Abstract
Functionally graded polyurethane elastomers (FGPUEs) were prepared with two molds fixed at different temperatures (30 and 150°C). The effects of the molar ratio of the curing agent (60/40, 75/25, or 97/3 1,4-butane diol/1,1,1-trimethylol propane) and the molecular weight of the polymer glycol (number-average molecular weight = 2000 or 3000) on the molecular aggregation state and mechanical properties of the FGPUEs were investigated with differential scanning calorimetry, polarized optical microscopy, dynamic viscoelastic measurements, and tensile tests. The aggregation state of the FGPUEs was changed continuously from the one side (lower temperature side) to the other side (higher temperature side); for example, the glass-transition temperature gradually increased in this direction. Also, the number of spherulites formed in the FGPUEs increased in the same manner. In the mechanical tests, the tensile strength and elongation at break of the lower temperature side were higher than those of the higher temperature side. This was correlated with the strong phase separation of the lower temperature side. The poly(oxytetramethylene glycol)-based FGPUE with a chain extender of 75 wt% showed the largest degree of the temperature gradient.
Original language | English |
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Pages (from-to) | 2355-2364 |
Number of pages | 10 |
Journal | Journal of Polymer Science, Part B: Polymer Physics |
Volume | 41 |
Issue number | 20 |
DOIs | |
Publication status | Published - Oct 15 2003 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Polymers and Plastics
- Materials Chemistry