scholarly journals Effectiveness of Esterification Catalysts in the Synthesis of Poly(Ethylene Vanillate)

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 822
Author(s):  
Eleftheria Xanthopoulou ◽  
Alexandra Zamboulis ◽  
Zoi Terzopoulou ◽  
Margaritis Kostoglou ◽  
Dimitrios N. Bikiaris ◽  
...  
Keyword(s):  
Evolved Gas Analysis ◽  
Group Analysis ◽  
Polymeric Materials ◽  
Gas Analysis ◽  
Color Measurement ◽  
Resonance Spectroscopy ◽  
Antimony Trioxide ◽  
Scanning Calorimetry ◽  
Titanium Butoxide ◽  
Poly Ethylene

Over the last few decades, bio-based polymers have attracted considerable attention from both academic and industrial fields regarding the minimization of the environmental impact arising from the excessive use of petrochemically-based polymeric materials. In this context, poly(ethylene vanillate) (PEV), an alipharomatic polyester prepared from 4-(2-hydroxyethoxy)-3-methoxybenzoic acid, a monomer originating from lignin-derived vanillic acid, has shown promising thermal and mechanical properties. Herein, the effects of three different catalysts, namely titanium butoxide (TBT), titanium isopropoxide (TIS), and antimony trioxide (Sb2O3), on the synthesis of PEV via a two-stage melt polycondensation method are investigated. The progress of the reaction is assessed using various complementary techniques, such as intrinsic viscosity measurement (IV), end group analysis (AV), nuclear magnetic resonance spectroscopy (NMR), Fourier-transformed infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The thermal stability of the produced polyesters is studied by evolved gas analysis mass spectrometry (EGA-MS). Moreover, as the discoloration in polymers affects their applications, color measurement is performed here. Finally, theoretical kinetic studies are carried out to rationalize the experimental observations.

scholarly journals Synthesis of Hydrophilic Poly(butylene succinate-butylene dilinoleate) (PBS-DLS) Copolymers Containing Poly(ethylene glycol) (PEG) of Variable Molecular Weights

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3177
Author(s):  
Moein Zarei ◽  
Miroslawa El Fray
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Ethylene Glycol ◽  
Polymeric Materials ◽  
Glycol Succinate ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Butylene Succinate ◽  
Molecular Weights

Polymeric materials have numerous applications from the industrial to medical fields because of their vast controllable properties. In this study, we aimed to synthesize series of poly(butylene succinate-dilinoleic succinate-ethylene glycol succinate) (PBS-DLS-PEG) copolymers, by two-step polycondensation using a heterogeneous catalyst and a two-step process. PEG of different molecular weights, namely, 1000 g/mol and 6000 g/mol, was used in order to study its effect on the surface and thermal properties. The amount of the PBS hard segment in all copolymers was fixed at 70 wt%, while different ratios between the soft segments (DLS and PEG) were applied. The chemical structure of PBS-DLS-PEG was evaluated using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Gel permeation chromatography was used to determine the molecular weight and dispersity index. The results of structural analysis indicate the incorporation of PEG in the macrochain. The physical and thermal properties of the newly synthesized copolymers were also evaluated using water contact angle measurements, differential scanning calorimetry and dynamic thermomechanical analysis. It was found that increasing the amount of PEG of a higher molecular weight increased the surface wettability of the new materials while maintaining their thermal properties. Importantly, the two-step melt polycondensation allowed a direct fabrication of a polymeric filament with a well-controlled diameter directly from the reactor. The obtained results clearly show that the use of two-step polycondensation in the melt allows obtaining novel PBS-DLS-PEG copolymers and creates new opportunities for the controlled processing of these hydrophilic and thermally stable copolymers for 3D printing technology, which is increasingly used in medical techniques.

scholarly journals Preparation and Characterization of Poly(ethylene-co-vinyl alcohol)/poly(ε-caprolactone) Blend for Bioscaffolding Applications

