Dielectric and free volume of Poly methyl methacrylate/silver nanoparticles- polyhydroxybutyrate nanocomposites (PMMA- AgNP/PHB): positron annihilation lifetime study

Solution casting technique was used successfully to prepare Poly methyl methacrylate/silver nanoparticles-polyhydroxybutyrate blend with different polyhydroxybutyrate (PHB) concentrations. FTIR results assure and confirm the good compatibility between the two polymers. X-ray results of the PHB/PMMA-AgNP blend show an increase in crystallinity with increasing PHB loading. A non-destructive Positron annihilation lifetime measurements were conducted at room temperature as a function of PHB concentration. Measurements of a dielectric constant were performed in the frequency range of 50 Hz to 50 MHz at RT. It was observed that O-Ps lifetime, tau 3, O-Ps intensity, I3, free volume hole size, FV, and fractional free volume, FFV, were found to decrease with increasing PHB percentage. The dielectric constant epsilon/ showed a declined behaviour with increasing PHB content. The fabricated blend shows anomalous behaviour regarding the dielectric properties and free volume properties, indicating that blending PMMA with PHB alters the blend polarization behaviour in an external electric field.