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UBC Theses and Dissertations

Poling of barium titanate nanoparticles-incorporated piezoelectric paper substrates Sumanasinghe, Vithanaarachchige Aeranda Sajana

Abstract

Paper manufacturing is a strategic industry for Canada. However, rapidly changing markets, weak prices, increasing transportation costs, frequent wildfires, and recent mill closures have significantly impacted the pulp and paper industry. According to Canadian Industry Statistics, in British Columbia alone, the gross domestic product contribution from pulp and paper industry has declined by more than 25% from 2018 to 2020. Developing paper-based composites for specialized applications such as transducers will open new markets for pulp and paper industry. Incorporating piezoelectric particles in paper matrices leads to composites that can be employed as piezoelectric transducers whilst retaining the intrinsic properties of paper such as porosity and flexibility. Yet, to impart piezoelectric properties, these composites need to be electrically poled. This research project focuses on corona poling of 300 nm barium titanate nanoparticles incorporated paper based piezoelectric composites manufactured using unrefined and refined Northern Bleached Softwood Kraft (NBSK) pulp. The highest piezoelectric charge constant of 37.2 pC/N (comparable to commercially available polymers such as PVdF) was obtained for the composite manufactured using 300 kWh/t refined NBSK pulp with a barium titanate mass loading of 69.3 wt.%. This was attributed to increased surface roughness of fibers and enhanced stress transfer within the compact paper matrix formed due to refining, and enhanced polarization paths due to nanoparticle clusters within the paper composite. Best poling conditions were identified based on the studies on the effects of grid voltage in the corona triad, poling temperature, and poling time on the piezoelectric response. The observed decay in piezoelectric response of the composite over time was attributed to the dielectric contrast in constituent materials in the composite, hindrance to domain motion due to particle size, and depolarization fields caused by space charges. Findings of this work can be transferred to develop practical applications of barium titanate nanoparticles-incorporated paper-based piezoelectric composites such as tactile sensors, accelerometers, and smart packaging systems.

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Attribution-NonCommercial-NoDerivatives 4.0 International