Ethylene Glycol Distearate Research Articles

Controlling Temporally and Spatially Homogeneous Temperature Distribution of Paper Substrates by Biogenic Phase Change Hybrid Material Coatings

AbstractHere the performance of phase change material (PCM)‐coated paper made from unbleached kraft pulp is introduced. The applied PCM consists of a mixture of ethylene glycol distearate (EGDS), a well‐known PCM wax material, and a fully substituted cellulose stearoyl ester (CSE). Transfer of the PCM material onto/into paper is achieved by spray as well as blade coating of EGDS + CSE mixture. It is shown that the kind of coating method used does not interfere with observed PCM properties. The significantly higher melt viscosity of the EGDS + CSE blends ensures that the EGDS wax is not bleeding out of the paper, which avoids the use of further encapsulation processes. The PCM behavior, as observed by thermal load measurements, and the thermal buffering of the coated paper is a function of the applied mass of the PCM material applied. The thermal retention exhibited a quasi‐isothermal behavior at ≈65 °C with EGDS + CSE coatings. These effects can offset fluctuations in temperature, and the PCM papers can be employed to achieve a more uniform temperature setting. PCM‐modified papers are therefore interesting candidates for paper‐based packaging or for use in paper‐based sensors, where overheating can strongly affect reliability of results.

Dermal exposure to synthetic musks: Human health risk assessment, mechanism, and control strategy

Synthetic musks (SMs) have been widely used as odor additives in personal care products (PCPs). Dermal exposure to SMs is the main pathway of the accumulation of these chemicals in human kerateins and poses potential health risks. In this study, in silico methods were established to reduce the human health risk of SMs from dermal exposure by investigating the risk mechanisms, designing lower bioaccumulation ability SMs and suggesting proper PCP ingredients using molecular docking, molecular dynamics simulation, and quantitative structure-activity relationship (QSAR) models. The binding energy, a parameter reflecting the binding ability of SMs and human keratin protein (4ZRY), was used as the indicator to assess the human health risk of SMs. According to the mechanism analysis, total energy was found as the most influential molecular structural feature influencing the bioaccumulation ability of a SM, and as one of the main factors influencing the function (i.e., odor sensitivity) of an SM. The 3D-QSAR models were constructed to control the human health risk of SMs by designing lower-risk SMs derivatives. The phantolide (PHAN)− 58 was determined to be the optimum SM derivative with lower bioaccumulation ability (reduced 17.25%) and improved odor sensitivity (increased 7.91%). A further reduction of bioaccumulation ability of PHAN-58 was found when adding proper body wash ingredients (i.e., alkyl ethoxylate sulfate (AES), dimethyloldimethyl (DMDM), EDTA-Na4, ethylene glycol distearate (EGDS), hydroxyethyl cellulose (HEC), lemon yellow and octyl glucose), leading to a significant reduction of the bioaccumulation ability (42.27%) compared with that of PHAN. Results demonstrated that the proposed theoretical mechanism and control strategies could effectively reduce the human health risk of SMs from dermal exposure.

Solvent-free esterification of stearic acid and ethylene glycol with heterogeneous catalysis in a stirred batch microwave reactor

Ethylene glycol distearate (EGDS) is extensively used in the pharmaceutical and cosmetics industries. Even in textile industries as a softener, EGDS is in demand. In this paper, synthesis of EGDS by esterification of ethylene glycol and stearic acid has been described using a solid acid catalyst under microwave (MW) irradiation in a solvent-free system. Conventional heating takes more than 4–6 h to give a mixture of EGDS and ethylene glycol monostearate (EGMS). Under MW irradiation, the highest conversion of 97% of the acid was obtained in 10 min. The reaction mixture was analyzed by acid value, FT-IR, 1H-NMR and mass spectroscopy. The EGDS synthesis was optimized concerning various parameters such as reaction time, different catalysts, catalyst loading (wt/wt%), temperature, and MW power. Heterogeneous catalysis, intensified with MW irradiation, makes the esterification process more promising route for possible application at industrial scale.

