Synthesis of sequence-controlled maleimide copolymers and application to the design of thermoresistant and transparent polymer materials

Abstract

Maleimide copolymers are high-performance transparent polymer materials with excellent thermal, optical, and mechanical properties. In this comprehensive paper, we describe the control of the sequence structures for such polymers. We investigated the 1: 1 alternating and 2: 1 sequence-controlled copolymerizations of N-substituted maleimides with various styrene and olefin derivatives. The monomer reactivity ratios were calculated based on the analysis of the comonomer-copolymer composition curves using terminal and penultimate unit models. The 2: 1 sequence-controlled (AAB-type) copolymers were produced under the penultimate unit control. The sensitivity of the penultimate unit effect depends on the structures of the comonomers and the solvents used for the copolymerization. Maleimide copolymers with excellent thermal, optical, and mechanical properties were fabricated by alternating and 2:1 sequence-controlled radical copolymerizations and subsequent postpolymerization reactions including thiol-ene reactions. An organic-inorganic hybrid was also synthesized by the thiol-ene reaction of the copolymer with silica nanoparticles and the thermal and optical properties of the obtained hybrids were investigated.