Butane-1,4-diol Research Articles

Research on the performance of three-dimensional-braided-glass fiber reinforced in-situ polymerized TPU

In this study, thermoplastic polyurethane (TPU) is prepared by using 4,4′-methylenediphenyl diisocyanate (4,4′-MDI), poly (1,4-butylene adipate) (PBA), and butane-1,4-diol (BDO). PBA as soft segment for TPU. 4,4′- MDI and BDO as hard segment for TPU. The effects of isocyanate index, hard segment content, and soft segment molecular weight on TPU micro-phase separation, molecular weight, and thermal performance are investigated. 3D-Braided-Glass Fiber (GF) reinforced TPU composites are prepared by in-situ polymerized TPU as the matrix resin. Investigation is conducted into how the mechanical properties and microstructure of the composites are affected by the matrix resin TPU’s structural parameters. As the isocyanate index increases, the mechanical properties of the composites first enhance and then weaken, and the interface bonding between TPU and GF gradually deteriorates. Increasing the molecular weight of soft segments has the same trend of change. With the increase of hard segment content, the mechanical properties of the composites are enhanced. The results demonstrate that the mechanical properties of the TPU/GF composites are at their best when the isocyanate index is 1.01, the hard segment content is 43%, and the PBA molecular weight is 2000, with the stretching strength being 289.6 MPa, the impact strength being 141.8 KJ/mm2, the bending strength being 183.2 MPa, and the flexural modulus being 10.7 GPa.

The strengthening mechanism of mechanical performance for polyurethanes with micro-content crosslinkers

Chemical crosslinking is one widely used method to endow polyurethane (PU) with desirable properties. However, the introduction of crosslinkers in PU elastomers can often lead to the destruction of phase separation, resulting in weakened mechanical properties. Herein, a series of PUs with micro-content crosslinker were synthesized from poly(oxytetramethylene) glycol (PTMG), diphenylmethane-4,4′-diisocyanate (MDI), and chain extender of butane-1,4-diol (BDO) containing varied amounts of glycerol. The phase separation of PUs decreases with increased glycerol content, while the tensile strength increases. To elucidate this enhancement in mechanical properties, morphology investigation with capability of direct observation of components distribution is employed. An increased thickness of interphase between the domain of hard segment (HS) and soft segment (SS) is observed, which indicates that more HS is moved to the interphase upon the introduction of glycerol. The results of electron energy loss spectroscopy (EELS) further disclosed that glycerol formed aggregations located at the interphase. These aggregations increase the crosslinking density of the interphase, which strengthens HS domains and prevents them from being destroyed under tension, thereby increasing the tensile strength. It is the first time of disclosing distribution feature of micro-content crosslinker of PU as well its strengthening mechanism in tensile strength, which could assist in developing PU with desirable mechanical properties.

Alcohol‐Treated Nickel‐Aluminium Catalyst for One‐Step Highly‐Selective Butane‐1,4‐Diol Synthesis from 2‐Butyne‐1,4‐Diol

AbstractThe development of low‐cost nickel‐based catalysts for direct and selective hydrogenation of 2‐butyne‐1,4‐diol (BYD) to butane‐1,4‐diol (BAD) under mild conditions is an important and attractive target both in fundamental research and industrialization but remains a formidable challenge. The primary industrial production method for BAD synthesis is a two‐step reaction route, which suffers from complicated catalysis conditions and high equipment costs. Herein, we develop a high‐performance catalyst via a facile alcohol‐treated strategy for highly selective BAD synthesis at moderate operation conditions. The as‐synthesized NA‐80E catalyst exhibits outstanding BAD selectivity of 98.82 % and BYD conversion of 100 % at 60 °C and 4 MPa, outperforming most reported results for BAD formation in a one‐step process and even being comparable to those obtained by the two‐step hydrogenation reaction route under much high temperatures and pressures. Crucially, we found that after facile alcohol (ethanol) treatment, an intriguing phenomenon of suppression of adjacent acid‐assisted hydrogenolysis via extra acidic Al species at the NiO‐Al2O3 interface is observed, contributing to the precise enhancement of BAD selectivity by inhibiting the production of butanol (BOL). This facile alcohol‐treated method along with the revealed mechanism of blocked hydrogenolysis opens vast possibilities for designing high‐performance and highly‐selective hydrogenation catalysts.

