"Mechano-Optical Behavior during Processing of High-performance Bio-based/Biodegradable Polymers for Electronics Applications" 

Henry Davis, MSE PhD Candidate 

Advisor: Professor Miko Cakmak

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ABSTRACT

Increasing urgency for solving climate and pollution issues has led to the development of many bio-based and biodegradable plastics. However, current biodegradable plastics cannot replicate the properties of plastics used in many high-performance applications, like flexible substrates for printed electronics. In response, we have developed a high-performance bio-based and biodegradable plastic called poly cannabidiol carbonate (pCBDC), derived from cannabidiol extracted from the hemp plant. We examine real-time optical and mechano-optical behavior during solution casting and uniaxial stretching of pCBDC films to enable this polymer to be used in industry film manufacturing. Solution casting analysis reveals that higher molecular weight, lower solution concentration, lower thickness, and lower drying temperature lead to the highest in-plane polymer chain alignment as measured using birefringence. Analysis during uniaxial stretching shows different behavior during stretching below vs above the liquid-liquid transition temperature (Tll), with the greatest chain alignment and best strain hardening occurring when stretched close to, but not above Tll. Additionally, higher molecular weight leads to increased chain alignment and strain hardening at lower strains. As strain hardening is essential for thickness uniformity, this quality will enable pCBDC films to be used as biodegradable substrates for future flexible electronics, replacing current nondegradable materials like PET, PEN, and others.