Characterization of new polyether-diols with different molar masses and modality prepared by ring opening polymerization of oxiranes initiated with anhydrous potassium hydroxide

Abstract

Several new polyether-diols were prepared by ring-opening polymerization of monosubstituted oxiranes in the presence of anhydrous potassium hydroxide. 1,2-Butylene oxide (BO), styrene oxide (SO), isopropyl glycidyl ether (IPGE), allyl glycidyl ether (AGE), phenyl glycidyl ether (BGE), p-methoxyphenyl glycidyl ether (MPGE) and benzyl glycidyl ether (BGE) were chosen as monomers. Macrocyclic ligands complexing metal cations, i.e. coronand 18C6 or cryptand C222 were used as activators in these systems. All polymerizations were carried out in tetrahydrofuran solution at room temperature. Molar mass (M_n) and dispersity (M_w/M_n) of the polymers obtained with KOH depends on the kind of monomer, initial concentration of the initiator and the presence and kind of ligand or water. For example, PBO-diols prepared without ligand are bimodal and for the main fraction M_n > M_calc. However, after addition of 18C6 polymers are unimodal and unexpectedly have much higher M_n = 13,700–15,800 and very low dispersity (M_w/M_n = 1.04–1.08). M_n of PBO-diols decrease with increase of [KOH]_o and do not change at [BO]_o = 2.0–9.0 mol/dm³. Addition of C222 results in M_n decrease of PBO-diols. Similar effects were observed in the polymerization of PAGE-diols and PPGE-diols. In the polymerization of SO, PGE, MPGE and BGE initiator efficiency (f) is high and M_n < M_calc. Polymodality of some polymers obtained was discussed in term of the formation of various species propagating with different rate constants.

Graphical abstract

Polyether-diols synthesized using anhydrous hydroxide as initiator.

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