Dioctyl Sebacate Research Articles

Understanding the alkyl effect of geminal dinitropropyl ester energetic plasticizers on hydroxyl terminated polybutadiene (HTPB): Simultaneous tuning on low temperature behavior and processability

Geminal dinitropropyl ester plasticizers (DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane chain parts, and systematically investigate their structure-property relationships. Results show that DNPEPs have impact sensitivities all higher than 25.2 J, thermal decomposition temperatures all higher than 254 °C, and glass transition temperatures ( T g ) lower than −90 °C. Furthermore, the effects of DNPEPs as plasticizer are studied on hydroxyl terminated polybutadiene (HTPB) in detail, including the viscosity, glass transition temperatures and others. It is noteworthy that 2,2-dinitropropyl nonanoate (DNPNc) among these DNPEPs exhibits the most expected simultaneous tuning effects on both viscosity and T g of HTPB systems, providing favorable potentials to replace the conventional plastizers as dioctyl sebacate (DOS) in the HTPB based propellants and explosives.

A Comparison of the High-Pressure Viscometry and Optical Inference Methods Used to Determine the Pressure-Viscosity Coefficient

Abstract Pressure-viscosity coefficients (PVC) are used in the predictions of elastohydrodynamic lubricated (EHL) componentry. These coefficients are obtained by either viscometry or optical EHL inference. The literature indicates that each method differs in its conclusion. Those who favor viscometry believe optical methods yield a misleading coefficient. Those who favor optical methods suggest low shear viscometric results over-predict the high shear-influenced film thickness. This work compares each method relative to di-(ethylhexyl) sebacate (DEHS), and five MIL and DOD spec lubricants. PVC results from viscometry and two optical methods are presented. Comparisons are made relative to other published measurements. Conclusions show PVCs inferred from optical film thickness measurements, differ from those obtained by viscometry. Viscometry methods are demonstrated as being consistent. Optically inferred results have uncertainty and require ample data to align with classical dimensionless speed exponents. While the optical measurements are truly EHL, the test conditions fall outside the fitted window of classical algebraic film equations, like that of Hamrock and Dowson. The PVC discrepancies, between optical inference and viscometry and for the studied fluids, cannot be explained by the proper account of the refractive index, shear thinning models, and/or film thickness correction models.

Ion-Selective Electrodes for the Determination of Periodate IO4- Using Periodate - Tetrazolium Chloride (TTC) as an Ion-Pair and its Applications

Poly (vinyl chloride) (PVC) membrane-based of 2, 3, 5 –Triphenyltetrazolium Chloride (TTC)- KIO4 with sodium tetraphenylborate (NaTPB) as an anion excluder and dioctylphthalate (DOP) and dioctylsebacate (DOS) as plasticizer were prepared and studied as a KIO4– selective electrode. The best performance was observed with the membrane having the ligand (TTC KIO4 – PVC – plasticizer (DOP) – NaTPB (sodium tetraphenylborate) composition 5: 100: 200: 5mg, respectively, which worked well over a wide concentration range (1.5×10−6 M – 1.0×10−1M) with a Nernstian slope of 50–55.0 mV per decade of activity between pH 3 and 10.0. These electrodes showed a fast response time of 5 – 15 s and were used over a period of 90 dyes with good reproducibility. The selectivity coefficient for monovalent and divalent anions indicated excellent selectivity for IO4- ions over a large number of anions. The sensor has been used to determine IO4- ions from Ojela and Jalu/ Libyan water wells and wastewater.

Preparation and anti‐migration performance of ethylene propylene diene terpolymer composites modified with GO‐SiO2 hybrid nanomaterials

AbstractThe anti‐migration ethylene propylene diene terpolymer (EPDM) inhibitor coating was prepared by using EPDM as a composite matrix and silicon‐functionalized graphene oxide (GO‐SiO2) as modifiers to prevent the migration of energetic plasticizers in propellants. The anti‐migration performance at different temperatures was analyzed by investigating the diffusion of dioctyl sebacate (DOS) using thermal analysis and immersion tests. After adding 1.0 wt% GO‐SiO2, the overall performance of the inhibitor coating was the best, and the concentration of DOS that migrated into the inhibitor coating at 30°C was reduced from 45.1% to 38.8% (13.9% decrease). The results confirmed that the introduction of GO‐SiO2 prevented the migration of dioctyl sebacate to the EPDM inhibitor coating. The scanning electron microscopy results showed that GO‐SiO2 was well‐dispersed in the inhibitor coating, and the tensile strength increased from 1.80 to 2.11 MPa. Migration kinetics analysis showed that the anti‐migration performance was closely related to the crosslink density.

