Ring - opening copolymerization of maleic anhydride alAn ) with propylene oxide (PO) was successfully caacced out by using rare earth complexes (i. e.
Nd (P204)3
Nd (P507)3
Nd (naph)3 and Nd(acac)3 3H2O ) in combinationwith aluminum alkyls as catalysts for the first time. The relative concentration oftriads of the MAn-PO copolylner obtained was investigated on the basis of1H-NMR in devil. The results showed that the rare earth coordination systemswere favourable catalysts for the copolymerizahon of MAn with PO
giving high yield and almost alternating opolymer. The number- average molecular weight and molecular weight distribution were in the range of 2000-3000 and 1.3-1.7 respectively. The composition and the monomer distribution were affect-ed by the monomer charge ratio
the sort of catalyst
and the property of solvent.It was also found that the monmer composition of copolymer predicted from the thire- order Markoffian process fit the observed 1H-NMR data perfectly.