Shear-induced enhancements of crystallization kinetics and morphological transformation for long chain branched polylactides with different branching degrees.

ABSTRACT: The effects of long chain branching (LCB) degree on the shear-induced isothermal crystallization kinetics of a series of LCB polylactides (LCB PLAs) have been investigated by using rotational rheometer, polarized optical microscopy (POM) and scanning electron microscopy (SEM). Dynamic viscoelastic properties obtained by small-amplitude oscillatory shear (SAOS) tests indicate that LCB PLAs show more broadened relaxation time spectra with increasing LCB degree. Upon a pre-shear at the shear rate of 1 s(-1) LCB PLAs show much faster crystallization kinetics than linear PLA and the crystallization kinetics is enhanced with increasing LCB degree. By modeling the system as a suspension the quantitative evaluation of nucleation density can be derived from rheological experiments. The nucleation d

SUBMITTER: Wang J 

PROVIDER: S-EPMC4887888 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature