Viscosity-temperature Relationship Research Articles

Influence of TiO2/SiO2 and BaO/CaO ratios on viscosity, crystallization and structure of high-TiO2 mold slags for casting of high-Ti steel

In the current study, the influence of TiO2/SiO2 and BaO/CaO ratios on viscosity, crystallization and structure of high-TiO2 mold slags was discussed through the measurement of viscosity-temperature relationship, melting temperature, crystallization temperature, crystallization rate and phases, and Raman spectrum. With the substitution of SiO2 by TiO2 in slags from 0 % to 12 %, the viscosity at 1300 °C, the melting temperature and break temperature decreased and then increased, while those of slags with the substitution of CaO by BaO from 4 % to 16 % decreased. With the substitution of SiO2 by TiO2 from 0 % to 10 %, crystallization phases gradually changed from cuspidine (Ca4Si2F2O7) to perovskite (CaTiO3), the initial and complete crystallization temperatures had the tendency to increase from 918 °C to 1260 °C and from 857 °C to 1139 °C, respectively, and the overall crystallization ability of slags increased. With the substitution of CaO by BaO from 4 % to 16 %, the initial and complete crystallization temperature of these slags decreased, and the overall crystalline ability decreased. With the substitution of SiO2 by TiO2 from 0 % to 10 %, structural units changed from the simple units to complex units, but the transition was opposite with the substitution from 10 % to 12 %, which was related to the transition of TiO2 from basic oxide to amphoteric oxide. With the substitution of CaO by BaO from 4 % to 16 %, the degree of polymerization and the viscosity of theses slags decreased, which was related to the supplement of more active O2− ion from BaO. Hence, the excessive substitution of SiO2 by TiO2 under the steel-slag reaction would cause the increase of the slag viscosity and crystallization ability, while the substitution of CaO by BaO could weaken the variation of slag viscosity and crystallization ability.

Design, Manufacturing, and Comparative Analysis of a Mini Extruder for Polymer Flow Characterization: A Case Study on HDPE and PMMA Polymers

Polymer extrusion is one of the most widely used polymer processing methods and the sole option for many standard products. The modern extrusion machine has a very sophisticated design; for example, the extrusion screw has different zones and complex geometry. Determining the proper processing settings is always a challenge for engineers. Additionally, complex rheological properties of the polymers in extrusion sometimes yield challenging and unpredictable problems to troubleshoot. For convenience, a small-scale extrusion machine can be used to troubleshoot and analyze the polymers rather than the large manufacturing machines that are hard to work with. This study has produced a small-scale extrusion machine that is easy to manufacture without deviating from the extrusion process's nature. The extruder, whose production details are given, was tested with two different polymers: HDPE and PMMA. The correct temperature and screw rotation speed were determined with the extruder for the proper process parameters. In addition, the temperature-viscosity relationship of the polymers' flow nature was also determined.

Investigation of rheological properties of asphalt modified with low-temperature microencapsulated eutectic phase change materials

The effects of microencapsulated eutectic phase change materials (MEPCMs) on the viscosity-temperature relationship, viscoelasticity, creep recovery, and low-temperature properties of base asphalt and SBS asphalt were investigated using dynamic shear rheometer (DSR) and bending beam rheometer (BBR). The results revealed that the incorporation of microcapsules led to a reduction in the complex modulus and viscosity of the asphalt. Notably, at a concentration of 13 wt%, microcapsules disrupted the linear viscoelastic behavior of the asphalt and compromised its phase uniformity. However, the addition of microcapsules improved the low-temperature rheological properties of the asphalt. Specifically, the S and m-values of the asphalt decreased and increased, respectively, with increasing microcapsule content. Moreover, SBS asphalt exhibited less susceptibility to the effects of microcapsules compared to base asphalt, owing to its superior performance across a wide range of temperatures. This characteristic renders SBS asphalt more compatible with MPCMs for practical applications.

Temperature dependence of polymer melt viscosity obtained based on DSC data and the consistency between thermodynamic and kinetic fragility

AbstractThe viscosity of the polymer melt has an impact on both the processing and properties of the product. However, conventional viscosity measurement methods have limitations such as strict testing conditions, large sample sizes, and long response times. This paper proposes a simplified method that utilizes differential scanning calorimetry to determine the viscosity–temperature relationship of the polymer melt. The research subjects consist of four noncrystalline polymers and five crystalline polymers. A new thermodynamic fragility formula of crystalline polymer is obtained. Additionally, high‐temperature limiting viscosity shows a good linear relationship with fragility. Compared with the traditional viscosity measurement, this method is a simpler and more effective way to model the viscosity of polymer melt and has broad prospects in application.

