Diethylene Glycol Adipate Research Articles

Thermal and mechanical behaviour of some new crosslinked poly(ester-siloxane)urethanes

New cross-linked poly(ester-siloxane)urethanes were prepared by multistep polyaddition from aromatic diisocyanates and diglycerin maleate, as the hard segment, and poly(ethylene glycol adipate) or poly (diethylene glycol adipate) and poly(dimethyl siloxane), as the soft segment. In some cases the soft segment was extended with polybutadiene segments. The influence of structure and position across the chain of the hard and soft containing segments upon mechanical and thermal properties were studied using thermogravimetric and mechanical techniques.

Synthesis and Thermal Properties of Biodegradable Poly(ester-urethane)s Based on Chemo-Synthetic Poly[(R,S)-3-hydroxybutyrate

A series of telechelic oligo[(R,S)-3-hydroxybutyrate]-diols (PHB-diols) was synthesized from ethyl (R,S)-3-hydroxybutyrate (ethyl (HB)) and four different aliphatic diols, namely, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol and 1,10-decanediol by transesterification and condensation in bulk. The structures of the synthesized oligomers were confirmed by 1 H NMR spectroscopy and MALDI-TOF mass spectroscopy. The use of 1,4-butanediol results in an oligoester with hydroxyl functionality of approximately 2. In the case of the higher aliphatic diols, the number average functionalities were found to be lower than 2. These differences were ascribed to side reactions which occur during polymerization, yielding unreactive end groups. Other novel families of biodegradable poly(ester urethane)s were synthesized either from PHB-diol alone, or PHB-diol mixed with poly(e-caprolactone)-diol (PCL-diol), poly(butylene adipate)-diol (PBA-diol) or poly(diethylene glycol adipate)-diol (PDEGA-diol). In each case, 1,6-hexamethylene diisocyanate was used as a nontoxic connecting agent. The homopolymers prepared from PCL-diol, PBA-diol and PDEGA-diol were also synthesized for the sake of comparison. All the prepared copolymers possess high molecular weight with glass transition temperature (T g ) values varying from -54 to 23°C. Some of the prepared copoly(ester-urethane)s are partially crystalline with melting temperatures (T m 's) varying from 37 to 56°C.

Dynamic-mechanical and differential scanning calorimetry measurements on crosslinked poly(ester-siloxane)-urethanes

Various crosslinked poly(ester-siloxane)-urethanes containing hard and soft segments, were prepared by a one-step melting/polyaddition. Thus, soft sequences based on poly(ethylene glycol adipate)diol (PEGA) or poly(diethylene glycol adipate)diol (PDEGA) as ester components, α,ω-poly(dimethylsiloxane)diol (PDMS) and/or polybutadienediol (PBD), were built. The hard segments were composed from diglycerin maleate tetrol (DGMA) and two aromatic diisocyanates, 4,4′-diphenylmethane diisocyanate (MDI) and 2,4-tolylene diisocyanate (TDI). Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) were employed to characterise crosslinked polyurethane materials. The obtained data revealed that the thermal curves are influenced significantly by the soft and hard segment structures in the temperature range studied.

Purification and properties of culture-broth-secreted esterase from the polyurethane degrader Comamonas acidovorans TB-35

The polyester-polyurethane (PUR)-degrading bacterium Comamonas acidovorans TB-35 produces two kinds of esterases, one cell-bound esterase (PUR esterase) and the other secreted in the culture broth (CBS esterase). In this study, the CBS esterase and the two recombinant esterases were purified. Identification of the physical and biochemical properties of the CBS and PUR esterases revealed that they have the same polypeptide from one gene. This finding was supported by the observation that Escherichia coli harboring the PUR esterase gene also produced two kinds of esterases. Though the PUR esterase degraded PUR and poly(diethylene glycol adipate), the soft segment of the PUR, the CBS esterase degraded only poly(diethylene glycol adipate). Furthermore, the hydrophobicity of the CBS esterase was lower than that of the PUR esterase. As the PUR esterase has been previously indicated to possess a PUR-binding domain, it was assumed that structural change around the PUR-binding domain of the CBS esterase was responsible for its inability to degrade PUR.

