Abstract
The effect of allophanate crosslinking according to the NCO/OH molar ratio on the shape memory properties of polyurethane was investigated. Shape memory polyurethanes were polymerized with the variation of NCO/OH ratio keeping the content of total hard segment constant. The result of DSC and DMA showed that the glass transition temperature (Tg) of the soft segment in polyurethane slightly increased as the NCO/OH ratio varied from 1 to 1.2, but decreased at 1.3. In thermomechanical cycling test, as the NCO/OH ratio was changed from 1 to 1.2, the residual strain was decreased, the stress at maximun strain was maintained, and the recovery stress measured at reheating step was increased. However, the enhancement of shape memory properties was not found at NCO/OH = 1.3.
| Original language | English |
|---|---|
| Pages (from-to) | 461-467 |
| Number of pages | 7 |
| Journal | Polymer (Korea) |
| Volume | 22 |
| Issue number | 3 |
| Publication status | Published - 1998 |
Keywords
- Allophanate crosslinking
- NCO/OH molar ratio
- Polyurethane
- Shape memory
- Thermomechanical cycling test
ASJC Scopus subject areas
- Chemical Engineering(all)
- Polymers and Plastics
- Materials Chemistry