Rheological behavior of high-pour-point oil: Insights into viscosity–temperature prediction and viscoelastic-yielding transition

The rheological characteristics of high-pour-point (high-PPT) oil are crucial for its economical and safe production and transportation. However, current research on the viscosity–temperature prediction and viscoelastic-yielding transition of high-PPT oil is insufficient. The Arrhenius formula faces challenges in accurately depicting the viscosity–temperature relationship, and there is a lack of a quantitative description of the viscoelastic-yielding transition behavior in gelled high-PPT oil. This study addresses these gaps through a series of rheological experiments. The results reveal that the viscosity–temperature relationship of high-PPT oil can be classified into three regions, each associated with a sequentially increasing activation energy Ea. Introducing two characteristic parameters, T0 and n, yields a modified Arrhenius formula with an extended range of applicability. Thixotropy and gelation process experiments demonstrate an exponential increase in thixotropic strength with a decreasing temperature below the wax appearance temperature, while an optimum cooling rate maximizes the gelation degree of high-PPT oil. A brittleness index BI was defined to quantitatively describe the fracture mode of gelled crude. Critical characteristic strains and BI exhibit a decrease with an increase in the reciprocal of the average free degree 1/wfree, where the diminishing trend of BI follows a robust power-law form. This comprehensive investigation contributes valuable insights into the rheological behavior of high-PPT oil, offering a foundation for more accurate modeling and control strategies in its production and transportation.

Influence of structural properties on the suspension performance of ultra-high temperature stabilizers

One of the key challenges preventing the exploration and development of ultra-deep oil and gas deposits is the settlement instability of cement slurry at extremely high temperatures. In the previous work, an ultra-high temperature suspension stabilizer was created to enhance the cement slurry's high temperature settlement stability. This work investigates its mechanism from the standpoint of structural characteristics based on the prior research. Thermal stability tests and calculations of the pyrolysis activation energy were used to examine the structural features of the suspension stabilizer. The viscosity-temperature relationship, the microstructure of the suspension stabilizer solution, the molecular structure change of the suspension stabilizer in the solution environment, and the interaction energy with water molecules were all studied in conjunction with contemporary material testing techniques and molecular dynamics simulation calculations. The findings indicate that: 1) The bulk structure of the suspension stabilizer has a pyrolysis temperature of 330 °C, which indicates a degree of heat resistance; 2) In a solution environment, the viscosity of the solution is a critical factor in determining the stability of the cement slurry's sedimentation, which is dependent on the integrity of the amide group in the suspension stabilizer. The cyclic functional group's ortho action prevents the amide monomer from hydrolyzing in the ultra-high temperature suspension stabilizer. The cement slurry has good sedimentation stability because the hydrogen link between the retained amide group and the water molecule has not entirely broken down, and the solution still has some viscosity.

Temperature-dependent viscometry of baobab pectin (Adansonia digitata L.)

This study uses the Arrhenius-type equation and the Frenkel-Eyring equation to evaluate the viscosity-temperature dependency of the baobab pectin (BoP) solution at 278.16-353.16 K. The viscosity parameters (apparent viscosity, ηA and intrinsic viscosity, [η]) were analysed for polymeric systems of WEp (pectin extracted using water), AEp (pectin extracted using acid), and Cp (citrus pectin, a control). A Vibro-viscometer was used to measure ηA, while [η] values were estimated from the Kuwara equation. The viscosity parameters decrease with an increase in temperature, though the effects were more pronounced in WEp than in AEp and Cp. Data from [η] indicated that activation energy Ea was higher for AEp (12.24 kJ/mol) and lower for WEp (10.18 kJ/mol). In contrast, the ηA data had a higher Ea for WEp (21.38 kJ/mol) and a lower Ea for Cp (16.49 kJ/mol). The ηA data showed a non-linear viscosity-temperature relationship, and the Vogel-Fulcher-Tammann-Hesse equation was used instead to relate the temperature dependency of BoP. The flow patterns of all pectin solutions showed positive entropy (ΔS + v ), positive enthalpy (ΔH+ v ), and negative Gibbs free energy (ΔG−v ). This revealed that the flow was disordered, dependent on temperature, and spontaneous. Overall, the viscous flow of WEp was more sensitive and less dependent on temperature compared to AEp and Cp.

