Toughening Effect of Physically Blended Polyethylene Oxide on Polyglycolic Acid

Abstract

Polyglycolic acid (PGA), a linear aliphatic polyester with excellent biodegradability and biocompatibility, is widely used as a medical material. However, the inherent brittleness of this material may limit its use in many other industrial applications. This study explored the toughening effect of physically blending PGA with polyethylene oxide (PEO). Standard tensile samples of different PGA/PEO blends were prepared by a torque rheometer and a microinjection molding machine. The thermodynamic properties, mechanical properties, and microstructure of the PGA/PEO samples were investigated by differential scanning calorimetry (DSC), a universal tensile testing machine, a cantilever impact tester, and field emission scanning electron microscopy (FE-SEM). The experiment ultimately found that the addition of 15 wt% PEO greatly improved the toughness of the blended PGA/PEO. A yielding process could be observed in the tensile tests, and the elongation-at-break increased from 3.67% for pure PGA to 54.14% for PGA/PEO 85:15, which shows an increase of 1475.2%. It can be concluded that the addition of PEO is a good way to increase the PGA toughness. The mechanism of PGA toughening by PEO was further analyzed, and the increase in toughness could be attributed to the existence of a continuous PEO phase that facilitated the formation and evolution of cavities between the partially compatible PGA and PEO phases.