Browsing by Subject "Nylon"
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item Conductive nickel nanostrand-reinforced polymer nanocomposites(2013-05) Lu, Chunhong; Krifa, MouradConductive and flexible nanocomposites can have wide applications in textiles, including wearable sensors, antenna, electrodes, etc. The objective of this research is to develop electrically conductive fibers and films that are flexible and deformable for use in textile structures able to accommodate the drape and movement of the human body. To achieve this objective, we evaluate the electrical properties of PEDOT:PSS/nickel nanostrand as well as nylon 6/nickel nanostrand nanocomposites. Nickel nanostrands (NiNS) were first used to reinforce an intrinsically conductive polymer, Poly(3,4-ethylenedioxythiophene) (PEDOT:PSS), in order to fabricate nanocomposite films with high electrical conductivity. The electrical properties of the films were evaluated by the Van der Pauw method. The addition of 10 wt% nanostrands in PDOT:PSS provided a two order of magnitude improvement in electrical conductivity. In addition to PDOT:PSS, nylon 6/NiNS nanocomposite fibers were produced using electrospinning and exhibited diameters in the sub-micron range. The NiNS-reinforced fibers had electrical conductivity that exceeded the ESD range, which offers the potential for use in protective textile applications.Item Evaluation of nylon 6,6 in use in Fire Foe® fire suppression systems within plutonium gloveboxes(2012-12) Millsap, Donald William; Landsberger, Sheldon; Biegalski, StevenGloveboxes, where special nuclear material is handled and such as those present at Los Alamos National Labs, LANL, provide an experimental area confined within a protective shell and with strict environmental controls. These gloveboxes allow workers to indirectly interact with hazardous material. Unfortunately, these gloveboxes are not fail proof and are subject to occasional accidental failures resulting in possible breaches of containment and release of nuclear material. In particular, fires within the gloveboxes are of major concern with regard to the potential for breaches and damage to not only the glovebox but also to surrounding areas as well. Another, potentially even catastrophic, result of glovebox fires is the potential for the spread of radioactive contamination. There is some historical precedent of contaminant release resulting from glovebox fires, such as those at the Rocky Flats Plant (Buffer, 2012). Gloveboxes at LANL are currently equipped with manually activated fire suppression systems. In the event of an incident, a worker would hit a nearby emergency button and the system would be activated. However, this method relies on the worker to have the presence of mind in the face of danger to activate the system, and as such there is no true guarantee that the systems will be triggered. Since the level of consequence is dire, then the ideal situation requires that other fire suppression systems be present which do not rely on human interaction to function. The Fire Foe™ system has been chosen as a secondary failsafe measure in order to meet this need. Analysis of how the casing of the Fire Foe™ system, composed of nylon 6,6 polymer, weathers under irradiation in gloveboxes is paramount in determining the effectiveness and potential lifetimes of the systems within the gloveboxes. Samples of nylon 6,6 were exposed to a 5 Ci PuBe neutron source located at the University of Texas as well as a high dose rate beam of 4.5 MeV alpha particles located at Los Alamos to determine the effect of neutron and alpha particle damage on the polymer material. Subsequent mechanical testing was conducted to determine alteration to the tensile properties of the nylon 6,6 material for both irradiated and non-irradiated samples.Item Polyamide-layered silicate nanocomposites by melt processing(2003) Fornes, Timothy Dean; Paul, Donald R.Polyamide-layered silicate nanocomposites based on nylon-6, 11, and 12 and organically modified montmorillonites (organoclay) were prepared by twin screw extrusion. Carefully designed component structure-nanocomposite morphology and property investigations on these materials were executed to understand why nylon-6 readily exfoliates organoclay. The polyamide structure strongly influences the extent of clay platelet delamination and level of property enhancement, as determined by X-ray, transmission electron microscopy and stress-strain analyses. High molecular weight nylon-6 materials lead to better organoclay exfoliation and greater nanocomposite moduli and yield strengths than lower molecular weight materials; this is attributed to higher levels of shear stress imparted on the clay by the higher viscosity polymer. The ratio of amide to methylene units in the repeat structure of nylon-6 appears to affect the polymer- organoclay affinity since a large increase in aliphatic content, i.e., nylon-6 versus nylon-12, results in less organoclay dispersion and lower reinforcing efficiency. The structure of the organoclay is also critical for producing wellexfoliated nylon-6 nanocomposites. Alkyl ammonium surfactants that cover less montmorillonite surface in the organoclay are more effective at exfoliating clay and generating improved nanocomposite stiffness and strength; such surfactants facilitate more desirable polyamide-silicate interactions, yet maintain sufficient organoclay gallery spacings needed both to overcome the cohesive forces between neighboring platelets and to facilitate polymer intercalation. The source of sodium montmorillonite used to form the organoclay is also important. The superior properties observed in nylon-6 nanocomposites may be explained by conventional ideas of reinforcement as predicted by composite theories like those of Halpin-Tsai or Mori-Tanaka. Based on good agreement between experimental nanocomposite moduli and model predictions it is clear that superior reinforcement stems from the high modulus and aspect ratio of montmorillonite; however, montmorillonite particles clearly affect the proprieties of the polymer phase which may have additional effects on the composite. Differential scanning calorimetry and X-ray analyses show that the clay can alter the nucleation, growth, and type of nylon-6 crystals formed under certain crystallization conditions. Furthermore, exposure of organoclay surfaces during processing can cause considerable polymer degradation and color formation depending upon the type of nylon-6 used and the surfactant structure in the organoclay.