Radical Copolymerization Reactivity of N-Substituted Maleimides with α-Substituted Styrenes with Various N- and α-Substituents and the Thermal and Optical Properties of the Resulting Copolymers

The radical alternating copolymerization of N‐substituted maleimides (RMIs) with N‐methyl, n‐butyl, and 2‐ethylhexyl groups and styrene derivatives with various α‐substituents (RSs) is carried out. The yield and the molecular weight of the obtained copolymers significantly decrease with an increase in the size of the α‐substituent of RSs, but are independent of the N‐substituents. The glass‐transition temperature of the copolymers increases on the introduction of the large substituents into the RS repeating units. The high‐molecular‐weight poly(RMI‐alt‐RS)s are soluble in organic solvents and provide flexible and transparent films with excellent transparency by casting the solutions. The radical alternating copolymerization of N‐substituted maleimides (RMIs) and α‐substituent styrenes (RSs) is carried out to investigate the effects of their N‐ and α‐substituents on the copolymerization reactivity, as well as the properties of the resulting copolymers. The obtained high‐molecular‐weight poly(RMI‐alt‐RS)s have provided flexible and transparent films with a high glass‐transition temperature.