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This work reports yarn pull-out studies of commercially available Kevlar® KM2+ individual yarns coated with metallic layers (copper, aluminum, aluminum nitride and silver) via a directed vapor deposition process. The uncoated control and metal-coated Kevlar® yarns are hand-woven into fabric swatches for quasi-static pull-out experiments. To perform these experiments, a yarn pull-out fixture is custom-designed and fabricated to apply transverse pre-tension to the fabric. Three levels of transverse pre-tensions are studied at 100 N, 200 N, and 400 N. The results showed that both peak pull-out force and energy absorption during the pull-out process increase with increase in transverse pre-tension. All the metal-coated groups showed an approximately 200% increase in peak pull-out force and a 20% reduction in tenacity compared to uncoated control. Furthermore, all the metal-coated groups showed an increase in energy absorption, with aluminum-coated yarns showing the highest increase of 230% compared to control. These results suggest enhanced frictional interactions during yarn pull-out in metal-coated yarns compared to uncoated control as evidenced by the surface roughness profile of individual fibers and inter-yarn frictional calculations. [ABSTRACT FROM AUTHOR]

The conductive quality of the aromatic amine polyaniline (PANI) has potential electronics applications. The stability and electrochemical attributes of PANI make them good materials for organic lightweight batteries and microelectronics. Thus, experiments were conducted to analyze the enzymatic and chemical polymerization of aniline. Aniline samples were analyzed in the presence of the polyelectrolyte template sulfonated polyestrene (SPS). The experiments yielded a a water-soluble, electroactive and conducting PANI/SPS complex.

Conformal atomic layer deposition (ALD) of Al2O3 and TiO2 thin films on Kevlar®, poly(p-phenylene terephthalamide) (PPTA) fibers at 50 and 100 °C affects the fiber cut resistance. Systematic studies of ALD coatings between 10 to 400 A thick formed at 50 and 100 °C revealed excellent conformality, and trends in cutting performance depended on materials and process details. Å 50 Å/50 Å TiO2/Al2O3 bilayer formed at 50 °C increased cut resistance of PPTA by 30% compared to untreated fiber materials. In situ infrared analysis shows that trimethylaluminum (TMA) Al2O3 precursor reacts sub-surface with PPTA and tends to degraded mechanical performance. The TiCl4 TiO2 precursor reacts to form a barrier that limits TMA/PPTA interactions, allowing a harder Al2O3 layer to form on top of TiO2. The thin ALD coatings do not substantially affect durability, flexibility, or weight of the PPTA, making ALD a potentially viable means to enhance the protective properties of Kevlar and other polymer fiber systems. [ABSTRACT FROM AUTHOR]

The synthesis, fabrication, fluorescence and fluorescence quenching behavior of fluorescent polymer, polyacrylic acid-poly (pyrene methanol) (PAA-PM) are reported. The Stern-Volmer plots of the electrospun membranes exhibited good linearity for Fe3+, Hg2+ and DNT and the Stern-Volmer constants Ksv are 4.4×104 (M-1), 3.5×104 (M-1) and 2.9×104 (M-1), respectively. These values are one order of magnitude more than those obtained previously from films made by electrostatic layer-by-layer adsorption of the same polymer. [ABSTRACT FROM AUTHOR]