Tropsch Paraffin Wax Research Articles

Rheological and Thermo-Oxidative Aging Properties of Asphalt Modified with a Combination of Sasobit and Linear Low-Density Polyethylene

Research of different asphalt modifiers has been necessary for the attempt to construct durable roads with higher standards. Fischer Tropsch-paraffin wax (Sasobit) has recently attracted considerable attention over polymer modification due to its capacity to lower the energy requirements for asphaltic mix construction. In this study, Sasobit was used to recover the performance as well as the workability of 3 wt% linear low-density polyethylene (LLDPE) modified asphalt. A base asphalt binder with a penetration grade of 50/70 was blended with 3 wt% LLDPE and 3 wt% Sasobit separately and then combined with different Sasobit dosages (1–3 wt%). The performance of modified asphalt binders was evaluated using conventional, rheological, and thermal tests. As a result, it was found that loading Sasobit (1–3 wt%) into LLDPE-asphalt mixture steadily decreased the penetration and ductility at 25 °C from 25 to 12 dmm and 31 to 18 cm, respectively, and softening point increased by 20% indicating improved high-temperature performance. The binder workability and mix temperature were improved since the addition of Sasobit reduced the LLDPE-asphalt viscosity from 0.292 to 0.189 Pa.s (22% less). Sasobit improved the thermo-oxidative aging resistance of the binder by showing less weight variation (less than 0.001%) after the Rolling Thin-Film Oven Test (RTFOT) and high ductility retention (65%). Thermogravimetry (TG) and kinetics analysis results indicated that Sasobit-LLDPE delayed the initial and maximum decomposition temperature by 11 °C and hence increased the thermal stability of modified binders. Thus, the proposed binders are a suitable solution for asphalt pavement construction in regions that encounter high-temperature changes.

Experimental investigation of low viscosity grade binder modified with Fischer Tropsch-Paraffin wax

The purpose of this study aims at investigating the effect of “Fischer Tropsch-Paraffin wax” (Sasobit) on the properties of low viscosity grade bitumen. Bitumen with viscosity grade-10 is selected as the control binder and later it is modified with different additive dosages of Sasobit (1–5%). Penetration, softening point and ductility tests were employed for evaluating the effect of Sasobit on basic physical properties of modified bitumen. A Dynamic Shear Rheometer (DSR) is also utilized for evaluating the rheological properties of the base and modified bitumen, for both aged and unaged bitumen. Based on the conventional and basic rheological tests, it was seen that the addition of Sasobit improved the high-temperature performance of modified bitumen and adversely affected the low-temperature performance at higher additive dosages greater than 1.5%. Therefore, the additive dosage has been optimized at 1.5% by weight of bitumen and thus the remaining tests have been carried out at 1.5% dosage. Multiple Stress Creep and Recovery (MSCR) test results revealed that the addition of wax improved the creep and recovery of modified binders for both stress intensities (0.1 kPa and 3.2 kPa) which confirms that the modified binder is more rut resistant. Also, the incorporation of Sasobit changed performance grade (PG) from 64 to 70. The isochronal and isothermal plots revealed that the Sasobit addition increases complex modulus. The increase is more prominent at higher frequencies. Thermal analysis has been performed by using thermogravimetry (TG) and results indicated that Sasobit delayed the initial decomposition temperature by 50°C and hence increased the thermal stability of modified binders. Also, Fourier Transform Infrared Spectroscopy (FTIR) is employed to study the effect of Sasobit on modified binders. It was observed that the addition of Sasobit did not alter the peaks. This specifies that asphalt and Sasobit have good miscibility and compatibility.

