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Nano-additives for Intumescent Materials. Jeffrey W. Gilman Materials and Products Group Fire Science Division NIST. Outline. Background Nano-additives for intumescent materials High Throughput Methods Image analysis – confocal Flammability of polymers Gradient coatings.
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Nano-additives for Intumescent Materials Jeffrey W. Gilman Materials and Products Group Fire Science Division NIST
Outline • Background • Nano-additives for intumescent materials • High ThroughputMethods • Image analysis – confocal • Flammability of polymers • Gradient coatings
Gasification of Polystyrene Layered-silicate Nanocomposites Char or Coke Formation
Nano-additives Layered Double Hydroxide Layered Silicates Mg(OH)64- Al(OH)63- Zammerano-Chimteclab POSS Carbon nanotubes Nano silica Coughlin-U Mass Kashiwagi - NIST Bellayer - NIST
New additives for intumescent materials Imidazolium Dicyanamide New Char Forming Systems Layered Double Hydroxides Epoxy LDH nanocomposite coating Polyurea LDH nanocomposite coating New Char Forming Systems Imidazolium Dicyanamide Layered Double Hydroxides
Parameter Space (~ 106 Experiments) for Polymer Nanocomposites
Fluorescence Monitoring of Exfoliation Laser Scanning Confocal Microscope; 100s of images, 200-1000 nm slices Charles Wu, Lipiin Sung
20 μm Confocal Laser Scanning Fluorescence Microscopy PS + 0.5% MWNT (NB)1 min + 2σ - 2σ Distance (μm)
Confocal Imaging of LDH Nanocomposites Projection Projection PC Mg6Al/DBS+MO Daca 7 min – Step size Confocal 0.40 micron EVA(18%VA)/DBS+MO Daca 7 min – Step size Confocal 0.4 micron
20 μm 20 μm 20 μm 20 μm Distance (μm) Confocal Laser Scanning Fluorescence Microscopy Distance (μm) Distance (μm) Distance (μm) PS + 0.5% MWNT (NB)1 min PS + 0.5% MWNT (NB)10 min PS + 0.5% MWNT + 0.5% DMHDIm-TFB (NB) 10 min PS + 0.5% DMHDIm-TFB (NB) 10 min 2σ/ m = 0.38 2σ/ m = 0.18 2σ/ m = 0.09 2σ/ m = 0.09 • The lower intensity regions are possibly due to a MWNTquenching mechanism • The lower (2/m) the more homogeneous the sample • Complements the TEM data
High Throughput Gradient Approaches Schematic drawings flame spread on homogenous sample exposed to a gradient flux intensity (Workflow 1)
Flame Spread Flux Gradient High Low
Different Critical Fluxes for Flame-Spread PS/APP-PER 50 % 50 % 40 % 20 % 5 % 50 % 40 % 5 % 20 %
High Throughput Gradient Approaches Simultaneous flame spread (MFFS) and heat release measurements using the Cone Calorimeter Heat Release rate Flux
Gradient and Rapid Coating System Polymers, catalysts, nano-additives, co-additives, and processing variables Conventional Material Characterization: TEM, GPC, XRD… Conventional Property Characterization: Tensile testing, DMA, UL94, Cone calorimetry Compare results Compare results High Throughput Property Characterization:Nanoindentation, flame spead, rapid calorimetry High Throughput Material characterization: on-line sensors, Micro-FTIR, COnfocal, UV-Vis spectra
High Throughput System-2 Gradient Coatings samples FluidicSystems (CEO:Bruce Menck) Computer control panel NIST Project team: Cindy Montgomery, Dick Harris
ISO/CH2 0.07 Curing time (hr) target 0.39 0.67 21 65 165 112 42 37 160 107 16 60 32 55 102 155 11 Accelerator concentration (% x 10-3) 1.50 1.55 1.60 1.65 1.70 1.75 1.80 High Throughput Screeningof Military Aircraft Topcoat Accelerators Project Gradient #3, 1000, 1600, 32s, (2100- 2551)/(2700-3040)cm-1 Naomi Eidelman
Conclusions • Nano-additives enhance the performance of intumescent systems • Gradient Spray Coating Facility provides rapid sample preparation • FTIR-Microscopy, Optical probes and Confocal are inherently High Throughput vs. alternatives • Gradient Flux Flame Spread and Tign vs Flux allows HT evaluation of FR
Research Team Rick Davis, Takashi Kashiwagi, Marc Nyden, Richard Harris, Greg Linteris, John Shields, Walid Awad, Lori Brassell, Michael Smith - BFRL/NIST; David VanderHart, Atsuchi Asano, Anthony Bur - MSEL/NIST Joe Lichtenhan –Hybrid Plastics Paul Maupin –DOE Paul C. Trulove and Hugh DeLong -Air Force Office of Scientific Research Doug Fox – NRL, Naval Academy Funding ($): Air Force Office of Scientific Research (ISSA - AFOSR- ISSA-01-0001 ) AFRL – High Throughput Screening of Military Aircraft Accelerators - Joel Johnson High Throughput Methods for Materials Flammability Consortium (AFRL, FAA, Rhodia, Dow) FAA, Richard Lyon at William J. Hughes Technical Center (IAA- DTFA03-99-X-90009)