Structure and properties of in situ reactive blend of polylactide and thermoplastic starch

In this study, in situ reactive extrusion of polylactide and thermoplastic starch modified with chloropropyl trimethoxysilane coupling agent (PLA/mTPS) is proposed. The success of covalent bond formation between PLAmatrix and mTPS phase is clarified by two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy with H-1-H-1 TOCSY mode. This chemically bound PLA with starch gives the remarkable compatibility in the PLA/mTPS film, with not only a decreased glass transition temperature (47 degrees C) but also an increased crystallinity of PLA (X-c of 50%). It consequently increases oxygen barrier significantly and also enhances the film flexibility as observed from the drastic increase of elongation at break (from 3% to 50%). Moreover, the PLA/mTPS 60/40 (w/w) film exhibits the accelerated degradation as compared with pure PLA film. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study successfully demonstrated the formation of covalent bonds between PLA and mTPS phases using 2D-NMR, leading to improved degradation rate and flexibility of the PLA film.