Abstract
Some recent experiments show that the intrinsic viscosities of ABA-type triblock copolymers are sometimes smaller than those of the precursors B in the θ solvent for side blocks A.To explain this fact, a triblock copolymer is represented by three spherical segmental distributions connected with each other by four freely jointed sticks.The partition function is evaluated by the Bragg—Williams approximation with the lattice model. Expressions for the free energy and the volume-expansion factor of ABA-type triblock copolymers are obtained and conformational anomalies which have an effect upon the intrinsic viscosities are discussed by comparing the interaction energy and the unperturbed radius of gyration in the ring conformation with those for the averaged case.
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Endo, H., Yamamoto, M. Volume-Expansion Factor of ABA Block Copolymer. Polym J 6, 356–363 (1974). https://doi.org/10.1295/polymj.6.356
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DOI: https://doi.org/10.1295/polymj.6.356