Tribological and Mechanical Properties of Poly[(R)-3-hydroxybutyric acid] Grafted with Vinyl Compounds: Insight into Possible Application

Abstract

Biodegradable graft copolymers were prepared by gamma radiation-induced graft polymerization of two vinyl monomers, vinyl acetate and vinyl alcohol, onto poly[(R)-3-hydroxybutyric acid]. Success of the grafting reaction was verified by Fourier-transform infrared and nuclear magnetic resonance spectroscopy. Thermal remolding was used to create membranes from the copolymers. We determined tribological and mechanical properties of the membranes obtained. The lowest elongation at break in tensile testing is seen for P(3HB) and the highest for P(3HB-g-VA). Up to 5 N or so, the highest scratch resistance is exhibited by P(3HB-g-VA). Piezoelectric behavior is seen for P(3HB-g-VA) while P(3HB-g-VAc) and plain P(3HB) showed no electric response. Explanation of the piezoelectric behavior in terms of molecular structures is provided.

Keywords:

• Membrane tensile testing
• Membrane tribology
• Piezoelectricity
• Poly(vinyl acetate)
• Poly(vinyl alcohol)
• Poly[(R)-3-hydroxybutyric acid]

ACKNOWLEDGEMENTS

We are grateful to Gerardo Fonseca and Domingo Rangel for their assistance in mechanical testing. We are also indebted to Blanca Huerta and Guadalupe Mendez for their contribution to the drafting of the article.