Excess Glycol Research Articles

Importance of hydrogen bonding in base-catalyzed transesterification reactions with vicinal diols

The transesterification reaction kinetics of 2-(benzoyloxy)ethyl benzoate with various alcohols (ethylene glycol, 1,3-propanediol, 1-butanol, propylene glycol and 1,2-butylene glycol) using various cyclic amidine catalysts were investigated. For transesterification with excess glycol (glycolysis), the rate was nearly zero order in diester and glycol concentration, which is substantially different from classical transesterification kinetics with mono-alcohols. The measured kinetic parameters during glycolysis are consistent with a reaction path that is kinetically limited by the decomposition of the reaction intermediate formed from the alkoxide and diester. The DFT-calculated reaction energy and activation barrier for decomposition of this intermediate reveal a critical role of intramolecular hydrogen-bond stabilization made possible by the vicinal –OH of the glycol that effectively increases the concentration of the intermediate during reaction resulting in acceleration of the overall transesterification rate. These findings indicate the nature of both the alcohol solvent and the catalyst influence transesterification rate, and results suggest they are also important in the deconstruction of carbonyl-containing condensation polymers.

Sustainable PET Waste Recycling: Labels from PET Water Bottles Used as a Catalyst for the Chemical Recycling of the Same Bottles.

We report using a waste material, poly(ethylene terephthalate) (PET) water bottle labels, for the chemical recycling of the same PET water bottles. The solid fillers used for the manufacturing of the packaging labels were recovered by thermolysis in an electrical furnace at 600, 800, and 1000 °C with 13.5, 12.0, and 10.4 wt % recovery. Characterization of the solid residue showed the presence of calcium carbonate, calcium oxide, and titanium dioxide, which are typical fillers used for packaging film manufacturing, such as water bottle labels. These solid residues were then used as a catalyst for PET depolymerization by glycolysis, in which the catalyst recovered from bottle labels and shredded PET reacted in the presence of excess ethylene glycol at 200 °C. The reaction mixtures were analyzed for PET conversion and the yield of the bis(2-hydroxyethyl)terephthalate (BHET) monomer as the final product of the glycolysis reaction to determine the efficiency of the catalyst. Our results show that the catalyst prepared at 800 °C (Cat-800) has the best performance and provides a 100% PET conversion with a 95.8% BHET yield with a 1.0 wt % loading in 1.5 h. The catalyst from the PET water bottle labels is nontoxic, readily available, cost-effective, environmentally friendly, and can be used as a model for the self-sufficient chemical recycling of PET via glycolysis.

Glycol losses calculation in a gas dehydration unit

The gas dehydration process separates gas from water content by mixing absorbents such as glycol in the gas dehydration unit. The gas dehydration process can use triethylene glycol type glycol, reducing the water content to a minimum of 7 lb/mmscfd. In the dehydration process, glycol losses will usually occur either in the reboiler or contactor; for this reason, this study aims to determine the causes of glycol losses, calculate the water content absorbed in the contactor, determine the percentage of glycol losses and calculate how much glycol is needed in each 1mmscfd of gas. Glycol losses are classified into two types: expected and up-standard. In this case, the research method starts by calculating the amount of water content that can be absorbed, the percentage of glycol losses, and the amount of glycol volume required in every one mmscfd of gas. Causes of glycol losses include the number of trays, contact time, absorption surface area, flow rate, and temperature in the reboiler. Of the 60.96 mmscfd of wet gas that entered the contactor, it was found that 32.11 lb/mmscfd of water managed to absorb glycol. Based on the calculation of glycol losses in some test data, the average glycol losses (0.087 gal/mmscf) are still categorized as ordinary losses because the glycol losses that occur do not exceed the safe limit set by the industry, which is 0.01 – 0.15 gal /mmscf. One way to reduce the occurrence of glycol losses is to adjust the pump discharge to the incoming gas flow so that excess glycol is not used when there is contact between glycol and wet gas.

