Coupling to produce inside-out star polymers with expanded cores
US5773521A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1995 |
| Grant date | Jun 30, 1998 |
| Priority date | — |
| Expiry date | Dec 19, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F297/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
In the production of "inside-out" star polymers where a first polymer lithium chain is formed, coupled and thereafter additional monomer is introduced to produce the "out" polymer chains, improved control over the second polymerization is obtained by coupling with a mixture of a monoalkenyl-substituted aromatic compound and a polyalkenyl-substituted aromatic compound. For example, a mixture of divinylbenzene and styrene can be used. In another embodiment, an ether is introduced after completion of the first polymer chain formation. The presence of the ether also improves the second stage chain formation. Utilization of both the mixed coupling agents and the ether, preferably a diether such as 1,2-diethoxyethane gives the greatest control over the uniformity of the second stage polymerization, making possible the production of narrower molecular weight distribution polymer having no indication of bimodal distribution. The narrow molecular weight distribution is advantageous in many applications.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.