Effects on properties of varying the cis/trans isomer distribution in polyurethane elastomers made with 1,4-cyclohexane diisocyanate
✍ Scribed by Michael D. Joseph; Michael R. Savina; Robert F. Harris
- Book ID
- 102734505
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 858 KB
- Volume
- 44
- Category
- Article
- ISSN
- 0021-8995
No coin nor oath required. For personal study only.
✦ Synopsis
Polyurethane elastomers have been made using 1,4-cyclohexane diisocyanate ( CHDI) ,1,4butanediol (BDO) and a 2000 M , polyether diol soft segment. The cisltrans isomer distribution of the CHDI was varied between 23% and 100% trans. This variation in isomer distribution had significant effects on the polyurethane's thermal and physical properties.
Decreasing the trans CHDI content gives polyurethanes with lower hardness, lower thermal stability, higher Coefficient of Linear Thermal Expansion (C.L.T.E.) values and decreased modulus values. Morphology studies showed good phase separation between the hard and soft segment blocks as well as a block copolymer morphology between the cis and trans CHDI/BDO blocks in the hard segment. The polyurethanes made were compared to polyurethanes made with MDI and HI,MDI, the leading aromatic and aliphatic diisocyanates respectively.