Method for controlling the functionality distribution of liquid copolymers
US4358566A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 11, 1978 |
| Grant date | Nov 9, 1982 |
| Priority date | — |
| Expiry date | Sep 11, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F8/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Macromolecules with a distribution of molecular weights and functionality which can be rendered useful by heterogeneous catalytic modification are selectively modified on the basis of molecular dimensions and diffusion rates, using catalysts with specific pore size and particle size distribution. For example, liquid polymers are produced having both hydroxyl and carbonyl functionality with the carbonyl/hydroxyl ratio increasing with molecular weight. More specifically, a high molecular weight polymer is cleaved by ozonation with subsequent reduction with a heterogeneous catalyst having some pores smaller than the radii of gyration of the largest fractions but larger than the radii of gyration of other fractions of the molecular weight distribution of the polymer. The reduction may be performed in an intraparticle mass transfer controlling regime which further influences reduction efficiency as a function of molecular weight. This selectivity is used to narrow or otherwise modify the functionality distribution and make the product generally more useful.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.