BIO

My name is Matthew Stephens and I am going to be a 2024 graduate at FSU. I am from Milton, Florida. I am majoring in Dietetics and hoping to eventually achieve my MS degree in Sports Nutrition.

The Composite that is Recoverable

Abstract

The demand for lightweight and strong materials continues to rise especially for weight critical applications such as aerospace and automotive. Along with this demand the desirability for materials to be recoverable after deformation is also increasing. In this work, we fabricated a special lightweight nanocomposite, which is made by infiltrating a thermoplastic polymer into the nanocarbon foam. The nanocarbon foam is made up of carbon nanotubes (CNTs) and nano-scaled graphitic carbon and has biporous and open-cell structure. After infiltration, the polymer is coated onto the surface of the CNTs and reinforce the structure effectively. The compressive strength is increased while the electrical property is kept intact. The nanocomposites are not elastic. When compressed, the permanent deformation occurs due to the plastic deformation undergone by the polymer. It’s found that the permanent deformation can be recovered by simply using heat via direct heating, IR light, and application of electrical voltage. Heating the deformed nanocomposite to the temperature around the glass transition temperature (Tg) range of polymer, results in the full strain recovery of the nanocomposite. It is because that the polymer assumes a soft and rubbery behavior beyond Tg, while the intrinsically elastic CNTs, which are still surrounded by polymer, are able to rebound and exhibit their elasticity by overcoming the force applied by the enclosing polymer upon the reduction in its Young’s modulus. The nanocomposite becomes rigid again when its temperature is lower than Tg. It is remarkable that the recovery in both structure and property can be repeated.

Keywords: Composite, Recoverable, CNT