US EPA

4583202 

Journal Article 

Ring opening polymerization of styrene oxide initiated with potassium alkoxides and hydroxyalkoxides activated by 18-crown-6: determination of mechanism and preparation of new polyether-polyols 

Grobelny, Z; Matlengiewicz, M; Jurek-Suliga, J; Golba, S; Skrzeczyna, K; Kwapulinska, D 

2017 

1 

Polymer Bulletin
ISSN: 0170-0839
EISSN: 1436-2449 

74 

11 

4763-4780 

10.1007/s00289-017-1976-4 

WOS:000410445900026 

It was stated that initiation in ring opening polymerization of styrene oxide depends on the kind of potassium alkoxide activated by 18-crown-6 used. In the presence of potassium methoxide the oxirane ring opening occurs exclusively in the beta-position and not in the beta or alpha position, i.e., contrary to the previous data. A similar result was obtained in the systems initiated with potassium t-butoxide, 2-methylpropoxide and 1-phenylethoxide. Unexpectedly, potassium i-propoxide and 1-methylpropoxide open the oxirane ring in the beta or alpha position. In all polymerizations, deprotonation of methine group in the monomer takes place under the influence of the initiator and in chain transfer reaction to the monomer. It leads to the formation of macromolecules with unsaturated starting group. However, deprotonation of methylene group in the monomer does not occur. Applying of potassium hydroxyalkoxides, i.e., monopotassium salt of dipropylene glycol or tripotassium salt of 2,2,6,6-tetrakis(hydroxymethyl) cyclohexanol it was possible to synthesize PSO-diols and PSO-pentols without unsaturation. Molar masses of polymers (M-n = 1700-4800 Da) are much higher than reported in literature for other anionic systems. Dispersity of polymers is rather low (M-w/M-n = 1.07-1.15) indicating relatively high rate of initiation and cation exchange reaction. 

ROP; Oxiranes anionic polymerization; Styrene oxide; Potassium alkoxides; Polyether polyols