Trimethylolethane Research Articles

Investigation of high-enthalpy organic phase-change materials for heat storage and thermal management

The growing interest in phase-change materials (PCM) is related to their possible role in thermal energy storage and thermal management. The choice of materials depends strongly on the required temperature range, whereas the latent heat of solid–liquid phase transition has to be as high as possible. Among other organic PCM, sugar alcohols have gained some attention due to their availability and certain advantageous properties. However, the thermal processes in these materials still require investigation. In the present work, we focused on the materials with solid–liquid phase change within 80 °C–100 °C. A comprehensive literature survey was conducted to elucidate the available sugar alcohols relevant to this range. It was found that the use of pure materials of this type is not very practical, because of their scarcity in the required range and their specific features, like difficulties with crystallization and solidification. On the other hand, based on the literature, we have discerned three eutectic mixtures of erythritol with other organic materials, namely, erythritol–xylitol, erythritol–urea and erythritol– trimethylolethane (TME). In all those cases, it is remarkable that while the components commonly have rather high melting temperatures, the eutectic mixtures had the phase transitions in the required range. Still, each of these mixtures has its own peculiar features, especially at cooling and solidification. An extensive experimental study was performed to provide detailed visualization of these major processes. The results revealed the melting temperature and latent heat of the mixtures to be: 84 °C and 190 J g−1 for erythritol–xylitol, 82 °C and 227 J g−1 for erythritol–urea. Erythritol–TME has two phase transitions at 82 °C and 97 °C, with total latent heat of 198 J g−1. Based on the present findings, the erythritol–urea mixture is the best PCM candidate for the melting range within 80 °C–100 °C.

Synthesis and Evaluation of Jatropha Oil Branched Esters as Potential Fire Resistant Hydraulic Fluids

Jatropha oil (Jatropha curcas L.), a non-edible oil with oleic acid (45.7%) and linoleic acid (33%) as major components, was used to prepare basestocks for biolubricants. The hydrolyzed fatty acids underwent reaction with two iso-alcohols, 2-ethyl-1-hexanol (EH) and 3,5,5-trimethyl-1-hexanol (TMH) and 5 different polyols, namely neopentyl glycol (NPG), 2-methyl-2-propyl-1,3-propandiol (MPPD), trimethylolpropane (TMP), trimethylolethane (TME) and pentaerythritol (PE) at around 140 ºC in presence of catalyst p-toluenesulfonic acid (p-TSA) and xylene as solvent. The yields for the branched mono- and polyol esters ranged from 90% to 97.5%. The physico-chemical, lubricant and tribological properties of these esters as well as their 1H NMR, 13C NMR, IR and ESI-MS techniques were investigated. Among the products, polyol esters were found to possess good viscosity indices, good foam stability, higher thermal stability and higher flash and auto ignition points compared to branched mono esters. TMP and TME esters have matched the specifications of ISO VG 46 and PE esters match ISO VG 68 fire resistant hydraulic fluids, which are in high demand.

Effects of the species of crosslinking reagents on the structures and properties of biodegradable poly (butanediol sebacate ‐ butanediol terephthalate) copolyester

AbstractIn the present study, poly(butylene sebacate‐co‐terephthalate)s having different crosslinking reagents were synthesized with a random distribution by a two‐step esterification and one‐step polycondensation process. In detail, the using crosslinking agents were included trimethylolethane (TME), trimethylolpropane, tris(hydroxymethyl)aminoethane, glycerol (GL). Particularly, CS refers to a sample with no crosslinking agent added. The copolyester with TME was the least crystalline sample, and the melting peaks of all copolyesters corresponding to both, sebacate and terephthalate‐rich phases were still observable in second calorimetric heating runs. These copolyesters were associated with interesting thermal and mechanical properties. The melting points of all samples were higher than 118°C and the puncture resistance and tensile strength of GL, the tear strength of TME, and the Young's modulus of all samples have been improved. Enzymatic degradability was assessed and the effect of composition and crystallinity on the degradation rate was investigated. The copolyester adding GL appears as a highly promising biodegradable material since it showed a significant weight loss during exposure to all selected degradation media, but also exhibited good performance and properties that were comparable to those characteristic of polyethylene. In brief, the improvement of PBSeT's puncture resistance, tear strength, and degradation performance is extremely important for the development and promotion of degradable foam, film, and elastomer materials.

