Kinetics and mechanism of oxetanes polymerization catalyzed by R₃Al. Part I. Kinetic evidence of long‐living active species in the 3,‐3‐bis(chloromethyl)oxetane polymerization catalyzed by (i‐C₄H₉)₃Al. KurzmiLteilung

Abstract

Polymerization of several cyclic monomers has been recently described in terms of living polymerization introduced originally by SZWARC~).Living polymers of tetrahydrofuran were obtained with R,Al-cocatalysts 2), Ph,CeMeeXn3), SbCl,, BF3-cocatalysts4) and other systems. According to some authors the heterogeneous polymerization of trioxane bears also resemblance to living polymerization5), although in this case the possibility of immobilization of active centers should be taken into account6y7). I n this case as well as in the case of propylene oxide/R2Zn/H20 systemE and propylene oxide/R,Al/H,O system9) the chain transfer to polymer, accompanied with active center stabilization (with or without chain scission or cyclization), had introduced important deviations from the true living system.

Synthesis of polymers containing pseudohalide groups by cationic polymerization, 1. Homopolymerization of 3,3‐bis(azidomethyl)oxetane and its copolymerization with 3‐chloromethyl‐3‐(2,5,8‐trioxadecyl)oxetane

“…2. The fact that the overall functionality of BCMO oligomers was found lower than 2 indicates that cyclisation occurs, and this conclusion goes against the fact that polymerization proceeds through the activated-monomer mechanism 16). These experiments also show that lower initiator concentrations were required to obtain appreciable BCMO polymerization yields, even at 0 "C, than for BAMO.…”