All ETDs from UAB

Advisory Committee Chair

Derrick R Dean

Advisory Committee Members

J Barry Andrews

Uday K Vaidya

Document Type


Date of Award


Degree Name by School

Master of Science in Materials Engineering (MSMtE) School of Engineering


Fiber-reinforced polymer composites (FRCs) have shown great promise as high strength structural materials due to their high stiffness to weight ratio and their ease in processing. They have found extensive use in aerospace, automotive, construction, and recreational equipment material applications. Research in polymer-based nanocomposites (PNCs) has shown explosive growth in the past decade with much emphasis focused on PNC using thermosetting polymer matrices. Modifying conventional FRCs with a PNC matrix result in the emergence of a hybrid composite material termed multiscale fiber-reinforced composites (M-FRCs). The current research addresses carbon nanofiber (CNF) surface modification, carbon nanofiber/epoxy polymer nanocomposite (CNF/PNC) development and M-FRC fabrication. Vacuum assisted resin infusion molding (VARIM) is used to produce MFRC. The materials used in this research are surface modified and modified CNFs, aerospace grade high temperature epoxy resin, and plain-weave E-glass fiber preforms. The VARIM process used to produce M-FRC is explained in detail. The effects of using a CNF/PNC nanophased polymer matrix is presented and thoroughly investigated. iii Flexural, thermomechanical, and rheological studies are presented on the CNF/PNC nanophased matrix and compared with the neat epoxy resin. Flexural, interlaminar shear strength (ILSS) and thermomechanical tests are presented for the 0.1 and 1 wt% M-FRCs and compared with the neat FRC. Experimental results indicate that the glass transition temperatures (Tg) of the CNF/PNC and M-FRC samples were higher than the neat epoxy resin and neat FRC samples, respectively. Coefficients of thermal expansion (CTE) properties of the CNF/PNC and M-FRC samples were lower than the neat epoxy resin and neat FRC, respectively. Flexural studies indicated increases in flexural strength (16-20%) and flexural modulus (23-26%) for M-FRC samples. The ILSS studies indicated increases in ILSS (8-23%) for M-FRC samples. The improved Tg and CTE properties in the CNF/PNC samples are believed to be due to achieving good nanoparticle dispersion. While the increased properties in the M-FRC samples are believed to be due to synergistic interactions between the CNF/PNC nanophased matrix and glass-fiber interactions.

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Engineering Commons



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