecular weight and comonomer distribution. Crystallization, thermal and rheological behavior were evaluated following differential scanning calorimetry, polarization light microscopy, and rheometric mechanical spectrometry. The resins with higher soluble fraction in trichlorobenzene below 80°C (highly branched low molecular weight chains) exhibited longer crystallization time based on the crystallization kinetic obtained from the Avrami model. Rheological determination of the molecular weight between entanglements (M_e) and the average lamella thickness based on the Gibbs–Thomson equation revealed that the entanglement density and impact strength decreased, and the average lamella thickness increased with an increase in the ratio of CEF eluted fraction below 80°C to the crystallizable fraction in the range of 80–90°C.     

Supercritical carbon dioxide extraction,purification, and characterization of wax from sorghum and sorghum by-products as an alternative natural wax

The objective of this work was to obtain high purity natural wax from sorghum and by-products of sorghum processing (sorghum dried distillers grains with solubles [DDGS] and sorghum bran) using a green process based on supercritical carbon dioxide (SC-CO₂). SC-CO₂ extractions were carried out at varying temperatures (50, 70°C) and pressures (30, 40 MPa) at a CO₂ flow rate 1 L/min for 120 min. Significantly higher wax yield (4.9%) from DDGS was obtained by SC-CO₂ at 40 MPa/70°C compared with whole kernel (0.6%) and bran (3.3%) (p < 0.05). The yield of the extracts obtained by SC-CO₂ extraction was higher than that of the conventional hexane extraction for all three sorghum sources. The highest fraction of wax in the SC-CO₂ extracts was obtained from whole kernel extracts (89%), whereas it was 53.3% from the DDGS and 26.8% from the bran at the same extraction conditions. SC-CO₂ and hexane extracts from sorghum whole kernel shared a similar melting peak temperature of 76.3–77.9 and 79.7°C, respectively, while DDGS and bran extracts by SC-CO₂ showed a much lower melting temperature in the range of 50.7–61.9°C, indicating the presence of lower melting point components such as triacylglycerols. However, the melting points of the DDGS and bran extracts after ethanol purification were significantly increased with the observed peak temperature of 80.8 and 82.0°C, respectively. While the wax yield from DDGS and bran was higher than that of whole kernel, the sorghum whole kernel feedstock was found to be a more feasible feedstock to obtain higher purity wax.     

Pyrolysis kinetics of Athabasca bitumen using a TGA under the influence of reservoir sand

Pyrolysis kinetics of thermal decomposition of bitumen was investigated by thermogravimetric analysis (TGA). TGA experiments were conducted at multiple heating rates of 5, 10, 20°C min^–1 up to 800°C to obtain the pyrolysis characteristics of bitumen. Weight loss curve from TGA shows that two different stages occurred during bitumen pyrolysis. Differential method has been used for determining the kinetic parameters and the best fit for the order of reaction was found based on the R² values. Kinetics results confirm the presence of two different stages in bitumen pyrolysis with varying kinetic parameters. The average activation energy for the first and second stage was 29 and 60 kJ mol^?1 and the average order of the reaction was 1.5 and 0.25, respectively. Experiments have been conducted with different reservoir sand. The effect of different source of sand reveals no effect on the pyrolysis behaviour of bitumen. A considerable difference was found with the pyrolysis of bitumen–sand mixtures and bitumen alone based on coke yield and activation energy. © 2011 Canadian Society for Chemical Engineering