Laboratory and field evaluation of the warm fiber reinforced high performance asphalt mixtures (case study Karaj – Chaloos Road)

Using modified asphalt mixture is inevitable to improve technical performance of asphalt pavement and it will be achieved via asphalt mixture or bitumen improvement. In the present study, a combination of these methods are applied simultaneously using Fischer–Tropsch Paraffin wax (Sasobit) as one of the most widely used bitumen modifiers in the production of warm mix asphalt mixtures, and Polyolefin – Aramid FORTA polymer fibers as a reinforcing factor of asphalt mixture. The modified and unmodified asphalt performance at high, intermediate, and low temperatures were evaluated on two stages of laboratory and field sampling using dynamic creep, rutting, resilient modulus indirect tensile fatigue, moisture sensitivity, resistance for compaction, and fracture tests. The results indicate that simultaneous use of Polyolefin – Aramid FORTA polymer fibers and Fischer–Tropsch Paraffin wax (Sasobit) not only increase significantly the asphalt mixture resistance, but also it helps to improve asphalt mixture workability, including mixing, transportation, paving, and compacting. This will result in environmental pollutions and implementation cost reduction as well as asphalt life extension.

The effect of expanded graphite on the flammability and thermal conductivity properties of phase change material based on PP/wax blends

The study reports on the flammability, thermal stability, impact properties and thermal conductivity of shape-stabilized phase change materials based on a soft Fischer–Tropsch paraffin wax blended with polypropylene (PP). The blends were melt-mixed with expanded graphite (EG) up to 9 wt% to improve the thermal conductivity and flammability resistance of the material. The thermal stability and flammability results show an increase in thermal stability and flame resistance of PP in the presence of EG, with the flammability further increasing in the presence of wax, probably because of the smaller and better dispersed EG particles in the PP/wax/EG composite that gave rise to a more compact char layer. Although the thermal degradation mechanism did not change in the presence of EG, the EG particles retarded the evolution of the volatile degradation products. The storage modulus of the PP/wax/EG composite was lower than those of PP and PP/EG, and decreased with increasing in wax content because of the softening effect of the wax. The impact strength of the PP/wax/EG composites increased with increasing EG content in all the samples, but decreased with increasing wax content.

The effect of expanded graphite on the thermal stability, latent heat, and flammability properties of EVA/wax phase change blends

This article reports on the morphology, melting and crystallization behavior, thermal stability, flammability and thermal conductivity of shape‐stabilized phase‐change materials (PCM) for thermal energy storage, based on a soft Fischer–Tropsch paraffin wax, the PCM, blended with ethylene vinyl acetate (EVA). These immiscible blends were melt‐mixed with expanded graphite (EG) (up to 9 wt%) to improve the thermal conductivity and flame resistance of the material. It was observed that the EG particles agglomerate in the absence of wax, but disperse much better in the EVA/wax blend, probably because the wax penetrates in between the EG layers (there seems to be a better interaction between wax and EG than between EVA and EG) and separates the layers, giving rise to smaller and better dispersed EG particles. This gives rise to better thermal conductivity and flame resistance. There were no significant changes in the melting temperature of EVA in the EVA/EG composites, while the crystallinities of EVA were observably lower in the presence of EG. The thermal stability and flammability results show an increase in thermal stability and flame resistance of EVA, which further improved in the presence of wax because of the smaller and better dispersed EG particles in these systems. POLYM. ENG. SCI., 55:1255–1262, 2015. © 2015 Society of Plastics Engineers

Preparation and properties of polystyrene encapsulated paraffin wax as possible phase change material in a polypropylene matrix

The study deals with the preparation and characterization of polystyrene (PS) capsules containing Fischer–Tropsch paraffin wax (PS:wax) as phase change material (PCM) for thermal energy storage embedded in a polypropylene (PP) matrix. Blends of PP/PS:wax were prepared without and with polystyrene–block–poly(ethylene-ran-butylene)-block-polystyrene (SEBS) as a modifier. The influence of PS:wax microcapsules on the morphology, as well as thermal and mechanical properties of the PP was investigated. The scanning electron microscopy (SEM) images of the microencapsulated PCM show that the capsules were grouped in irregular spherical agglomerates of size 16–24μm. However, after melt-blending with PP smaller, perfectly spherical microcapsules were well dispersed in the PP matrix. There was fairly good interaction between the microcapsules and the matrix, even in the absence of SEBS modification. The FTIR spectrum of the microcapsules is almost exactly the same as that of polystyrene, which indicates that the microcapsules were mostly intact and that the FTIR only detected the polystyrene shell. The amount of wax in the PS:wax microcapsules was determined as 20–30% by weight. An increase in PS:wax content resulted in a decrease in the melting peak temperatures of PP. The thermal stability of the blends decreased with an increase in PS:wax microcapsules content as a consequence of the lower thermal stability of both the wax and PS. There was a drop in storage modulus with increasing PS:wax microcapsules content.

