Dynamic rheological behavior and morphology of polylactide/poly(butylenes adipate‐<i>co</i>‐terephthalate) blends with various composition ratios

Abstract

Abstract Polylactide (PLA)/poly(butylenes adipate‐ co ‐terephthalate) (PBAT) blends with various composition ratios were prepared via melt compounding using a twin‐screw extruder. The dynamic rheological behavior and morphology of the blends were studied using a parallel‐plate rheometer and a scanning electron microscope (SEM), respectively. The results showed that the shear‐thinning tendency of blends became stronger with increasing PBAT content. Moreover, at low frequencies, the complex viscosity, storage modulus and loss modulus for blends with 20 wt% PBAT content were higher than that of other samples when PBAT content was less than 50 wt%. Based on SEM images, three distinct morphologies—spherical droplet, elongated fibrous structure, and co‐continuous structure—were observed as the content of PBAT increased from 5 to 50 wt%. When the PBAT content reached 70 wt% and above, the morphology became droplets again, with PLA droplets dispersing within the PBAT matrix. In addition, the PLA droplets in the PBAT/PLA (80/20 w/w) blend were smaller and more regular than the PBAT droplets in the PLA/PBAT (80/20 w/w) blend, despite the same composition ratio. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 150–157, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20212