Bradley A. Newcomb

Polyacrylonitrile Fibers Containing Graphene Oxide Nanoribbons

Graphene oxide nanoribbon (GONR) made by the oxidative unzipping of multiwalled carbon nanotube was dispersed in dimethylformamide and mixed with polyacrylonitrile (PAN) to fabricate continuous PAN/GONR composite fibers by gel spinning. Subsequently, PAN/GONR composite fibers were stabilized and carbonized in a batch process to fabricate composite carbon fibers. Structure, processing, and properties of the composite precursor and carbon fibers have been studied. This study shows that GONR can be used to make porous precursor and carbon fibers. In addition, GONR also shows the potential to make higher mechanical property carbon fibers than that achieved from PAN precursor only.

Development of single filament testing procedure for polyacrylonitrile precursor and polyacrylonitrile-based carbon fibers

Single filament testing protocols for polyacrylonitrile precursor and polyacrylonitrile-based carbon fibers have been developed to ensure reliable tensile results that can be compared to the standard testing protocols used by the industry. Accurate carbon fiber linear density measurement by vibroscope was quite sensitive to the pre-stress applied to the fiber. Gauge length dependence testing of the commercial carbon fibers exhibited that tensile strengths obtained at 25.4 mm gauge length are comparable to those reported by the manufacturer using the standard strand testing results. On the other hand, experimental carbon fibers that have not been surface treated or sized, showed that single filament tensile strength values at 6 mm gauge length was comparable to the strand testing results. In addition, the compliance corrected tensile moduli of carbon fibers obtained by single filament tests were also comparable to the moduli obtained from the standard strand testing results. A modified Weibull analysis, which accounts for sample volume effects, has also been used to determine the Weibull modulus of both the commercial and experimental carbon fibers.

Microfibrous borate bioactive glass dressing sequesters bone-bound bisphosphonate in the presence of simulated body fluid

Ion exchange occurs between borate bioactive glass and simulated body fluid. Borate bioactive glass dressings may be used for managing bisphosphonate-related osteonecrosis of the jaw through the formation of a complex incorporating leached calcium and borate ions and sequestered bone-bound bisphosphonates.