Hydrates for Cold Storage: Formation Characteristics, Stability, and Promoters

The potential of hydrates formed from R141b (CH3CCl2F), trimethylolethane (TME), and tetra-n-butylammonium bromide/tetra-n-butylammonium chloride (TBAB/TBAC) to be used as working substances for cold storage was investigated to provide a solution for unbalanced energy grids. In this study, the characteristics of hydrate formation, crystal morphology of hydrates, and the stability of hydrate in cyclic formation under 0.1 MPa and at 5 °C were carried out. It found that the ice had a positive effect on the hydrate formation under same conditions. Upon the addition of the ice cube, the induction time of R141b, TME, and TBAB/TBAC hydrates decreased markedly, and significantly high formation rates were obtained. Under magnetic stirring, the rate at which TBAB/TBAC formed hydrates was significantly lower than that when ice was used. In microscopic experiments, it was observed that the TBAB/TBAC mixture formed hydrates with more nucleation sites and compact structures, which may increase the hydrate formation rate. In the multiple cycle formation of TBAB/TBAC hydrates, the induction time gradually decreased with the increasing number of formation cycles and finally stabilized, which indicated the potential of the TBAB/TBAC hydrates for application in cold storage owing to their good durability and short process time for heat absorption and release.

Synthesis, characterization, and curing of propylene oxide and glycidyl nitrate random copolymer (GN-ran-PO) and investigation of its compatibility with different energetic plasticizers

In this research, arandom copolymer of propylene oxide and glycidyl nitrate (poly [GN-ran-PO]) (Mn = 1152 g.mol−1) was synthesized via ring-opening polymerization of epoxides in the presence of boron trifluoride etherate (BF3.OEt2) as the catalyst. This copolymer has a potential use as a binder in the propellant industries. The obtained product has characterized by 1H and 13C NMR spectroscopy, FTIR, and gel permeation chromatography (GPC). The thermal behavior of the random copolymer was determined by differential scanning calorimetry (DSC). Energetic polyurethane was synthesized by curing of the random copolymer with different curing agents such as toluene-2,4-diisocyanate(TDI), isophorone diisocyanate(IPDI), desmodurN100, (IPDI/N100) and different NCO/OH ratios. To evaluate the plasticizing effect of the different plasticizers on the thermo-mechanical properties of the polyurethane, the compatibility of the copolymer with three energetic plasticizersincludingn‐butyl nitroxyethyl nitramine (BuNENA), trimethylol ethane trinitrate (TMETN), and 1,2,4-butanetriol trinitrate (BTTN) has studied using the solubility parameter, rheological and thermal analysis. The solubility parameter differences indicate that the BuNENA has better miscibility with this copolymer than others. This plasticizer reduced the glass transition temperature of its composition with copolymer from -47 °C to -58 °C. Moreover, the rheological analysis also confirms that BuNENA is more compatible with the copolymer. The mechanical properties effect of the BuNENA plasticizer on the polyurethane network has investigated using dynamic mechanical analysis (DMA) as well as the tensile test. The IPDI/N100 curing agents-polyurethane mixture, demonstrate appropriate mechanical properties (0.6 MPa stress and 109% elongation) that make it a suitable binder system comparison with pure PGN (unstable and de-cured). Also, the mechanical properties of the prepared polyurethane containing 20 wt.% BuNENA showed 0.42 MPa stress and 124% elongation.

Preparation of a novel polyurethane network based on PPG–PGN–PPG: investigation of the effect of plasticizers on its properties

In this research to improve the thermal and mechanical properties of polyglycidyl nitrate (PGN)-based energetic polyurethane network was used a novel flexible chain triblock copolymer based on polypropylene glycol–poly glycidyl nitrate–polypropylene glycol (PPG–PGN–PPG). Energetic polyurethane was prepared by curing of the triblock copolymer with different curing agents (TDI, IPDI, N100, IPDI/N100) and different NCO/OH ratios. To evaluate the effect of plasticizer on the thermo-mechanical properties of the polyurethane, the compatibility of copolymer with three energetic plasticizers, including n‐butyl nitroxyethyl nitramine (BuNENA), trimethylol ethane trinitrate (TMETN), and 1,2,4-butanetriol trinitrate (BTTN) was studied using the swelling test and thermal analysis. The results indicate that BuNENA is more compatible with this copolymer than other plasticizers. The mechanical properties effect of the BuNENA plasticizer on the polyurethane network was investigated using dynamic mechanical analysis as well as the tensile test. The IPDI/N100 curing agents-polyurethane mixture, demonstrated appropriate mechanical properties (0.35 MPa stress and 70% elongation) that make it a suitable binder system comparison with pure PGN (unstable and de-cured). Also the mechanical properties of the prepared polyurethane containing 15 wt% BuNENA showed 0.17 MPa stress and 98% elongation.

