𝔖 Bobbio Scriptorium
✦   LIBER   ✦

On the Mechanism of the Ring-Expansion Polymerization of Thiiranes

✍ Scribed by Jan-Hendrik Schuetz; Philipp Vana

Publisher
John Wiley and Sons
Year
2011
Tongue
English
Weight
644 KB
Volume
212
Category
Article
ISSN
1022-1352

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Ring polymers are synthesized using a cyclic bifunctional thioester as initiator for REP of thiiranes. PMT yields satisfactory results, whereas polymerization with MT appears to develop dead polymeric material as by‐product and TBMT gives only negligible conversion rates. The process produces high yields and high conversion rates. The corresponding molecular weight distributions show increasing broadening and multimodal character with increasing reaction time due to thermodynamically controlled ring‐merging reactions between macrocycles. The polymerization rate of PMT obeys a pseudo first‐order kinetics with an activation energy of 38.8 kJ mol^βˆ’1^. ^1^H NMR, ESI‐MS, and glass transition temperatures independent of the molecular weight demonstrate the presence of cyclic polymer. magnified image

πŸ“œ SIMILAR VOLUMES

On the mechanism of ring-opening polymer
On the mechanism of ring-opening polymerization of cyclo-olefins
✍ B.A. Dolgoplosk; K.L. Makovetsky; T.G. Golenko; Yu.V. Korshak; E.I. Tinyakova πŸ“‚ Article πŸ“… 1974 πŸ› Elsevier Science 🌐 English βš– 296 KB

From experimental data, a conclusion is drawn on chain character of cyclo-olefin ring-opening polymerization. It was suggested that the active centres of this process are carbene complexes of transition metals (W, Mo, Re). The confirmation of this view comes from studies on the initiation of ring-op

Mechanism of the concerted ring expansio
Mechanism of the concerted ring expansion of singlet cyclopropyl nitrene
✍ Huabin Sun; Chengbu Liu; Liming Zhao; Lu Deng πŸ“‚ Article πŸ“… 1994 πŸ› Elsevier Science 🌐 English βš– 391 KB

The isomerization by concerted ring expanding of singlet cyclopropyl nitrene has been studied using the self-consistent field (SCF) method with the 3-21G basis set. The transition state has been obtained. The disrotation-conrotation mechanism has been proposed and discussed with the Woodward-Hoffman

The mechanism of the ring-opening polyme
The mechanism of the ring-opening polymerization of lactide and glycolide
✍ F.E. Kohn; J.G. Van Ommen; J. Feijen πŸ“‚ Article πŸ“… 1983 πŸ› Elsevier Science 🌐 English βš– 676 KB

To obtain more insight in the ring-opening polymerization of lactones, complex formation of the initiators tetraphenyltin, stannous octoate, tin tetrachloride, aluminium bromide and triisobutylaluminium (TIBA), and the monomers L(-)-lactide, D,e-lactide and glycolide was studied by i.r.-spectroscopy