Polyaddition of B2 and BB‘2 Type Monomers to A2 Type Monomer. 1. Synthesis of Highly Branched Copoly(sulfone−amine)s

A new approach for preparation of highly branched copolymers from A 2, B 2, and BB‘ 2 type monomers was reported in this work. Highly branched copoly(sulfone−amine)s were synthesized by polyaddition of piperazine (B 2 ) and 1-(2-aminoethyl)piperazine (BB‘ 2 ) to divinyl sulfone (A 2 ). The polymerization mechanism was investigated with FTIR and LC-MSD. During the polymerization, secondary amino groups of B 2 and BB‘ 2 monomers react rapidly with vinyl groups of A 2 monomers within 40 s, and then the residual A groups react with B‘ groups resulting in highly branched copoly(sulfone−amine)s. Thermal properties and the aggregation structure of resulting polymers were characterized with DSC and X-ray diffraction, respectively. When the initial mole ratio of B 2 to BB‘ 2 ( r ) is equal to or higher than three ( r ≥ 3 or B/B‘ ≥ 3.5), resulting branched copolymers are semicrystalline, while copolymers in the case of r < 3 are amorphous. The degree of branching (DB) of the highly branched copoly(sulfone−amine)s was defined and determined by 1 H NMR. The degree of branching of the products increased with decreasing the fed ratio of piperazine to 1-(2-aminoethyl)piperazine. The ratio of the inherent viscosity to the molecular weight decreased with increasing the degree of branching.