Hydrophilic polyurethane films containing gastrodin as potential temporary biomaterials

Elastomeric polyurethane films containing HDI or IPDI diisocyanate, poly(caprolactone) diol and butane-1,4-diol (BD) or gastrodin (GS) were synthesized in two-step polyaddition reaction. Their chemical structures were confirmed by FTIR and NMR spectroscopy. The phase structure was analyzed by WAXD and DSC methods, confirming the presence of a crystalline phase in the hard domains. The introduction of GS instead of BD results in an increase in the free surface energy of the films (FSE > 40 mJ/m2). The consequence of this is an increase in the water uptake, but at the same time a reduction in resistance to hydrolysis in Baxter's salt solution, as well as increased biodegradability in contact with bacterial strains (Bacillus sp. - gram positive, Pseudomonas sp. - gram negative). PU elastomeric films modified by gastrodin can be applied in tissue engineering films as temporary biomaterials with hydrophilic properties, capable of biodegradation in the body.

Effect of chain extenders on the hydrolytic degradation of soybean polyurethane

AbstractThis publication highlights the effect that different chain extenders (CEs) have on the structure–property relationships of soy‐based polyurethanes that have been exposed to hydrolytic degradation for 480 and 960 h at 80°C. Gel content, crosslinking densities, surface energy, atomic force microscopy, dielectric, and dynamic mechanics were used for monitored structural changes. Polyurethanes (PU) is composed of a structure with minor phase separation when a chain extender is not used, maintaining all properties over time. However, when a chain extender, butane‐1.4‐diol (BDO), ethane‐1.2‐diol (MEG) our (2‐hydroxypropoxy)‐propane‐2‐ol are added, it is noted that there is a more significant degradation in the flexible domains, modifying the fraction between the initial rigid (HS)/soft (SS) segment that makes the polymer stiff and brittle. The hydrolysis degradation generates new Fourier transform infrared bands relative to urea (1640 cm−1) and amide (1800 cm−1). The reduction in band intensity of the C=Ofree at 1730 cm−1, while increasing the intensity of C=Obonded at 1710 cm−1 indicated a higher phase separation degree. After 960 h the TgS decreased, while the TgH was practically unchanged. The higher polarization observed in the PUs with BDO and MEG samples indicates the increased phase separation resulting in hydrolytic degradation.

Microwave-assisted chemical recycling of polylactide (PLA) by alcoholysis with various diols

A process for the chemical recycling of degradable polylactide (PLA) has been developed, to convert its disposable wastes into small-sized products for further use as value-added starting materials for specialty products. A microwave-assisted alcoholysis reaction, using diols and tetrabutyl orthotitanate (TBT) catalyst, was employed. The effects of the types of diols and PLA/diol feeding ratios on the structures and properties of the resulting alcoholized products were examined by using ethylene glycol (EG), propane-1,3-diol (PDO), and butane-1,4-diol (BDO). The PLA/diol ratios were varied from 1:1 to 4:1 wt/wt. The products were characterized by ATR-FTIR, 1H NMR, and 2D-NMR HMQC and HMBC spectroscopy. The products compost to diol-capped lactate sequences with different lengths, i.e., lactate, lactyllactate, and poly-lactate. The yield of the shortest lactate was about 65% for the LBDOT11 system, and 90% for the LEGT11 and LPDOT11 systems, when a feeding ratio of 1:1 wt/wt was employed. The yield decreased with an increase in the ratios, from 1:1 to 4:1 wt/wt. In contrast, the yields of longer lactyllactate and poly-lactate increased with an increase in the ratios. In terms of OH-endcapping efficiency, the products have two structures: (A) LA-O-(CH2)x-OH and (B) LA-O-(CH2)x-O-LA. The contents depend on diol types and the PLA/diol feeding ratio. The alcoholized products were then used as starting polyols in the preparation of lactide-based polyurethanes (PUs) by reacting with 1,6-diisocyanatohexane (HDI) and BDO chain extender. The resulting PUs exhibit promising mechanical and thermal properties. These PUs are suitable for use as either single-component materials, e.g., 3D-printing filaments and degradable adhesives, or as toughness-enhancing agents for brittle polymers, especially PLA.

Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane.

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

The effect of pre-set extension on the degree of hydrolytic degradation in multicomponent polyurethane elastomers

The impact of pre-set extension on the degree of hydrolytic degradation in all-aliphatic polyurethane (PU) films was tested in phosphate-buffered saline (PBS) for a period of up to 12 months. The PUs were synthesized from polycarbonate-based macrodiol (MD), diisocyanate-1,6-hexane (HDI), butane-1,4-diol (BD) and d,l-lactide-based oligomeric diol (DLL). Macrodiol with molecular weights of ∼2800 Da, three DLL oligomers (∼400, 660 and 850 Da) and three MD-to-BD-to-DLL molar ratios were chosen for PU synthesis. The isocyanate-to-total-hydroxyl-group ratio was kept constant at 1.05. The functional properties of raw polyurethane films and the samples immersed for 1, 3, 6, 9 and 12 months in a model physiological environment (37 °C, pH = 7.4) were studied. The pre-set extension varied from 20 up to 150% and was applied on PUs with or without any DLL. The given pre-set strain had only slight – but varying – influence on the extent of the hydrolytic process, compared to the non-extended analogues. In samples that underwent efficient orientation and crystallization under strain (three-component PU and PU containing DLL ca. 400 Da), the degradation process was slightly inhibited compared with that of the unstrained analogues. If the systems were composed of sequences not capable of efficient crystallization under strain (PUs containing DLL ca. 660 and 850 Da), then the hydrolytic degradation of the pre-strained samples was accelerated. The observed changes in the functional properties of the mechanically strained PU materials subjected to the long-term hydrolytic process under physiology-mimicking conditions are important for potential medical, package coating, and film applications.

The influence of the length of the degradable segment on the functional properties and hydrolytic stability of multi-component polyurethane elastomeric films

The hydrolytic degradation of aliphatic polyurethane (PU) films made from polycarbonate-based macrodiol (MD), diisocyanate-1,6-hexane, butane-1,4-diol (BD) and d,l-lactide-based oligomeric diol (DLL) was studied. The influence of the length of DLL was tested in phosphate-buffered saline (PBS) for periods of up to 12 months. One macrodiol (molecular weight ∼2000 Da), three DLL oligomers (∼400, 660 and 850 Da) and three MD-to-BD-to-DLL molar ratios were chosen for the PU synthesis. The isocyanate-to-total hydroxyl-group ratio was kept constant at 1.05. The functional properties of raw polyurethane films and samples immersed for 1, 3, 6, 9 and 12 months in a model physiological environment (37 °C, pH = 7.4) were studied from the segmental to the macroscopic level. Tensile testing and water uptake experiments, as well as differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR) and wide-angle X-ray diffraction (XRD) analyses, were used for the characterization of the raw and PBS-treated films. The study shows that the length of the DLL chain is much more important for functional PU properties than the mass content of DLL in the PU film. The incorporation of the shortest DLL into the PU backbone leads to a degradable PU material with outstanding tensile properties when not subjected to the hydrolytic treatment. However, the incorporation of oligomers with longer DLL chains results in PU materials with substantially deteriorated tensile characteristics due to more pronounced phase separation compared to systems without DLL or with the shortest DLL. The degradability of the PU films can be controlled to a relatively broad extent by altering DLL content and length. The investigation of functional properties of new PU materials during the hydrolytic process under physiology-mimicking conditions is important for potential medical/package coating/film applications.

