Microcrystalline Wax Research Articles

A comprehensive investigation into the structure-property relationship of wax and how it influences the properties of hot melt adhesives

A detailed study was conducted on seven different waxes used in hot melt adhesive formulations together with conventional resins and tackifiers, to characterize the waxes and investigate the effects of wax structure and morphology on the thermal behaviour and basic properties of the resultant hot melt adhesive formulations (HMAs). The waxes selected included representatives of each of the following types: Fischer-Tropsch wax (FT), fully refined paraffin wax (FRP), by-product polyethylene wax (BPPE), microcrystalline wax (microwax), alpha-olefin wax (AO), carnauba wax and first intention polyethylene wax (FIPE). Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), high temperature size exclusion chromatography (HT-SEC), nuclear magnetic resonance spectroscopy (NMR) and confocal laser scanning microscopy (CLSM) were used as analytical tools to characterize the waxes. Molecular chain architecture as determined by solution 13C NMR highlighted the superior chain linearity of FT wax. Methyl, ethyl and butyl short chain branching were detected in other waxes. Solid-state 13C CP-MAS NMR provided information on the semi-crystalline nature of the waxes. FIPE, AO and Microwax showed significant structural mobility at room temperature as observed by 1H Wideline NMR and was attributed to chain branching and mobile crystalline domains respectively. This was supported by CLSM micrographs. All waxes enhanced crystallinity in both metallocene catalysed polyethylene (mPE) and ethylene-vinyl acetate (EVA) based HMAs. This was confirmed by the characteristic splitting in FTIR bands and increased DSC enthalpies observed for the HMA relative to the neat polymers. Of the formulations containing high melting waxes, FT wax resulted in HMAs with narrower crystallization profiles, an important factor in determining HMA set times. HMA viscosities were found to be dependent on the molecular weight of the wax while the HMA melting temperatures and enthalpies were more dependent on the crystalline morphology of the waxes.

Evaluation of alkenones, a renewably sourced, plant-derived wax as a structuring agent for lipsticks.

OBJECTIVEWaxes are used as structuring agents in lipsticks. There are a variety of waxes combined in a single lipstick to provide good stability, pleasant texture and good pay‐off. Due to a significant growth for natural, green and sustainable products, there is a constant search for alternatives to animal‐derived and petroleum‐derived ingredients. In this study, a green, non‐animalderived wax, namely long‐chain ketones (referred to as alkenones), sourced from marine microalgae was formulated into lipsticks and evaluated as a structuring agent.METHODSAlkenones were used as a substitute for microcrystalline wax, ozokerite and candelilla wax, typical structuring agents. In total, 384 lipsticks were formulated: L1 (control, no alkenones), L2 (alkenones as a substitute for ozokerite), L3 (alkenones as a substitute for microcrystalline wax) and L4 (alkenones as a substitute for candelilla wax). Products were tested for hardness (bending force), stiffness, firmness (needle penetration), pay‐off (using a texture analyser and a consumer panel), friction, melting point and stability for 12 weeks at 25 and 45°C.RESULTSAlkenones influenced each characteristic evaluated. In general, lipsticks with alkenones (L2‐L4) became softer and easier to bend compared to the control (L1). In terms of firmness, lipsticks were similar to the control, except for L4, which was significantly (P < 0.05) firmer. The effect on pay‐off was not consistent. L2 and L3 had higher pay‐off to skin and fabric than L1. In addition, L4 had the lowest amount transferred, but it still had the highest colour intensity on skin. Alkenones influenced friction (glide) positively; the average friction decreased for L2‐L4. The lowest friction (i.e. best glide) was shown in L4. Melting point of the lipsticks was lower when alkenones were present. Overall, L4, containing 7% of 4 alkenones in combination with microcrystalline wax, ozokerite and carnauba wax, was found to have the most desirable attributes, including ease of bending, high level of firmness, low pay‐off in terms of amount, high colour intensity on skin and low friction (i.e. better glide). Consumers preferred L4 the most overall.CONCLUSIONResults of this study indicate that alkenones offer a sustainable, non‐animal and non‐petroleum‐derived choice as a structuring agent for lipsticks.