Dual catalytic activity of antimony (III) oxide: The polymerization catalyst for synthesis of polyethylene terephthalate also catalyze depolymerization

In this study polyethylene terephthalate (PET) waste from drinking water bottles was converted to bis(2-hydroxyethyl) terephthalate (BHET) in the presence of antimony (III) oxide (Sb2O3) as the catalyst and excess ethylene glycol (EG). The yield of BHET, using 0.5 wt% of the catalyst, under 200°C and 2.1 bar was 97.5%, achieved in only 1 h. The crude of the reaction and the purified monomer was characterized by differential scanning calorimetry, infrared spectroscopy, high pressure liquid chromatography, thermogravimetric analysis, and nuclear magnetic resonance. The influences of reaction parameters, such as the catalyst loading, reaction time, EG:PET weight ratio, and reaction pressure on the yield of BHET was investigated. In addition, the activity of this catalyst was compared to zinc acetate, antimony (III) acetate, and antimony (V) oxide, demonstrating the highest catalytic activity of Sb2O3 for PET glycolysis. Since Sb2O3 is one of the catalysts for the industrial synthesis of PET, the results from this work can open up a venue for the synthesis of repolymerized PET from waste PET in the same glycolysis reactor.

Multistage Chemical Recycling of Polyurethanes and Dicarbamates: A Glycolysis–Hydrolysis Demonstration

The use of polyurethanes and, therefore, the quantity of its scrap are increasing. Considering the thermoset characteristic of most polyurethanes, the most circular recycling method is by means of chemical depolymerization, for which glycolysis is finding its way into the industry. The main goal of polyurethane glycolysis is to recover the polyols used, but only limited attempts were made toward recovering the aromatic dicarbamate residues and derivates from the used isocyanates. By the split-phase glycolysis method, the recovered polyols form a top-layer phase and the bottom layer contain transreacted carbamates, excess glycol, amines, urea, and other side products. The hydrolysis of carbamates results in amines and CO2 as the main products. Consequently, the carbamates in the bottom layer of polyurethane split-phase glycolysis can also be hydrolyzed in a separate process, generating amines, which can serve as feedstock for isocyanate production to complete the polyurethane material cycle. In this paper, the full recycling of polyurethanes is reviewed and experimentally studied. As a matter of demonstration, combined glycolysis and hydrolysis led to an amine production yield of about 30% for model systems. With this result, we show the high potential for further research by future optimization of reaction conditions and catalysis.

Glycolysis of poly(ethylene terephthalate) waste catalyzed by mixed Lewis acidic ionic liquids

Widely used poly(ethylene terephthalate) (PET) material induces environmental concern on its wastes. In this paper, different 1-hexyl-3-methylimidazolium (Hmim) halometallates, including [Hmim]ZnCl3, [Hmim]CoCl3, [Hmim]FeCl4 and [Hmim]CuCl3, are synthesized as Lewis acidic ionic liquids (LAIL) catalysts for PET degradation in excess ethylene glycol (EG). By using individual or mixed LAIL catalysts, product bis(hydroxyethyl) terephthalate (BHET) is characterized by FT-IR, 1H-NMR and DSC et al. From the PET conversion and yield of BHET product, a synergistic effect is found in mixed [Hmim]ZnCl3 and [Hmim]CoCl3 complexes. 87.1% BHET from original PET wastes catalyzed by equimolar [Hmim]ZnCl3 and [Hmim]CoCl3 mixture is higher than any individual IL halometallate. The filter residues after removing the BHET products with different reacting time using [Hmim]ZnCl3 and [Hmim]CoCl3 as catalyst, respectively, are characterized by 1H-NMR. The area ratio of the methylene protons of COO–CH2 (δ = 4.30 ppm) and the aromatic protons of the benzene ring (δ = 8.12 ppm) of filter residues suggests that more by-products will be produced by [Hmim]ZnCl3 because of its relatively higher catalytic activity in the chain scission stage. The glycolysis synergy comes from the balance between high reactivity of [Hmim]ZnCl3 and high selectivity of [Hmim]CoCl3.

Four-factor optimization for PET glycolysis with consideration of the effect of sodium bicarbonate catalyst using response surface methodology

