EFFECT OF CONTROLLABLE MODIFICATION OF SRTIO3 CERAMIC NANOPARTICLES ON PIEZO-ACTIVE NANOCOMPOSITES PROPERTIES

In this work the P(VDF-co-HFP) was chosen as a matrix due to the better mechanical properties compared to neat PVDF. Strontium titanate (SrTiO3) was chosen as one of the lead-free ceramics and to observe its impact of modification on nanocomposite properties. SrTiO3 nanoparticles were successfully coated with (2,2,2 triflouroethyl methacrylate) short polymer brushes using surface-initiated atom transfer radical polymerization (SI-ATRP) in order to improve the compatibility between the particles and polymer matrix. Polymer grafted from the particles surface was analyzed by gel permeation chromatography (polymer chain length and polydispersity index) and using nuclear magnetic resonance (monomer conversion). Both, neat SrTiO3 nanoparticles and their modified analogues were characterized and further compounded with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) to obtain homogenous nanocomposites. Mechanical properties were analyzed using DMA and tensile tests. Characteristic temperatures and crystallinity were evaluated using DSC. The beta-phase content was calculated using FTIR. Finally,. It was found out that modification of nanoparticles significantly enhanced the piezo-electric activity namely d33 coefficient due to the better homogeneity of the system and improved mechanical properties.