A framework for data-driven analysis of materials under uncertainty: Countering the curse of dimensionality

Morphological, thermal and tensile properties of halloysite nanotubes filled ethylene propylene diene monomer (EPDM) nanocomposites

Improving reinforcement of natural rubber by networking of activated carbon nanotubes

It is a challenge to retain the high stretchability of an elastomer when used in polymer composites. Likewise, the high conductivity of organic conductors is typically compromised when used as filler in composite systems. Here, it is possible to achieve elastomeric fiber composites with high electrical conductivity at relatively low loading of the conductor and, more importantly, to attain mechanical properties that are useful in strain-sensing applications. The preparation of homogenous composite formulations from polyurethane (PU) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) that are also processable by fiber wet-spinning techniques are systematically evaluated. With increasing PEDOT:PSS loading in the fiber composites, the Young's modulus increases exponentially and the yield stress increases linearly. A model describing the effects of the reversible and irreversible deformations as a result of the re-arrangement of PEDOT:PSS filler networks within PU and how this relates to the electromechanical properties of the fibers during the tensile and cyclic stretching is presented. Conducting elastomeric fibers based on a composite of polyurethane (PU) and PEDOT:PSS, produced by a wet-spinning method, have high electrical conductivity and stretchability. These fibers can sense large strains by changes in resistance. The PU/PEDOT:PSS fiber is optimized to achieve the best strain sensing. PU/PEDOT:PSS fibers can be produced on a large scale and integrated into conventional textiles by weaving or knitting. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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Strain-Responsive Polyurethane/PEDOT:PSS Elastomeric Composite Fibers with High Electrical Conductivity

We explore filler reinforcement (i.e., increase of elastic modulus G‘ due to incorporation of fillers) and Payne effect (i.e., decrease of G‘ at large strain amplitudes) in terms of the matrix molecular weight, filler loading, and time scales used to probe the viscoelasticity of filled melts. Use of monodisperse non-cross-linked 1,4-polybutadiene (PBD) along with a silica filler allows illustration of different mechanisms of filler reinforcement in the elastic and liquid regimes. The greater filler reinforcement for matrices of higher molecular weight indicates the filler association through chain adsorption and bridging. The role of matrix-mediated filler−filler interactions is explicitly illustrated in terms of the increased elastic modulus in the terminal region due to replacement a fraction of the matrix chains with longer chains of the same kind. The Payne effect is seen to be time-dependent and comprised of an instantly recoverable and a slowly recovering component. Measuring G‘ at both high and low...

Investigating linear and nonlinear viscoelastic behavior using model silica-particle-filled polybutadiene

The role of active fillers like carbon black and silica has been studied in the rubber matrix for a better understanding of the rubber performance and the mechanism of reinforcement. In particular the influence of basic properties of carbon blacks, such as specific surface area, structure and surface activity on the Payne-effect, was investigated with the Rubber-Process-Analyzer (RPA) which allows a testing of the strength of the filler network and the filler-polymer interaction in the green compound as well as in the vulcanizate in a wide range of shear amplitudes. A comparison between carbon black and the silica-silane system leads to further scientific findings for the understanding of the dynamic behavior of filled rubber compounds.

The effect of filler–filler and filler–elastomer interaction on rubber reinforcement

Today's tires are highly sophisticated and have to fulfil contradictory dynamic properties like improved treadwear, better handling and traction as well as good energy efficiency (rolling resistance). The role of active fillers like carbon black and silica has been studied in the rubber matrix for a better understanding of the tire performance and the mechanism of reinforcement. In particular the influence of basic properties of carbon blacks, such as surface area, structure and surface activity on the Payne effect, was investigated with the Rubber-Process-Analyzer (RPA) which allows a testing of the strength of the filler network and the filler-polymer interaction in the green compound as well as in the vulcanizate in a large shear range. A comparison between carbon black and the silica-silane system leads to further scientific findings for the understanding of the dynamic behavior of filled rubber compounds. These investigations provide a deep insight into the mechanism of reinforcement of active fillers in the rubber matrix and may enable a further improvement of the tire performance.

W. Niedermeier

Papers

The effect of filler–filler and filler–elastomer interaction on rubber reinforcement

Reinforcement mechanism in the rubber matrix by active fillers