In situ optical sensor for aerosol ovality and size

Sensors for in situ detection of aerosols using conventional optical scattering methods generally fail to identify the types and sources of particles, and they even have a large discrepancy in particle size measurements because the particles are overly simplistically assumed to be spherical. To address this issue, we investigate the effects of particle shape on light-scattering patterns and develop a portable sensor that can simultaneously determine the particle shape and size. To describe all particles, particularly irregular particles with a generalization parameter, we define ovality to represent the properties of particle shape, which is a distinctive feature related to particle type and source. Furthermore, we analyze the multi-angle light-scattering patterns that vary for particles of different shapes and sizes. On this basis, a sensing method is proposed to simultaneously determine the ovality and size of particles by jointly assessing the light-scattering pattern features. Finally, an 8-channel sensor is developed and tested with di-ethyl-hexyl-sebacate (DEHS) aerosol, Duke particles, and N-Heptane combustion smoke. The DEHS aerosols are used for the calibration of our sensor. The average error of the shape and size of Duke particles determined by the experimental measurements of our sensor is 4.01 %. The measurement error of N-Heptane compared to an ellipsoid with an ovality of 15:1 is 5.84 %. The experimental results show that our sensor has the potential to measure the properties of particle shape to identify the types and formation mechanisms of aerosols. • The effects of particle shape on light-scattering patterns are investigated. • The conventional calculation algorithm is improved according to the geometric properties of the shape determined by our sensing method, for combustion smoke and other examples that deviate greatly from the spherical shape. • A portable sensor that can simultaneously determine the particle properties and size is developed. • Extensive experiments are repeated for proving that the developed sensor is highly portable and suitable for aerosol measurement.

Preparation and Properties of Spherical CL-20 Composites.

Micrometer-sized spherical composites based on 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) with fluororubber (F2604), dioctyl sebacate (DOS), and polyvinyl butyral (PVB) were prepared by an electrospray method. After preparation, the morphology, chemical bonds, thermal decomposition properties, mechanical sensitivity, and explosion performance were characterized. The main explosive CL-20 transformed from ε-CL-20 to β-CL-20 after electrospray preparation. With an insensitive additive mass ratio of 5 wt %, the CL-20/F2604 composite had the highest maximum peak exothermic temperature and the lowest mechanical sensitivity. The explosion pressures of the composites with the same mass ratio of additives decreased in the order CL-20/F2604 > CL-20/PVB > CL-20/DOS and were lower than that of raw CL-20.

Investigation of the Possibility of Application of Metal Fibrous Media in the Process of Filtration of Liquid Aerosols

This manuscript presents a study of the possibility of applying metallic fibre filter media made of stainless steel for the filtration process of liquid aerosols. To perform the experiment, three types of filters were used: single layer and symmetric or non-symmetric multi-layered filters. Filters have been loaded with DEHS (Di-Ethyl-Hexyl-Sebacate) aerosol while the pressure drop and the collection efficiency were monitored. The impact of the filtration velocity on the saturation pressure drop has been quantified for monolayer filters. The building of a draining film on the free surface of the multi-layered filters has been studied and the impact of this phenomenon on the filtration performances and saturation ratio of the medium are discussed. For multilayer filters, the clogging dynamic, occurring by a successive loading of the draining layers, is highlighted in this work. Finally, propositions are made to evaluate the behaviour of metallic multi-layered filters for liquid aerosol filtration applications.

A Proposed Pressure–Viscosity Coefficient Model Through Processing of Falling Body Viscometry Data for Di-(Ethylhexyl) Sebacate

Abstract The relative volume and falling body viscosity of a common high-pressure rheology reference lubricant, di-(2-ethylhexyl) sebacate (DEHS), are presented. Relative volume measurements up to 300 MPa are completed with a piezo-bellows relative volume cartridge. Viscosity measurements up to 1 GPa are completed with a pressurized falling body viscometer. Digital signal-processing routines used for viscosity and relative volume measurements are discussed. The viscosity data are then fit into the modified Yasutomi model. Integration of this fit, as well as that of other models found in the literature, is used to propose a pressure–viscosity coefficient model. Comparisons are first made to DEHS, followed by the application of the study results to 17 other well-documented fluids. The validity of this method is investigated using the integrated viscosity model of DEHS as well as other available datasets presented in literature. The authors perform a comparison between the calculated pressure–viscosity coefficient α* and those presented for the mentioned datasets created with the signal-processing routines. The analysis shows that the proposed pressure–viscosity coefficient model is able to accurately capture the inverse of the asymptotic isoviscous pressure response of the majority of data when compared to other calculation methods.