Thermophysical properties of trimethylolethane (TME) hydrate as phase change material for cooling lithium-ion battery in electric vehicle

Management for the temperature increase of lithium-ion batteries in electric vehicles (EV) is required for safety and energy efficiency. As a cooling medium for lithium-ion batteries, one suitable candidate is trimethylolethane (TME) hydrate, which may be utilized as a phase change material (PCM). This hydrate has a large dissociation heat and will form/dissociate at approximately 30 °C under atmospheric pressure conditions. A cooling system which uses TME hydrate can have a high performance with regards to the efficiency and the stability of heat transfer process. However, in previous studies, the equilibrium temperature and the dissociation heat of TME hydrate have been reported only for a TME mass fraction of 0.625. Since TME hydrate forms in an aqueous solution, it is necessary to know how these thermophysical properties change for a range of TME mass fractions. Therefore, in this study, the equilibrium temperatures and the dissociation heats were measured respectively by the visual observation method and differential scanning calorimetry measurements for TME mass fraction range from 0.20 to 0.80. The highest equilibrium temperature was 29.6 °C at the mass fraction of 0.60. For the cooling system, the largest dissociation heat was 190.1 kJ kg−1, also at the mass fraction of 0.60.

Macroscopic Scaffold Control for Lipase‐Catalyzed Dendritic Polyol‐Polyesters

AbstractHerein, structurally regular dendritic trimethylolethane (TME) polyester is robustly obtained by polymerizing with suberic acid. Through properly modeled chain growth behaviors, differences of scaffolds forming between TME and glycerol polyesters are thoroughly discussed. The scaffolds of polyol‐polyesters can be easily controlled by adjusting feed ratio and temperature. However, to achieve regular dendritic scaffolds, apart from the monomer feed ratio of 1/1 and high temperature(80 °C), selection of proper polyols is much more important. TME with three equal primary hydroxyls tends to undergo pure dendritic growth, forming into regular scaffolds while glycerol with secondary hydroxyls is inclined to have linear and grafted growth successively, which results in irregular dendritic scaffolds. However, glycerol polyesters tend to have linear growth under mild temperature (40 °C), hence, regular linear scaffolds can be obtained. Besides, a scaffold determination and control system are built up, giving general guidance of obtaining polol‐polyesters with targeted topologies.

Al distribution and catalytic performance of ZSM-5 zeolites synthesized with various alcohols

The distribution of Al atoms in ZSM-5 has been recognized as an important factor in catalytic activity. Here, ZSM-5 zeolites were synthesized from synthetic gels containing various alcohols, including straight- and branched-chains alcohols. The effect of the alcohols in the synthetic gel on the Al distribution in the MFI framework was investigated based on 27Al MAS NMR, Co(II) ion UV−vis DRS, and constraint index value. Thus synthesized ZSM-5 zeolites were applied to catalysts for the cracking of n-hexane and the methanol-to-olefins (MTO) reactions in order to investigate the impact of the Al distribution on the catalytic properties. A unique Al distribution in the MFI framework was achieved by the use of trimethylolethane (TME) in combination with Na cations, and thus-prepared ZSM-5 catalyst showed a long catalytic life for both the cracking of n-hexane and the MTO reaction.

