Electrical and mechanical properties of free-standing PMMA-MMT clay composites

Abstract

Modified MMT clay-doped PMMA composites have been prepared by solvent casting method for different weight percentages. The prepared composite films were characterized by FTIR and SEM. Also, the DC conductivity was carried out for PMMA and PMMA composite films. Among all composites, it was found that 30 wt% shows highest conductivity of 1.59 × 10-3 S/cm. The negative thermal coefficient behavior of these polymer composite films confirms that the increase in conductivity is due to the elongation of polymer chain which helps in charge transport mechanism. Dielectric study also shows that 30 wt% has the lowest dielectric constant and dielectric loss of 2.5 and 3.3, respectively, resulting in an increase in conductivity of 5 × 10-3 S/cm. The isotropic nature of 30 wt% composite film shows a high quality factor of 0.005 because of overdamping of electron at 104 Hz. Cole-cole plots show that the semi arc originated from a single point and its area decreases with filler concentration up to 30 wt% due to drop in the electrical resistance. Tensile modulus increases because of high MMT aspect ratio and distribution ratio. The 30 wt% of the composite shows high tensile strength at 55 MPa which induces 8% of strain in the PMMA-MMT clay composite films. Therefore, these composite films can be used in many sensor and solar technologies as encapsulation materials. Copyright © 2014 Materials Research Society.