Interphase contribution

The dynamic mechanical properties (shear modulus and loss tangent) of polymer composites prepared from carbon fiber and thermosetting and thermoplastic resins were studied in the frequency range 0.01-5.0 Hz. The stxrface of the fiber was covered by the interlayer from styrene-co-maleic anhydride polymer. It was estabhshed that different interphase composition causes a difference of dynamic mechanical behavior and that the interphase contributes both to glass transition and to energy dissipation. 

Still another approach to the estimation of interphase contribution to dynamic properties was proposed by Theokaris. Interphase (or mesophase, in the terminology of Theocaris) is viewed as having its own glass transition temperature and the properties of composite may be derived from analyzing a mechanical model based on the well-known mechanical models of Maxwell and Voigt. 

As we see, values of A/ change in a nonmonotonous way depending on the network ratio, the fraction of free volume being higher in IPNs at all ratios but W2/W1 = 0.03-0.07. The compHcated dependence of the free volume on composition may be attributed to the formation of the intermediate region of the interphase between two phases in the IPN. A looser interphase contributes to the increasing free volume of the whole system. 

Silane coupling agents may contribute hydrophilic properties to the interface, especially when amino functional silanes, such as epoxies and urethane silanes, are used as primers for reactive polymers. The primer may supply much more amine functionality than can possibly react with the resin at the interphase. Those amines that could not react are hydrophilic and, therefore, responsible for the poor water resistance of bonds. An effective way to use hydrophilic silanes is to blend them with hydrophobic silanes such as phenyltrimethoxysilane. Mixed siloxane primers also have an improved thermal stability, which is typical for aromatic silicones [42]. 

It was concluded that the filler partition and the contribution of the interphase thickness in mbber blends can be quantitatively estimated by dynamic mechanical analysis and good fitting results can be obtained by using modified spline fit functions. The volume fraction and thickness of the interphase decrease in accordance with the intensity of intermolecular interaction. 

The surface potential x consists of the contributions of ions present in the interphase x(ion) and contributions from dipoles oriented in this region X(dip) ... 

Let us consider the general electrochemical cell shown in Figure 5.2. The potential difference across the electrochemical cell, denoted , is a measurable quantity called the electromotive force (EMF) of the cell. The potential difference in Figure 5.2 is made up of four contributions since there are four phase boundaries in this cell two metal-solution interphases and two metal-metal interfaces. The cell in Figure 5.2 can be represented schematically as Pt/M7S/M/Pt. 

The study and application of composite materials are a truly interdisciplinary endeavor that has been enriched by contributions from chemistry, physics, materials science, mechanics and manufacturing engineering. The understanding of the interface (or interphase) in composites is the central point of this interdisciplinary effort. From the early development of composite materials of various nature, the optimization of the interface has been of major importance. While there are many reference books available on composite materials, few of them deal specifically with the science and mechanics of the interface of fiber reinforced composites. Further, many recent advances devoted solely to research in composite interfaces are scattered in different published literature and have yet to be assembled in a readily accessible form. To this end this book is an attempt to bring together recent developments in the field, both from the materials science and mechanics perspective, in a single convenient volume. 

In the case of a metal/solution interface, the charge on the metal is one of the signals that can be picked up. This electrode charge is mirrored on the solution side by an equal and opposite net charge constituted of separate contributions of the positive and negative charges, i.e., the relative concentrations of cations and anions in the interphase. However, are these ions on the metal or near the metal ... 

These differences between intrinsic and doped, or impurity, semiconductors complicate the mathematics of the solution of the Poisson-Boltzmann equation, but the picture that emerges remains basically the same A charged cloud, or space charge, and therefore a potential drop, develops inside the semiconductor the space charge contributes to the capacity of the interphase, etc. 

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