MOLECULAR DESIGN OF VISCOELASTICITY AND DAMPING PROPERTIES IN VITRIMERS
Abstract
We will develop new polymers for improved vibration and sound damping. The approach combines the synthesis of vitrimers, polymer networks held together by dynamic bonds, with mechanical and sound wave measurements. Vitrimers have an unconventional temperature dependence of modulus, specifically the ratio of liquid-like to solid-like behavior which is important for damping applications. Through organic materials chemistry, the glass transition temperature (Tg), modulus, and dynamic bond kinetics can be independently tuned which is a unique feature compared to typical polymers. We hypothesize that dynamic bonds will provide additional processes which can occur at a similar or widely separated frequency compared to the glass transition. This tunability will lead to materials which are effective at suppressing one particular frequency, for example associated with a helicopter gear, or a broad range of noise, for instance in an aircraft cabin. Fast exchanging bonds can also improve damping of high frequency processes such as shockwaves which lead to traumatic brain injury and related issues. We will probe acoustic wave transport in vitrimers with a range of dynamic bonds and polymer chemistries to identify molecular structures which lead to improved sound damping. Nanofillers will then be added to modify the loss spectrum and provide hard-soft interfaces to scatter sound waves. The combination of new materials synthesis and characterization across a broad range of frequencies, temperatures, and timescales will provide design rules for the next-generation of damping materials.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA95502010262
Entities
People
- Christopher M Evans
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Illinois Urbana–Champaign