CHARACTERISTIC LENGTH AND COMBUSTION EFFICIENCY OF ALUMINIZED SOLID FUEL FOR HYBRID ROCKET

This study investigates the effects of enlarged aft-chamber volume of a hybrid rocket and of aluminum powder added to solid fuel. To confirm the aluminum powder ignition, we conduct flame temperature analysis and scanning electron microscopy (SEM) analysis of the residue. Solid fuel used for the experiment is microcrystalline wax and 3 μ.m aluminum powder. Combustion experiments are conducted with three aft-chamber lengths of 55, 75, and 115 mm. Only one length of solid fuel is used. Results demonstrate that the regression rate tends to increase by adding aluminum powder. Furthermore, a high regression rate is obtained in the region of low oxidizer mass flux. However, the increase in the aft-chamber does not affect the regression rate. The combustion efficiency increases concomitantly with increased aft-chamber volume and increased characteristic length. Addition of the aluminum powder raises the rate of increase of combustion efficiency against the characteristic length. Under the characteristic length conditions used for this study, the combustion efficiency is low and insufficient. When aluminum powder is added, temperature analysis shows a rise in the flame temperature near the nozzle exit. By analyzing the residue around the nozzle after combustion using SEM, we confirmed the presence of shells of aluminum particles that had been ignited and burned. Temperature analysis and SEM analysis results suggest that the aluminum powder ignited and burned. However, Al powder ignition is not a phenomenon occurring only in the combustion chamber.

Infrared thermographic investigation of the use of microcrystalline wax to preserve apples from thermal shocks

This paper aims to prove the feasibility and effectiveness of using microcrystalline wax in order to preserve fruit from thermal shocks due to temperature changes or thermal excursions during food supply chain. Wax is a natural substance which covers the surface of some species of fruits such as the apples. This wax layer protects the fruit against parasites, atmospheric agents, thermal excursions, moisture loss, mechanical damage and microbiological infections. These singular features are currently object of studies and research activities aimed to develop new synthetic substances obtained by natural extracts or essences.Active infrared thermography has been used in this work to study the thermal response of apples to ambient temperature changes. The experimentation has been performed on the Golden Delicious variety. Two different apple sets have been considered. The first set was composed of apples covered by their own natural wax layer. The second set was composed of apples coated with an additional artificial microcrystalline wax layer. Their thermal responses have been put in comparison after a cooling process inside a climatic chamber. Measurements have been performed under controlled environmental conditions to assure the repeatability and reproducibility of data. By using an infrared camera, the thermal response of the two apple sets has been recorded and the heating rates have been compared. The wax coated apples have showed a slower heating rate due to the thicker wax layer. As a consequence, the coated apples have shown a reduced influence to external temperature variations. The final aim of this study is to reproduce artificially bio-wax films in order to cover and protect fruits during their life cycle from the tree to the table.

Fabrication of a Large-Area, Fused Polymer Micromold Based on Electric-Field-Driven (EFD) μ-3D Printing.