In this study, Response Surface Methodology based on four-factor Box-Behnken design was applied to suggest the optimal conditions for glycolysis of polyethylene terephthalate (PET) and to analyze the individual and interaction effects of the factors on the process. Four independent factors of interest, namely reaction time (3–5 h), reaction temperature (192–200 °C), mass ratio of ethylene glycol (EG) to PET (2.5–7.5), and mass ratio of sodium bicarbonate (NaHCO3) to PET (0.6–1.0%), were under consideration for their catalyst effect on the process. A regression model as a mathematical function of the four factors was obtained to predict the yield of bis(2-hydroxyethyl) terephthalate (BHET) yield and its reliability was evaluated by analysis of variance. A remarkably high yield of 75.7% was obtained with 1.3% error from the predicted value at the optimal operating conditions for temperature, time, EG:PET mass ratio, and NaHCO3:PET mass ratio of 192 °C, 3.02 h, 6.09 and 0.82%, respectively. The experimental results and analysis of response surfaces revealed that an inappropriately large amount of catalyst might restrict monomer conversion under excess EG conditions. Moreover, PET glycolysis process could be carried out under lower temperature and shorter time due to the profound effect of excess EG at a suitable concentration level of NaHCO3. This suggested future in-depth analysis with wider parameter space to optimize PET glycolysis under conditions of large amount of EG and to gain insight into the interaction effect between EG amount and catalyst concentration.

Regenerated cationic dyeable polyester deriving from poly(ethylene terephthalate) waste

In this paper, sodium-5-sulfo-bis(hydroxyethyl)-isophthalate (SIPE) comonomer, which could copolymerized with bis(hydroxyethyl) terephthalate (BHET) for dyeability modification of poly(ethylene terephthalate) (PET), was prepared through transesterification reaction of sodium dimethyl 5-sulfoisophthalate (SIPM) and ethylene glycol (EG). The obtained SIPE was then polycondensation reacted with BHET which was extracted from waste PET fiber depolymerization under nitrogen atmosphere with excess EG as glycolysis agent and zinc acetate (Zn(Ac)2) as catalyst, to achieve regenerated cationic dyeable polyester (rCDP). Chemical structure, thermal properties, intrinsic viscosity and thermal properties of rCDP were analyzed and compared with virgin CDP (vCDP). Effects of SIPE on rheological property and dyeability of rCDP were also investigated.

Effect of excess hydrogen bond donors on the electrode-electrolyte interface between choline chloride-ethylene glycol based solvents and copper

The fine tuning of deep eutectic solvents (DES) via the addition of co-solvents such as water or excess ethylene glycol, to improve the electrodeposition of metals is becoming increasingly common. However, as these changes become commonplace, our understanding of their effect must deepen as well. In this work, we look into how water, a secondary hydrogen bond donor (HBD), added to choline chloride:ethylene glycol (1:2 ChCl:EG) DES changes the electrochemical behaviour of the solution. We use time-of-flight secondary ion mass spectrometry (ToF-SIMS) to identify and map the organic molecules that have interacted with the surface. A copper surface was used as an electrochemically active substrate. The molecular maps provide insights into how solvent composition changes electrolyte reactivity, as well as showing the main driver behind the entrapment of organic compounds in metal deposits from DES. This behaviour was studied at different potentials based on the information provided by linear sweep voltammetry data of the copper in the solution. These results are then contrasted against a 1:4 ChCl:EG solution, where the excess ethylene glycol acts as secondary HBD, in order to determine the individual contributions of the co-solvents and how they affect the electrochemistry of the media and their reactions with the copper electrode. This information can be used as a set of guidelines for the tuning and optimisation of ethylene glycol based DES for metal deposition.

Decolorization and reusing of PET depolymerization waste liquid by electrochemical method with magnetic nanoelectrodes.

This work is aimed at electrochemical decolorization of real waste liquid which obtained in the PET depolymerization process. Firstly, PET fabrics were glycolysized by utilizing excess ethylene glycol (EG). Then, the glycolysis product was mixed with water and purified through repeated crystallization to get bis(2-hydroxyethyl) terephthalate (BHET) crystal. At last, the waste liquid of the depolymerization process was electrochemical decolorized by utilizing chitosan/Fe3O4 nanoparticles as the dispersed electrodes under a DC voltage. The UV-Vis absorptions at 338, 531, and 635nm which were due to the dyes in the waste liquid decreased with the electrolysis time. In contrast, slight change of absorption of EG (at 322nm) indicated that EG was not destroyed in the electrolytic process. The variation of color removal efficiency with dosage of chitosan/Fe3O4 nanoparticles, applied voltage, concentration of electrolyte, pH and electrolytic time were investigated. The max color removal efficiency was 87.24%. PET fabrics were depolymerized by using the decolorized waste liquid or mixture of decolorized waste liquid and EG (1:1 v/v), and the yields of BHET were 72.3% and 76.6%, respectively. The products were BHET without dyes which were confirmed by DSC and FTIR spectroscopy. Graphical abstract.

