Structure, chain dynamics and mechanical properties of poly(vinyl alcohol)/phytic acid composites

The global micro- and nano-plastic issue has greatly triggered the development of advanced biodegradable polymeric materials. The creation of biodegradable polyvinyl alcohol (PVA)/phytic acid (PhyAc) composite represents a sustainable solution. However, it remains unclear how PhyAc molecules affect intermolecular hydrogen-bonding (H-bonding), structure, chain dynamics and mechanical properties of PVA so far. Herein, we explore structure, chain dynamics and mechanical properties of PVA/PhyAc composite by combining molecular dynamics simulation and experimental. The number of PVA-PhyAc H-bonds per PhyAc molecule and that of total H-bonds show different PhyAc content dependence. The PVA composite with 1.9 wt% of PhyAc shows a lower free volume and a smaller diffusion coefficient. Meanwhile, the glass transition temperature (Tg) of PVA reaches the maximum value at ca. 1.25 wt% of PhyAc. Interestingly, 10 wt% PhyAc endows PVA with the highest tensile strength in addition to a good antibacterial capability. This work reveals how small molecules affect structure and mechanical properties of polymers and contributes to expanding practical applications of PVA/PhyAc in industry.