Ring opening in the polymerization of propylene oxide by the initiator systems aluminium isopropoxide or aluminium isopropoxide/zinc chloride (1:1) and the microstructure of the resulting polymers

Abstract 2‐Methyloxirane (propylene oxide) was polymerized by aluminium isopropoxide [Al(OiPr) 3 ] and by the initiator system Al(OiPr) 3 /zinc chloride (1:1). The microstructure of the resulting polymers was investigated by 13 C NMR spectroscopy. The polymer obtained with Al(OiPr) 3 alone was found to contain head‐to‐tail and head‐to‐head linkages in the chain, indicating an oxirane ring opening in both α‐ and β‐positions. The polymerization by the aluminium isopropoxide/zinc chloride initiator system led to the formation of a crystalline, highly isotactic fraction and to an amorphous, almost atactic fraction of the polymer with head‐to‐tail linkages only.