DMA of polyester-based polyurethane elastomers for composite rocket propellants containing different energetic plasticizers

The aim of this work is to evaluate the effect of several types of plasticizers on the glass–rubber transition temperatures (Tg) of polyester-based polyurethane binders, using dynamic mechanical analysis (DMA). The polyester polyol commercially named Desmophen® 2200 (D2200®) has been investigated for use as binder for composite propellant applications due to its good ballistic properties and also due to its potential glass–rubber transition temperature when mixed with polar energetic plasticizers. Therefore, it is important to evaluate the behavior of D2200® with different energetic plasticizers. In the present work, this inert polar binder was mixed individually with several different plasticizers and cured with a polyisocyanate commercially named Desmodur® N3400. The plasticizers used were: nitrate ester methyl trimethylol ethane trinitrate (TMETN), N-(n-butyl)-N-(2-nitroxyethyl) nitramine (Bu-NENA), bis-(2,2-dinitropropyl) formal and bis-(2,2-dinitropropyl) acetal mix 1:1 (BDNPF-A), nearly monodispersed low molar mass azido-terminated glycidyl azide polymer (GAP-A), ethylene glycol bis-(azidoacetate) (EGBAA) and 1,2-bis-(2-azidoethoxy) ethane (TEGDA) or BATEG, bis-azido-triethylene glycol, in an amount of 35 mass/%. The cured elastomers were characterized using torsion DMA at several frequencies, and the loss factor curves were described with exponentially modified Gaussian (EMG) distribution functions. Increasing deformation frequency in DMA increases Tg, and an apparent activation energy was correlated with plasticizer performance. The plasticizer ability to decrease Tg follows the order: TEGDA > butyl-NENA > GAP-A > EGBAA > BDNPF-A > TMETN. The ability of each energetic plasticizer could be related to its molecular structure, as well as to its molar mass and interaction possibilities with the polymer chains.

Alkyd nanocomposite coatings based on waste pet glicolyzates and modified silica nanoparticles

Synthesis of high-performance alkyd resins (ARs) based on waste poly(ethylene terephthalate) (PET) glycolyzates is presented. PET glycolyzates were synthesized by catalytic depolymerization with trimethylolpropane (TMP) and trimethylolethane (TME) and used as replacement of polyhydroxylic component during the ARs synthesis. The obtained glycolyzates and produced ARs were analyzed using FTIR, 1H and 13C NMR spectroscopy and acid, iodine, and hydroxyl value were determined. Rheological properties of the synthesized ARs, as well as, thickness, adhesion, hardness and the gloss values were determined. All synthesized ARs show good adhesion and hardness and the gloss values are greater than 95%. The influence of the addition of vinyl modified nanosilica Aerosil® R380, functionalized with 3-(trimethoxysilyl)propyl methacrylate (TMSPM) and tris(2-methoxyethoxy)(vinyl)silane (TMEVS), on the mechanical and anticorrosive characteristics of the prepared nanocomposite coatings, based on ARs, was investigated.

Fabrication Process of Silica Hard-shell Microcapsule (HSMC) Containing Phase-change Materials

Abstract A fabrication process via the double-emulsion method is proposed for silica hard-shell microcapsules (HSMCs) that contain trimethylolethane (TME) hydrate. The TME-encapsulating silica-HSMCs are promising materials for reusable phase-change materials for latent-heat transportation systems. The obtained silica-HSMCs were visualized by a scanning electron microscope. The amount of TME hydrate inside the capsules was confirmed using a differential scanning calorimeter. The measured latent heat of the TME-encapsulating silica-HSMC was a reasonable fit to the predicted value.

Effect of molar ratio of counter-ions to cationic surfactants on drag reduction characteristics of trimethylolethane hydrate slurries

An experimental study on flow characteristics of trimethylolethane (TME) hydrate slurries treated with drag-reducing surfactants has been performed in order to investigate the effect of molar ratio of counter-ions to surfactants. As drag-reducing surfactants, oleylbishydroxyethylmethylammonium chloride was used. The molar ratio of counter-ions of sodium salicylate to surfactants ranged from 0 to 100 and surfactant concentration was changed in two steps; 1000 ppm and 2.000 ppm while the concentration of TME in water was set constant at 25 wt%. From the results, it was found that the drag reduction limitation becomes larger when the molar ratio of the counter-ions to surfactants is set around 20 for each surfactant concentration. From the detailed discussions, the drag reduction characteristics in a higher range of the molar ratio of counter-ions to surfactants were found to relate to the molar ratio of counter-ions to TME more significantly. Under the present conditions, it was concluded that 0.05 of the molar ratio of counter-ions to TME shows the most effective drag reduction.

