287258 Microwave Radiation Absorption Polyurethane Nanocomposites

Monday, October 29, 2012: 1:45 PM
Cambria East (Westin )
Zhanhu Guo1, Jiahua Zhu1 and Suying Wei2, (1)Integrated Composites Laboratory (ICL), Dan F Smith Department of Chemical Engineering, Lamar University, Beaumont, TX, (2)Chemistry and Biochemistry, Lamar University, Beaumont, TX

Iron-silica core-shell structured particles (both micro- and nano- scale) with controlled shell thickness are fabricated using a sol-gel method by controlled hydrolysis and condensation of tetraethyl orthosilicate (TEOS). Polyurethane (PU) nanocomposites (PNCs) filled with iron and iron-silica particles are fabricated with a surface initialized polymerization (SIP) method. The thermal stability of iron-silica NPs and its corresponding PNCs is significantly enhanced due to the barrier effect of silica shell to oxygen. The anti-corrosive property of the core-shell particle is dramatically improved which is able to keep stable in 1M acid solutions. Salt fog exposure tests on PNCs reveal a better anti-corrosive performance with the incorporation of core-shell particles. By embedding different NPs, unique physical properties such as enlarged coercivity and dielectric constant (real permittivity) are observed. After coating a silica layer on iron NPs, the PNCs show lower real permittivity as compared to the PNCs filled with pure NPs. However, it is interesting to observe that only slight difference in real permeability is observed in both samples at the same loading. The permittivity and permeability of the PNCs are investigated with frequency ranging from 2-18 GHz. With the obtained permittivity and permeability data, we then simulate the reflection loss using the transmission line theory. Results indicate that the PNCs reinforced with core-shell NPs exhibit a reflection loss in wider frequency ranges. The optimal reflection loss reaches around -20 dB, which is practically useful in real applications.

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See more of this Session: Composites
See more of this Group/Topical: Materials Engineering and Sciences Division