Poly microwave absorption

P. Chandrasekhar, K. Naishadham, Broadband Microwave Absorption and Shielding Properties of a Poly(Aniline). Synth. Met. 1999,105,115-120. 

For example, blends and semi-IPN of polypyrrole and EPDM rubber, prepared by calendering, absorb 85% of microwave radiation in the 10-13 GHz range [167]. Surface deposition of polypyrrole onto poly-(vinylchloride) produced composites with microwave absorption properties in the 0.1-20 GHz frequency range [168]. The same authors also studied the shielding characteristics of blends of polyaniline and poly(3-octylthiophene) with polystyrene and with the copolymer of ethylene and vinyl acetate. For defense purposes, however, a larger frequency range should be covered, but this only encourages continuation of the research. 

Figure 1.13 Increase in the microwave absorption of poly(methylphenylsilane) at v = 30.4 GHz, indicating the formation of electrical charge carriers after irradiation with a 12 ns pulse of 266-nm light. Reproduced from Ref [101].

Ohlan A, Singh K, Chandra A, Dhawan SK (2010) Microwave absorption behavior of core-Shell structured poly (3,4-ethylenedioxy thiophene)-barium ferrite nanocomposites. ACS Appl Mater Interfaces 2 927-933... 

Liu P, Huang Y, Zhang X (2015) Preparation and excellent microwave absorption properties of ferromagnetic graphene/poly(3, 4-ethylenedioxythiophene)/CoFe204 nanocomposites. Powder Technol 276 112-117... 

The direct absorption of moderate to low frequency, nonionizing, electromagnetic radiation - microwaves - by DNA polymer molecules is a potential source of biological effects. As an introductory study of this question, we have evaluated the absorption of isolated homopolymer straight chains of poly dG-poly dC. For some absorption processes we have also investigated some effects of a surrounding aqueous medium. 

After being dried, the samples were reexamined by nitrogen sorption and mercury intrusion, and a portion of the material was analyzed to determine the residual mercury levels. This analysis was achieved by acid digestion (10 mL of 50% aqua regia sample sizes were approximately 0.2 g in all cases) in pressure-sealed poly(tetrafluoroethylene) (PTFE) tubes heated to 140 °C for 10 min in a microwave oven (CEM). The solutions were analyzed after suitable dilution in distilled water with a graphite furnace atomic absorption spectrometer (Perkin Elmer 5100-PC). The detection limit for this method is estimated to be 6 ppm of mercury on the dry solid. 

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