2020 ◽  
Vol 21 (16) ◽  
pp. 5881 ◽  
Author(s):  
Abdulaziz Ali Alghamdi ◽  
Hussain Alattas ◽  
Waseem Sharaf Saeed ◽  
Abdel-Basit Al-Odayni ◽  
Ali Alrahlah ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Vinyl Alcohol ◽  
Polymeric Materials ◽  
In Vitro Cytotoxicity ◽  
Hydroxyl Groups ◽  
Scanning Calorimetry ◽  
Reduced Pressure ◽  
Static Contact ◽  
Poly Ethylene

In order to improve the cell adhesion on poly(ε-caprolactone) (PCL) scaffolds, poly(ethylene-co-vinyl alcohol) (E-VAL) which has hydroxyl groups capable of developing hydrogen bonds with celling was blended with this polymer. To reach this goal, a series of E-VAL/PCL blends with different compositions were prepared by the solvent casting method. The miscibility of the polymer blend was proved by differential scanning calorimetry and Fourier-transform infrared spectroscopy spectrometry. Furthermore, the mechanical properties of the polymer blends were assessed in their wet state by dynamic mechanical analysis. The surfaces wettability of blends and their components were examined through static contact angle measurements. The pore interconnections in the resulted scaffolds were achieved by the incorporation of naphthalene microparticles which were used as porogen and then removed in its gas state by sublimation under reduced pressure. The presence of pores interconnected inside the polymeric materials and their surface morphologies was examined by scanning electron microscopy. The in-vitro cytotoxicity and cell adhesion on the prepared materials were examined by an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay.

scholarly journals Relationship between Degree of Polymeric Ionisation and Hydrolytic Degradation of Eudragit® E Polymers under Extreme Acid Conditions

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1010 ◽  
Author(s):  
Valentina Linares ◽  
Cristhian J. Yarce ◽  
Juan D. Echeverri ◽  
Elkin Galeano ◽  
Constain H. Salamanca
Keyword(s):  
Sessile Drop ◽  
Aqueous Media ◽  
Hydrolytic Degradation ◽  
Flow Characteristics ◽  
Polymeric Materials ◽  
Two Dimensions ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Angle Measurements ◽  
Window Method

The commercial copolymers Eudragit® E 100 and Eudragit® PO are widely used materials in the pharmaceutical field as coating systems. Such materials derived from amino-methacrylate groups under acidulated conditions may acquire an ionisable fraction or undergo hydrolytic degradation of the polymeric structure. This work focused on establishing the chemical, physical, and surface changes of two reprocessed polymeric materials, here named as EuCl-E-100 and EuCl-E-PO, which were obtained from the commercial Eudragit® E 100 and Eudragit® E PO, respectively. The commercial materials were exposed to extreme acid conditions, where the polymers were solubilised and subsequently dried by the refractance window method. The materials obtained were chemically characterised by potentiometric titration, nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR) in one and two dimensions (COSY, HSQC, and HMBC), infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. Changes in the physical properties of the materials were evaluated through studies of flowability, compactability, and their ability to gain and lose humidity. Surface thermodynamic studies were carried out through contact angle measurements using the sessile drop method. The results showed that the processed polymeric materials acquired a substantial degree of ionisation without undergoing hydrolysis of the esterified groups. Furthermore, such changes improved the flow characteristics of the material and the solubility in aqueous media at pH > 5, while also maintaining the hydrophobicity degree of the polymeric surface.

The Pyrolytic Decomposition of Owens-Illinois Resin Gr650, an Organosilicon Compound

1984 ◽  
Vol 32 ◽  
Author(s):  
B. G. Bagley ◽  
P. K. Gallagher ◽  
W. E. Quinn ◽  
L. J. Amos
Keyword(s):  
Room Temperature ◽  
Evolved Gas Analysis ◽  
Condensation Reaction ◽  
Gas Analysis ◽  
Weight Loss Curve ◽  
Reaction Products ◽  
Scanning Calorimetry ◽  
Evolved Gas ◽  
Temperature Range ◽  
Pyrolytic Decomposition