Structure and properties of phase-change materials based on high-density polyethylene, hard Fischer-Tropsch paraffin wax, and wood flour

Phase-change materials based on high-density polyethylene (HDPE), a hard Fischer–Tropsch paraffin wax (H1 wax), and alkali-treated wood flour (WF) were investigated. The blends and composites were prepared by melt-mixing. They were characterized in terms of their morphology as well as thermal, mechanical, thermomechanical, and water absorption properties. Although the scanning electron microscopy micrographs showed some evidence of intimate contact between WF and the HDPE matrix, there were poor filler dispersion and interfacial adhesion. The percentage miscibility of H1 wax in HDPE seems to have decreased with increasing wax content in the blends. A fairly strong affinity between the WF and H1 wax was noticed. There was plasticization of the HDPE matrix by the wax as well as inhomogeneity and uneven wax dispersion within the polymer matrix. The presence of H1 wax and WF influenced the crystallization behavior of the HDPE matrix. The incorporation of wax reduced the thermal stability of the blends and composites, but stabilized the WF. The H1 wax and WF differently influenced the viscoelastic properties of the HDPE matrix. In contrast to the blends where the tensile properties improved in the presence of wax, the composites showed poorer properties. An increase in wax content resulted in a decrease in water uptake by the composites. POLYM. COMPOS., 32:1155–1163, 2011. a 2011 Society

Comparison of LDPE, LLDPE and HDPE as matrices for phase change materials based on a soft Fischer–Tropsch paraffin wax

Phase change materials based on LDPE, LLDPE and HDPE blended with soft paraffin wax were studied in this work. The purpose of this study was to compare the influence of wax content on the thermal and tensile properties of PE/wax blends. It was found that the different polyethylene/wax blends were immiscible for the samples containing 30–50% wax. The presence of wax influenced the melting and crystallization behaviour of the different polyethylenes in different ways, and the thermal analysis results show that the waxes were evenly distributed in the polymer matrices and that there was no wax leaking during sample preparation. For all the blends the thermal stability decreased with an increase in wax content, and the PE/wax blends degraded in two clearly distinguishable steps. The presence of wax generally caused a reduction in tensile properties, but the extent of the wax’ influence depended upon the morphology of the polyethylene.

Phase change materials formed by uv curable epoxy matrix and Fischer–Tropsch paraffin wax

The use of an oxidized hard Fischer–Tropsch paraffin wax as phase change material in an epoxy resin matrix has been investigated. Samples were prepared by mechanical mixing of the wax powder with liquid resin at room temperature, followed by uv-curing of the samples. The results indicated the presence of spherical wax particles in the epoxy matrix, even after heating the sample to a temperature above the melting point of the wax, and cooling. At low wax contents the wax distribution was fairly heterogeneous, but the homogeneity improved with increasing wax content. The epoxy–wax interaction seems to be weak, and the presence of wax has an observable influence on the dynamic mechanical properties of the samples, especially above the melting point of the wax. Although the wax starts decomposing at a much lower temperature than the epoxy resin, the decomposition of the mixtures occurred in a single step.

Thermal behaviour of low and high molecular weight paraffin waxes used for designing phase change materials

Two waxes, a soft petroleum wax and a hard Fischer–Tropsch paraffin wax, have been investigated to find the reasons for multiple endothermic peaks observed during heating in a DSC. DSC curves, molar mass distribution curves, and variable-temperature XRD results were compared, and it was confirmed that the first endothermic peak for the soft petroleum wax was due to a solid–solid transition, while the second endothermic peak was due to melting. However, for the hard Fischer–Tropsch paraffin wax there was no evidence of a solid–solid transition, and it was concluded that the multiple endothermic peaks in this case were due to melting of different molar mass fractions.

