20. (スチレン-α-メチルスチレン)・ブロック共重合体に関する研究 : II.稀薄溶液中における(スチレン-α-メチルスチレン)・ブロック共重合体の形態的挙動

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Intrinsic viscosities [η] of the (styrene-α-methylstyrene) block copolymers having the structures B_mA_nB_m, A_<n'>B_mA_nB_mA_<n'>, B_mA_<n'>B_mA_nB_mA_<n'>B_m and A_<n'>B_mA_<n'>B_mA_nB_mA_<n'>B_mA_<n'> (A; styrene monomer unit, B; α-methylstyrene monomer unit), were measured in the three solvents; toluene (good solvent), cyclohexane (theta solvent) and butanone (selective solvent). The unperturbed mean square end-to-end distance <L_0^2>/M of these block copolymers was obtained from viscosity data and light scattering measurements in theta solvents. It was found that the value of <L_0^2>/M slightly increases with an increase of the number of blocks in the copolymers. The intrinsic viscosity-molecular weight relation was examined for the triblock copolymers, and compared with that of the parent homopolymers; the [η]'s of the block copolymers in toluene (good solvent for both polystyrene and poly-α-methylstyrene) are larger than the average of the two homopolymers, and the [η]'s in butanone (solvent for polystyrene but non-solvent for poly-α-methylstyrene) are smaller than that of polystyrene but an anomaly in [η] which was often suggested as that due to "intrachain phase separation" in the copolymer chains was not observed.
東京女子大学の論文
1972-03-25