A New Approach to Chemical Recycling of Polyamide 6.6 and Synthesis of Polyurethanes with Recovered Intermediates

A new efficient method for the chemical decomposition of polyamide 6.6 by the glycolysis and amino-glycolysis processes was proposed. The glycolysis was conducted using the mass excess of ethylene glycol (EG) as a decomposing agent in the presence of a catalyst. Also, a mixture of EG and triethylenetetramine was used as another decomposing agent in the amino-glycolysis process. The described process of decomposition did not require the use of elevated pressure. The hydroxyl and amine numbers, rheology behavior and the presence of characteristic chemical groups in the obtained glycolysates and aminoglycolysates were determined in order to characterize the reaction products. The decomposition products were defined as non-Newtonian fluids that could be described by suitable mathematical models. The conducted studies showed that the properties of the obtained intermediates depend on the mass excess of the decomposing agent used. The resulting semi-products are suitable for reusing in the synthesis of polyurethanes, which has been confirmed by the exemplary synthesis. In the reaction, 10 and 15 wt% of commercial polyol were replaced with the recovered intermediates.

Process simulation of bis (2- hydroxyethyl) terephthalate and its recovery using two stage evaporation systems

To preserve the petroleum feedstock and eliminate the environmental problems peculiar to polyethene terephthalate (PET) bottles littering the environment. Chemical recycling method was adopted to convert PET into useful products of prosperous sizeable industrial application. This work employed ASPEN PLUS V8.8 to simulate chemical glycolysis depolymerisation process of PET plastic wastes, using plug flow reactor for commercial production of pure bis (2- hydroxyethyl) terephthalate (BHET). The data for modelling were gotten from the experimental PET glycolysis depolymerisation work. Excess ethylene glycol (EG) was used to degrade PET waste with zinc acetate (Zn(Ac)2) as the active catalyst. The optimum operating conditions of the reaction were mean particle size PET of 127.5 μm, EG:PET (w/w) ratio of 5:1,469 K temperature, 101325 N/m 2 pressure and 3 h residence time. Reaction results were 100 % depolymerisation of PET, 85.24 % yield of BHET and 14.76 % Oligomer. Purification of the BHET was done with two stages evaporation processes using flash columns and crystallizer. Higher temperature and lower pressure were observed to increase the efficiency of the evaporators, but the heat duties increased and momentarily reduced the BHET recovery. BHET recovery was observed to decrease with increase in temperature in the case of crystallisation operation. This work achieved a higher yield and purity of BHET, a higher EG removal for re-use and less heat duties demanded in comparison to previous works. The processes with its operating conditions can be used for future scaling up of commercial processes.

Carbios develops bio-recycling technology in 5-year project

Poly (ethylene terephthalate) (PET) products consumption has been increased dramatically over the past few decades which have resulted in generation of large quantity of PET waste. Disposal of this waste is a global concern due to its nonbiodegradability. In the present study, we report the effect of electron beam (EB) radiations on degradation of PET and its subsequent effect on glycolysis by using excess ethylene glycol (EG). The results as analyzed by molecular weight determination showed an increase in the extent of depolymerization of PET proportional to the dose of EB irradiation. The irradiated PET samples were further subjected to chemical recycling by glycolysis using conventional and microwave method in presence of excess EG and zinc acetate (0.5%) as a catalyst. Depolymerization of PET by EB irradiation resulted in increased yield of BHET after variable time intervals. The recycled material BHET was subjected to esterification using linseed oil fatty acid, further epoxidation using formic acid and hydrogen peroxide and subsequent hydrolysis to prepare ecofriendly polyol. The individual step product was analyzed for its physical and chemical parameters like% NVM, hydroxyl value, acid value, iodine value, oxirane oxygen content etc. and also characterized by spectroscopic analysis like FTIR, 1H NMR, 13C NMR and GPC technique for molecular weight determination. Polyurethane coatings based on this polyol were prepared using various commercial polyisocyanate curing agents. The coated films were evaluated for their optical, mechanical and chemical properties. Thermal properties of coatings were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

Synthesis and sizing performances of water-soluble polyester based on bis(2-hydroxyethyl) terephthalate derived from depolymerized waste poly(ethylene terephthalate) fabrics

