TITLE:
Viscoelastic Response of Graphite Platelet and CTBN Reinforced Vinyl Ester Nanocomposites
AUTHORS:
Brahmananda Pramanik, P. Raju Mantena
KEYWORDS:
Nanocomposite, CTBN, Viscoelastic, TTS, Material Damping, Energy Absorption
JOURNAL NAME:
Materials Sciences and Applications,
Vol.2 No.11,
November
16,
2011
ABSTRACT: Developing stronger, safer and more cost-effective structural materials for the new generation naval ships is the focus of ongoing research at University of Mississippi. The light-weight nanoparticle reinforced glass/carbon polymeric based composites and structural foams for blast, shock and impact mitigation are emphasized in this research. Derakane 510A-40 brominated vinyl ester nanocomposite resin systems are considered to be used in the composite face sheets of sandwich structures with fire-resistant foam core to reduce flammability along with optimal flexural rigidity, vibrational damping and enhanced energy absorption. In this work, the viscoelastic performance of 1.25 and 2.5 weight percent exfoliated graphite nanoplatelet (xGnP) added with 10 weight percent Carboxy Terminated Butadiene Nitrile (CTBN) reinforced brominated vinyl ester nanocomposites are studied. A Dynamic Mechanical Analyzer (DMA) - TA Instruments Model Q800 was used to obtain the viscoelastic properties, modulus (stiffness), creep/stress relaxation, and damping (energy dissipation), of the exfoliated graphite platelet and CTBN reinforced brominated vinyl ester. Effects of frequency (time) on the viscoelastic behavior were investigated by sweeping the frequency over three decades: 0.01, 0.1, 1.0 and 10 Hz, temperature range from 30°C to 15°C at 4°C per minute step rate. Master curves were generated by time-temperature superpositioning (TTS) of the experimental data at 50°C reference temperature. Addition of CTBN in xGnP reinforced brominated vinyl ester composites resulted in greater intrinsic material damping, indicating the possibility of higher energy absorption with the new configuration.