Elastic constants of self-healing polyethylene co-methacrylic acid determined via resonant ultrasound spectroscopy

Abstract

Self-healing polyethylene co-methacrylic acid (EMAA) is a thermoplastic material that can be shaped into structures that are capable of autonomously healing after being cut, punctured, or shot. In this work, we present results from several samples of self-healing EMAA-0.6 Na, with 60% of the methacrylic acid groups neutralized by sodium, known as DuPont Surlyn 8920. This ionomer, unlike typical crystals with extremely high quality factors and easily identifiable ultrasonic resonances, is a relatively soft polymeric material with significant damping, resulting in sample resonances that can overlap and are often difficult to identify and isolate. In this work, we show the resonant spectrum of several different EMAA-0.6 Na samples as well as the methods used to isolate individual resonances and determine the elastic constants.