Synthesis, Structural, Magnetic and High-Frequency Electrical Properties of Mn0.8Zn0.2Fe2O4/Polypyrrole Core–Shell Composite Using Waste Batteries

Interface Optimizing Core-Shell PZT@Carbon/Polyurethane Composites with Enhanced Passive Piezoelectric Vibration Damping Performance

Presently, piezoelectric materials are gradually playing a significant role within composites to improve the damping and vibrational attenuation capacities of host composites. Previous studies paid attention to isolating the mechanical damping contribution and piezoelectric contribution of polymer-based piezoelectric composites (PPCs). However, reports detailing the piezoelectric damping of such materials have not paid sufficient attention to the technologies and methods to improve the piezoelectric damping of PPCs. In this study, we propose novel damping polyurethane (PU)-based piezoelectric composites with carbon-coated piezoelectric fillers (PZT@C/PU) with improved piezoelectric damping ability. The mechanical damping and piezoelectric damping of composites were theoretically decoupled, and we elaborate on the mechanism enhancing piezoelectric damping through the carbon coating strategy by comparing with the composites with nonpiezoelectric fillers. The as-fabricated core-shell structure having an optimized interface exhibits the proposed PZT@C/PU composite pads with relatively prominent damping ability (loss factor tan δmax = 1.0, tan δRT = 0.3), ductility (400.63%), and sound isolating behavior (transmission loss TL > 23 dB). Moreover, the vibration test results of as-fabricated sandwich structural PZT@C/PU composite damping devices exhibit outstanding vibration attenuating behavior (damping ratio ζ = 0.198). The study herein validates that the carbon shell coated on piezoelectric fillers would effectively increase damping performance of PU-based piezoelectric composites by the enhancement of piezoelectric performance caused by carbon coating piezoelectric fillers, which indicates that this material has potential for future applications in the field of vibration and noise reduction, thereby driving forward and expanding the fundamental understanding in the area of PPCs damping and vibration attenuation.

Synthesis, Characterization and Dye Removal Capability of Conducting Polypyrrole/Mn0.8Zn0.2Fe2O4/Graphite Oxide Ternary Composites

Herein, ternary composites from polypyrrole (PPy), Mn0.8Zn0.2Fe2O4 (MZF), and graphite oxide (GO) were prepared to remove acid red dye (AR1) from wastewater. MZF was synthesized using spent Zn–C batteries, acid leaching, and sucrose auto-combustion processes; GO was prepared via oxidation and exfoliation of graphite. The composites were prepared by adding MZF and GO during the in-situ polymerization of pyrrole. Different PPy/MZF/GO (PMG) composites were prepared by changing the weight ratios of the PPy, MZF, and GO. We investigated the prepared composites’ structural, magnetic, and electrical/dielectric properties. We evaluated different experimental conditions’ influences on dye removal performance, such as pH, dosage, dye concentration, temperature, and contact time. XRD, FT-IR, and magnetic properties indicated that PPy completely coated the other contents. The electrical/dielectric properties improved while increasing the GO ratio. The PMG at GO content 50 wt.% (PMG50) showed the most efficient ratio for better removing AR1 from wastewater.