Multiple melting in blends of poly(vinylidene fluoride) with isotactic poly(ethyl methacrylate)

Multiple melting phenomena have been studied in blends of poly(vinylidene fluoride) (PVF2) with low molar mass isotactic poly(ethyl methacrylate) (it-PEMA). In all blends, as well as in pure PVF2, a transition (T1) was observed prior to the main melting point (T2). T1 is probably connected with the melting of secondarily-crystallized material. In addition to this, a high temperature melting endotherm (T3) was observed, which could be ascribed completely to recrystallization of PVF2. The highest transition (T4) was caused by melting of the σ form of PVF2. From Hoffman-Weeks plots—T2 vs. crystallization temperature, Tc — it could be concluded that no thermody amic depression of the melting point of PVF2 occurred in the blends. The stabilities of PVF2 crystallites in the various blends were derived from the slopes of Hoffman-Weeks plots and were in good agreement with lamellar thicknesses found from SAXS measurements