The crystallization behaviors of incompatible poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)/PS

PHBV/PMMA crystalline/amorphous blends with different ratios and different crystallization temperatures were investigated

with particular emphasis on the effect of amorphous components

such as PS or PMMA

on the morphology of PHBV ring-banded spherulites.PHBV ring-banded spherulites with slightly fuzzy bands were obtained when the content of PHBV in blends was 75%

which was similar to pure PHBV.Petal shaped spherulites were obtained at the crystallization temperature slightly lower than Tg of amorphous components when the content of PHBV in blends was 50%.When the content of PHBV in blends was 25%

irregular crystal morphologies were obtained in PHBV/PS blends

whereas no crystal was observed under POM in PHBV/PMMA blends.In the incompatible blends

the dispersion state and blends ratio of amorphous content had the decisive effect on the formation of PHBV ring-banded spherulites:ring-banded spherulites developed only at low crystallization temperatures when amorphous component content was high

and ring-banded spherulites generated at a wide range of crystallization temperature when amorphous component content was low

whereas the effect of amorphous content on the growth of lamellae at the front of spherulites was the main cause of the formation of petal shaped spherulites.