Nanocomposites made from thermoplastic waterborne polyurethane and colloidal silica. The influence of nanosilica type and amount on the functional properties

Abstract Novel waterborne polyurethane/silica nanocomposites were prepared via blending of two aqueous dispersions. Polyurethane water dispersion (PUD) was synthesized from polycarbonate diol (PC), 1,6-diisocyanatohexane (HDI) and butane-1,4-diol (BD) in order to provide solely linear character of PU chain. Two types of commercial colloidal silica, Ludox AS and Ludox TMA, differing in the size, shape and type of counter ions were used. The nanocomposites were made from negatively charged PUD and aqueous nanofiller sol at concentrations 5, 32 and 50 wt% of nanosilica. The films were obtained after slow drying of the water mixtures and characterized by AFM, SEM, tensile testing, DMTA, TG and water uptake measurements. It was found that all films are thermoplastics materials, reinforced by hydrogen bonds between silica particles and the polymer matrix, soluble in organic solvents and possible to re-production of PUD. Ludox AS was smaller than TMA and revealed better improvement of PUD-based films due to higher physical cross-linking density. It was observed that film containing 32 wt% of silica Ludox AS showed ten-times increasing Young’s modulus with slight improvement of elongation at break and two-times higher melting temperature in comparison to the neat PU matrix. Moreover sample with 5 wt% of AS nanofiller loading revealed excellent water resistance (swelling 0.8%). The obtained PU/silica nanocomposites have promising applications in recyclable environment-friendly waterborne coatings.

Experimental study of the simulated process of degradation of polycarbonate- and d,l-lactide-based polyurethane elastomers under conditions mimicking the physiological environment

The extent of the hydrolytic degradation of aliphatic polyurethane (PU) films made from polycarbonate-based aliphatic macrodiol (MD), diisocyanate-1,6-hexane, butane-1,4-diol (BD) and d,l-lactide-based oligomeric diol (DLL) was tested in phosphate-buffered saline (PBS) for a period of up to 12 months. Two macrodiols of equal molecular weight (∼2000 Da), differing in chain composition and regularity, and equal MD-to-BD-to-DLL molar ratios were chosen for the PU synthesis. The isocyanate-to-total hydroxyl group ratio was kept constant at 1.05. The functional properties of raw four-component polyurethane films and samples immersed for 1, 3, 6, 9 and 12 months in a model physiological environment (37 °C, pH = 7.4) were studied from the segmental up to the macroscopic level. Tensile testing and water uptake experiments, as well as DSC, SEM, AFM, FTIR and WAXD analyses, were used for the comprehensive characterization of the raw and PBS-treated films. The study shows that the untreated four-component PU films are highly elastomeric materials with very high tensile strength and suitable thermal properties for potential medical coating/film applications. The DLL oligomeric diol turned out to be a very efficiently degradable unit, leading to substantial mechanical property deterioration. The products of more regular macrodiol have higher tendency to the degradation process; 89% or 94% of the original toughness value is lost in just 12 months of immersion. The studied type of PU can be practically used either as fairly stable high-performance elastomers for short-term applications (up to 3 months) or as degradable materials, when the time of exposure to the physiology-mimicking conditions is sufficient.

Hydrolytic stability of polycarbonate-based polyurethane elastomers tested in physiologically simulated conditions

The hydrolytic stability of all-aliphatic polyurethane (PU) films made from polycarbonate-based aliphatic macrodiols (MD), diisocyanate-1,6-hexane and butane-1,4-diol (BD) were tested at 37 °C in phosphate buffer for a period up to 12 months. Two macrodiols, differing in composition and chain regularity and two MD-to-BD ratios were chosen for PU synthesis. The isocyanate-to-total hydroxyl ratio was kept constant and equal to 1.05. The functional properties of the original polyurethane films and films being immersed for 1, 3, 6 and 12 months in model physiological environment (37 °C at pH = 7.4) were studied on segmental up to macroscopic levels. The combination of SEM, AFM, FTIR, DSC, tensile and swelling analyses were used. It was found that prepared PU films are very good elastomeric materials with outstanding mechanical and suitable thermal properties keeping these properties practically unchanged for a period of up to 12 months. They can be practically used for example as strong and durable topcoats.

