Properties of linear elastomeric polyurethanes
β Scribed by Stuart L. Cooper; Arthur V. Tobolsky
- Publisher
- John Wiley and Sons
- Year
- 1966
- Tongue
- English
- Weight
- 403 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0021-8995
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β¦ Synopsis
The viscoelastic properties of some polyester-urethanes are compared with the properties of other polymers. The behavior observed is anomalous in that these polyurethanes exhibit an unusually high value of modulus well above their T,, unaccounted for by either crosslinking or crystallinity. Various experiments including incorporation of plasticizers of widely varying chemical composition have suggested interpretation of the system as a block copolymer, each block having its own T,. Each of the two types of blocks seems to associate with similar blocks from other molecules.
π SIMILAR VOLUMES
A new high-temperature elwtomer, SiB-2, has been investigated by stress relaxation, niodulis-temperature, and volume-temperature techniques. SiB-2 was found to be more stable than a related elastomer, radiation-cured silicone rubber, having about twice as long a chemical relaxation time at 250Β°C. Po