An electric-field-driven (EFD), μ-3D printed, fused polymer technique has been developed for the fabrication of large-area microscale prototype molds using typical polymer materials, including microcrystalline wax (MC-wax), polycaprolactone (PCL), and polymathic methacrylate (PMMA). This work proposes an alternative for large area microscale modes and overcomes the limitation of high cost in the traditional mold manufacturing industry. The EFD principle enables printing of fused polymers materials more than one order of magnitude lower than the nozzle diameter, contributing to the necking effect of the Taylor cone jet, which is the key factor to achieve the microscale manufacturing. Numerical simulation of electric field distribution between the meniscus and substrate was carried out to elucidate the dependence of electric field distribution on the meniscus condition of three types of polymers under printable voltage, and the electrical field parameters for the EFD μ-3D printing were determined. A number of experiments were printed successfully using a large range of viscosity materials, ranging from tens of mPa·s to hundreds of thousands of mPa·s of PCL and PMMA. The differences in parameters of different materials, such as viscosity, tensile properties, and surface energy, were studied to assess their use in different fields. Using proper process parameters and a nozzle with an inner diameter of 200 μm, three different application cases were completed, including a Wax microarray and microchannel with a minimum dot diameter of 20 μm, a PCL mesh structure with a minimum line width of 5 μm, and a PMMA large-area mold with a maximum aspect ratio of 0.8. Results show that the EFD μ-3D printing has the outstanding advantages of high printing resolution and polymer material universality.

Improving Physical Properties of Wax-Based Fuels and Its Effect on Regression Rate

Wax is a brittle thermoplastic material, and its physical properties must be improved so that it can be used as fuel in hybrid rockets. In this study, we use microcrystalline wax and paraffin wax by mixing ethylene vinyl acetate copolymer (EVA) and stearic acid; conduct tensile tests and firing tests; and measure viscosities to obtain the effect of improvement in physical properties on the regression rate. According to the results, microcrystalline wax has higher strength than paraffin wax, and the tensile strength increases as the EVA and the stearic acid contents increase. By contrast, mixing EVA with wax decreases the regression rate, but mixing stearic acid hardly affects the regression rate. The regression rates of these wax-based fuels increase almost proportionally with power of the coefficient of the viscosity of molten fuel at a constant temperature, which agrees with the results of the theoretical analysis.

A novel technology for the corrosion protection of iron archaeological artefacts using parylene base removable bilayer

Abstract Combinations of different acrylic resins and microcrystalline waxes are most often used for conservation and preservation these days. However, their properties are not sufficient and satisfactory in many ways. A novel barrier coating for the conservation of iron archaeological artefacts composed of parylene C polymer and Laksil lacquer is proposed within this article. Parylene C is a commercial name of poly(chloro-p-xylylene) polymer, and it was prepared via modified chemical vapour deposition. Parylene removability was ensured through the xylene soluble interlayer made of Laksil silicone-acrylic lacquer which was applied between a protected iron model substrate and parylene thin film. The corrosion tests in salt spray showed excellent barrier properties of Laksil/parylene bilayer. The surface roughness measured by the profilometry and the surface morphology shown by the SEM displayed the synergic effect between the Laksil and parylene layer which leads to the exceptional barrier and anticorrosion function of Laksil/parylene bilayer. First, the Laksil layer flattened out rough surface of a substrate; second, thereon deposited parylene film became smooth and defect free and acted as a good diffusion barrier. The colouristic measurements proved that the bilayer does not change the appearance of item, in terms of colour. The EDX and TGA confirmed entirely successful removal of bilayer and thus the reversibility of conservation treatment is enabled. The characteristics of Laksil/parylene bilayer were compared with the conventional conservation coating composed of Paraloid B72 acrylic resin and Revax microcrystalline wax prepared by professional conservators. The Laksil/parylene bilayer demonstrated significantly superior properties in this comparison.

Effect of Polymer Blends on the Properties of Foamed Wood-Polymer Composites.

The polypropylene (PP)/wood flour (WF) composites were prepared using a co-rotating twin-screw extruder followed by a single-screw extruder foaming system in this paper. Polymers, such as polyolefin elastomer (POE), high-density polyethylene (HDPE) or microcrystalline wax, were blended with PP in the preparation of composites to improve the melt strength. And a cavity transfer mixer was introduced to increase the distribution uniformity of components in composites. Meanwhile, the effect of the polymer blends on the microstructure and mechanical properties of samples was investigated. The experimental results show that the addition of POE and HDPE resulted in the second melting peak in the differential scanning calorimeter (DSC) curves and a great decrease in the cell size was caused by the added POE. However, due to the velocity difference of composites in the die, the shape of bubbles gradually became irregular. Moreover, the impact strength of samples significantly increased by 85% for the added POE and the apparent density decreased by 6.7%. And the minimum Vicat softening temperature of 133.7 °C was obtained when the mass ratio of HDPE to PP was 4/6.