New recycling method of lubricant oil and the effect on the viscosity and viscous shear as an environmentally friendly

Abstract The present investigation adopts a new method to recycle the oils. The used and recycled lubricants were compared to fresh oil. Accordingly, an investigation was carried out to evaluate the viscous shear of different oil grades at each certain temperature using the Walther formula of the viscosity–temperature relationship. The investigation indicates acceptable and fair results in front of a technical point of view and environmental improvement by reducing pollution. The results show lower viscosity of the recycling oil than the used oil, which affects the viscous shear as it is directly proportional to the velocity gradient and the fluid’s viscosity at ascertaining temperature. In the present investigation, alum (Al2(SO4)3(H2O)18) was used, which gives good precipitation according to the practical results mentioned in this work. The used oils of grades 5w20, 5w30, and 10w30 under consideration are collected from the local internal combustion engines. Both kinematic viscosity and viscous shear for 10w30 oil grade record the highest values, and 5w20 records the lowest values for all oil types (fresh, recycled, and used oil).

Effect of BaO/Al2O3 ratio and Li2O content on viscosity and crystallization of BaO–Al2O3–TiO2-based mold slags

In the current study, the influence of different BaO/Al2O3 ratios and Li2O contents on the viscosity, melting temperature, crystallization behavior and structure of BaO–Al2O3–TiO2-based mold slags was investigated through the measurement of the viscosity-temperature relationship, hemisphere point method, crystallization process and crystallization temperature, and the calculation of NBO/T and optical basicity. With the increase of the BaO/Al2O3 ratio from 0.60 to 1.67, the viscosity at 1573 K and the melting temperature of mold slags decreased from 0.3 to 0.05 Pa s, and 1261 K–1217 K, respectively, while those also slightly decreased from 0.15 Pa s to 0.11 Pa s, and 1244 K–1213 K with the Li2O content from 4 % to 6 %, respectively, which was related to the increase of fluxing reagent or oxygen ions released by basic oxide in slags. In current slags, precipitated phases mainly existed as LiTiO2 and BaTiO3, and the difference of the BaO/Al2O3 ratio and Li2O content resulted in the competitive precipitation of these phases. With the increase of BaO/Al2O3 ratio from 0.60 to 1.67, precipitated phases gradually changed from LiTiO2 to BaTiO3, and the initial crystallization temperature had the tendency to decrease and increase. On the contrary, the precipitated phase gradually changed from BaTiO3 to LiTiO2, and the initial crystallization temperature as well as the break temperature decreased with the Li2O from 4 % to 8 %. The parameter NBO/T and optical basicity of molten slags increased with the increase of BaO/Al2O3 and Li2O content, and the polymerization degree of the melt decreased, resulting in the decrease of the activation energy of viscous flow and the viscosity. Hence, the increase of the BaO/Al2O3 ratio and Li2O content within limits could lower the viscosity, melting temperature, break temperature and crystallization ability of mold slags, and then improve the lubrication of the slag on solidified shell.

A Study of Temperature Effect on the Dripping Mode of Electrohydrodynamic Atomization with Viscous Liquids

Electrohydrodynamic atomization (EHDA) has advantages in producing fine uniform droplets with low energy consumption. In this work, the droplets generated by the EHDA under the dripping mode have been captured by a backlit high-speed imaging system under various liquid temperatures T (293–343 K) and electric Bond numbers BoE (0–0.75). The temperature-viscosity relationships of the working fluids (G20, G40, G50, and G66) were fitted by an Arrhenius-type model. The effects of BoE, We, and T on the dimensionless droplet limiting length l* and oscillation frequency f were investigated through extensive experiments. The experimental results show that the droplet limiting length elongated with the higher liquid viscosity. However, the oscillation frequency of the meniscus declines with the liquid viscosity. By the elevation of liquid temperatures, the droplet limiting length diminishes, but the oscillation frequency of the liquid meniscus accelerates. Coefficients to estimate the effects of the flow rate and the temperature on oscillation frequency are introduced into the classical theory of meniscus oscillation to develop a semi-empirical model. The proposed model could estimate oscillation frequency for the meniscus under various electric Bond numbers, Weber numbers, and temperatures. The prediction achieves good agreements with experimental results.

