Melt-processed poly (vinyl alcohol)/corn starch/nanocellulose composites with improved mechanical properties.

Abstract

This study describes the fabrication of biodegradable poly(vinyl alcohol) (PVA) composites reinforced with corn starch (CS) and cellulose nanofibrils (CNFs) via melt-processing. Regulation of the hydrogen bonding network within the composite system broadened the processing window substantially to 131.46 °C and enhanced thermoplasticity. Infrared and Raman spectroscopic analyses confirmed disruption of intra- and inter-molecular hydrogen bonds in PVA and the concurrent formation of new hydrogen bonds among PVA, CS, and CNFs. At loadings of 10 wt% CS and 10 wt% CNFs, the composites achieved a tensile strength of 28.19 MPa, a modulus of 1572.54 MPa, and an elongation at break of 10.72%. The approach offers a pathway for producing complex three-dimensional PVA articles by melt-processing and may be applicable to improving the mechanical performance of other biodegradable polymer systems.

Mechanism

During melt-processing, existing intra- and inter-molecular hydrogen bonds in PVA are disrupted, and new hydrogen bonds form among PVA, corn starch, and cellulose nanofibrils, thereby widening the processing window and improving mechanical properties.