Accession Number : ADA183245

Title :   Low Polydispersity Homo- and Block Copolymers by Ring-Opening of 5,6-Dicarbomethoxynorbornene.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMISTRY

Personal Author(s) : Murdzek,John S ; Schrock,Richard R

PDF Url : ADA183245

Report Date : 31 Jul 1987

Pagination or Media Count : 14

Abstract : Addition of 50-200 eq of norbornene to Mo(CH Superscript t Bu) (NAr) (O Superscript t Bu)2 yields living polymers, Mo?CH(C5H8)CHxCH Superscript t Bu (NAr)(O Superscript t Bu)2 (55% trans), that are stable for days in the absence of water and oxygen with essentially no isomerization of the double bonds in the chain. Addition of benzaldehyde cleaves off the polymer in a Wittig-like reaction to yield polynorbornenens with polydispersities in the range 1.04-1.11. Analogous reactions involving 50-200 eq of endo, endo-5,6-dicarbomethoxynorbornene yields homopolymers with polydispersities in the range 1.11-1.22. Block copolymers containing 50 eq of endo,endo-5,6-dicarbomethoxynorbornene and 200 eq of norbornene prepared by adding one or the other monomer first are virtually identical (polydispersities 1.06 and 1.09 with M sub n 57200 and 59900, respectively). These results suggest that the molybdenum catalyst will not react significantly with up to 100 eq of ester functionality during the time of a typical polymerization reaction (approx. 15 m at 25 degs.).

Descriptors :   *ALDEHYDES, *BENZYL RADICALS, *BLOCK COPOLYMERS, *POLYMERS, *CARBONYL COMPOUNDS, BONDED JOINTS, CATALYSTS, MOLYBDENUM, ISOMERIZATION, POLYMERIZATION, RESPONSE

Subject Categories : Polymer Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE