RARE GARTH POLYMER COMPLEX CATALYST FOR RING-OPENING POLYMERIZATION OF EPICHLOROHYDRIN

A novel complex composed of chitosan(CS) and neodymium(Nd) was prepared and the ring opening polymerization of epichlorohydrin(ECH) with a new catalytic system comprising this new rare earth polymer complex (CS . Nd) has been successfully carried out for the first time. It has been found that the new catalytic system composed of CS . Nd-Al (i-Bu)(3)-methyl benzoxylate (I) is an excellent catalyst for the polymerization of epichlorohydrin which shows a catalytic activity 60 times higher than that of conventional rare earth catalyst. Under the following reaction conditions: Nd = 1 X 10(-6) mol/g monomer, Al/Nd = 60 molar ratio, I/Al = 0.6 molar ratio, the monomer conversion and pECH molecular weight are as high as 92.9% and 28.2 X 10(5) respectively and the polymer prepared has a low crystallinity. The kinetics investigation revealed that the polymerization has a short induction period of several minutes and the rate of polymerization is of first order with respect ro the monomer concentration and the catalyst concentration. The activation energy of the polymerization reaction was found to be 25.5 kJ/mol which is lower than that of common rare earth catalyst.