Understanding the role of kinetic parameters on the crystallization of miscible semicrystalline polymer blends
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This dissertation discusses results of crystallization kinetic, morphology and scattering studies on miscible semi crystalline blends of poly(pivalolactone)/ poly(vinylidene fluoride)(pPVLIPVF2) and poly(pivalolactone)/poly(vinylidene fluorideco- tetrafluoroethylene)(95-5) (PPVL/P(VF2-TFE)(95-5)) prepared by solution blending. The spherulitic growth rates of the Î±-phase PPVL from miscible blends with PVF2 or P(VF2- TFE)(95-5) were measured by polarized optical microscopy as a function of blend composition and isothermal crystallization temperature, Tx, between 160Â°C and 215.5Â°C. The PPVL weight fraction in the blends ranged from 100 to 10 wt%. Using the Lauritzen-Hoffman kinetic theory of polymer crystal growth, the equilibrium melting temperatures of the Î±-phase PPVL in both the PPVL/PVF2 and the PPVL/P(VF2-TFE)(95-5) blends have been determined, for the first time, directly from the spherulitic growth rate data. Analysis of the composition dependence of the nucleation constant, Kg suggests that the Î±-phase PPVL crystal/melt lateral interface free energy, Ï , in the blends decreases markedly with increasing PVF2 or P(VF2-TFE)(95-5) concentration.
- Doctoral Dissertations