Effect of Molar Ratio of Counter-Ions to Cationic Surfactants Treating Trimethylolethane Hydrate Slurries

Experimental studies on flow characteristics and particle size distributions of trimethylolethane (TME) hydrate slurries treated with drag-reducing surfactants have been conducted to investigate the effect of the molar ratio of counter-ions to surfactants. Oleylbishydroxyethylmethylammonium chloride is used as the drag-reducing surfactants. The molar ratio of sodium salicylate supplying counter-ions to surfactants is adjusted from 0 to 100 while the concentrations of TME in water and of surfactants remains constant at 25 wt% and at 2000 ppm, respectively. Results unexpectedly indicate that the drag reduction is greatest when the molar ratio of the counterions to surfactants is 20 against the fact that the higher molar ratio shows the higher drag reduction in water case. This indicates that some interaction between the counter-ions and TME molecules occurs and that it disturbs the formation of rod-like micellar structures causing the drag reduction. Thus, a molar ratio of counterions to surfactants of 20 is concluded to be the optimum for the drag reduction although it has a detrimental effect on the particle size under the present experimental conditions used.

WHAT IS THE IN VIVO AXIAL STRAIN OF A PORCINE CORONARY ARTERY?

The solid state phase transformations in some hydrocarbon molecular crystals reversibly absorb large amounts of heat. Some of these materials have potential for use in composite building materials as heat storage media. In particular, the homologous series of polyhydric alcohols related to pentaerythritol can be used for heat storage over a range of temperatures suitable for solar heated buildings.The thermodynamic properties and mechanisms of solid state transformations have been studied for pentaerythritol (C(CH2OH)4); trimethylol ethane [(CH3)C(CH2OH)3], neopentyl glycol ((CH3)2C(CH2OH)2) and their mixtures. Differential scanning calorimetry was used to characterize the temperatures and enthalpies of transformations and to measure the heat capacities over a range of temperature from ambient to above the melting temperatures. Infrared spectroscopy was performed on the pure alcohols over a range of temperatures including the solid state transformation. Partially deuterated samples of pentaerythritol were also studied.Results of these measurements support a mechanism for the solid state transformation which involves reversible breaking of nearest-neighbor hydrogen resonance bonds in the molecular crystals at the transformation temperatures. The binary mixtures of these three alcohols also exhibit solid state transformations which appear to occur by the same mechanism.

Cast aluminized explosives (review)

This paper reviews the current status and future trends of aluminized explosives. The major focus is on cast compositions, which encompass both the melt-cast trinitrotoluene (TNT) based and the slurry cast polymer-based compositions. Widely reported RDX and HMX based aluminized compositions with TNT used as a binder are discussed in detail. Various researchers have suggested a 15–20% Al content as an optimum from the viewpoint of velocity of detonation. A higher Al content, however, is incorporated in most of the compositions for a sustained blast effect, due to the potential of secondary reactions of Al with detonation products. The effect of the aluminum particle size on performance parameters (velocity of detonation, etc.) is included. There are some recent works on nanometric Al based compositions, and the results obtained by various researchers suggest mixed trends for RDX-TNT compositions. Studies on nitrotriazol and TNT based compositions bring out their low vulnerability. Some of the interesting findings on ammonium dinitramide and bis(2,2,2-trinitro-ethyl)nitramine (BTNEN) based compositions are also included. The review brings out superiority of polymer based aluminized explosives, as compared to conventional TNT based compositions, particularly, with respect to low vulnerability. In general, aluminized plastic bonded explosives find numerous underwater applications. Ammonium perchlorate (AP) is also incorporated, particularly, for enhancing underwater shock wave and bubble energy. Hydroxyl terminated polybutadiene appears to be the binder of choice. However, nitrocellulose, polyethylene glycol, and polycaprolactone polymer based compositions with energetic plasticizers, like bis-dinitropropyl acetal/formal (BDNPA/F, 1/1 mix), trimethylol ethane trinitrate, and triethylene glycol dinitrate are also investigated. Polyethylene glycol and polycaprolactone polymer based compositions are found to be low vulnerable, particularly, in terms of shock sensitivity. Highly insensitive polymer bonded nitrotriazol based compositions are being pursued all over the globe. The highly insensitive CL-20/AP combination meets the demands of high density and high velocity of detonation. Glycidyl azide polymer and poly nitratomethyl methyl oxetane appear to be binders of interest for plastic bonded explosives in view of their superior energetics. The vulnerability aspects of these compositions, however, need to be studied in detail. Brief information on plastic bonded and gelled thermobaric explosives is also included.

