Graduate Defense: Jason Hatfield

Dissertation Information

Title: Optimizing Recyclable Materials for Industrial Applications

Program: Master of Materials Science and Engineering

Advisor: Dr. Scott Phillips, Materials Science and Engineering

Committee Members: Dr. Amy Moll, Materials Science and Engineering and Dr. Eric Jankowski, Materials Science and Engineering

Abstract

The plastics industry exploded during the Second World War because of the unique ability of plastic to be lightweight, flexible, and cheap and work as a substitute for many traditional materials. These benefits of plastics have led to them being mass-produced. However, most plastics produced are not recycled. This thesis explores two methods for curbing the amount of plastic waste accumulated. The first method addresses the issue of plastic waste not being recycled by removing one of the most time-consuming recycling steps: sorting. Our solution to mixed plastics is to compress these plastics together at low pressure and temperature to form mixed plastic composite boards that have similar properties to engineered wood boards. The second method to address the issue of plastic waste is to discover a new class of polymers that are far easier to recycle. We show this by using poly(alkyl aldehyde)s in the pressure-sensitive adhesive industry, where a small amount of this plastic can be used as a coating for the adhesive instead of label-backing rolls that cannot be recycled. The adhesive can be exposed for application through the ability of the polymer to depolymerize on demand. After depolymerization, the poly(alkyl aldehyde) reverts to its monomer and can be collected and repolymerized into a new adhesive backing. With this method, plastic waste from label backing rolls could be eliminated from industrial use through the scale-up methods explored below.