Composition‐dependent properties of segmented polyurethanes

AbstractWe studied segmented polyurethanes (SPU) from poly(diethylene glycol adipate) with molar masses MSFT = 780, 1365, 1780 and 3200 g/mol (soft fragments, SFT), 2,4‐toluene diisocyanate and 2,4‐toluene diamine (stiff fragments, STF) with essentially monodisperse molar mass distribution of STF. They were characterized by WAXS, SAXS, heat capacity measurements, mainly from 150–450 K, and enthalpies of solution in dimethyl formamide at room temperature, ΔHsol. The experimental results may be summarized as follows. The glass transition temperatures of SFT decrease with an increase of MSFT, but remain essentially composition‐invariant at fixed MSFT, whatever the STF volume fraction φ. The surface‐to‐volume ratio of STF domains exhibits sudden, jump‐like transitions at volume fractions φ* = 0.23 and φ** = 0.40, respectively. Exothermic (i.e., negative) values of ΔHSOl exhibit a jump‐like decrease at φ* = 0.23. It has been shown that the main cause of the latter effect is the transition of SFT from a somewhat extended to an essentially unperturbed conformation.

Evaluation of butanoic, pentanoic and hexanoic acids as internal standards for analysis of acidic fermentation end-products from Bacillus stearothermophilus by gas-liquid chromatography

The use of butanoic, pentanoic and hexanoic acids as internal standards for chromatographic analysis of complex mixtures of by-products from acidic fermentation, produced by Bacillus stearothermophilus grown in xylose-containing medium, was evaluated. After addition of the internal standards, the aqueous supernatant microbial fermentation fluids were submitted to the derivatisation process with methanol and sulphuric acid at 50° C. Injection of 1-μl aliquots of the lower chloroform layer was carried out. The esterified compounds were separated in approximately 14 min by temperature programming on a glass column packed with 10% (w/w) diethyleneglycol adipate and 2% phosphoric acid, and analysed with a flame ionisation detector. Chromatograms of the methyl esters derivates have shown that both pentanoic and hexanoic acids can be used as internal standards for gas-chromatographic analysis of acidic fermentation end-products, since they are well separated and resolved. Under the experimental conditioss established, the methyl ester of butanoic acid was masked by the chloroform peak and so is not a convenient compound for further use.

Determination of physicochemical properties of some fatty acid methyl esters by gas liquid chromatography

Physicochemical data such as vapor pressures (p0), heats of vaporization (ΔHv), activity coefficents at infinite dilution (γ∞) and excess partial molar entropy (ΔSe0) are considered important for conducting unit processes and designing reactor equipment. Scanty information regarding such data is available in the literature for the higher fatty acid methyl esters. The objective of this research was to determine the physicochemical properties of higher fatty acid methyl esters (C11–C23) by a gas‐liquid chromatographic technique with SE‐30 and diethylene glycol adipate as stationary phases. Correlations between carbon numbers and various thermodynamic properties have indicated definite trends, which could be useful in predicting the properties of unknown fatty acid methyl esters. The data generated may be useful to chemical engineers in the construction of storage tanks, solvent extractors and distillation columns.

Poly(diethylene glycol adipate): A Study of Its Behavior as a PVC Plasticizer

Abstract The compatibility of PVC with poly(diethylene glycol adipate) M n = 1500 was evaluated by DSC, indicating a limit value of 15 phr. The behavior of the oligomer as a PVC plasticizer, alone or in combination with dioctylphthalate (DOP), was investigated by measurements such as hardness, glass transition temperature, heat stability, and solvent resistance. In spite of its limited compatibility the oligoester can act as a secondary plasticizer enhancing the overall performance of the compositions.

A comparative study of the gas chromatographic behavior of liquid crystals and polyester stationary phases using paraffinic hydrocarbons as standards

AbstractTwo new categories of stationary phase have been studied: liquid crystals and polyesters. The liquid crystals were p,p′‐azoxyphenetol, p(n‐hexyloxy)phenyl‐p′‐methoxy benzoate, and p‐pentyloxy‐p′‐ethoxyazoxybenzene; and the polyester phases 1,4‐butanediol succinate (LAC‐860), ethylene glycol succinate (LAC‐886), diethylene glycol succinate (LAC‐738), diethylene glycol adipate (LAC‐296), and neopentyl glycol adipate (LAC‐769).Abnormal chromatographic behavior, has been observed: an increase in specific retention volumes and an improvement in the separation of normal, branched, and cycloparaffins, depending on their structures, at high temperatures within a specified range. This phenomenon is the opposite of the behavior of traditional stationary phases. From the chromatograms obtained, plots of log v against 1/T, and differential thermal analysis it is concluded that this abnormal behavior may be attributed to the penetration of solutes through the ordered structure of the mesophase and the rod‐like molecules of the polyesters. Furthermore, the chromatographic behavior of some of the polyester (LAC‐series) stationary phases in respect of temperature changes is similar to that of the nematic mesophases.