A redox effect on the viscosity of molten pyrolite

The viscosity of molten Earth mantle has been determined for various redox states using very high temperature viscometry at 1 bar. The viscosity-temperature relationship of the most oxidised pyrolite studied here is comparable to that of a previous determination of the viscosity of a peridotite melt. For the first time, the effect of iron redox state on molten mantle viscosity has been determined by calorimetric analysis of the glass transition on extremely carefully characterised glassy samples quenched from conditions of variable fO2 using gas-mixing levitation. There is a clear trend of decreasing viscosity with increasing redox state over the range of Fe3+/ΣFe. = 0.07–0.29. We also observe an increase in glass transition temperatures with increasing melt depolymerisation (i.e., higher NBO/T ratios). Both the negative oxidation dependence of viscosity and glass transition behaviour upon depolymerisation are contradictory to the trends observed from redox viscometry of more silica-rich melts but may be consistent with the broadly diminishing positive redox viscometry trends of melts with increasing basicity.

Efficient Demulsification Performance of Emulsified Condensate Oil by Hyperbranched Low-Temperature Demulsifiers.

Focusing on the problem of poor demulsification performance of light crude oil emulsions in low-permeability oilfields at low temperatures, the composition of the emulsion samples, clay particle size distribution, and the viscosity-temperature relationship curve of samples were analyzed. Based on the results of emulsion composition analysis and characteristics, the bottle test method was used to analyze the demulsifying effect of different commercial types of demulsifiers, revealing the demulsification mechanism. The field tests confirm the demulsification capabilities of Polyoxyethylene polyoxypropylene quaternized polyoxyolefins surfactants (PR demulsifiers). The results reveal that PR demulsifiers combine the features of decreasing the interfacial tension between oil and water and adsorbing SiO2, allowing for quick demulsification and flocculation at low temperatures. This research serves as a theoretical and practical foundation for the study and advancement of low-temperature demulsification technology in oilfields.

Further thoughts on buoyancy-induced instability of a variable viscosity fluid saturating a porous slab

The stability of buoyant flow in a vertical porous layer bounded by impermeable-isothermal boundaries is studied insofar as the variability of fluid viscosity with temperature is concerned. The flow is governed by modified Darcy's law with two different forms of viscosity–temperature relationships namely, quadratic and exponential. The modal analysis is carried out with a velocity–temperature formulation of the governing equations for the perturbations. The temperature-dependence of the viscosity forbids the energy analysis of Gill [“A proof that convection in a porous vertical slab is stable,” J. Fluid Mech. 35, 545–547 (1969)] in embarking upon any definite conclusion on the stability of fluid flow even under the limit of an infinite Prandtl–Darcy number, and consequently, the stability eigenvalue problem is solved numerically. Types of temperature-dependent viscosity laws are found to demonstrate conflicting behavior on the stability characteristics of the base flow. The results show that the base flow is linearly stable if the viscosity varies with temperature quadratically. On the contrary, instability emerges for an exponential type of variation in viscosity beyond a certain range of values of the corresponding viscosity parameter depending on the Prandtl–Darcy number. It is established that an increase in the value of the viscosity parameter is to decrease the critical Darcy–Rayleigh number markedly and thereby destabilizes the fluid flow.

An insight into the thermal processability of highly bioactive borosilicate glasses through kinetic approach

AbstractThe paucity of crystallization resistant bioactive glasses with desired biological functions stands as a bottleneck toward the fabrication of various biomedical constructs such as amorphous coatings, scaffolds, and fibers for advanced tissue engineering applications. In this context, a series of borosilicate‐based bioactive glasses with a range of compositions: (53.88 − x)SiO2–21.7Na2O–21.7CaO–1.7P2O5–xB2O3 (mol%) where x = 0, 13.47, 22.45, 31.43, and 40.41 were prepared to address such limitation. The glasses were primarily investigated for their potential to be processed into amorphous scaffolds through evaluation of crystallization kinetics, sintering behavior, and viscosity–temperature dependence. The inclusion of B2O3 gradually reduces the activation energy of crystallization (Ea), according to the prediction from different kinetic models, whereas Friedman's model‐free method unraveled the variation in Ea as crystallization progresses. The crystallization event is further elucidated by obtaining the Avrami parameter (n) and dimensionality (m) through Matusita–Sakka equation. The optimization of the sintering schedule for amorphous scaffold preparation was accomplished by exploiting isothermal prediction from Avrami–Erofeev model. Moreover, viscosity–temperature relationship for the studied glasses was established to identify the processing window for drawing and sintering. This study proposes a comprehensive approach adopting theoretical models to elucidate suitable high‐temperature process parameters of bioactive glasses avoiding devitrification.

