Amount Of Diethylene Glycol Research Articles

ОПТИМИЗАЦИЯ УСЛОВИЙ СИНТЕЗА ПОЛИЭТИЛЕНТЕРЕФТАЛАТА И ВЛИЯНИЕ КАТАЛИЗАТОРОВ НА ЕГО СВОЙСТВА

In order to study the influence of the nature of the catalyst on the production process and the physicochemical properties of polyethylene terephthalate, samples were synthesized using catalysts based on antimony and titanium. Optimal catalyst concentrations were established for the production of polyethylene terephthalate with values close to those of industrial designs EKOPET samples: the characteristic viscosity (0.55-0.75 dl/g), melting temperature (max. 256°С), color number (L* ≥ 82.0; b * -1.5 ± 2.0) and acetaldehyde content (max. 1.0 ppm). The structure and properties of synthesized polyethylene terephthalate samples were studied using the methods of infrared spectroscopy and differential scanning calorimetry; transparency (L*) and color (b*) indicators, intrinsic viscosity, the amount of diethylene glycol, acetaldehyde and the content of terminal carboxyl groups were determined. Questions about the influence of nature, as well as the quantitative ratio of the catalyst on the indicators of color, transparency, intrinsic viscosity and the content of terminal carboxyl groups were discussed. It was revealed that titanium-containing compounds, in comparison with antimony catalysts, increase catalytic activity, which helps reduce the duration of the production process and produce polyethylene terephthalate with high molecular weight characteristics.

TECHNOLOGY FOR OBTAINING SUPERCONCENTRATES (MASTERBATCH) BASED ON ALCOHOLYSIS PRODUCTS OF SECONDARY POLYETHYLENE TEREPHTHALATE

Regularities of alcoholysis of secondary polyethylene terephthalate (RPET) by diethylene glycol (DEG) have been studied. It is shown that with an increase in the amount of diethylene glycol taken for alcoholysis from 0.1 mol to 0.4 mol per 1 mol of the elementary unit of HPET, a decrease in molecular weight from 1480 to 707 and the associated melting point from 215 to 145 °C are observed, and also intrinsic viscosity from 0.075 to 0.05 dl/g. The physicochemical properties of the products of alcoholysis of SPET (PAPET) have been determined. It has been revealed that PAPET is slightly colored and this is an undesirable factor affecting the individuality of the color of masterbatches based on them. Washing out with PAPET leads to some increase in the molecular weight values and related other indicators of the final oligomers. The structure of PAPET has been studied by infrared spectroscopy and differential scanning calorimetry. It has been revealed that PAPET synthesized at a molar ratio of SPET : DEG of 1:0.4, in which the dropping point according to Ubellode is 155 °C, is most suitable for obtaining superconcentrates. On the basis of PAPET obtained under these conditions, formulations of black and white masterbatches for polyethylene terephthalate fibers have been developed. To ensure uniform dispersion of white (TiO2) and black (K-354 carbon black) pigments, polyethylene wax was added to the superconcentrates. Masterbatches have been obtained by dry method in a twin screw compounder equipped with a double strand head and a granulator. The technological properties of the developed black and white superconcentrates have been determined, which turned out to be very close to those of the superconcentrates used in production. Conducted production tests of these masterbatches have showed that they are not inferior in terms of performance to similar industrial masterbatches used for dyeing threads.

Zirconia‐Pillaring in Layered HNb3O8 and HNbMoO6

In this work, the pillaring of two layered niobium-based oxides (HNb3 O8 and HNbMoO6 ) with zirconia was investigated in detail. Two novel zirconia-pillared layered metal oxides, zirconia-pillared layered HNb3 O8 and zirconia-pillared layered HNbMoO6 , have been successfully prepared. Both pillared products exhibited a higher thermal stability exceeding 673 K. For the pillaring of layered HNb3 O8 , two different pre-expanding agents, 1-dodecanamine and 1,12-dodecanediamine, were alternatively used, and two kinds of zirconium-pillaring solutions containing zirconium(IV) polyoxocations obtained through two different ways were employed. The 1,12-dodecanediamine-pre-expanded layered intermediate was applicable and 1-dodecanamine-pre-expanded one was not applicable to the intercalation of zirconium(IV) polyoxocations in interlayer regions of the layered niobium-based oxides. More interestingly, the zirconium-pillaring solutions prepared by using an appropriate amount of diethylene glycol as stabilizing agent was advantage for constructing the ordered zirconia-pillared product, whereas the zirconium-pillaring solutions obtained in the case of absence of diethylene glycol seemed not to conduct well an ions-exchange reaction with the alkylamine-pre-expanded layered intermediates. The order degree of zirconia-pillared layered transition metal oxides was closely related to the host sheets. The zirconia-pillared layered HNb3 O8 contained more defects, while the zirconia-pillared layered HNbMoO6 had fewer defects.