Thioether functional chain extender for thermoplastic polyurethanes

In this study, a novel three functional chain extender (TATATRIOL) was synthesized from the reaction of 1,3,5-tri(prop-2-en-1-yl)-1,3,5-triazinane-2,4,6-trione (TATA) with 2-sulfanylethanol. Then new thermoplastic polyurethanes (TPUs) were synthesized by a one-step bulk polymerization from the reaction of 1,1′-methanediylbis(4-isocyanatocyclohexane) (H12MDI), a poly(ethylene adipate) based polyester polyol and a chain extender. Butane-1,4-diol (BD) and the newly synthesized monomer, TATATRIOL, were used as chain extenders. The effects of TATATRIOL on the properties of the TPU were investigated and compared to those of the TPU prepared with BD. The TPUs which derived from the sulfur containing chain extender displayed lower modulus and high elongation at break values than the analogous TPUs derived from BD. Moreover sulfur containing TPUs exhibited higher thermal stability.

Thermal and mechanical properties of multiple‐component aliphatic degradable polyurethanes

ABSTRACTMacroscopic thermal and mechanical properties of complex aliphatic polycarbonate‐based polyurethane (PU) films containing degradable ester units in PU backbone were studied by a combination of several experimental techniques. Differential scanning calorimetry (DSC) revealed that the synthesized oligomeric diol (DL‐L) contributes (in addition to polycarbonate diol) to the formation of soft‐segment domains, while the hard‐segment domains are formed from 1,6‐diisocyanatohexane (HDI) and butane‐1,4‐diol (BD). Three main phase transitions were detected by DSC and by dynamic mechanical thermal analysis. Thermogravimetric analysis (TGA) of two‐component PUs showed that the PU made from DL‐L and HDI is the least thermostable product, while the PU made from polycarbonate diol and HDI is the most stable one. The differences in the thermal stability of different four‐component PUs are not important. Tensile properties very sensitively reflect the changes in composition and in microstructure of PU samples; the best tensile properties exhibits the degradable sample containing the equimolar ratio of hydroxyl groups of macrodiol, oligomeric diol DL‐L and butane‐1,4‐diol. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41872.

Multiscale approach to the morphology, structure, and segmental dynamics of complex degradable aliphatic polyurethanes

ABSTRACTA multiscale approach spanning from the segmental (subnanometer) up to micrometer level was applied for detailed study of the self‐assembly of aliphatic block polyurethane (PU) elastomers. To understand the principles of the self‐organization of hard and soft segments in the complex multi‐component systems, several two‐component model PU samples, that is, the products of 1,6‐diisocyanatohexane (HDI) with three diols differing in the length and constitution were also prepared, characterized, and investigated: (i) polycarbonate‐based macrodiol (MD), (ii) biodegradable oligomeric diol (DL‐L; product of butane‐1,4‐diol and D,L‐lactide), and (iii) butane‐1,4‐diol (BD). The study (particularly 13C‐1H PILGRIM NMR spectra) reveals complex internal organization and interesting (application appealing) behavior of multi‐component PUs. Hard segments (HDI+BD products) feature self‐assembled and significantly folded chain conformations with interdomain spacing 15–22 nm (small‐angle X‐ray scattering analysis). The small domains are hierarchically assembled in various structural formations of µm size (spherulites) depending on PU composition, as detected by transmission electron microscopy and atomic force microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41590.

Hypothermic and toxic actions of 2-butyne-1, 4-diol and other related diols in the rat.

Abstract The effects of 2-butyne-1,4-diol (BYDL) and related congeners on the body temperature of the rat have been determined. BYDL, at doses above 0·4 mmol kg−1 intraperitoneally, produced a significant fall in body temperature which was dose dependent. 2-butene-1,4-diol (BEDL) had no hypothermic action, and butane-1,4-diol (BDL) produced only a moderate fall in temperature (1·9°) which correlated with the time course of the hypnotic effect of the drug. γ-Butyrolac-tone (GBL), γ-hydroxybutyric acid (GHB) and pentobarbitone at hypnotic doses had similar hypothermic actions which correlated with the period of hypnosis. The hypothermia produced by BYDL could not be prevented by pretreatment with scopolamine or by maintaining the rats at high environmental temperature (32°). BYDL was far more toxic than the other diols examined (LD50 = 0·609-0·635 mmol kg−1 compared to BEDL: 3·71-3·74 mmol kg−1 and BDL: 11·87-11·90 mmol kg−1). Pretreatment of rats with pyrazole, an inhibitor of liver alcohol dehydrogenase, prevented the toxic and hypothermic actions of BYDL. From earlier studies with pyrazole and BDL it was concluded that BYDL itself was not active but that it was possibly converted in vivo by liver alcohol dehydrogenase to a toxic metabolite.

