SYNTHESIS AND CHARACTERIZATION OF MALEIMIDE POLYMERS WITH PENDANT PYRAZOLE GROUPS .4. COPOLYMERIZATION OF PYRAZOLE-MODIFIED MALEIMIDES WITHVINYL ETHERS

The synthesis of maleimides that have pyrazolic or bipyrazolic pendant groups is described. Their homopolymerization and their copolymerizat ion with 2-chloroethyl vinyl ether (CEVE) is reported. The homopolymer izations of such maleimides were performed under various conditions an d led to low molecular-weight polymers. However, alternating copolymer s were obtained from CEVE as comonomers whatever the monomers feed com positions. A similar behavior was also observed for maleimides that do not exhibit any spacer, whereas for bulky vinyl ethers, random copoly mers were produced. A comparison of the thermal behavior between these copolymers (glass transition temperatures, T-g, and decomposition tem peratures) and other copolymers having different spacers between the n itrogenated cycles and the chain are related. Thus, an important decre ase of T-g was observed when C3H6CO2CH2 groups were used as the spacer instead of methylene groups. Moreover, the thermal weakness of these copolymers may come from the substituents of the vinyl ether and is di scussed. (C) 1994 John Wiley & Sons, Inc.