Experimental investigation of the effects of paraffin/aluminum blended fuels on aluminum particle size

The combustion behavior of paraffin/aluminum blended fuels was investigated to determine the effects on the size of nano- and micro-sized aluminum particles and assess their respective combustion performance in hybrid rocket applications. The base paraffin fuel considered in this study was Sasol 0907 microcrystalline wax. Two additional blended fuels, each with particles with average sizes of 8 μm and 100 nm were used. The thermal and rheological behavior of the paraffin/aluminum blended fuels were evaluated, and their homogeneity was verified by scanning electron microscopy. Results confirmed that the nano-sized and micro-sized particles were well distributed in space without agglomeration. The average regression rate of the paraffin added with micro-sized particles was higher than that of the case with nano-sized particles mainly because of the strong viscosity of the nanofuel. This result was justified by the augmented average chamber pressure of the micro-sized paraffin fuel. Generally, the characteristic velocity of the microfuel was greater than that of the nanofuel for the overall range of the oxidizer-to-fuel ratio considered in this study. This difference became pronounced as the oxidizer mass flux increased. The characteristic velocity efficiency of the two blended fuels (microfuel and nanofuel) merely showed a notable difference in the oxidizer-to-fuel ratio range, except for the particle-free base fuel, which showed a wide scatter of combustion efficiency probably because of its low melt layer viscosity, which leads to an undesirable high entrainment of non-combusted pure paraffin fuel.

In vivo temperature-sensitive drug release system trigged by cooling using low-melting-point microcrystalline wax

Temperature-sensitive formulations are attractive controlled-release formulations, which release an incorporated drug by changes in body temperature induced by external temperature stimulation. Recently, it has been reported that wax matrix (WM) particles composed of a low-melting-point microcrystalline wax (MCW) released only a small amount of the drug at 37 °C, whereas faster drug release occurred at 25 °C. In this study, temperature-sensitive formulations composed of low-melting-point MCW that release drugs triggered by cooling, rather than heating, were developed. In an in vitro dissolution test in which the test medium was repeatedly cooled from 37 to 25 °C, control of the promotion and suppression of drug release was achieved. The drug concentration in the plasma of rats administered the particles was significantly increased by cooling compared with non-cooling, indicating that the drug release from the particles was promoted by cooling both in vitro and in vivo. Therefore, particles composed of low-melting-point MCW should be useful for the development of cooling-triggered, temperature-sensitive formulations.

Influence of thermal history on the intermediate and low-temperature reversible aging properties of asphalt binders

This paper aims to investigate the influence of thermal history on the intermediate and low-temperature characterisation of asphalt binders. First, various asphalt binder intermediate and low-temperature characterisation methods and the significance of thermal history on asphalt characterisation were reviewed. Second, regular Superpave performance grading (PG) test, extended bending beam rheometer (Ex-BBR) test, double edge-notched tension (DENT) test and torsion bar low-temperature frequency sweep test were performed on selected asphalt samples with different treated thermal history. In addition, black space diagrams were also drawn to show the phase separation properties of varying asphalt binder formulations. The results showed that grade loss of wax-based warm mix asphalt almost kept constant when a small amount of microcrystalline wax (1% by mass of binder) was added. However, grade loss increased obviously with adding more microcrystalline wax (higher than 2%). Prolonged isothermal conditioning had a different degree of influence on the small-strain rheological and large-strain damage properties of asphalt binder. Applying slower loading frequency in dynamic shear rheometer (DSR) caused more obvious decrease in phase angle due to prolonged conditioning time.

