The Effect of Precursor Design On the Thermal Properties of Polyacrlonitrile Based Carbon Fiber Precursors

Document Type

Conference Proceeding

Publication Date

10-5-2018

School

Polymer Science and Engineering

Abstract

Current polyacrylonitrile based carbon fiber only demonstrates ten percent of their theoretical tensile strength due to morphological defects within the black fiber. These defects are often attributed to poor precursor molecular design, comonomer composition and distribution, and fiber processing. This study directed precursor design through the controlled polymerization technique reversible addition fragmentation chain transfer and compared the thermal properties of these precursors to copolymers synthesized by traditional uncontrolled free radical polymerization in an effort understand the influence of precursor design on thermal properties. Additionally, the incorporation of acrylamide comonomers with increased steric substituents from ethyl, isopropyl, and tert-butyl is hypothesized to systematically disrupt the semi-crystalline morphology and improve thermal properties such as the extent of stabilization and exotherm. The extent of cyclization was analyzed by fourier transform infrared spectroscopy. Exotherm and activation energy was determined by differential scanning calorimetry. Precursors prepared by free radical polymerization afforded the lowest extent of stabilization and highest activation energy as compared to precursors synthesized via controlled polymerization techniques. This work provided key insights on the effect of precursor design on the thermal ring closure properties as well as successfully prepared novel acrylamide polyacrylonitrile precursors in an effort to understand morphology disruption.

Publication Title

CAMX 2018 - Composites and Advanced Materials Expo

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