Evaluation of Thermo-Viscous Properties of Bitumen Concerning the Chemical Composition

The quality of bitumen is standardized by conventional tests. With the development of new techniques, rotational and oscillatory measuring systems are applied to evaluate bitumen under defined geometric, temperature, frequency, stress, and strain conditions that correspond to loads during asphalt production and service. Several studies have focused on determining the effect of composition on bitumen properties at service temperatures. However, there is a lack of information related to the effect of composition on viscosity at higher temperatures, which influences production processes. The different types of bitumen, samples of 50/70, 35/50, 45/80-75, and 25/55-60 bitumen, had different viscosity values in intervals corresponding to a confidence level of 95%. The viscosity-temperature relationship in temperature range of 120 to 180 °C was observed in values of 3.87 and 3.70 for unmodified bitumen and 3.09 and 3.22 for modified bitumen. The effect of differences in SARA fractions content on the variation in viscosity using regression analysis showed the importance of asphaltenes (direct correlation) and aromates (negative correlation) contents for 50/70 bitumen with a coefficient of linear regression above 0.7. In comparison, the strong effect of saturates and asphaltenes (negative correlation) and resins was identified for 45/80-75 bitumen samples with correlation of 0.5 to 0.7.

Characteristics, mechanisms, and environmental LCA of WMA containing sasobit: An analysis perspective combing viscosity-temperature regression and interface bonding strength

Warm mix asphalt (WMA) with organic additive technology has been highly recommended in asphalt pavement. However, the viscosity-reduction mechanism, viscosity-temperature relationship, and field application effects have yet to be well excavated. Therefore, the characteristics, mechanisms, and environmental benefits of WMA containing sasobit warm agent (SWA) were developed. Kinetic viscosity, Brookfield viscosity, modified BBS tests, and rheological property tests were performed. The results showed that WMA with SWA significantly lowered the mixing and compaction temperatures. They were reduced by 38.9 °C and 36.8 °C using 4% SWA, respectively, compared with 70# base asphalt. The bonding strength between WMA and asphalt or aggregate was also improved after adding SWA. Based on the balanced performance design, the optimum SWA dosage was 3%. Measured field data showed that the asphalt fume, BSO, and benzopyrene reductions were more than 80% in WMA pavement construction adding 3% SWA. Moreover, energy consumption and carbon emissions in the LCA of WMA pavement construction adding 4% SWA were reduced by 134.86 MJ/t (21.56%) and 112.03 kg/t (40.60%), respectively. Overall, the characteristic, mechanism, and LCA analysis of WMA with SWA confirmed its great potential and application prospects.

Application of fumed silica-enhanced polymeric fracturing fluids in highly mineralized water

Fumed silica is combined with highly mineralized water to configure polymeric fracturing fluids for fracture and oil-repellent applications. The properties of fracturing fluids have been systematically studied with regard to thixotropy, shear viscosity, viscoelasticity, and viscosity–temperature relationships. Molecular dynamics simulations are commonly used to discover how fumed silica works in highly mineralized fracturing fluid. Results show that fumed silica can effectively enhance the thixotropy of highly mineralized fracturing fluid. Fumed silica enhances the temperature resistance of highly mineralized fracturing fluid (variation of the Arrhenius constant). Based on SEM analysis, fumed silica can help polymers bond together. In highly mineralized fracturing fluid, fumed silica generates a supramolecular weak gel, which strengthens the weak gel. In addition, molecular dynamics simulations indicate that fumed silica strengthens polymer–nanoparticle–water interactions.

Simultaneous measurement of microscale fluid viscosity, temperature, and velocity fields by tracking Janus particle on microparticle image velocimetry