ABSTRACTThe pyrolytic conversion of an organosilsesquioxane (Owens-Illinois resin GR650) to SiO2 is characterized by ir spectroscopy, thermogravimetry and evolved gas analysis (line-of-sight mass spectroscopy). Scanning calorimetry, ramping at 10°C/min, on the as-received (room temperature annealed) resin indicates a glass transition temperature of 67°C which decreases to 58°C for an unrelaxed sample. The ir spectra have bands which can be assigned to Si-CH3 and Si-O-Si modes. For 30 minute isothermal anneals at temperatures above 420°C there is a continuous decrease in the bands associated with the Si-CH3 groups such that after 30 minutes at 650°C the ir spectrum has evolved to that for SiO2. Evolved gas analysis indicates that there are four major components evolving. Over the temperature range (ramping at 10°C/min) ∼180 to ∼500°C we observe C2H5OH and H2O, both of which are condensation reaction products from the curing reaction. Methane is a major evolving species over the temperature range ∼500 to ∼800°C and the thermal spectrum is double peaked which we attribute to CH3+ bound to the inside and outside of the polymer cage structures. The final major component detected was H2, over the temperature range ∼600 to ∼1100°C, which was attributed to pyrolysis of the organic components, both trapped and evolving. The features of the weight loss curve can be accounted for by the measured evolving species spectra.

Fourier Transform Infrared Evolved Gas Analysis: Additional Considerations and Options

1981 ◽  
Vol 35 (1) ◽  
pp. 95-101 ◽  
Author(s):  
John O. Lephardt ◽  
Robert A. Fenner
Keyword(s):  
Fourier Transform ◽  
Functional Group ◽  
Evolved Gas Analysis ◽  
Group Analysis ◽  
Fourier Transform Infrared ◽  
Gas Analysis ◽  
Evolved Gas ◽  
Qualitative And Quantitative ◽  
Yield Information ◽  
Functional Group Analysis

The technique of Fourier transform infrared evolved gas analysis described previously has been expanded both with respect to data processing options and to application areas. In this paper several of these additional options and applications are described. For improved qualitative and quantitative capabilities, smoothing and integration have been found beneficial. The use of interferometric processing permits compound specific profiles to be generated quickly. By considering reaction properties, the operations of spectral subtraction and factor analysis can be shown to yield information on both reaction stoichiometries and the number of reactions occurring vs temperature. In the area of applications, the examination of polymer chain length, functional group analysis, and intermolecular interactions are discussed.

scholarly journals Thermoanalytical studies of carbamazepine: hydration/dehydration, thermal decomposition, and solid phase transitions

2014 ◽  
Vol 50 (4) ◽  
pp. 877-884 ◽  
Author(s):  
Mônia Aparecida Lemos Pinto ◽  
Beatriz Ambrozini ◽  
Ana Paula Garcia Ferreira ◽  
Éder Tadeu Gomes Cavalheiro
Keyword(s):  
Solid Phase ◽  
Evolved Gas Analysis ◽  
Anticonvulsant Drug ◽  
Kinetic Studies ◽  
Gas Analysis ◽  
Scanning Calorimetry ◽  
Evolved Gas ◽  
Solid State Decomposition ◽  
Thermoanalytical Studies ◽  
Polymorphic Forms

Carbamazepine (CBZ), a widely used anticonvulsant drug, can crystallize and exhibits four polymorphic forms and one dihydrate. Anhydrous CBZ can spontaneously absorb water and convert to the hydrate form whose different crystallinity leads to lower biological activity. The present study was concerned to the possibility of recovering the hydrated form by heating. The thermal behavior of spontaneously hydrated carbamazepine was investigated by TG/DTG-DTA and DSC in dynamic atmospheres of air and nitrogen, which revealed that the spontaneous hydration of this pharmaceutical resulted in a Form III hydrate with 1.5 water molecules. After dehydration, this anhydrous Form III converted to Form I, which melted and decomposed in a single event, releasing isocyanic acid, as shown by evolved gas analysis using TG-FTIR. Differential scanning calorimetry analyses revealed that Form III melted and crystallized as Form I, and that subsequent cooling cycles only generated Form I by crystallization. Solid state decomposition kinetic studies showed that there was no change in the substance after the elimination of water by heating to 120 °C. Activation energies of 98 ± 2 and 93 ± 2 kJ mol-1 were found for the hydrated and dried samples, respectively, and similar profiles of activation energy as a function of conversion factor were observed for these samples.

