In this study, we obtained and characterized a piezoelectric composite with 1-3 connectivity from castor oil polyurethane (PUR) and lead zirconate titanate (PZT) rods. Two samples were obtained, one with 15% PZT volume and the other with 34% PZT volume. The ac electrical properties of the 1-3 piezoelectric composite samples demonstrated the frequency-dependence behavior of disordered solids. The piezoelectric coefficient (d33) was greatly influenced by the number of PZT rods and the matrix curing process. The sample with 34% PZT volume showed a higher d33 value, (246 pC/N measured after 30 d of polarization). The composites were evaluated for use in acoustic emission wave sensors for application in structural health monitoring.

In this work microfiber mats of Nile tilapia (Oreochromis niloticus) gelatin were successfully fabricated by using Solution Blow Spinning technique. The concentration and viscosity of fish gelatin solution, in acid acetic/water (80% v/v), were correleted to the morphology and diameter of the gelatin microfibers. It was found that increased solution viscosity leads to increase of fibers diameters from approximately 280 nm at viscosity ~ 0.085 Pa.s. to approximately 1195 nm at viscosity ~ 1.877 Pa.s. The TG thermograms showed similar thermal profiles for all fibrous mat gelatins with thermal stability at temperatures below 180°C. The DSC curve showed two endothermic peaks being the second one, in the range of 100-130°C, strongly influenced by the microfiber diameters. It shifts to higher temperature increasing the microfiber diameter. This behavior was associated to the diffusion of water in the microfibers. Combined DSC/TG results showed a significant influence of the microfiber diameter on the water absorption and desorption process.

A composite of natural rubber (NR) with polyaniline (PANI) was obtained by mixing an aqueous dispersion of dodecylbenzenesulfonic acid (DBSA)-doped PANI with NR latex in different concentrations. Films were obtained by the casting method and characterized by ultraviolet visible near-infrared (UV-Vis-NIR) spectroscopy, thermogravimetry/differential thermogravimetry (TG/DTG), stress-strain testing, differential scanning calorimetry (DSC), and DC electrical conductivity measurements. The UV-vis-NIR spectrum showed that PANI remained doped in the composite, and this improved the mechanical and electrical proprieties of NR films and afforded them good thermal stability up to ~200ºC. The percolation threshold did not follow the universal critical exponent, and in this case, conduction preferentially occurs by hopping and tunneling.