Mechanism of Drug Release From Temperature-Sensitive Formulations Composed of Low-Melting-Point Microcrystalline Wax

It was reported that wax matrix (WM) particles composed of low-melting-point microcrystalline wax showed unique release behaviors; the particles released only a small amount of the entrapped drug (non–diffusion-controlled release) at 37°C, whereas it showed comparatively fast drug release in a diffusion-controlled manner at 25°C. However, the mechanism of the drug release is still unclear. The objective of this study was to determine the mechanism of drug release from the WM particles using X-ray computed tomography. In the WM particles collected during dissolution tests at 25°C, the void space derived from drug release increased with increasing time, and there was no change in the structure, indicating that the WM particles released drug while maintaining the particle shape at 25°C. In the WM particles collected during dissolution tests at 37°C, the void space was confirmed at initial time point; however, at subsequent time points, the void space was disappeared, and the roughness of the surface was evident. This structural change may have blocked the conveyance pathway of the outer medium, which would inhibit the drug release. The difference between the drug-release mechanisms of the WM particles at the 2 temperatures will be valuable for developing cooling-triggered, temperature-sensitive formulations.

Thixotropic properties of multi-functional binder and compaction behaviour of the low alloyed binder-treated powder

ABSTRACTA new multi-functional binder with adhesive and lubricant effect was designed, and the thixotropic properties of the binder components and the resulting binder, the adhesive effect and compaction behaviour of the binder-treated powder were investigated. The results demonstrate that the thixotropic components in the binder are polyethylene wax and microcrystalline wax. With the increase of polyethylene wax content, the critical solid–liquid shear stress of binders decreases gradually. The main lubrication components in the low-pressure and high-pressure stages during the compaction process are found to be polyethylene wax and microcrystalline wax, respectively. The fine metal or graphite additives are effectively bonded on the surface of iron particles and filled in the pits. The green density reaches 7.25 g cm−3 at 600 MPa when the content of polyethylene wax is 30%. From 400 to 750 MPa, the content of polyethylene wax corresponding to the minimum ejection pressure decreases from 20 to 0%.

Viscoelastic and adhesion properties of hot-melts made with blends of ethylene-co-n-butyl acrylate (EBA) and ethylene-co-vinyl acetate (EVA) copolymers

Several hot-melts (HMAs) were prepared by using blends of ethylene-co-n-butyl acrylate (EBA) and ethylene-co-vinyl acetate (EVA) copolymers - EBA/EVA. HMAs were prepared with mixtures of EVA copolymers with 18 (EVA18) and 27 (EVA27) wt% vinyl acetate contents and EBA copolymer with 27 wt% n-butyl acrylate, polyterpene resin and mixture of microcrystalline and Fischer-Tropsch waxes. HMAs made with EBA/EVA blends showed lower viscosities and reduced shear thinning than the ones made with EBA or EVA due to differences in compatibility, but both the set time and the open time were not affected as they depended mainly on the wax nature and amount. The increase of the vinyl acetate (VA) content in EVA copolymer reduced the crystallinity of the EBA/EVA blends. Even EBA copolymer was more compatible with EVA27 than with EVA18 (the α- and β-transitions shown in DMTA plots were closer) and the compatibility did not vary with the EBA content in the blends. The addition of polyterpene resin and the mixture of waxes decreased the compatibility of the EBA/EVA blends, the higher compatibility was observed for the HMAs made with only one copolymer. The tack of the HMAs depended on their EBA/EVA contents, EBA/EVA27 HMAs showed broader temperature interval with higher tack, while the tack of EBA/EVA18 HMAs blend decreased and the temperature interval with tack was shortened and shifted to lower temperatures. Adhesion to polypropylene film was improved in HMAs made with 75 wt% EBA/25 wt% EVA18 and 50–75 wt% EBA/50-25 wt% EVA27. The adhesion to aluminum film of EBA or EVA hot melts was improved only in the joints made with EBA/EVA 27 HMAs, more noticeably when they contained higher EBA content.