Effect of Humidity on the Thermal Properties of Aluminum Nanopowders with Different Surface Coatings

To investigate the effect of surface coating materials on the humidity stability of aluminum (Al) nanopowders, three kinds of core–shell structure Al nanopowders with an Al2O3 passivation coating, carbon coating, and plasticizer dioctyl sebacate (DOS) coating were prepared through laser-induction complex heating method. After one year’s storage at 95% relative humidity, their thermal properties were tested through differential scanning calorimeter (DSC) and thermal gravimeter (TG) analysis. The results show that the thermal properties of Al2O3-passivated Al nanopowders are entirely lost under high humidity because the Al2O3 passivation coating is very sensitive to moisture. The thermal properties of carbon-coated Al nanopowders are not well-protected under a high humidity due to the uneven thickness and structural defects of carbon coatings. However, the thermal enthalpy of DOS-coated Al nanopowders remains at 3.56 KJ/g under high humidity, which indicates that an organic DOS coating with a hydrophobic nature has an excellent protective effect on the thermal properties of the Al nanopowders. Given the good forming performance of organic DOS coatings and other components of propellants, DOS-coated Al nanopowders are a kind of energetic material with potential application value.

Atomic coatings effects on the combustion of aluminium hydride nanoparticles dispersed in liquid oxygen: Molecular dynamics simulation for the oxygenated environments

In the present study, the combustion of the AlH3 structures coated with various structures in a liquid oxygen environment was examined. This paper examined the combustion process (CP) of coated AlH3 nanoparticles (NPs) with changes in the number of permeated oxygen atoms into AlH3 NPs, temperature, and potential energy using the molecular dynamics (MD) approach. And the temperature and combustion time changes were investigated with two potential functions of LJ/EAM and Reaxff. The results show that temperature converges to 1097, 1117, and 1103 K for HTPB, Dioctyl sebacate, and Diethyl ether atomic coating, respectively (with LJ/EAM force field) after the CP. Also, the temperature converged to 1007 K, 1018 K, and 1012 K for HTPB, Dioctyl sebacate, and Diethyl ether, respectively, using the ReaxFF force field. Also, by adding these atomic coatings, the potential energy rates increase, and the combustion time of the simulated structure decreases. Numerically, adding the atomic coatings of HTPB, Dioctyl sebacate, and Diethyl ether, the potential energy reached −502.11, −495.21, and −529.17 eV. Among the studied atomic coatings, the simulated sample with dimethyl ether coating has the shortest combustion time (1.25 ns). Also, with the addition of Diethyl ether atomic coatings, the number of permeated oxygen atoms increases from 107 to 165. As the atomic coating is added to the primary NP, the amount of adsorbent exerted to the atoms of oxygen in the structures increases; this procedure reasons more oxygen to penetrate the overall structure of the NP. Generally, The outcomes display that adding atomic coatings to simulated structures improves combustion behaviour.

A Simple Optical Aerosol Sensing Method of Sauter Mean Diameter for Particulate Matter Monitoring.

Mass concentration is a commonly used but insufficient metric to evaluate the particulate matter (PM) exposure hazard. Recent studies have declared that small particles have more serious impacts on human health than big particles given the same mass concentration. However, state-of-the-art PM sensors cannot provide explicit information of the particle size for further analysis. In this work, we adopt Sauter mean diameter (SMD) as a key metric to reflect the particle size besides the mass concentration. To measure SMD, an effective optical sensing method and a proof-of-concept prototype sensor are proposed by using dual wavelengths technology. In the proposed method, a non-linear conversion model is developed to improve the SMD measurement accuracy for aerosol samples of different particle size distributions and reflective indices based on multiple scattering channels. In the experiment of Di-Ethyl-Hexyl-Sebacate (DEHS) aerosols, the outputs of our prototype sensor demonstrated a good agreement with existing laboratory reference instruments with maximum SMD measurement error down to 7.04%. Furthermore, the simplicity, feasibility and low-cost features of this new method present great potential for distributed PM monitoring, to support sophisticated human exposure hazard assessment.

