%0 journal article
%@ 1060-1325
%A Kricheldorf, H.R., Behnken, G., Schwarz, G., Simon, P., Brinkmann, M.

%D 2009
%J Journal of Macromolecular Science  A
%N 4
%P 353-359 
%R doi:10.1080/10601320902724800
%T High Molar Mass Poly(trimethylene carbonate) by Ph2BiOEt and Ph2BiBr-Initiated Ring-Opening Polymerizations
%U https://doi.org/10.1080/10601320902724800
4 
%X Trimethylene carbonate, (TMC), was polymerized in bulk with Ph2BiOEt or Ph2BiBr as initiators. The dependence of the molecular weight on the monomer-initiator ratio (M/I) and the MALDI-TOF (MT) mass spectra suggest that these polymerizations obey a coordination-insertion mechanism. Due to “back-biting” cyclic oligomers were also formed. With Ph2BiBr particularly high molecular weights were achieved (number averages, Mns, up to 340 times 103 Da), but the Mns were significantly higher than the M/Is. However, a satisfactory control of Mn was achieved by addition of tetraethylene glycol as coinitiator. In the case of Ph2BiOEt the Mns fell below the M/Is and only a crude control of the Mns was achieved. Both Bi-compounds were more reactive than Sn(II)2-ethylhexanoate (SnOct2) activated with ethanol. This difference was particularly conspicuous at temperatures below 100°C.