A synchrotron SAXS study of miscible blends of semicrystalline poly(vinylidenefluoride) and semicrystalline poly(1,4-butylene adipate). II. Crystallization, morphology, and PBA inclusion in PVF2 spherulites

Autor: Benjamin Chu, J. P. Penning, Li-Zhi Liu, R. St. John Manley
Rok vydání: 2000
Předmět:
Zdroj: Journal of Polymer Science Part B: Polymer Physics. 38:2296-2308
ISSN: 1099-0488
0887-6266
DOI: 10.1002/1099-0488(20000901)38:17<2296::aid-polb100>3.0.co;2-m
Popis: The incorporation of poly(1,4-butylene adipate) (PBA) and its crystallization behavior within poly(vinylidenefluoride) (PVF 2 ) spherulites in miscible PVF 2 /PBA blends have been further studied with small-angle X-ray synchrotron scattering (SAXS). The incorporation of PBA into the PVF 2 interlamellar region was found to be dependent on the PVF 2 crystallization conditions. In our previous work, where the blends were crystallized by a one-step quenching process directly from 190 (a single-phase region) to 20 °C (a three-phase region), the transition from PBA inclusion in the PVF 2 interlamellar region to interlamellar exclusion occurred at a PBA weight fraction of ∼ 0.5. In this case, where the blends were first quenched from 190 (a single-phase region) to 130 °C (a two-phase region) and then further quenched to 20 °C (a three-phase region), the transition occurred at a PBA weight fraction of less than 0.3. That is, when a blend is crystallized under different conditions, different amounts of the PBA component are incorporated into the PVF 2 interlamellar phase. The thickness of the PVF 2 interlamellar phase, in turn, may affect the PBA crystalline structure in the interlamellar region. Time-resolved SAXS was used to probe the crystallization dynamics of both PVF 2 and PBA components in a blend containing 60 wt % PBA. The blend was quenched from the single-phase region at 190 to 130 °C to crystallize the PVF 2 component and was then further quenched to 20 °C to crystallize the PBA component. This study, together with our earlier results, shows that the time dependence of the PVF 2 crystallization rate and crystalline lamellar thickness is a function of the PBA content in the blend. The glass-transition temperature of the blend and the PBA diffusion process are the two dominant factors that control the PVF 2 crystallization dynamics.
Databáze: OpenAIRE
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