Abstract: Aseries of poly(ε-caprolactone) segmented polyurethane with different molecular weights (PCL) were synthesized. The kinetics of the chain extension reaction was studied by infrared (IR) spectroscopy. The kinetics parameters show the following characteristics of the chain extension reaction. The rate constants decrease with increase in the number average molecular weightmn of the soft segment at the same hard segment reactant content. The influences of M_n on the reaction rate vary with the variation of the hard segment reactant contents. All of the chain extension reactions studied in this work were of second order. The activation energies were essentially insensitive to the M_n, but they increased a little with increase of hard segment reactant content.

Key words: Poly(ε-caprolactone) segmented polyurethane, Chain extension reaction, Soft segment reactant molecular weight, Hard segment reactant content