Biocatalytic synthesis of dioctyl sebacate in toluene using an immobilised lipase

Sebacic esters have excellent lubricity, thermal stability, and biodegradability and therefore are widely used as aerospace lubricants, metal working oil, or engine oil. They are mainly produced by chemical synthesis which, however, may cause environmental pollution, its enzymatic synthesis represents a more environmentally friendly alternative. A few reports have described the synthesis of sebacic esters employing immobilised lipases, but these biocatalytic reactions were exclusively carried out in solvent-free systems and thus, could have been limited by slow reaction rates and high reaction temperatures due to poor enzyme dispersion, low substrate solubility, and high viscosity of the reaction mixture. The current study investigated the biosynthesis of dioctyl sebacate in toluene by Novozym 435, a commercial immobilised lipase. The reaction parameters were investigated using the single factor approach and an orthogonal array design. The optimal conditions obtained were as follows: 10 mL toluene, sebacic acid,1 mmol (202.25 mg); molar ratio of sebacic acid to 1-octanol, 1:3; Novozym 435, 0.03 g; 4 Å molecular sieves, 1.5 g; reaction temperature, 40 °C; reaction time, 30 h. A dioctyl sebacate conversion rate of 93% was achieved under these optimal conditions. In particular, the addition of molecular sieves to the reaction mixture markedly improved the product yield. The reaction temperature was low enough to make the operation easy and energy-efficient and therefore, well suited for large-scale production.

Cost-effective chitosan thermal bonded nonwovens serving as an anti-viral inhibitor layer in face mask

Face masks have globally been accepted as an effective protection tool to prevent viral transmission. However, most face masks are typically absent of antiviral properties. This study firstly used chitosan thermal bonded nonwovens (CS) as a functional layer to endow the face masks to inhibit virus activity. Results showed that the CS could effectively inactivate the Enterovirus 71 (EV71) that can be spread by aerosol and showed good biocompatibility toward human embryonic lung fibroblasts (HELF). Moreover, when CS was used as an additional layer of polypropylene melt-blown nonwovens (PP), the removal efficiencies of PP/CS were 97.95 ± 0.61% for dioctyl sebacate and 96.61 ± 1.73% for NaCl particles. The results suggest that CS may exert antiviral properties as a functional layer in a face mask to provide additional protection and lower the risk of secondary transmission.

A Method to Generate Experimental Aerosol with Similar Particle Size Distribution to Atmospheric Aerosol

The SARS-CoV virus spreads in the atmosphere mainly in the form of aerosols. Particle air filters are widely used in indoor heating, ventilation, and air-conditioning (HVAC) systems and filtration equipment to reduce aerosol concentration and improve indoor air quality. Requirements arise to rate filters according to their mass-based filtration efficiency. The size distribution of test aerosol greatly affects the measurement results of mass-based filtration efficiency and dust loading of filters, as well as the calibration of optical instruments for fine-particle (PM2.5) mass concentration measurement. The main objective of this study was to find a new method to generate a chemically nontoxic aerosol with a similar particle size distribution to atmospheric aerosol. We measured the size distribution of aerosols generated by DEHS (di-ethyl-hexyl-sebacate), PSL (poly-styrene latex), olive oil, and 20% sucrose solution with a collision nebulizer in a wide range of 15 nm–20 μm. Individually, none of the solutions generated particles that share a similar size distribution to atmospheric aerosol. We found that the 20% sucrose solution + olive oil mixture solution (Vss:Voo = 1:2) could be used to generate a chemically nontoxic aerosol with similar particle number/volume size distribution to the atmospheric aerosol (t-test, p < 0.05). The differences in the mass-base filtration efficiency measured by the generated aerosol and the atmospheric aerosol were smaller than 2% for MERV 7, 10, 13, and 16 rated filters. The aerosol generated by the new method also performed well in the calibration of optical-principle-based PM2.5 concentration measurement instruments. The average relative difference measured by a tapered element oscillating microbalance (TEOM) and a Dusttrak Model 8530 (calibrated by aerosol generated by the new method) was smaller than 5.8% in the real-situation measurement.

