Growth of banded spherulites of poly(∈-caprolactone) from the blends: An examination of the modeling of spherulitic growth

For the banded spherulites of poly(∈-caprolactone), PCL, grown from the blends with miscible polymers of polyvinyl butyral and poly(styrene-co-acrylonitrile), the effects of blended amorphous polymers on the band spacing have been examined experimentally. The results reconfirmed the strong influence of the second components even with small amount (c.a. 0.09 wt%). For the crystallization under the strong influence of the second components probably on the lamellar surface, we have examined the applicability of our modeling of spherulitic growth and its limit. Important findings in this paper are the followings: 1) On the confirmation of the applicability of the modeling for the amount of the second component small enough and the band spacing long enough. 2) On the violation of the predicted relationship of the modeling with increasing amount of the second component, which caused sharp decrease in the band spacing. 3) On the observation of the lower bound of the band spacing, to which the band spacing approached with the increase in the second component. With approaching the lower bound, the band spacing eventually became independent of other growth conditions such as crystallization temperature.