Effects of diethylene glycol on TiO2 thin film properties prepared by sol–gel process

A technological approach for the sol–gel processing of stabilized thin film titanium dioxide on the stainless steel has been extensively investigated in this paper. Diethylene glycol was used as a drying control additive agent. The transformation of a titanium dioxide thin film was studied by X-ray diffraction. The surface morphology was observed by scanning electron microscope (SEM). As results, this substance helped in stabilizing the solution and improving the adhesive property of the film. Without diethylene glycol, the thin film peeled off. Substantially improvement of film was seen with the high amount of diethylene glycol applied. This effect was confirmed by adhesive test and the morphology of stainless steel surface. In addition, adding diethylene glycol to the sol—gel solution exerted less effect on transformation of anatase to rutile phase in titanium dioxide structure. Thus, the nanocrystalline anatase phase of thin film TiO2 can be controlled and the high photoactivity of the film is secure.

Synthesis and characterization of oligoethylene bibenzoate with hydroxyethyl end groups

In the process of exploring the potential advantage of 4,4′-biphenyl dicarboxylic acid (BDA) as a comonomer in poly(ethylene terephthalate) (PET), it was found that BDA needs to be derivatized for effective incorporation in PET specifically if high levels of BDA incorporation are desired. Bis-hydroxyethylbibenzoate (HEB) was synthesized with the anticipation that it would be compatible with both the continuous PET process which uses high-purity terephthalic acid as well as the batch PET process which utilizes dimethyl terephthalate. This article describes the synthesis of HEB and some of the oligoethylene bibenzoates produced in the process. Diethylene glycol is produced as an undesirable by-product during the reaction. In an effort to produce a minimum amount of diethylene glycol, a catalytic process was investigated which resulted in diethylene glycol levels of less than 0.5%. Quantitative analysis of diethylene glycol, performed by gas chromatography, and the oligomer structure studies performed by 1H- and 13C-NMR are described. © 1996 John Wiley & Sons, Inc.

Effect of diethylene glycol (DEG) on the crystallization behavior of poly(ethylene terephthalate) (PET)

AbstractThe effect of diethylene glycol (DEG) on the crystallization of poly(ethylene terephthalate) (PET) was studied under isothermal and dynamic conditions. The strain‐induced crystallization of PET and its relationship to DEG content was also studied. The samples were isothermally and dynamically crystallized in the differential scanning calorimeter (DSC). The thermograms were then analyzed to determine the kinetic parameters. Strain‐induced crystallization was studied by stretching samples at different strain rates. These samples were then annealed for various periods of time and quenched to room temperature. Birefringence and density were measured on the annealed samples. Results indicate that the DEG content reduces the rate of crystallization of PET when crystallizing from the melt, isothermally and dynamically. When crystallizing from the glassy state, the effects of DEG are not prominent. The mechanism of crystallization is not affected by the amount of DEG, within the range of DEG contents evaluated. In the case of strain‐induced crystallization, increased DEG content reduces the crystallinity of PET at intermediate strain rates, but at higher strain rates, the crystallinity is not affected by the DEG content. © 1993 John Wiley & Sons, Inc.

Formation of diethylene glycol by dehydration of glycol in the presence of terephthalic acid

AbstractThe amount of diethylene glycol (DEG) formed as a result of the dehydration reaction of ethylene glycol (EG) in the presence of terephthalic acid (TPA) was measured. It became clear that the amount of DEG formed at the boiling point of EG can be expressed by a regression equation. It was confirmed that by this equation, the amount of DEG formed under the carboxylic end group concentration of 0.0 to 0.6 Eq/kg and the reaction time of 0 to 20 h can be estimated with high accuracy.

Influence of Metal Catalysts on the Formation of Ether Links in Polyethylene Terephthalate

Abstract The formation of ether linkages in polyethylene terephthalate was investigated using three different metal acetates as catalysts. The zinc salt was found to produce more ether bonds than either lead(II) or manganese(II) acetate. The amount of diethylene glycol detected in the fibers increased with rising catalyst concentration as well as with increasing polycondensation time. Negligible at the reesterification temperature of 195°C, ether formation became more important during the preheating period during which the polycondensation temperature was achieved (280°C). Most of the ether linkages were formed during the first 30 min of polycondensation and only a slow increase was observed thereafter. Model experiments conducted by heating pure ethylene glycol with the catalysts were in agreement with the polycondensation results.