Intrinsic viscosities of diethylene glycol adipate solutions of various functionalities

The size and flexibility of molecules in solutions has been studied by determining the intrinsic viscosities of diethylene glycol adipate oligomers (DEGA). The Huggins constant of the oligomer solutions in MEK has been found to be in the range 0.2–0.5 and to decrease with the functionality; it was independent of the mol.wt. in a series of similar functionalities. The intrinsic viscosity as a function of the mol.wt. is given by [ η]= K 0· M 0.5, but is unreliable where the oligo-esters have differing functionalities. The found [η]-values have been used to estimate the average size of the molecules. The persistent length of the macromolecules depends on the number of OH-groups and increases on changing from the non-functional DEGA oligomers to the bifunctional. The found persistent length classifies the DEGA oligomers as flexible-chain polymers.

Study of molecular distributions in linear oligoester acrylates using oligo(diethyleneglycol adipate) dimethacrylates

Molecular weight distribution (MWD) and distribution according to types of functionality of oligodiethyleneglycoladipates with hydroxyl and methacryl end groups were studied by adsorption chromatography, extraction in columns and gas-permeation chromatography (GPC). The presence of cyclic esters consisting of 65–75 wt.% dimers was observed in all the products studied. MWD of the linear part of oligomers of both types corresponds to the most likely distribution. To analyse oligoester acrylates it was proposed to determine by GPC the content of rings and then calculate the composition of the linear part using the modified Flory equation.

Gas chromatography of isoprenoid alkanes

The retention indices of ten isoprenoid alkanes on Apiezon L, SE-30 and diethylene glycol adipate polyester cross-linked with pentaerythritol at different temperatures have been determined. The regularities in the variation of the retention indices within homologous series are discussed. A certain similarity in the structure of the compounds investigated enabled two methods to be developed for calculating retention indices based on retention increments and Wiener's structural constant. The Kováts retention indices of twelve compounds have been calculated. For 3,7,11-trimethyltridecane and 2,6,10,14-tetramethyloctadecane, the average divergences between the calculated and experimental retention indices were found to be ± 0.5 and ± 2.6 units, respectively. With the aid of the calculated retention indices, the presence of 3,7,11-trimethylalkanes and higher isoprenoids in a sample of Romashkino petroleum was demonstrated.

Thermodynamics of high-elastic deformation of polyurethanes

The thermoelastic behavior of polyurethanes based on diethylene glycol adipate and tolylene diisocyanate with different network densities has been investigated in connection with their tensile deformation. The change in entropy and internal energy is calculated at strains up to 100%. It is shown that during extension both the entropy and the internal energy decrease. The reduction in internal energy depends on the relative importance of the physical and chemical bonds in the network and is attributable to the redistribution of intermolecular bonds.

Determination of Steam-Volatile Organic Acids in Fermentation Media by Gas-Liquid Chromatography

