Parameters determined from binary experiments were used to predict the behavior of multicomponent A/B/A-C polymer blends, where A is saturated polybutadiene with 90% 1,2-addition (sPB90), B is polyisobutylene (PIB), and C is also saturated polybutadiene but with 63% 1,2-addition (sPB63). The polymers were chosen such that the binary interactions (A/B, A/C, and B/C) are analogous to those in oil (A)/water (B)/nonionic surfactant (A-C) systems, where A/B and A/C are unfavorable interactions (χ > 0) and B/C is a favorable interaction (χ < 0). The Flory-Huggins interaction parameters (χ AB, χAC, and χBC) and the statistical segment lengths (lA, lB, and lC) were all determined experimentally by fitting the random phase approximation (RPA) to small-angle neutron scattering (SANS) data from the three binary homopolymer blends. These parameters were successfully used to predict the scattering from concentration fluctuations in a homogeneous A/B/A-C blend using multicomponent RPA. These same binary parameters were also used as the only inputs to self-consistent field theory (SCFT) calculations of ordered multicomponent polymer blends. The SCFT calculations enabled quantitative interpretation of the SANS profiles from microphase separated A/B/A-C blends. The phase separation temperatures predicted by theory for the blends were within the experimental error, and the theoretical domain spacings were within 10% of the experimental values.

The initiation and catalysis of isobutylene polymerization from several new metallocene and nonmetallocene initiator‐catalysts that contain the noncoordinating anions (NCA), B(C6F5)4− and RB(C6F6)3−, is reported. Application of these initiator‐catalysts is extended to styrenics and vinyl ethers. The NCA does not contribute to termination and can be used in low concentrations compared with conventional Lewis acids. These qualities provide for isobutylene polymerizations that yield low Mn oligomers or high Mn polymer, dependent upon the initiator and polymerization conditions. Mechanistic aspects of initiation, transfer and termination as well as the participation of adventitious water are considered for each class of initiator‐catalyst. The influence of the NCA on the stereoregularity of cationic styrene polymerization is also considered. NCAs do not cause the stereospecific carbocationic polymerization of styrene. We suggest that under conditions not conducive to carbocationic polymerization, NCA/metallocenes mediate the coordination polymerization of styrene. © 1997 John Wiley & Sons, Inc.

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