Polyaddition of bifunctional spiro orthoesters with bifunctional acid chlorides accompanying double ring-opening isomerization

Polyaddition of bifunctional spiro orthoesters (SOEs) with bifunctional aci d chlorides tvas examined to develop zero-shrinkage polymerization. The pol yaddition afforded the corresponding polyether-esters by repeating the addi tion reaction accompanying the double ring-opening isomerization of the SOE moiety in a manner similar to the reaction of monofunctional SOEs with aci d chlorides. The polyaddition accompanied a slight shrinkage or expansion i n volume. (C) 2000 John Wiley & Sons, Inc.