Alkenones as a Promising Green Alternative for Waxes in Cosmetics and Personal Care Products

The move toward green, sustainable, natural products has been growing in the cosmetic and personal care industry. Ingredients derived from marine organisms and algae are present in many cosmetic products. In this study, a new green ingredient, a wax (i.e., long-chain alkenones) derived from Isochyrsis sp., was evaluated as an alternative for cosmetic waxes. First, the melting point was determined (71.1–77.4 °C), then the alkenones’ thickening capability in five emollients was evaluated and compared to microcrystalline wax and ozokerite. Alkenones were compatible with three emollients and thickened the emollients similarly to the other waxes. Then, lipsticks and lip balms were formulated with and without alkenones. All products remained stable at room temperature for 10 weeks. Lipstick formulated with alkenones was the most resistant to high temperature. Finally, alkenones were compared to three cosmetic thickening waxes in creams. Viscosity, rheology, and stability of the creams were evaluated. All creams had a gel-like behavior. Both viscosity and storage modulus increased in the same order: cream with alkenones &lt; cetyl alcohol &lt; stearic acid &lt; glyceryl monostearate. Overall, alkenones’ performance was comparable to the other three waxes. Alkenones can thus offer a potential green choice as a new cosmetic structuring agent.

Experimentation of a novel composite phase change material for thermal comfort improvement and energy saving in buildings

This study focuses on the preparation of a novel composite phase change material (PCM) for an application of Latent Heat Thermal Energy Storage in buildings. The aim of this application is to improve thermal inertia in buildings. A good thermal inertia, involves the improvement of thermal comfort and energy saving. The experimented materials’ components are selected for their availability, safety and low cost. Paraffin with a melting temperature range close to 30°C is selected as a PCM; it is composed of microcrystalline wax and liquid paraffin. The matrix is prepared from plaster, graphite powder and cellulose fibers. The PCM is introduced in the matrix following the immersion method. Several samples are prepared; there after they are subjected to a thermal treatment at 50°C for 30 min on a filter paper. The purpose is to identify the performance of each sample to retain the PCM without leakages. Thermal and physicochemical characterizations are performed to study the composites’ properties: Scanning Electron Microscopy (SEM) is used to observe its microstructure; X-Ray Diffraction (XRD) identifies the crystallographic structure of the composite-PCM while Fourier Transformed Infrared Spectroscopy (FT-IR) reveals the chemical compatibility between its different components. Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) are performed for thermal characterization. The thermal performance of the composite-PCM is verified experimentally using thermocouple measurements connected to a temperature recorder apparatus. The measurements are done simultaneously on two pellets; the first contains PCM while the second does not contain PCM.

Experimentation of a novel composite phase change material for thermal comfort improvement and energy saving in buildings

This study focuses on the preparation of a novel composite phase change material (PCM) for an application of Latent Heat Thermal Energy Storage in buildings. The aim of this application is to improve thermal inertia in buildings. A good thermal inertia, involves the improvement of thermal comfort and energy saving. The experimented materials’ components are selected for their availability, safety and low cost. Paraffin with a melting temperature range close to 30°C is selected as a PCM; it is composed of microcrystalline wax and liquid paraffin. The matrix is prepared from plaster, graphite powder and cellulose fibers. The PCM is introduced in the matrix following the immersion method. Several samples are prepared; there after they are subjected to a thermal treatment at 50°C for 30 min on a filter paper. The purpose is to identify the performance of each sample to retain the PCM without leakages.&#x0D; Thermal and physicochemical characterizations are performed to study the composites’ properties: Scanning Electron Microscopy (SEM) is used to observe its microstructure; X-Ray Diffraction (XRD) identifies the crystallographic structure of the composite-PCM while Fourier Transformed Infrared Spectroscopy (FT-IR) reveals the chemical compatibility between its different components. Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) are performed for thermal characterization. The thermal performance of the composite-PCM is verified experimentally using thermocouple measurements connected to a temperature recorder apparatus. The measurements are done simultaneously on two pellets; the first contains PCM while the second does not contain PCM.

