Nearly constant dielectric loss behavior in poly(3-hydroxybutyrate-co-3- hydroxyvalerate) biodegradable polyester

The measurement of dielectric spectroscopy over a broad frequency range of 0.01- 107Hz has been conducted to examine the segmental motions in poly[3-hydroxybutyrate-co-3-hydroxyvalerate] (PHBV) biopolymers. The ac conductivity at either low temperatures or high frequencies is almost temperature independent, indicating clearly that the nearly constant loss (NCL) phenomenon also takes place in polymers. The respective data were analyzed by adding a NCL term to the Jonscher relation. NCL in PHBV is discussed to be originated from the vibrational motion model. PHBV may have potential application as a biodegradable dielectric material.