Application and performance of maleated thermoplastic starch-poly(butylene adipate-co-terephthalate) blends for films

Abstract

In this work, we studied the effect of the percentage of maleated thermoplastic starch (MTPS) in MTPS-poly(butylene adipate-co-terephthalate) (PBAT) blends that were used to produce extruded films. The materials were characterized by their mechanical properties (tensile and puncture tests), their barrier properties (carbon dioxide, oxygen, and water-vapor permeability tests), and microstructural analysis [transmission electron microscopy (TEM)], and the biobased content of the materials was determined. The results of the testing show that increasing the MTPS content decreased the tensile strength (from 19.7 to 8.6 MPa in the machine direction and from 15.3 to 7.1 MPa in the transverse direction) and puncture force (from 42.5 to 30.3 N) of the films; however, the elongation was not significantly affected. The permeability of the films to oxygen and carbon dioxide decreased with increasing MTPS content. The oxygen permeability decreased from 1.68 × 10 -17 to 6.0 × 10 -18 kg m m -2 s -1 Pa -1, whereas the carbon dioxide permeability decreased from 3.0 × 10 -16 to 1.1 × 10 -16 kg m m -2 s -1 Pa -1. However, the permeability to water vapor increased from 5.0 × 10 -15 to 1.04 × 10 -14 kg m m -2 s -1 Pa -1. Finally, TEM showed that PBAT was the continuous phase and MTPS was the dispersed phase. As the amount of MTPS in the samples increased, the dispersed phase became finer and more regularly spaced. © 2012 Wiley Periodicals, Inc.