Study on shape-memory behavior of polyether-based polyurethanes. I. Influence of the hard-segment content

✍ Scribed by J. R. Lin; L. W. Chen

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 279 KB
• Volume: 69
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980822)69:8<1563::aid-app11>3.0.co;2-w

✦ Synopsis

Shape-memory polyurethanes (PUs) were synthesized by 4,4 -diphenylmethane diisocyanate (MDI), 1,4-butanediol (BD), and poly(tetramethyl oxide)glycol (PTMO). The morphology of PUs was studied using DSC, DMA, and TEM. The results indicated that the PUs would show different morphology by changing the mol ratio of MDI and BD (hard segment). The specimens would show the shape-memory behavior that was fixing and recovering the deformation at different operating temperature ranges. These results demonstrated that the shape-memory behavior of the PUs would be affected by the morphology and the modulus ratio that was defined as E T g 020ЊC /E T g /20ЊC in DMA analysis. The amount of the hard-segment-rich phase would affect the ratio of recovery, that is, the low content would lead to the recovery of the deformed specimen being incomplete. The recovering rate would be influenced by the modulus ratio and the size of the dispersed phase in the micromorphology. On the other hand, the shape-memory behavior of PUs could be enhanced by the training process.