Ring‐opening polymerization of oxetanes by cationic initiators: Polymerization of 3‐azidomethyl‐ 3 ‐ methyloxetane with bis(chlorodimethylsilyl)benzene/silver hexafluoroantimonate initiating system
Abstract
Quasi‐living cationic polymerization of 3‐azidomethyl‐3‐methyloxetane (AMMO) was achieved with a bis(chlorodimethylsilyl)benzene/silver hexafluoroantimonate (BSB/AgSbF6) initiating system in methylene chloride at −78°C. The average molecular weight (Mn) increased linearly with an increasing monomer/ initiator ([M]/[I]) ratio and a linear Mn vs. [M]/[I] ratio plot passes through the origin. Mn's observed were higher than the calculated value. This indicates the initial loss of initiator or slow initiation during the polymerization of AMMO with BSB/AgSbF6 initiating system, or the combination of both. Theoretically, in a system where the initiation is slower than the propagation, a diblock copolymer will be formed. Similarly, impurities, such as water, will cause chain transfer to the propagating chains during polymerization and form a homopolymer and a diblock copolymer in addition to the desired triblock copolymer. In short, a perfect triblock copolymer will be formed for a difunctional cationic initiator when the system is pure and dry and the initiation of polymerization is faster than the propagation.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 01, 1991
- Source ID
- 10.1002/masy.19910420141
Entities
People
- M. A. H. Talukder
Organizations
- Office of Naval Research