Telechelic cis-1,4-oligoisoprenes through the selective oxidolysis of epoxidized monomer units and polyisoprenic monomer units in cis-1,4-polyisoprenes
✍ Scribed by Sandrine Gillier-Ritoit; Danièle Reyx; Irène Campistron; Albert Laguerre; Raj Pal Singh
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 102 KB
- Volume
- 87
- Category
- Article
- ISSN
- 0021-8995
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Telechelic cis‐1,4‐oligoisoprenes were prepared by the selective cleavage of weak epoxidized units (E) in epoxidized cis‐1,4‐polyisoprenes (EPIs) and by the random cleavage of isoprenic units (I) in cis‐1,4‐polyisoprene (PI). In both cases, cleavage by periodic acid (H~5~IO~6~) in tetrahydrofuran led to aldehydic and ketonic chain ends. Through variations in the E/(I + E) molar percentage (E%) in the cleavage of EPI and through variations in the H~5~IO~6~/I molar percentage (PA%) in the cleavage of PI, a polydispersity index near 2 and a number‐average molecular weight of 2 – 20 × 10^3^ were obtained. The correlation of the degree of scission with E% and PA%, combined with kinetic, led to the proposal of a two‐step mechanism for the H~5~IO~6~ cleavage of double bonds. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 42–46, 2003