Five gas chromatographic liquid phases (25% Carbowax 20 M plus 4% H(3)PO(4), 17.5% dioctyl sebacate plus 7.5% sebacic acid, 17.5% dioctyl sebacate plus 7.5% docosanoic acid, 5% Tween 80, and 20% LAC-296 [poly (diethylene glycol adipate)] plus 2% H(3)PO(4)) were studied with respect to their utility in the separation and quantitation of steam-volatile organic acids commonly produced in fermentation. Optimal operating conditions and column stability for routine analysis were established. An Aerograph Hy-Fi gas chromatograph was used for all work, except the studies with Tween 80 in which an Aerograph A-90-C was employed. Chromatographic traces are presented of volatile fatty acid analyses with each of the liquid phases. Complete separation of all isomers of the fatty acids from C(2) to C(5) was accomplished by the Carbowax 20 M plus H(3)PO(4), dioctyl sebacate plus sebacic acid, and dioctyl sebacate plus docosanoic acid columns. The latter two liquid phases were extremely unstable and proved to be unsatisfactory for analysis of aqueous samples. A column of Carbowax 20 M + H(3)PO(4) separated steam-volatile organic acids completely. The volatile fatty acid isomers were separated by 5% Tween 80 somewhat less completely, and the peak shapes were not as sharp and symmetrical as that desired for good quantitative work. LAC-296 (20%) plus 2% H(3)PO(4) proved to be the most satisfactory of the liquid phases for routine analysis of deproteinated in vitro rumen fermentation media. The column has been used for routine analysis of rumen fermentation fluid and in vitro rumen incubation fluid. All the organic acids from C(2) to C(5), except isobutyric, could be quantitated with this column. Stability of the column with the aqueous solutions was extremely good. The standard deviation of the analysis of each volatile acid component in a fermentation fluid was less than 0.5 molar per cent. The short-chain organic acids (C(2) to C(5)) were shown to be extremely stable in aqueous solution for as long as 6 months after preparation for gas chromatographic analysis by protein precipitation with metaphosphoric acid-H(2)SO(4) and refrigeration at 4 C in stoppered tubes.

DETERMINATION OF STEAM-VOLATILE ORGANIC ACIDS IN FERMENTATION MEDIA BY GAS-LIQUID CHROMATOGRAPHY.

Five gas chromatographic liquid phases (25% Carbowax 20 M plus 4% H(3)PO(4), 17.5% dioctyl sebacate plus 7.5% sebacic acid, 17.5% dioctyl sebacate plus 7.5% docosanoic acid, 5% Tween 80, and 20% LAC-296 [poly (diethylene glycol adipate)] plus 2% H(3)PO(4)) were studied with respect to their utility in the separation and quantitation of steam-volatile organic acids commonly produced in fermentation. Optimal operating conditions and column stability for routine analysis were established. An Aerograph Hy-Fi gas chromatograph was used for all work, except the studies with Tween 80 in which an Aerograph A-90-C was employed. Chromatographic traces are presented of volatile fatty acid analyses with each of the liquid phases. Complete separation of all isomers of the fatty acids from C(2) to C(5) was accomplished by the Carbowax 20 M plus H(3)PO(4), dioctyl sebacate plus sebacic acid, and dioctyl sebacate plus docosanoic acid columns. The latter two liquid phases were extremely unstable and proved to be unsatisfactory for analysis of aqueous samples. A column of Carbowax 20 M + H(3)PO(4) separated steam-volatile organic acids completely. The volatile fatty acid isomers were separated by 5% Tween 80 somewhat less completely, and the peak shapes were not as sharp and symmetrical as that desired for good quantitative work. LAC-296 (20%) plus 2% H(3)PO(4) proved to be the most satisfactory of the liquid phases for routine analysis of deproteinated in vitro rumen fermentation media. The column has been used for routine analysis of rumen fermentation fluid and in vitro rumen incubation fluid. All the organic acids from C(2) to C(5), except isobutyric, could be quantitated with this column. Stability of the column with the aqueous solutions was extremely good. The standard deviation of the analysis of each volatile acid component in a fermentation fluid was less than 0.5 molar per cent. The short-chain organic acids (C(2) to C(5)) were shown to be extremely stable in aqueous solution for as long as 6 months after preparation for gas chromatographic analysis by protein precipitation with metaphosphoric acid-H(2)SO(4) and refrigeration at 4 C in stoppered tubes.

Improved gas chromatography of unesterified fatty acids.

IT has been demonstrated by Bottcher et al.1 and by Hunter et al.2 that unesterified fatty acids can be separated, by gas chromatography, by the use of ‘liquid’ phases of the polyester type. Metcalfe3 has pointed out the necessity to have a highly acidic ‘liquid’ phase in order to suppress the association of the carboxyl group of the fatty acids, and has shown that the separation of C4–C22 fatty acids is very much improved by the incorporation of phosphoric acid in the polyester ‘liquid’ phase. Using a column packing of ‘Celite 545’ previously coated with 25 per cent of diethylene glycol adipate polyester and 2 per cent of phosphoric acid, mixtures of fatty acids were separated at temperatures of 220–235° C., yielding well-defined symmetrical peaks and separating saturated and unsaturated acids from each other.