Preparation and thermal properties of encapsulated ceramsite-supported phase change materials used in asphalt pavements

Two kinds of phase change materials (PCMs), poly(ethylene glycol) (PEG) and ethylene glycol distearate (EGD), were incorporated with ceramsite (CS) to obtain the composite PCMs (CPCMs) by vacuum impregnation method. The morphology of the samples was observed using scanning electron microscope (SEM) and the chemical compatibility was characterized by X-ray diffraction (XRD) and Fourier transformation infrared (FTIR). The PEG and EGD could be retained by 42.1 wt% and 34.0 wt% into pores of the CS, which was calculated according to the curves of the thermogravimetric (TG) analysis. The thermal properties and thermal reliability of the CPCMs were investigated via differential scanning calorimetry (DSC). The phase change temperature (Tm) and heat of fusion (ΔHm) of prepared CPCMs are in the range of 54–60 °C and 29–50 J/g, respectively. The ΔHm of the CPCMs decreased obviously after 100 melting/freezing cycling, which was improved by encapsulating the prepared CPCMs with novolac epoxy resins (NER) to produce the encapsulated CPCMs (E-CPCMs). The results of the leakage experiment and storage/release test also show that the E-CPCMs have good thermal exudation stability and thermal storage/release properties. Based on all the results of the experiment, the encapsulated PEG/CS composite (E-PEG/CS) was added into the asphalt mixture to substitute the corresponding aggregate for simulating the actual temperature-adjusting effects. The results indicate that the maximum temperature reduction of the upper surface reaches about 9.1 °C at 210 min. Therefore, the E-CPCMs have the potential to decrease the high temperatures and temperature fluctuations in the asphalt pavements.

Crystallization Behavior and Nucleation Kinetics of Organic Melt Droplets in a Microfluidic Device

The powerful technique of microfluidics is applied for the first time to investigate the crystallization behavior and nucleation kinetics of monodisperse organic melt droplets in the range of a few nanoliters. Multiple characteristic time scales in the fraction of (un)crystallized droplets are found. We interpret these findings regarding mechanisms discussed in microfluidics or oil-in-water emulsions and with the help of inverse Laplace transformation. Heterogeneous active centers, for example, various catalytic impurities, cause fast nucleation in multiple droplet populations with different rates. The nucleation of the remaining droplets in the later stage of the experiment is dominated by only one, slower nucleation rate. The related mechanism is most likely surfactant-driven heterogeneous nucleation at the surface or in the droplet volume. Homogeneous nucleation is excluded at this droplet size and the supercooling values examined. Hexadecane (C16) and ethylene glycol distearate (EGDS) are used as exem...

A Generic Polycarbonate Based Microfluidic Tool to Study Crystal Nucleation in Microdroplets

Crystal nucleation is important to control the product properties in industrial crystallization processes. To investigate crystallization phenomena, methods which rely on microscopic volumes have gained relevance over the last decade. Microfluidic devices are suitable for carrying out crystallization experiments based on a large set of individual droplets in the nanoliter range. In this work, we propose a simple method to manufacture such devices from polycarbonate as an alternative to conventional chips made of poly (dimethylsiloxane). The microfluidic device consists of two main functional parts: A T-junction for droplet generation and a section for storage and observation of up to 400 individual droplets. Using these manufactured devices, it is easy to produce and store highly monodisperse droplets of substances that require either a hydrophilic or hydrophobic surface of the microchannel. Since crystal nucleation is a stochastic process which depends on the sample volume, a reproducible droplet volume is of great importance for crystallization experiments. The versatile applicability of the manufactured devices is demonstrated for substances which are used in different crystallization applications, for example, solution crystallization (aqueous potassium nitrate solution) and melt crystallization (ethylene glycol distearate). Finally, we demonstrate that the manufactured microfluidic devices in our experimental setup can be used to conduct crystal nucleation measurements. Based on these measurements we discuss our results with respect to state-of-the-art nucleation models.

Negative Synergistic Effect on Foaming in Body Care Products with Silicone Oil and the Needle-Like Crystal of Ethylene Glycol Distearate

The foaming capability, which is related to the ratio of surfactants, the dosage and the crystallization rate of ethylene glycol distearate (EGDS), is discussed. By the same progress, with the proportion of ammonium lauryl sulfate (AESA) being increased, the foam height of the body care product is linearly improved. The crystal features of EGDS and pearlescence quality of the body care products are strongly linked to the surface aspect, the size distribution of EGDS crystals and their level of aggregation. Comparing the different crystallization processes, when rapidly being cooled with cold water and stirred at the speed of exceeding to 1 000 rpm, the aggregation of the crystals is decreased, and the pearlescence of the body care product is poor. When being ordinary cooled at room temperature and stirred at the speed of no more than 500 rpm, the aggregation of the crystals is increased, and the pearlescence of the body care products is obvious. The microstructures reveal that the oil drops are pierced to smaller by the EGDS needle crystals. Then the smaller oils act as antifoaming agents to cut down the foam height of the body care product. Consequently, the foam height of the body care products with good pearlescent effect is decreased. Furthermore, being added silicone oil emulsion, the foam height falls faster because of demulsifying. The result shows that the silicone oil and the needle-like crystals have a negative synergistic effect on foaming in the body care products.

