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| 003 | MX-MdCICY | ||
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| 090 | _aB-15830 | ||
| 245 | 1 | 0 | _aThermal degradation of segmented polyurethanes |
| 490 | 0 | _vJournal of Applied Polymer Science, 51(6), p.1087-1095, 1994 | |
| 520 | 3 | _aThermal degradation of polyurethane samples was studied by a thermogravimetric method. The effect of soft-segment length and soft-segment concentration on activation energy of the degradation process was measured. Three methods of calculation gave activation energies at different stages of the very complex weight loss process. It was shown that at initial stages of the weight loss the process was dominated by hard-segment degradation. Activation energy of the whole process calculated by the Ozawa-Flynn method did not offer clear insight into the structure-stability relationship of polyurethanes. The second method showed that activation energy of the initial stage of degradation increased with decrease in hard-segment length. The Flynn method of calculating activation energy produced fairly constant activation energy of the first 40 per cent degradation, at around 150 kJ/mol, for polymers in the C series. Generally, calculation of kinetic parameters of a complex degradation process as in polyurethanes gives results that are not easy to interpret. It has been shown qualitatively that polymers with higher soft-segment concentration display lower initial weight loss and higher onset temperatures of degradation. | |
| 650 | 1 | 4 | _aDEGRADATION |
| 650 | 1 | 4 | _aGRAVIMETRIC ANALYSIS |
| 650 | 1 | 4 | _aMATHEMATICAL MODELS |
| 650 | 1 | 4 | _aMOLECULAR STRUCTURE |
| 650 | 1 | 4 | _aREACTION KINETICS |
| 650 | 1 | 4 | _aTHERMAL EFFECTS |
| 650 | 1 | 4 | _aTHERMOANALYSIS |
| 650 | 1 | 4 | _aTHERMODYNAMIC STABILITY |
| 650 | 1 | 4 | _aACTIVATION ENERGY |
| 650 | 1 | 4 | _aSEGMENTED POLYURETHANES |
| 700 | 1 | 2 | _aPetrovic, Zoran S. |
| 700 | 1 | 2 | _aZavargo, Zoltan |
| 700 | 1 | 2 | _aFlynn, Joseph H. |
| 700 | 1 | 2 | _aMacknight, William J. |
| 856 | 4 | 0 |
_uhttps://drive.google.com/file/d/1SjrgcMwGYg0r9rBZ5NQseWIDeJK7f-ZT/view?usp=drivesdk _zPara ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx |
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