This thesis presents new data regarding the characterization of interfacial properties of highly aligned and densely packed solution-spun carbon nanotube fibers (CNTF) as a first step in a more sophisticated study on CNTF composites and their response to impact. Through characterization of the interphase region of a matrix-filler composite system, commentary on the efficiency of stress transfer between the bulk and reinforcement, and thus the quality of the adhesive bond, is provided. In order to acquire the necessary data for proper analysis, the single fiber pull-out test is employed using a high-precision rheometer. The data collected and presented herein are preliminary data for initial and first-ever insight into the newly developed CNT fibers, but larger batch sample sizes are required for increased statistical confidence in the results. Given the large impact of processing parameters on the mechanical characteristics of heterogeneous composite materials, minimal quantitative comparison to external studies is made. Instead, processes, characterization schemes, data reduction and analysis methods, and assessments are presented for simplified implementation of future data points in order to increase the significance of the results.