POLYMER ELECTROLYTE BLENDS OF MONO-CARBOXYLIC ACID–MODIFIED EPOXIDIZED NATURAL RUBBER AND POLY(ETHYLENEOXIDE)

2018 ◽  
Vol 91 (1) ◽  
pp. 120-135
Author(s):  
Wan Nurhidayah A. Karim ◽  
Jin Guan Ng ◽  
Chin Han Chan ◽  
Rosiyah Yahya ◽  
Seng Neon Gan
Keyword(s):  
Benzoic Acid ◽  
Natural Rubber ◽  
Lithium Perchlorate ◽  
Weight Fraction ◽  
Resonance Spectroscopy ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Ring Opening Reaction ◽  
Poly Ethylene ◽  
Ring Open

ABSTRACT Natural rubber with 50% of isoprene units epoxidized (ENR50) was treated with excess of mono-carboxylic acids to completely ring open the epoxide groups. The reaction was carried out by heating ENR50 dissolved in toluene with each of acetic and benzoic acid separately at 105 °C. The ring-opening reaction has produced hydroxyl –OH and ester –O-COR groups, leading to an increase in Tg. The products were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermal gravimetric analysis, and differential scanning calorimetry. By the solution casting method, each of the modified ENR50s was blended with poly(ethylene oxide) (PEO) in various ratios in toluene, and 2% lithium perchlorate (LiCIO4) was added as the dopant. Results show that the modified ENR and PEO formed incompatible blends. The PEO spherulite growth rate in the blends increased with PEO content. The electrical conductivity was found to increase with the weight fraction of PEO in the blend. At the ratio of 25/75, the acetic acid–modified ENR50/PEO blend exhibits a conductivity value of 3.1 × 10−8 S cm−1. The benzoic acid–modified ENR50/PEO achieved conductivity of 5.8 × 10−7 S cm−1 at the ratio of 30/70. These blends form conducting polymer electrolytes with potential application in batteries.

scholarly journals Thermal stability of polymeric carbon nitride (PCN)-Al2O3–ZrO2 nanocomposites used in photocatalysis

2021 ◽  
Author(s):  
Iwona Koltsov
Keyword(s):  
Thermal Stability ◽  
Carbon Nitride ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
Attenuated Total Reflection ◽  
Cyanic Acid ◽  
Scanning Calorimetry ◽  
And Performance ◽  
Polymeric Carbon ◽  
Thermal Stability Of

AbstractPolymeric carbon nitride (PCN) was recently found to have extensive applications in the field of photocatalysis. Knowledge about thermal stability of PCN nanocomposites is crucial for this application and designing the final product. In this work, the thermal stability of PCN-Al2O3–ZrO2 nanocomposites was investigated. PCN nanocomposites were obtained in two steps: (1) microwave hydrothermal synthesis of co-precipitated AlOOH and ZrO2 precursors, followed by drying; (2) mixing the nanopowders with melamine powder and annealing in air in a tube furnace at 400, and 450 °C. The PCN nanocomposites were examined by attenuated total reflection technique of Fourier transformed infrared spectroscopy. Also, the evolved gas analysis was performed combining differential scanning calorimetry and thermogravimetry coupled with mass spectroscopy and FTIR. The results show that only PCN-Al2O3–ZrO2 nanocomposite obtained at 400 °C is stable from room temperature up to 490 °C and during thermal decomposition, in one step releases ammonia (NH3), cyanic acid (HNCO), water (H2O), and carbon dioxide (CO2). The limitation of the PCN-Al2O3–ZrO2 thermal stability and performance is AlOOH–ZrO2 used as a nanocomposite component.

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