Crystallization behavior of poly(ethylene oxide) in its blends with cellulose.

Melt-crystallization behavior of poly (ethylene oxide) (PEO) in its blends with cellulose (CELL) was studied by differential scanning calorimetry (DSC). Blend samples were prepared from solutions in dimethylacetamide-lithium chloride by coagulation in a nonsolvent. Crystallization isotherms obtained at various temperatures for pure PEO and PEO-rich blends were analyzed by the application of a well-known Avrami equation. On increasing the CELL content of the samples, the overall crystallization rate became slower, while the Avrami exponent remained almost constant or tended to be larger, when compared under the same condition of undercooling. The observed dependence of the PEO crystallization kinetics on blend composition is quite similar to that found for other miscible crystalline/amorphous polymer blends. The slower crystallization kinetics of PEO in the blends was explicable in terms of a diluent effect of the CELL component. It was also found that the addition of CELL to PEO resulted in only a little reduction in the surface free energy of folding, σe, of PEO lamellar crystals.