This work aimed at effective chemical recycling of waste poly(ethylene terephthalate) (PET) fabrics into water-soluble polyester (WSP). For this, PET fabric waste was depolymerized using excess ethylene glycol (EG) in the presence of zinc acetate as catalyst. The glycolysis product of PET, bis(2-hydroxyethyl) terephthalate (BHET) was then used to synthesize WSP by a three-step method, that is, transesterification, esterification and polycondensation. The structures of BHET and WSP were identified by Fourier transform infrared spectra. Sizing performances of WSP were studied, and it was found that the surface tension of WSP size (57 mN/m, 22℃, 0.5% of weight) was lower than common sizes, the viscosity of WSP size was 1–2 mPa·S (95℃, 6% of weight) and the viscosity stability was larger than 90% at this temperature. The mixture of WSP and starch showed stronger adhesion to polyester–cotton roving and polyester roving than onefold starch. K/ S values of fibers before sizing and after desizing showed a slightly difference, which indicated that WSP would not influence the color of yarns when used as the sizing agent.

Synthesis of PET-PLA copolymer from recycle plastic bottle and study of its applications in the electrochromic devices with graphene conductive ink

In this study, waste poly(ethylene terephthalate) (PET) bottle was depolymerized using excess ethylene glycol (EG) in the presence of cobalt(II) acetate tetrahydrate ((CH3COO)2Co·4H2O) as a catalyst. It was found that the reacted products consist mainly of bis-2-hydroxy ethylene terephthalate (BHET) monomer. Poly(ethylene terephthalate)-poly(lactic acid) (PET-PLA) copolymers were synthesized by the reaction of BHET with L-lactic acid (LLA) monomers using the catalytic system. The samples were analyzed by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The 1H and 13C NMR studies confirm the incorporation of lactate units in PET chains after reaction. Further, we report the use of graphene conductive ink and PET-PLA as the electrochromic (EC) device. Copolymer film was coated with graphene ink by spin coating method. Our results primarily indicate that the configuration presents an easy and expeditious way.

New diols with imidazoquinazoline ring

The objective of these studies was to synthesize and characterize new diols with an imidazoquinazoline ring. New diols were obtained in reactions of 2,6-bis-(ethoxycarbonylmethyl)-1-phenylimidazo[1,5-c]quinazoline-3,5-dione with excess of ethylene glycol or in reaction of 1-phenyl-2H,6H-imidazo[1,5-c]quinazoline-3,5-dione with 2-M excess of ethylene oxide. The products were isolated at high yield and characterized by instrumental methods (IR, 1H- and 13C-NMR, MS-ESI, UV, TGA). The structure of 2,6-bis(2-hydroxyethyl)-1-phenylimidazo[1,5-c]quinazoline-3,5-dione (BEFIQ) was also investigated by single-crystal X-ray diffraction. BEFIQ crystallizes in the monoclinic P21/n space group with two molecules in the asymmetric unit of the crystal lattice. The nature of the packing of molecules in the crystal lattice of BEFIQ was investigated by Hirshfeld surface analysis. The described methods enable the synthesis of new diols with an imidazoquinazoline ring. The new diols are quite soluble in typical organic solvents. Therefore, they can be used as raw materials for the synthesis of thermally stable polymers, and they can also have biological activity.

Recycling of PET wastes using Electron beam radiations and preparation of polyurethane coatings using recycled material

Poly (ethylene terephthalate) (PET) products consumption has been increased dramatically over the past few decades which have resulted in generation of large quantity of PET waste. Disposal of this waste is a global concern due to its nonbiodegradability. In the present study, we report the effect of electron beam (EB) radiations on degradation of PET and its subsequent effect on glycolysis by using excess ethylene glycol (EG). The results as analyzed by molecular weight determination showed an increase in the extent of depolymerization of PET proportional to the dose of EB irradiation. The irradiated PET samples were further subjected to chemical recycling by glycolysis using conventional and microwave method in presence of excess EG and zinc acetate (0.5%) as a catalyst. Depolymerization of PET by EB irradiation resulted in increased yield of BHET after variable time intervals. The recycled material BHET was subjected to esterification using linseed oil fatty acid, further epoxidation using formic acid and hydrogen peroxide and subsequent hydrolysis to prepare ecofriendly polyol. The individual step product was analyzed for its physical and chemical parameters like% NVM, hydroxyl value, acid value, iodine value, oxirane oxygen content etc. and also characterized by spectroscopic analysis like FTIR, 1H NMR, 13C NMR and GPC technique for molecular weight determination. Polyurethane coatings based on this polyol were prepared using various commercial polyisocyanate curing agents. The coated films were evaluated for their optical, mechanical and chemical properties. Thermal properties of coatings were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

