Trifluoroacetylation has been successfully applied to polyamides in order to obtain polymers soluble in aprotic solvents; trifluoroacetylation of polyurethanes was reported to be much slower. In this work, the results of a study of the effect of trifluoroacetic anhydride/NH molar ratio, reaction tim
Segmented polyurethanes using fluorescein
β Scribed by G. N. Mahesh; S. Ramesh; Ganga Radhakrishnan
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 369 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0021-8995
No coin nor oath required. For personal study only.
β¦ Synopsis
Segmented Polyurethanes were prepared by chain extending the prepolymers based on poly(tetramethy1ene oxide)glycol and tolylene diisocyanate using fluorescein. The polymers were characterized using FTNMR and FTIR. Thermal stability of the polymers was studied using a thermogravimetric analyzer, and the glass transition temperature of the polymers was determined using a differential scanning calorimeter. Tensile strength and percentage of elongation of these segmented polyurethanes were evaluated using a Universal Testing Machine.
π SIMILAR VOLUMES
## Abstract Phase separation in a segmented polyurethane has been studied by differential scanning calorimetry. The glass transition temperature of the soft phase decreases logarithmically with time to a limiting value at each annealing temperature. The magnitude of the decrease is larger at low an
The thermal stabilities of two series of segmented polyurethane fibres have been compared with their chemical structure. The polyurethanes were synthesized from trimethylene diamine; 4, 4' diphenylmethane di-isocyanate and two polyether based macrodi-isocyanates. Thermal stability was measured by th
The synthesis of a hydroxylated polyurethane, by reduction with diborane of the corresponding carboxylated polymer, is described. The starting polyurethane, of the segmented type, contains as chain extender dihydroxymethylpropionic acid. Various conditions for hydrogenation of the carboxy group have