Polypropylene as a potential matrix for the creation of shape stabilized phase change materials

Phase change materials, based on isotactic polypropylene (PP) blended with soft and hard Fischer−Tropsch paraffin wax respectively, were studied in this paper. DSC, DMA, TGA and SEM were used to determine the structure and properties of the blends. While paraffin waxes in the blend changed state from solid to liquid, the PP matrix kept the material in a compact shape. Strong phase separation was observed in both cases, which was more pronounced in the case of soft paraffin wax. Despite the fact that both grades of paraffin wax are not miscible with PP due to different crystalline structures, it was shown that the hard Fischer−Tropsch paraffin wax is more compatible with PP than the soft one. Both waxes plasticized the PP matrix. TGA showed that PP blended with the hard Fischer−Tropsch wax degrades in just one step, whereas blends containing soft paraffin wax degrade in two distinguishable steps. SEM exposed a completely different morphology for the two paraffin waxes and confirmed the lower compatibility of PP and soft paraffin wax. The soft and hard characters of the waxes were manifested in the viscoelastic properties, where the blends containing soft paraffin wax exhibited a lower elastic modulus than pure polypropylene, whereas the hard Fisher−Tropsch paraffin wax solidified the matrix. However, both kinds of blends were able to sustain the dynamic forces applied by the DMA within five cycle runs implying good shape stability.

Modification of the polarity and adhesive properties of polyolefins through blending with maleic anhydride grafted Fischer–Tropsch paraffin wax

AbstractThe modification of the polarity and adhesive properties of linear low‐density polyethylene, low‐density polyethylene, and isotactic polypropylene through blending with paraffin wax (Fischer–Tropsch synthesis), grafted by maleic anhydride, was investigated. Maleic anhydride grafted paraffin wax significantly increased the polar component of the total surface free energy of polyolefins. Modified polyolefins also had significantly higher adhesion to the polar substrate, a crosslinked, epoxy‐based resin. The conservation of the good mechanical properties of the blends was observed up to 10 wt % wax, except for isotactic polypropylene blends, for which there was a reduction in the stress and strain at break at wax concentrations higher than 5%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3069–3074, 2006

Preparation of a maleated Fischer–Tropsch paraffin wax and FTIR analysis of grafted maleic anhydride

Grafting of maleic anhydride (MA) onto Fischer–Tropsch paraffin wax was performed by a melting process in the presence of dibenzoyl-peroxide (DBP). It was confirmed that suitable reaction conditions can give a product which does not contain unbound maleic anhydride. Washing of the final product in boiling water is not suitable in this case, due to the relatively high solubility of the final product in water. A simple method, using Fourier transform infrared spectroscopy (FTIR), was developed for the determination of the grafting degree of MA. The method is based on the evaluation of the ratio of the C–H wax vibration absorbance to that of the carbonyls of the grafted succinic anhydride ring. The identification of the main peaks was done and suitable peaks were chosen for FTIR analysis. The concentration of grafted maleic anhydride was calculated by an iteration technique based on a function derived from the Lambert–Beer law. The regression and statistical parameters of the calculated function, as well as the accuracy of the determined grafted anhydride content, were computed.

Changes in free surface energy as an indicator of polymer blend miscibility

Changes in free surface energy as a result of differences in polymer blend miscibility were investigated. When high density polyethylene (HDPE) and a hard Fischer–Tropsch paraffin wax are miscible, the total surface energy of the blend decreases compared to that of the pure polymer, and the polar part of the surface energy increases. At higher wax contents, the miscibility with HDPE is lower, and this is accompanied by a decrease in the polar part of the surface energy and an increase in the total surface energy. Differential scanning calorimetry was used to monitor the miscibility, and the determination of the surface energy was carried out on a surface energy evaluation system (SEES), which enables the calculation of the surface energy on the basis of the most often used models.

Wax crosslinking with dicumyl peroxide

AbstractA Fischer—Tropsch paraffin wax of high molecular weight, congealing point 205°F (96·1°C), was crosslinked with dicumyl peroxide as initiator. At peroxide/wax molar ratios of less than 1·15 : 1, crosslinked waxes with molecular weights up to approximately double that of the starting material are obtained. These products are characterised by an increase in elasticity. At peroxide/wax ratios greater than 1·15 : 1 insoluble and infusible gels are formed. The efficiency and fate of the initiator and possible side reactions are discussed.