Hydrolytic Degradation and Monomer Recovery of Poly(butylene succinate) and Poly(butylene succinate/adipate) in the Melt

AbstractAliphatic dicarboxylic acid/aliphatic diol‐derived polyesters, poly(butylene succinate) and poly(butylene succinate/adipate), have been hydrolytically degraded in the melt in high‐temperature and high‐pressure water over a wide temperature range of 180–300 °C for periods of up to 30 min. The formation/decomposition of succinic acid (SA), adipic acid (AA), and butane‐1,4‐diol (BD), plus the molecular weight change of PBS and PBSA were then investigated. SA and AA were recovered at maximum yields of 65–80%, whereas BD was recovered at a maximum yield of only 30%, probably because of its decomposition. The obtained results were compared with those reported for aliphatic hydroxycarboxylic acid‐derived polyesters and aromatic dicarboxylic acid/aliphatic diol‐derived polyesters.magnified image

Continuous Hydrogenation of 2-Butyne-1,4-diol to 2-Butene- and Butane-1,4-diols

Continuous catalytic hydrogenation of 2-butyne-1,4-diol (B 3D) was carried out in a fixed-bed reactor over 1% Pt/CaCO3 catalyst to give 2-butene-1,4-diol (B 2D) and butane-1,4-diol (B1D) without formation of any other side products. In case of continuous hydrogenation, higher selectivity (66%) to B2D could be obtained and the selectivity pattern was completely different from that found in case of batch slurry operation in which B 1D selectivity was very much higher (83%) than the B2D selectivity (17%). Another interesting feature was that by varying the contact time, the selectivity to both B 2D as well as B1D could be varied over a wide range which is an attractive option to obtain the desired products mix of B 1D and B2D, depending on the fluctuation in the market demand. Further, a mathematical model for reactor performance was also developed on the basis of the kinetic data obtained previously in a batch slurry reactor. The predicted values of conversion, selectivity, and rate of hydrogenation were found to agree with the experimental data over a wide range of conditions.

Elution behaviour of diolmodified epoxides in size exclusion chromatography

AbstractThe reaction of bisphenol A‐diglycidyl ether (BADGE) with butane‐1,4‐diol (BD) in the presence of Mg(ClO4)2 leads to linear and branched oligomers. The formation ratio of these products depends on the reaction temperature. In experiments at 100°C, an epoxide consumption of up to 70% can be observed using HPLC. In this range all products show good solubility in THF, so that it is possible to follow the increasing molar mass by using SEC. A characteristic relation of the molar mass against the conversion rate is derived and SEC data of a branched product are discussed.

Thermal and pyrolysis studies of copolyesters

AbstractRandom copolyesters of dimethyl terephthalate (DMT), ethylene glycol (EG), and butane‐1,4‐diol (BD) and the homopolyesters poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) have been subjected to degradation and pyrolysis studies. Differential thermal analysis (DTA) showed that the decomposition temperature is dependent on the percentage of EG and BD present in the copolyesters. Thermal volatilization analysis (TVA) also showed that the decomposition temperature is dependent on the percentage of EG and BD present in the copolyesters. The trend for the decomposition temperatures obtained from TVA studies for these copolyesters is similar to such other thermal properties as melting temperature Tm, ΔHf, ΔHc, etc. The subambient thermal volatilization analysis (SATVA) curves obtained for these polymers are also presented. The SATVA curve is the fingerprint of the total volatile products formed during the degradation in high vacuum. The isothermal pyrolysis of these materials was carried out in high vacuum at 450°C. The products formed were separated in a gas chromatograph and were subsequently identified in a mass spectrometer. The major pyrolysis products from PBT were butadiene and tetrahydrofuran, whereas those from PET were ethylene and acetaldehyde. The ratio of acetaldehyde to ethylene increases with the EG content in the copolyester, suggesting a different decomposition mechanism compared to the decomposition mechanism of PBT and PET.