Ideal Elastomer

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R Shanks - One of the best experts on this subject based on the ideXlab platform.

  • Linear and non-linear viscoelastic behaviour of natural rubber composites from micro- to nanoscales
    2020
    Co-Authors: R Shanks
    Abstract:

    Natural rubber has continued to be widely used because of its mostly elastic properties when crosslinked, compared with viscoelastic and irreversible viscous properties of highly filled and blended compositions. It has a wide linear viscoelastic window with low hysteresis. Deviation from Ideal Elastomer behaviour occurs at low extensions on first extension and at high extensions due to fully extended molecular segments between crosslinks and crystallization of fully extended segments. Natural rubber is adaptable through crosslink density, blending with other polymers and addition of fillers, with carbon black and silica being most important. Nanofillers offer greater adaption at small volume fractions with variation of geometry, surface area and coupling agents at the interface. Fillers create non-linear viscoelastic response through interaction with chain segments and filler-filler agglomeration that can be reversible when the composite is strained. This chapter reviews modification of viscoelastic character of natural rubber by formation of nanocomposites that further extend its exceptional deformation and thermodynamic response.

Robert A. Shanks - One of the best experts on this subject based on the ideXlab platform.

  • CHAPTER 20:Linear and Non-Linear Viscoelastic Behaviour of Natural Rubber Composites from Micro- to Nanoscales
    Polymer Chemistry Series, 2013
    Co-Authors: Robert A. Shanks
    Abstract:

    Natural rubber has continued to be widely used because of its mostly elastic properties when crosslinked, compared with viscoelastic and irreversible viscous properties of highly filled and blended compositions. It has a wide linear viscoelastic window with low hysteresis. Deviation from Ideal Elastomer behaviour occurs at low extensions on first extension and at high extensions due to fully extended molecular segments between crosslinks and crystallization of fully extended segments. Natural rubber is adaptable through crosslink density, blending with other polymers and addition of fillers, with carbon black and silica being most important. Nanofillers offer greater adaption at small volume fractions with variation of geometry, surface area and coupling agents at the interface. Fillers create non-linear viscoelastic response through interaction with chain segments and filler–filler agglomeration that can be reversible when the composite is strained. This chapter reviews modification of viscoelastic character of natural rubber by formation of nanocomposites that further extend its exceptional deformation and thermodynamic response.

Josefa Fernández - One of the best experts on this subject based on the ideXlab platform.

  • Thermodynamics of Rubber Elasticity
    Journal of Chemical Education, 2001
    Co-Authors: Julio Pellicer, José A. Manzanares, J. Zuniga, P. Utrillas, Josefa Fernández
    Abstract:

    A thermodynamic study of an isotropic rubber band under uniaxial stress is presented on the basis of its equation of state. The behavior of the rubber band is compared with both that of an Ideal Elastomer and that of an Ideal gas, considering the generalized Joule's law as the Ideality criterion.

Liang-chih Wang - One of the best experts on this subject based on the ideXlab platform.

  • Strain shapes the light in a photonic crystal nanocavity
    Photonics Research, 2019
    Co-Authors: Tsan-wen Lu, Liang-chih Wang
    Abstract:

    This study proposes and demonstrates a novel nanoclamp structure symmetrically disposed near a one-dimensional (1D) photonic crystal (PhC) nanocavity embedded in a deformable polydimethylsiloxane substrate. These nanoclamps show capabilities of locally shaping (including enhancing and inhibiting) the strain of PhC nanocavity. The produced artificial non-Ideal Elastomer leads to an enhanced wavelength response of −12.7  nm for every percentage compressive strain variation from the tunable PhC nanolasers in experiments. This result not only guarantees the excellent tunability of the 1D PhC nanolasers but also promises ultrahigh sensitivity in strain sensing. Moreover, such nanoclamps can further create a reconfigurable conversion between waveguide and nanocavity with a 1–2 order difference in the quality factor when applied to a 1D PhC waveguide. We believe this study provides a possibility for on-demand sculpturing of the optical properties of tunable PhC devices in the nanoscale by inserting additional nano- or micro-structures.

David W. Gerlach - One of the best experts on this subject based on the ideXlab platform.

  • Design Concepts and Development of Elastomer Heat Engines/Pumps
    Volume 6: Emerging Technologies: Alternative Energy Systems; Energy Systems: Analysis Thermodynamics and Sustainability, 2009
    Co-Authors: David W. Gerlach
    Abstract:

    Although Ideal Elastomer thermodynamics has been described by many authors, their use in heat engines/pumps remains a theoretical and pedagogical curiosity. Because Elastomers can generate large forces with small temperature changes, they may be useful in low delta T heat engines for energy recovery and bottoming cycles. In addition, the greater density of solid versus gas or two-phase working substances may enable a more compact system. Elastomer heat engines described in the literature are reviewed and compared. Most designs use an eccentric wheel design presenting design problems in sealing and physically separating the hot and cold sides. In addition, a variety of designs for rotary motors using the linear contraction of a solid that have been developed for thermoelastic shape memory alloy and mechanochemical systems are also pertinent. Several heat pump prototypes were constructed where an Ideally isothermal process was performed by stretching in contact with a hot and a cold heat transfer plate. However, the sliding friction on the plates prevented any measured cooling effect. Designs utilizing a continuous Elastomer belt winding over various configurations of rollers or pulleys appear to be most suited to Elastomer systems due to the flexibility of placement of the hot and cold reservoirs. A simplified two wheeled design is described.Copyright © 2009 by ASME