Masters Theses

Date of Award

12-2023

Degree Type

Thesis

Degree Name

Master of Science

Major

Chemical Engineering

Major Professor

Dr. Dayakar Penumadu

Committee Members

Dr. David Harper, Dr. Eric Boder

Abstract

The aim of this work is to study different various softwood lignins and manufacture and characterize neat ABS-lignin composites. This involved characterizing deodorized and non-deodorized softwood lignins using techniques such as differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and principle component analysis. These techniques are used to determine the similarities and differences among the various softwood lignins at the functional group level. Neat ABS-lignin is blended in different weight fractions and analyzed for thermal and mechanical properties. A microscopic analysis of the blends is completed to study the interfacial properties of neat ABS-lignin. This effort was a collaboration among the Center for Renewable Carbon (CRC) and the Civil and Environmental Engineering Department, and Prisma Renewable Composites, LLC. The ABS-lignin blends showed a range of tensile strength of 33.0-40.6 MPa and a tensile modulus of 2.01-2.64 GPa. All ABS-lignin blends showed superior tensile and flexural strength and modulus, but showed lower impact resistance than neat ABS. These results are a result of the higher modulus of the lignin increasing the overall modulus and strength of the blends. The brittle nature of lignin reduces the impact resistance of the ABS-lignin blends as well as the ultimate strain. Microscopic analysis shows uneven spatial distribution of lignin in ABS resin.

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