Preparation and thermal properties of acrylic polymers with pendant spirobislactone groups

A series of acrylic terpolymers containing varying concentrations of crosslinkable glycidyl, spirobislactone, and hydroxyl pendant groups was prepared by radical chain polymerization. The glass‐transition temperatures and weight average molecular weights of the terpolymers span broad ranges and can be independently selected by control of monomer composition. Cross‐linking at 210°C was monitored by infrared spectroscopy. The rate and extent of reaction of spirobislactone groups were found to be greater than those for glycidyl groups. The activation energies of the spirobislactone and glycidyl reactions in the range between 160 and 210°C were calculated by Arrhenius treatment of the curing kinetics and found to be 31.0 ± 1.1 kJ mol−1 and 59.1 ± 1.2 kJ mol−1, respectively. The double ring opening reaction of the spirobislactone groups has no effect on the volume of the cross‐linked polymers. © 1994 John Wiley & Sons, Inc.