Narrowing the molecular weight distribution of polytetrahydrofuran and of copolymers of tetrahydrofuran and alkylene oxides
US4933503A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 15, 1988 |
| Grant date | Jun 12, 1990 |
| Priority date | — |
| Expiry date | Aug 15, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G65/30
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The molecular weight distribution of polytetrahydrofuran and of copolymers of tetrahydrofuran and alkylene oxides are narrowed by a process in which low molecular weight fractions are distilled off from the polymers under pressures of less than 0.3 mbar and at from 200.degree. to 260.degree. C., the distillation residue is mixed with a solvent mixture consisting of (a) an alkanol, (b) a hydrocarbon and (c) water, the content of the individual components a, b and c in the mixture being from 4 to 60% by weight, the phases formed are then separated from one another and the polymer having a narrower molecular weight distribution is isolated from the phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.