GO/HTPB composite liner for anti-migration of small molecules

Hydroxyl-terminated polybutadiene/toluene diisocyanate (HTPB/TDI) system is widely used in composite solid propellants. The migrations of plasticizers and water molecules from solid propellants and surrounding environment to the inhibitor have always been the important issues. This study focuses on the preparation, characterization and anti-migration behavior of graphene oxide (GO)/HTPB nanocomposite liner. The GO/HTPB (GH) composite liners affect the migration of small molecules through a tighter cross-linked structure and weakening function of small molecule adsorption. The anti-migration performance of the liner at different temperatures was analyzed, and the influence of the added amount of GO on the anti-migration performance and adhesion performance was also systematically studied. The overall performance of the liner is optimized when the amount of GO filler is 0.3 wt%. After adding 0.3 wt% GO, the concentration of dioctyl sebacate (DOS) migrated into the liner is decreased by 23.28%, and the concentration of water molecules is decreased by 51.89%, indicating that the introduction of GO can significantly improve the anti-migration performance of the liner. In addition, the bond strength is greatly increased from 0.25 MPa to 0.95 MPa, which meets the application requirements of the current propellant system. This research provides an important way for the preparation of structure-function synergistic anti-migration composite liners.

Evaporation model of aqueous non-spherical nanoparticle in lab scale: A theoretical approach

We present a new approach to describe the equilibrium gas-particle partitioning of volatile and semi-volatile compositions in aqueous non-spherical nanoparticles. An evaporation model was derived from a theoretical analysis of composition, morphology, size, and continuous diffusion of aerosol particles. The mass transfer process from particle-phase into gas phase caused a change of phases. This model depicts the evaporation rate resulting from the change in the equilibrium state of the system in a thermal medium. The morphology dependence resulted in a noticeable change in particle mass concentration and size. The model was validated using Sodium Chloride particles coated with di-2-ethylhexyl-sebacate (DEHS). The model was evaluated using the results of direct measurement.

The mechanism of formation of boundary lubricating films during friction in a medium of di(2-ethylhexyl) sebacate

In this work, the mechanism of formation of boundary lubricating films during friction in synthetic oil di(2-ethylhexyl) sebacate (DEHS) was studied. The study of the kinetics of the interaction of DEHS with the metal surface showed that the formation of the boundary film proceeds in the first 40 s of friction. The unoxidized iron detected by the XPS method on the friction track accelerates the chemical transformations of lubricant molecules. Removing the oxide film from the friction surface is a mechanically activated process. When DEHS interacts with the iron surface, the reactions of decarboxylation of molecules proceed, as a result free radicals are formed. The sequence of transformations of free radicals and compounds with CC bonds leads to the formation of surface films upon friction. The retention of the film on the surface occurs due to the forces of interaction of the metal with free radicals or unsaturated bonds of organic molecules.

Formation of boundary lubricating films during friction in synthetic oil modified with naphthalene derivatives

The influence of additives of naphthalene derivatives on the formation of boundary lubricating layers during friction in a dioctyl sebacate synthetic oil is considered. It is determined, that the activity of the additives is determined by the presence of acidic groups in their molecules and the ability to form complex compounds with metals. Keywords: boundary film, dioctyl sebacate, naphthalene derivatives, complex formation, lubricating properties alekc_sap@mail.ru

STUDY OF THE EFFECT OF DIOCTYL SEBACATE ON THE PROPERTIES OF EPICHLOROHYDRIN RUBBERS

The effect of different technologies for the introduction of a plasticizer - dioctyl sebacate on the properties of rubbers based on epichlorohydrin rubber of the Hydrin T-6000 brand was investigated. When using the technology of rubber swelling in a plasticizer, dioctyl sebacate exhibits a shielding effect, reducing the interaction of the filler-polymer, which leads to an improvement in low-temperature properties and a deterioration in the physical and mechanical properties of the material.

Collection and decomposition of oil mist via corona discharge and surface dielectric barrier discharge

Oil mist emitted during cooking is one of the major sources of atmospheric particulate matter in urban areas. A conventional electrostatic precipitator (ESP) is used in some large restaurants; it requires regular electrode cleaning to maintain particle collection performance. However, oil mist generated during cooking is viscous and difficult to clean with water. Herein, we introduce a methodology and a device for cleaning collected oil mist using surface dielectric barrier discharge (surface-DBD) plasma. Our device uses corona discharge for the collection of oil mist. Subsequently, the oil mist collected is decomposed to gas-phase species by surface-DBD plasma. A maximum collection efficiency of 93.25% (for 230 nm di-ethyl hexyl sebacate (DEHS) particle) is obtained at a flow velocity of 1.5 m/s. The maximum oil mist decomposition efficiency is 96.4%. More than 80% of the decomposed oil mist is converted to CO2 and CO under all test conditions. Some of the byproducts other than CO and CO2 are released as particles. Higher frequency results in higher oil mist decomposition efficiency, but also higher byproduct formation of particles. The mechanism of oil mist decomposition by surface-DBD plasma is discussed using optical emission spectroscopy data.