Rheological characteristics of trimethylolethane hydrate slurry treated with drag-reducing surfactants

Rheological characteristics of trimethylolethane (TME) clathrate–hydrate slurry treated with drag-reducing surfactants were investigated. Friction coefficients and apparent viscosities were measured when the concentration of TME and its hydrate fraction treated with and without drag-reducing surfactants were changed in several steps. From the results, it is found that the surfactant addition causes effective drag reduction in a pipe flow when the hydrate fraction becomes high, while effective drag reduction disappears in the cases of low hydrate fraction. The results of viscosity measurements indicate that the TME molecules disturb the formation of shear-induced structures (SIS) causing drag reduction phenomena. To investigate this interaction between TME and surfactant micelles, the effect of TME concentration on viscosity and relaxation time of solutions was discussed. From this, it was found out that there exists a critical concentration of TME on the formation of SIS and that it becomes larger as shear rate increases. Thus, we conclude that this interaction between TME and micellar structures causes less drag reduction for the cases of low hydrate fraction, while the drag reduction appears in cases of high hydrate fraction because TME concentration in liquid phase becomes small.

New PCMs Prepared from Erythritol-Polyalcohols Mixtures for Latent Heat Storage between 80 and 100°C

The present study is concerned with preparation of erythritol–polyalcohols mixtures as PCMs, which may be applicable for heat storage in the temperature range between 80 and 100°C for a hot water supply system. The melting/solidification temperature was adjusted by adding polyalcohols such as trimethylolethane (TME), 2-ethyl-2-methyl-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 1,4-butanediol, 2-amino-1,3-propanediol and trimethylolpropane (TMP), to erythritol.It was found that a new PCM(86) composed of 40% erythritol and 60% TME melted at 86.1 and 97.8°C with a latent heat of 246 kJ/kg. Another PCM(80) composed of 90% PCM(86) and 10% TMP melted at 80.0 and 95.0°C with a latent heat of 231 kJ/kg. These new PCM(86) and PCM(80) derived from erythritol were considered potentially applicable for a hot water supply system, in terms of their relatively large heat storing capacities and specific heats, as well as high thermal conductivities.

A Study of Trimethylolethane Hydrate as a Phase Change Material.

The authors thought that Trimethylolethane (TME) hydrate had a great potential as a brand-new phase change material (PCM) due to organic hydrate, which was no flammable and no corrosive against metals. The present paper investigates the physical properties, phase separation and corrosiveness against metal about TME hydrate. The phase separation phenomena of TME hydrate in the stagnant melt was investigated on condition that the hydrate was used with a capsule type heat storage system. Furthermore, the corrosiveness of TME hydrate against metals had evaluated to ascertain the possibility of being used as a metal heat exchanger.It was confirmed that the melting point of TME hydrate is 302.8 K and heat of fusion is 218 kJ/kg. Moreover, basic physical properties were measured, such as specific heat capacity, thermal conductivity and density. It was found that TME hydrate can be used as a heat storage material without thickening agent under some concentration. The concentration of TME that occurs phase separation changes according to the melting temperature and retention time in a general system condition. Also, it was found that TME hydrate has no corrosiveness against aluminum, copper, carbon steel and stainless steel. It was suggested that metal heat exchangers made of copper and aluminum could be used for TME hydrate.

Effect of multifunctional comonomers on the properties of poly(ethylene terephthalate) copolymers

AbstractThe properties of poly(ethylene terephthalate) (PET) and its copolymers containing 0.04–0.15 mol% of pentaerythritol and trimethylolethane (TME) have been investigated. The molecular weight of the copolymers increased with comonomer content, and this effect was observed significantly with pentaerythritol copolymers, resulting in broad molecular weight distribution. The comonomer effect on the mechanical properties was small. The shear viscosity of the copolymers showed shear thinning within the experimental shear rate range. The crystallization rate and birefringence of the fibres containing 0.103 mol% pentaerythritol increased with the spin draw ratio, whereas they decreased with comonomer content.© 2002 Society of Chemical Industry