Multifunctional Dielectrics

Void-free phenolic networks can be prepared by crosslinking novolacs with epoxies instead of HMTA. A variety of difunctional and multifunctional epoxy reagents can be used to generate networks with excellent dielectric properties.2 One example of epoxy reagents used in diis manner is the epoxidized novolac (Fig. 7.34) derived from the reaction of novolac oligomers with an excess of epichlorohydrin. 

If we can combine ferroelectrically polarizable guest molecules with PCPMs, then we can obtain new types of multiferroic materials, where ferroelectricity and ferromagnetism coexist. Such multifunctional materials have recently aroused increasing interest from the viewpoint of the development of new materials with very large magnetoelectric effects. [Mn3(HCOO)6] EtOH is considered to be the first ferroelectric PCP.182 Because the desolvated compound [Mn3(HCOO)6] shows a very small and almost temperature-independent dielectric constant, irrespective of the direction of the electric field,183 the observed ferroelectric property is considered to come mainly from the guest EtOH molecules. 

Mijovic, J. Andjelic, S. Yee, C.F.W. Bellucci, F. Nicolais, L. (1995). A study of reaction kinetics by near infrared spectroscopy 2. Comparison with dielectric spectroscopy of model and multifunctional epoxy/amine. Macromolecules, Vol.28, No.8, (April 1995), pp. 2797-2806, ISSN 0024-9297. 

No.8, 10th April 1995, p.2797-806 STUDY OF REACTION KINETICS BY NEAR-INFRARED SPECTROSCOPY. H. COMPARISON WITH DIELECTRIC SPECTROSCOPY OF MODEL AND MULTIFUNCTIONAL EPOXY/ AMINE SYSTEMS... 

An investigation of the kinetics of two non-polymerforming epoxy/amine model systems and a polymer-forming multifunctional epoxy/amine formulation (Epon 825 plus 4,4 -methylenedianiline) was carried out by dielectric and near-IR spectroscopy. Dielectric... 

Thakur VK, Vennerberg D, Madbouly SA, Kessler MR (2014d) Bio-inspired green surface functionalization of PMMA for multifunctional capacitors. RSC Adv 4 6677-6684 Thakur VK, Thunga M, Madbouly SA, Kessler MR (2014e) PMMA-g-SOY as a sustainable novel dielectric material. RSC Adv 4 18240-18249... 

The same transducer structure can serve as either an actuator or a generator, depending on how it is electrically driven. Therefore, the relationship between motion and energy of deformation can be modulated. In other words, the transducer can be a variable impedance device in which stiffness and damping are electrically controllable. Since the same transducer structure can serve as an actuator, generator, sensor or variable impedance device, the transducer can be said to be multifunctional. The use of dielectric elastomers as variable stiffness devices is discussed in detail elsewhere [9]. 

Jiang J, Ai LH, liu AH (2010) A novel poly(o-anisidine)/CoFe204 multifunctional nanocomposite neparation, characterization and properties. Synth Met 160 333-336 Dey A, De A, De SK (2005) Electrical transport and dielectric relaxation in Fe304-polypytrole hybrid nanocomposites. J Phys Condens Matter 17 5895-5910... 

Bian, Y., Pejanovic, S., Kenny, J., Mijovic, J. Dynamics of multifunctional polyhedral oligomeric silsesquioxane/poly(propylene oxide) nanocomposites as studied by dielectric relaxation spectroscopy and d5mamic mechanical spectroscopy. Macromolecules 40 (2007) Boucher, V.M., Cangialosi, D., Alegria, A., Colmenero, J. Time dependence of the segmental relaxation time of poly(vinyl acetate)-silica nanocomposites. Phys. Rev. E 86, 041501 (2012)... 

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