(a) DSC thermograms of PEO/TA blends showing a depression of the melting peak of PEO with the addition of TA. The inset represents the enlarged dual melting peaks of PEO/TA 30/70 in various heating rates showing dual melting endotherms at low PEO contents. (b) DSC thermograms of PEO/TA blends showing a systematic shift of ’s with PEO contents. The heating rate was .
Plots of (a) glass transition temperature with PEO concentrations in comparison with Fox equation implying amorphous-amorphous miscibility and (b) melting point depression of PEO. The negative departure may be a consequence of PEO crystals preventing complete miscibility in the amorphous phase at high PEO contents.
Comparison between the calculated self-consistent solutions (solid lines) and the experimental melting temperatures (filled circles) of PEO/TA blends showing the crystal solid-liquid coexistence region bound by the liquidus and solidus lines. The parameters used were , , at , , , and at . The predicted UCST falls below the glass transition temperatures of the blends.
Temporal emergence of the PEO crystals in the blend of the PEO/TA showing the coexistence of liquid: (a) the aggregates of anisotropic lamellar structure of PEO in the continuum of TA-rich melt in the 5/95 PEO/TA blend at ; (b) the sheaflike structure in the 10/90 blend at ; (c) the fully grown spherulite structure in the 40/60 blend at .
Emerging PEO crystal structures following the isothermal crystallization by quenching various PEO/TA blends to : (a) 5/95, (b) 20/80, and (c) 50/50, showing the solvated spherulites in conformity with the predicted single-phase crystalline region of the phase diagram.
Calculated snapshots of the coexistence curves evolving with reaction time in comparison with the experimental phase diagram of PEO/TA blend: (a) before and (b) during photopolymerization. With the progression of reaction, both the UCST and the melting transition curves move upward and surpass the reaction temperature, inducing phase separation and crystallization.
Temporal evolution of phase morphology showing the liquid-liquid phase separation and crystallization during the course of photopolymerization of the 20/80 PEO/TA blends at (a) and (b) , respectively. The dark appearance under the crossed polarizers in Fig. 7(a) indicates the lack of orientation fluctuation (i.e., no crystalline order). The dashed line is the monotectic line representing the coexistence of phases at the 20% conversion, which virtually remains constant with further increase in the conversion.
(a) The liquid-liquid phase separation in the 30/70 PEO/TA blend driven by photopolymerization at and (b) polymerization-induced crystallization at , showing the epitaxial growth of PEO crystals.
Spatiotemporal evolution of the phase separated domains showing the fingerlike growth during photopolymerization of TA in the blends of 40/60 PEO/TA upon exposure at of filtered green light, showing (a) phase separated domains within the viscous fingering pattern at and (b) the regular viscous fingering without any phase separated texture at .
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