Date of Award

Spring 5-2016

Degree Type

Honors College Thesis

Department

Polymers and High Performance Materials

First Advisor

Jeff S. Wiggins

Advisor Department

Polymers and High Performance Materials

Abstract

The addition of comonomers into carbon fiber precursor, polyacrylonitrile (PAN), has shown to have effects on the extent of stabilization and thermal behavior.1 Acrylic Acid (AA) was added at varying initial apparent weight percent and added via semibatch reaction to copolymerize with acrylonitrile to form carbon fiber precursor. Accompanying batch reactions were synthesized for comparison. Degradation was found to be greater in the semibatch reactions although overall was comparable to the batch reactions. Differential scanning calorimetry (DSC) confirmed the addition of higher concentrations of AA into the reaction resulted in a less intense exotherm upon cyclization, along with a greater breadth and earlier onset temperature. These findings will extend to the semibatch reactions. The extent of stabilization was also found to be comparable among all of the polymers, however, the semibatch reaction with the highest AA concentration showed a much higher extent of stabilization. This has demonstrated that semibatch reactions can create comparable polymers when compared to batch reactions as well as the feed rate has an effect on the stabilization of the product and that this can be used to tune the backbone sequence. These findings eventually coupled with the ability to control the placement of the comonomers along the backbone could lead to greater ease of processing due to the need for lower cyclization temperatures as well as a less loss of product due to the smaller exothermic reaction while being able to achieve uniform ring structure along the backbone.

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