Multifunctional sensing capability enables a comprehensive understanding of the unknown target to be measured. Given that fluid viscosity, temperature, and velocity fields are usually coupled parameters in a system, simultaneous measurement of the three environmental factors can prevent cross-talk and improve reliability. However, the task is apparently challenging because of the microscale targets. A technique combining microparticle image velocimetry and Janus particles was developed in this study to address such demand. With the rotational diffusivity and particle trajectories measured by the proposed technique and an empirical water-based viscosity-temperature relationship, the three unknown variables in a microfluidic environment were solved. The blinking frequency was derived using the Hilbert Huang Transform. Compared with those in a static and uniform temperature field, the measured data had good agreement with the predicted values. However, the agreement was impaired when the heating rate exceeded 0.34 °C/s. The optimal temperature range was found between 10 °C and 40 °C in the water-based solution. For a steady-state and nonuniform temperature field, two-dimensional (2D) numerical simulations of three linear temperature gradients were also studied. Results showed that the deviation increased as the temperature gradient increased or was near the low-temperature region. The same procedure was eventually applied to a real thermophoretic flow induced by an IR laser in a microchip. The 2D fluid viscosity, temperature, and velocity fields in the microchip were successfully obtained by tracking 10 particles. The potential of the approach provides insight into understanding some microfluidic applications with mild changes in temperature or creeping flow. This study combined µPIV with Janus particles to achieve simultaneous measurement of 2D microscale fluid viscosity, temperature, and velocity fields. By simply tracking the particles, particle trajectories and blinking signal were obtained. Both parameters provided sophisticated information of particle velocity and rotational diffusivity. With the information, the viscosity and temperature were hence derived from the empirical viscosity–temperature relationship and the Stokes-Einstein-Debye relation. The velocity was derived alone based on the conventional cross-correlation algorithm. • Using Janus particles as tracers to provide dynamic information of blinking signal and trajectories. • Simultaneous measurement of whole field fluid viscosity, temperature, and velocity at the microscale. • Extraction of the frequency spectrum out of blinking signal by Hilbert Huang Transform. • A measurable temperature range between 10 °C and 40 °C.

Polymer Lubrication: Pressure–Viscosity–Temperature Dependence of Film Thickness for Highly Loaded Compliant Contacts in Elastohydrodynamic Lubrication Regime

Abstract The relevance of the compliant contacts operated in elastohydrodynamic lubrication regime has increased during the last decades. Polymers and elastomers have been preferred because of their low-cost production or their tribological performance in many mechanical and bioengineering applications, where the metals originally dominated. Especially, in high-performance applications, such as polymer gears, the current subject of interest covers the transition between Piezoviscous-elastic and Isoviscous-elastic regimes of elastohydrodynamic lubrication. Here, it is necessary to precisely determine operating conditions and lubricant properties such as rheology whose contribution to film thickness formation may be influenced by attributes of individual lubrication regimes. The high-pressure viscosimeter and the optical tribometer were used, the former to establish the pressure–viscosity–temperature relationship of two reference lubricants, natural Squalane and synthetic tri(2-ethylhexyl) trimellitate, and the latter to determine the central and minimum film thickness in the circular contact between the PMMA disc and the steel ball using the optical chromatic interferometry method. Experimental results of film thickness demonstrated a significant deviation from the soft elastohydrodynamic lubrication (EHL) models, independently of the lubricant used, load, entrainment speed, and temperature because the pressure–viscosity–temperature response of lubricant was not included. Due to this, film thickness data were regressed, and new power coefficients of dimensionless parameter G¯ were derived. Outcomes confirmed the operation of the compliant circular contact in the transition region between the Piezoviscous-elastic and Isoviscous-elastic regimes with the minimum film thickness identified on the side lobes of the horseshoe shape.

Viscosity and Density of Narrow Distillation Cuts from Refined Petroleum- and Synthetic-Derived Distillates in the -60 to +60 °C Range.

Aviation turbine fuel (jet fuel) must remain fluid enough for use at low temperatures typically experienced during high-altitude flights. The viscosity-temperature relationship of petroleum-derived jet fuel is described by the MacCoull correlation in ASTM D341. The maximum kinematic viscosity of jet fuel at -20 °C is regulated by specification, but for long-distance flights, viscosity of <12 mm2 s-1 at -40 °C is important. For synthesized paraffinic kerosene (SPK) to be approved as a synthetic jet fuel, compliance with these viscosity limits is imperative. A petroleum-based kerosene and SPK from wax hydrocracking were distilled into narrow cut (5 °C range) fractions, and for each narrow cut, density, viscosity, and refractive index values were measured over the temperature range from +60 to -60 °C. The viscosity-temperature dependences of the petroleum-derived and synthetic narrow cuts were described with comparable accuracy (relative deviation <5%) by the MacCoull correlation. Calculation of kinematic viscosity at -40 °C by extrapolating data measured at ≥-20 °C underpredicted viscosity for >200 °C boiling kerosene cuts, with a maximum relative deviation of 6.6%. The freezing point is another jet fuel property that is regulated by specification. Good agreement (±1.3 °C) was found between the end of the melting endotherm obtained by differential scanning calorimetry (DSC) and the freezing point determined according to ASTM D2386. Local maxima/minima in the freezing point of distillation cuts with increasing boiling point were observed and could be related to the freezing point characteristics of the n-alkanes.