Jyotsna Ramachandran

Georgia Institute of Technology | GT · School of Materials Science and Engineering

The primary goal of this work is to integrate a critical step (sizing application to fiber) of conventional carbon fiber-reinforced composite (CFRPs) manufacturing to carbon nanotube composite fabrication. A polyimide-based (Hydrosize HP 1632) sizing agent was used in studying the effect of sizing on interface-interphase properties of the CNT-BMI c...

While the addition of well‐dispersed carbon nanotubes (CNTs) in polymer nanocomposites typically improves the polymers' impact strength, herein, we report that good CNT dispersion alone is not a sufficient condition to improve the impact strength of the nanocomposites. Our results demonstrate that the impact strength of the nanocomposite also depen...

Block copolymer (BCP)-based porous carbon fibers represent an emerging structural and functional material for mechanical reinforcement and electrochemical energy storage. Herein, by gel-spinning polymer precursors of poly(acrylonitrile) (PAN) and poly(methyl methacrylate)-block-poly(acrylonitrile) (PMMA-b-PAN), we have produced a series of carbon f...

Stabilization is an energy-intensive and time-consuming step for making PAN-based carbon fiber. Here, a new pathway is shown that uses carbon nanotubes (CNT) to accelerate the reaction rate and to reduce the PAN stabilization time. Bi-component core-sheath PAN-PAN/CNT (10 wt% CNT) fibers and single-component PAN/CNT (10 wt% CNT) fibers were made. W...

Stabilization is one of the important processes used to convert polyacrylonitrile (PAN) fibers into carbon fiber and is usually driven by energy-intensive and time-consuming convective heating. A continuous and energy-efficient alternative is desirable. Here, a continuous Joule heating process has been used for the first time to stabilize PAN fiber...

Rheological studies play an important role in polymer processing including fiber spinning. In the current work, rheological behavior has been studied for polyacrylonitrile (PAN)/carbon nanotube (CNT) dispersions in dimethyl formamide (DMF), where CNT loading is as high as 15 wt% of the total solids (polymer + CNT). The presence of CNTs increased th...

Multifilament continuous hollow carbon fiber tows with a honeycomb cross-section have been produced using a gel-spun bicomponent islands-in-a-sea precursor with polyacrylonitrile (PAN) as the sea component and polymethylmethacrylate (PMMA) as the sacrificial island component. The density of the hollow carbon fibers is 1.15 g/cm³, more than 30% lowe...

For the first time, a polyacrylonitrile (PAN) fiber with up to 15 wt% single-wall carbon nanotubes (SWNTs) was produced by dry-jet wet-spinning while maintaining good SWNT individualization. These fibers exhibited a tensile modulus of 32.1 GPa, tensile strength of 0.8 GPa, and axial electrical conductivity of 2.2 S/m. This was possible by using SWN...

Blends of polyacrylonitrile (PAN) with three different sacrificial polymers: poly (acrylic acid) (PAA), poly (methyl methacrylate) (PMMA), and poly (styrene-coco-acrylonitrile) (SAN), were gel spun, oriented through the drawing process, stabilized and carbonized to obtain porous carbon fibers. Carbon fibers with an average pore diameter of 15 nm, 3...

Bi‐component, polyacrylonitrile (PAN)/carbon nanotube (CNT) fibers were processed, at different core‐sheath area ratios, by gel spinning. A percolated CNT network at 10 wt% CNT in the sheath enhanced electrical conductivity as compared to the neat PAN fiber, while PAN polymer in the core contributed to the good mechanical properties. Fibers with re...

Materials in nature such as nacre that are made of mechanically inferior building blocks exhibit extreme toughness at the macro scale because of the geometry and arrangement of their constituents. Taking a cue from these systems, we have investigated whether the molecular rearrangement in a heterogeneous polymeric system can alter toughness at the...

The study aims to develop a novel composite, with a combined contribution of reduced graphene oxide, poly(dimethyl-siloxane), and sodium bentonite (organoclay), for flame protection. Thermogravimetric analysis revealed an outstanding thermal stability of the composite as compared to its constituents. The superior composite is demonstrated to effici...