Application of coatings on silver studied with punctual and imaging techniques: from specimens to real cases

The protection of silver artifacts with a coating of organic material isolating the surface from oxygen and S-bearing gases is still one of the most used techniques for the preservation of silver surfaces. A variety of materials suitable to this purpose are being used in the conservation practice. Among them there are acrylic polymers, nitrocellulose lacquer, microcrystalline wax and combination of them in superimposing layers. They are applied either by brush or, in some cases, by spraying. The first stage in a conservation project is often the cleaning of residuals of old protectives, aimed at making the silver surface free from remnants of yellowish materials and enabling the application of new coatings. Unfortunately, removing aged coatings and applying new ones are “blind” processes, since the techniques available for not invasively monitoring the surface of silver artifacts are punctual and do not allow an overall overview of the surface. This is the case of reflectance FTIR and thickness measurement with the Eddy Current technique, which, apart from being punctual, are tricky to apply to uneven surfaces. In this paper, we aim to show the benefits of using an imaging technique, UV induced VIS luminescence, for monitoring the presence and the distribution of protective coatings on silver surfaces and of combining it with reflectance FTIR and thickness gauge. At first, our study was focused on specimens treated with nitrocellulose, acrylic emulsion and microcrystalline wax. The application of the treatments was studied with UV-induced VIS luminescence as well as with the abovementioned punctual techniques to cross-validate the outcome of each method and to assess their suitability for application on organic protective layers on silver artifacts. In a further stage, UV induced VIS luminescence was applied to a real case, a silver chalice that was treated with nitrocellulose lacquer after cleaning.

Influence of Microcrystalline Wax on the Properties of Model Wax-Oil Gels

The influence of microcrystalline wax addition upon the rheological properties of model wax-oil gels is investigated. Addition of less than 1 wt % microcrystalline wax to a model oil consisting of 5 wt % macrocrystalline wax in dodecane shows no significant impact on the WAT and gelation temperature. Beyond 1 wt % added microcrystalline wax, increases in WAT and gelation temperature are observed and are attributable to the higher crystallization temperature of the microcrystalline wax. The effect of microcrystalline wax addition upon the WAT and gelation temperature is shown to be attributed to merely overlapping compositions of macro- and microcrystalline wax. However, a substantive effect of microcrystalline wax addition is observed on the yield stress. Addition of 0.13 wt % microcrystalline wax reduces the yield stress of the waxy oil model from 238.0 to 22.5 Pa. Addition of 0.5 wt % microcrystalline wax decreases the yield stress to 5.4 Pa, which is close in value to the yield stress of neat 5 wt % mi...

The Occurrence of Paraffin and Other Petroleum Waxes in the Marine Environment: A Review of the Current Legislative Framework and Shipping Operational Practices

Among the various materials that make up marine debris, lumps of petroleum waxes such as paraffin and microcrystalline wax, are regularly found on beaches worldwide, although not included in the current definition of marine litter. Ingestion by marine organisms is occasionally documented in the scientific literature and mass beaching events are frequently reported along the European coasts, with obvious detrimental consequences to the local communities that have to manage the clean-up and disposal of this substance. According to Annex II of the MARPOL regulation, petroleum waxes are classified as “high viscosity, solidifying and persistent floating products”, whose discharge at sea of tank-washing residues is strictly regulated, but currently permitted within certain limits. Starting from the description of a large stranding event occurred along the Italian coasts in 2017, we review the existing knowledge and regulatory framework and urge the relevant authorities to address this issue, showing that wax pollution is creating evident damages to the European coastal municipalities. Pending further investigations on the potential hazard that this kind of pollution is posing to marine ecosystems, we suggest a careful and more stringent revision of the policies regulating discharges of these products at sea.