Investigation of Discrete Population Balance Models and Breakage Kernels for Dilute Emulsification Systems

A novel in situ video probe with automated image analysis was used to develop a population balance model for a breakage-dominated liquidliquid emulsification system. Experiments were performed in a 2 L tank, agitated by an axial flow propeller. The dispersed phase (ethylene glycol distearate) concentration was varied from 0.2 to 1.0% (w/w), and agitation rates werevariedfrom0.2to0.5W/kg,inthepresenceofexcesssurfactant.Threenumericaldiscretizationmethodswerecompared: fixed pivot, cell average, and finite volumes. The latter was then chosen for the subsequent simulations due to its rapidity and higher precision. An investigation of the different theories for bubble/droplet breakage was done and the frequencies (or breakage rate kernels) were compared. Four models were found applicable: the models developed by Coulaloglou and Tavlarides (Coulaloglou, C.A.; Tavlarides,L. L.Chem. Eng. Sci.1977,32,1289);Sathyagal and Ramkrishna (Sathyagal,A. N.; Ramkrishna, D.Chem. Eng. Sci. 1996,51,1377);Alopaeus,Koskinen,andKeskinen(Alopaeus,V.;Koskinen,J.;Keskinen,K.I.Chem.Eng.Sci.1999,54,5887);and BaldygaandPodgorska(Baldyga,J.;Podgorska,W.Can.J.Chem.Eng.1998,76,456).TheonebySathygalandRamkrishnaincluded thedaughtersizedistribution.Alog-normaldaughtersizedistributionwaschosenforthemodelsbyCoulaloglouandTavlaridesand Alopeus et al. Also, a normal distribution was used in the model by Baldyga and Podgorska. These models were compared with the experimental data to allow parameter identification. The model by Baldyga and Podgorska was found to give the best prediction of the shape of the distribution, its mean diameter, and standard deviation.

Effects of surfactants on crystallization of ethylene glycol distearate in oil-in-water emulsion

Ethylene glycol distearate (EGDS) was forced to crystallize as thin platelet in order to obtain a pearlescent effect. This was possible by performing a cooling surface crystallization in oil-in-water emulsion with the presence of an emulsifier. Under stagnant conditions, nucleation events and growth of faceted crystals in the oil phase were in situ monitored under microscope. After a first primary nucleation of dendritic crystals, a second population of faceted crystals arose by secondary nucleation and seemed to be the prevailing population. In a stirred vessel, the platelet shape of EGDS crystals was driven by the surfactant choice. Only a non-ionic surfactant, located at the liquid interface was supposed to interact with EGDS during the development of the crystals favouring a platelet habit. The nature of the interaction was not yet established. Moreover, the mastery of the platelet shape was lost when the amount of non-ionic surfactant relatively to the EGDS was decreased. This underlined the importance of the non-ionic surfactant for the obtaining of desired shape. The different physical qualities of crystals produced allowed us to confirm relationships between EGDS particle features with their effect of pearlescence of a cold pearl blend.

Steric Attraction: The Far Side

The concept of steric attractions is discussed in terms of the individual contributions of repulsive and attractive terms. Examples are given in which the attractive term dominates in the equilibrium distributions of conformers, the "more crowded" confromer is lower in energy. A molecular mechanics experiment is described that emphasizes the importance of steric attractive forces in defining the steric energy of two conformations, extended vs folded, of of ethylene glycol distearate.

Reaction of ethylene oxide or propylene oxide with long‐chain fatty acids. Mono‐ and diester formation

SummaryThe alkali‐catalyzed reaction of ethylene oxide or propylene oxide with fatty acids was shown to be complex. Mono‐ and diesters were formed in comparable amounts even at an early stage when only about one equivalent of the cyclic ether had been condensed.The following compounds were isolated in a pure state: ethylene glycol monolaurate, ethylene glycol dilaurate, diethylene glycol dilaurate, ethylene glycol distearate, 1,2‐propylene glycol dilaurate, and 1,2‐propylene glycol distearate. A monoester from propylene oxide was shown to be a mixture of the 1‐and 2‐monolaurate [C11H23CO2CH2CHOHCH3 and C11H23CO2CH(CH3)CH2OH].