Penetration of PBSU spherulite into P(VDC-VC) spherulite observed with microbeam- and macrobeam-SAXS/WAXS measurements

PBSU/P(VDC-VC) is a crystalline/crystalline miscible polymer blend, which has characteristics that (1) the melting temperature difference is small (ΔT=33 °C), (2) the spherulite of both components can be observed with polarized optical microscope (POM), and (3) the interpenetrated spherulite is formed under specific condition: Interpenetrated spherulite means a structure formed by the penetration of PBSU spherulite growing into P(VDC-VC) spherulite. In order to clarify the nano-structure of penetrated P(VDC-VC) spherulite and penetrating PBSU lamella, we have performed the microbeam (beam size: about 10×10 μm2) SAXS/WAXS simultaneous measurements as well as macrobeam SAXS/WAXS during formation of the interpenetrated spherulite. From our experimental results, we have concluded that P(VDC-VC) lamellae hardly stack and isolate from each other, and that PBSU penetrates into the inter-fibril region of P(VDC-VC) spherulite. Further, it is found that PBSU lamella penetrating into P(VDC-VC) spherulite excludes amorphous P(VDC-VC) from PBSU inter-lamella region.