Carbonation and decarbonation of non-aqueous solutions with different compositions of ethylene glycol and various amidines

A mixture of equivalent amounts of amidine, alcohol, and carbon dioxide forms alklycarbonate amidinium salts. Here we studied the effect of the composition of solutions consisting of ethylene glycol (EG) as the alcohol and one of various amidines on their ability to absorb and desorb carbon dioxide. Compounds containing single or multiple formamidine groups were synthesized and dissolved in EG. The ability of these solutions to absorb carbon dioxide was studied for various ratios of EG to amidine and at various temperatures. An excess of at least ten equivalents of EG relative to the amidine was required for rapid and complete reaction of the base with carbon dioxide. Excess EG also reduced the viscosity of the solution, and in this way increased the absorption rate. However, the excess EG appeared to have stabilized the formed alkyl carbonate salts via hydrogen bonding, resulting in a relatively low degree of decarbonation of the solution at elevated temperatures. This effect would cause the working capacity to be decreased were this type of material be used for carbon dioxide capture applications. Our results suggest that, in general, the compositions of the alcoholic solutions of superbases need to be optimized to achieve high-efficiency absorption and desorption of carbon dioxide.

Synthesis and structural characterization by NMR and X-ray of new Morita-Baylis-Hillman adducts derived from 7-chloroquinoline

Herein we describe the design, synthesis and structural characterization by NMR and X-ray of new molecular hybrids 4a-4c containing the nitroaromatic MBHA moiety and the 7-chloroquinoline pharmacophores, linked by an aliphatic spacer as a model for antiprotozoal drugs. Firstly, the 4,7-dichloroquinoline (7) reacted with excess of ethylene glycol, through a SNAr promoted by t-BuOK, to prepare the 2-(7-chloroquinolin-4-yloxy)ethanol (6) in 98% isolated yield. Then, the novel 2-(7-chloroquinolin-4-yloxy) ethyl acrylate (5) was synthesized in 78% isolated yield by reacting the alcohol (6) with acryloyl chloride and TEA in CH2Cl2. Finally, this acrylate (5) reacted with o-nitrobenzaldehyde, m-nitrobenzaldehyde and p-nitrobenzaldehyde through Morita-Baylis-Hillman reactions promoted by DABCO at room temperature, using t-BuOH:Water (9:1) as solvent, to afford the new hybrids 4a-4c in 73–76% isolated yields. Three-dimensional structures were characterized in both monomeric and intermolecular packing by X-Ray experiments.

Effect of γ‐irradiation on glycolysis of PET waste and preparation of ecofriendly coatings using bio‐based and recycled materials

Recycling of postconsumer poly (ethylene terephthalate) (PET) is a worldwide concern due to large increasing volume of these materials produced by society. In the present study, we report the effect of gamma irradiation on degradation of PET and its subsequent effect on glycolysis by using excess ethylene glycol (EG). The results as analyzed by molecular weight determination showed that extent of depolymerization of PET were dose dependent. The doses of 30, 50, 70, and 100 kGy resulted in decrease in the molecular weight by about 15%, 25%, 30%, and 40% respectively. The irradiated waste PET samples were further subjected to glycolysis using EG by conventional and microwave method which resulted in increased yield of monomeric product, bis (2‐hydroxyethylterephthalate) (BHET). The recycled material, BHET, was then used in combination with bio‐based monomers to prepare a new eco‐friendly polyester polyol which was analyzed for hydroxyl, saponification, acid value and further characterized by FTIR, 1HNMR, and GPC techniques for molecular weight determination. Polyurethane coatings were prepared from the polyester polyol and various commercial polyisocyanate curing agents. The coated films were evaluated for their performance properties. Thermal properties of coatings were investigated by differential scanning calorimetry and thermogravimetric analysis. POLYM. ENG. SCI., 55:2653–2660, 2015. © 2015 Society of Plastics Engineers