Hyperbranched Polymers Formed through Irreversible Step Polymerization of AB 2 ‐Type Monomer in a Continuous Flow Stirred‐Tank Reactor (CSTR)

Hyperbranched polymers formed through step polymerization of AB 2 ‐type monomer with equal reactivity for both B groups in a continuous flow stirred‐tank reactor (CSTR) are investigated theoretically. The weight fraction distribution at high molecular weight tail follows a power law, W ( P ) ∝ P −1/ξ for ξ ≤ 0.5 with ξ = k [ A ] 0 t ¯ , where t ¯ is the mean residence time. The degree of branching (DB) at the large degree of polymerization ( P ) limit is DB P →∞ = 0.6 irrespective of the ξ‐value, which is larger than the case for the corresponding batch polymerization that gives DB P →∞ = 0.5. The relationship between the radius of gyration 〈 s 2 〉 0 and P shows that the hyperbranched polymers formed in a CSTR are very compact, and the 〈 s 2 〉 0 ‐values for large polymers are even smaller than the smallest possible case for a batch reactor with DB P →∞ = 1. For large polymers, the power law 〈 s 2 〉 0 ∝ P  1/3 holds, which is 〈 s 2 〉 0 ∝ P  1/2 for batch polymerization.