Date of Award

2022-12-01

Degree Name

Master of Science

Department

Civil Engineering

Advisor(s)

Shane Walker

Second Advisor

Eva M. Deemer

Abstract

An interpenetrating polymer network (IPN) for cation exchange applications was synthesized from a blend of styrene-ethylene/butylene-styrene (SEBS) and acrylonitrile butadiene styrene (ABS), which was 3D printed, grafted with crosslinked polystyrene (PS), and sulfonated. A method for styrene grafting was applied to reduce the damage to polymer phases caused by the sulfonation reaction. Styrene and divinylbenzene monomers were introduced to the IPN and induced with heat treatment to polymerize in situ. The graft copolymerization reaction was enhanced with varying quantities of benzoyl peroxide as a chemical initiator. The samples were subsequently sulfonated with chlorosulfonic acid in dichloroethane and functionalized for ion exchange. These samples' chemical composition and morphology were characterized by the ion exchange capacity (IEC), FTIR spectroscopy, SEM imaging, and small angle X-ray scattering (SAXS). Analysis of the samples revealed that higher quantities of benzoyl peroxide improved the degree of grafting and created a more highly ordered internal arrangement of the styrene domains in the network. As a result, the resistance of ABS to chemical solvents was significantly improved, and the integrity of the polymer domains was protected from the sulfonation reaction. Lastly, the methodology was improved with respect to the swelling agent used in the sulfonation reaction. Samples were sulfonated with chlorosulfonic acid in dichloroethane, dichloromethane, and chloroform. Dichloroethane appeared to have the least destructive effect on the integrity and linearity of the polymer blend. These results indicate that a methodology and chemistry for producing ion exchange material from blended and 3D-printed SEBS/ABS polymers were successfully developed. This new strategy for functionalizing polymer blends can be applied in the future to improve the mechanical stability of membranes without the need for chemical crosslinking.

Language

en

Provenance

Received from ProQuest

File Size

66 p.

File Format

application/pdf

Rights Holder

Avianna Elaine Gallegos

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