Graduate Defense: Allison Christy

Dissertation Information

Title: Closed-Loop, Recyclable Plastics From Ethyl Cyanoacrylate

Program: Doctor of Philosophy in Materials Science and Engineering

Advisor: Dr. Scott Phillips, Materials Science and Engineering

Committee Members: Dr. Amy Moll, Materials Science and Engineering; Dr. Glauco Pilon dos Santos, Materials Science and Engineering; and Dr. Kris Campbell, Electrical and Computer Engineering

Abstract

Ethyl cyanoacrylate, commonly known as super glue, has held a prominent role as an adhesive for decades due to its propensity to rapidly polymerize into poly(ethyl cyanoacrylate) (PECA) under ambient conditions. Ethyl cyanoacrylate monomers and their resulting PECA polymers are bio-friendly, which has allowed them to be used as medical adhesives and to be applied to drug delivery systems. However, PECA has not been used as a plastic material due to the perceived difficulty of handling the ethyl cyanoacrylate monomer. Here, we present a novel PECA plastic that displays thermal stability and tensile strength values that are comparable to atactic poly(styrene) (PS). The high-molecular weight, low-PDI polymer is produced in high yields via a one-pot synthesis under ambient conditions. The PECA plastic can easily be recycled via depolymerization by thermal cracking that allows for the collection of pure monomer. Variation of the pure PECA using spontaneous copolymerization with vinyl comonomers produced new bulk plastic materials that mimic the properties of a range of other kinds of plastics, including silicone elastomers, poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET), and high and low-density poly(ethylene) (HDPE & LDPE). This bio-friendly PECA plastic may be a good replacement for traditional non-recyclable, petroleum based plastics, particularly because the monomer already is produced on commercial scale.