Kinetics of polyurethane formation between glycidyl azide polymer and a triisocyanate

Keskin, S
Özkar, Saim
Kinetics of the polyurethane formation between glycidyl azide polymer (GAP) and a polyisocyanate, Desmodur N-100, were studied in the bulk state by using quantitative FTIR spectroscopy. The reaction was followed by monitoring the change in intensity of the absorption band at 2270 cm-l for NCO stretching in the IR spectrum, and was shown to obey second-order kinetics up to 50% conversion. The activation parameters were obtained from the evaluation of kinetic data at different temperatures in the range of 50-80 degreesC. The enthalpy and entropy of activation were found to be DeltaH(double dagger) = 44.1 +/- 0.5 kJ . mol(-1) and DeltaS(double dagger) = -196 +/- 2 J . mol(-1)l . K-1, respectively. Dibutyltin dilaurate (DBTDL) was used as the curing catalyst. The kinetic study of the polyurethane formation between GAP and Desmodur N-100 showed that the reaction is enormously speeded up in the presence of the catalyst, and the reaction obeys second-order kinetics, provided that the catalyst concentration is kept constant. An investigation on the rate of the catalysed reaction depending on the catalyst concentration provided the order of the reaction, with respect to the DBTDL catalyst concentration, and the rate constant for the catalytic pathway of the reaction. The rate constant for the catalytic pathway was established to be 4.37 at 60 degreesC, while the uncatalyzed reaction has a rate constant of 3.88 x 10(-6) L mol-L s(-1) at the same temperature. A rate enhancement factor of 23 was achieved by using 50 ppm catalyst. (C) 2001 John Wiley & Sons, Inc.


Thermal characterization of glycidyl azide polymer (GAP) and GAP-based binders for composite propellants
Selim, K; Özkar, Saim; Yılmaz, Levent (Wiley, 2000-07-18)
Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were used to investigate the thermal behavior of glycidyl azide polymer (GAP) and GAP-based binders, which are of potential interest for the development of high-performance energetic propellants. The glass transition temperature (T-g) and decomposition temperature (T-d) of pure GAP were found to be -45 and 242 degrees C, respectively. The energy released during decomposition (Delta H-d) was measured as 485 cal/g. The effect of th...
Electrosynthesis of polyfuran in acetonitrile-boron trifluoride-ethyl ether mixture and its device application
Tirkeş, Süha; Önal, Ahmet Muhtar (Wiley, 2007-01-15)
Electrochemical polymerization of furan was achieved in acetonitrile/boron trifluoride/ethyl ether (CH3 CN/BF3/EE) mixture in the presence of tetrabutylammonium tetrafluoroborate via constant potential electrolysis at 1.4 V versus Ag/AgCl. Electrochemical behavior of furan was investigated in the same solvent mixture of varying ratios, utilizing cyclic voltammetry. Free-standing polyfuran (PFu) films were obtained in CH3CN/BF3/EE mixture (2/4/4; v/v/v) and characterized using FTIR spectroscopic technique. S...
Curing characteristics of glycidyl azide polymer-based binders
Kasikci, H; Pekel, F; Özkar, Saim (Wiley, 2001-04-04)
The curing of a glycidyl azide polymer (GAP) with a triisocyanate, Desmodur N-100, was followed by measuring the hardness and viscosity. The thermal behavior of the cured samples were investigated by a differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). Curing causes an increase in the glass transition temperature of GAP. The T-g of gumstocks also increases with an increasing NCO/OH ratio while the decomposition temperature remains practically unchanged. The ultimate hardness of ...
Synthesis and Characterization of a New Conducting Polymer Based on 4-(2,5-di-2-thiophen-2-yl-pyrrol-1-yl)-phthalonitrile
Yavuz, Arzu; Bezgin, Buket; Önal, Ahmet Muhtar (Wiley, 2009-12-05)
A new conducting polymer was synthesized by electrochemical polymerization of 4-(2,5-di-2-thiophen-2-yl-pyrrol-1-yl)-2-phthalonitrile (SNS-PN). Electrochemical polymerization of SNS-PN was performed in acetonitrile/0.2M LiClO4 solvent/electrolyte couple. Characterizations of the resulting polymer P(SNS-PN) were carried out by cyclic voltammetry, UV-vis, and Fourier transform infrared (FTIR) spectroscopic techniques. Spectroelectrochemical studies revealed that P(SNS-PN) has an electronic band gap of 2.45 eV...
Effect of surface treatment on electrical conductivity of carbon black filled conductive polymer composites
Koysuren, Ozcan; Yesil, Sertan; Bayram, Göknur (Wiley, 2007-06-05)
Two different types of surface modifiers, 3-aminopropyltriethoxysilane and formamide, were applied to carbon black (CB) particles to lower electrical resistivity of polymer composites prepared by treated CB. Two different matrices, low-density polyethylene and nylon 6, were chosen to compound with surface modified CB. Surface energy of CB was increased by adding amine or amide functional groups during surface treatment of CB. According to electron spectroscopy for chemical analysis (ESCA), chemical modifica...
Citation Formats
S. Keskin and S. Özkar, “Kinetics of polyurethane formation between glycidyl azide polymer and a triisocyanate,” JOURNAL OF APPLIED POLYMER SCIENCE, pp. 918–923, 2001, Accessed: 00, 2020. [Online]. Available: