Fiber composite, reinforced interphase

The three major constituents of any continuous fiber ceramic matrix composite are the reinforcing fibers, the matrix and a fiber-matrix interphase, usually included as a coating on the fibers. HiPerCompTM composites can be processed with various monofilament and multifilament fibers, such as the SCS family of monofilament SiC from Specialty Materials, Inc. CG-Nicalon and Hi-Nicalon Type S from Nippon Carbon Company Tyranno ZE , Tyranno ZMl and Tyranno S A from Ube Industries and Sylramic fiber from COl Ceramics. However, the composites described in this paper all utilize Hi-Nicalon SiC fiber from Nippon Carbon Company. A companion paper, in this book, by Jim DiCarlo [11] from NASA gives the properties of slurry cast composites reinforced with Sylramic and Sylramic-iBN fibers. 

Keywords Bioplastics Cellulose fiber Composite Fiber-matrix interphase PLA PP Reinforcement... 

The three major constituents of the SiC SiC composite are the reinforced SiC fiber, an interphase between the fiber and matrix, and the SiC matrix. SiC—matrix composites are highly tailorable materials in terms of fiber-type (SiC-based fibers such as Si—C—O, SiC + C or quasistoichiometric SiC reinforcements), interphase (pyrolytic carbon or... 

The plasma treatment of a yarn of polymer fibers used for composite reinforcement provides a typical example of the improvement in adherence [78]. The result is an increase in the strength of the final composite, due to the plasma-induced formation of a very thin interphase layer between the fiber and the composite matrix, causing in turn an improved bonding between the two components (see Figure 1.10). 

The fiber-reinforced composite materials include three phases surface of fiber side, the interface between fiber and matrix, and the interphase. These phases are collectively referred to as the interface [12]. The characteris-... 

Proper reinforcement of rubber matrix using hllers can be achieved only if there exists adequate adhesion between the hller and the mbber. Rubber-mbber adhesion and rubber-hller adhesion both without and with adhesion promoters have been studied extensively [125-127]. Fiber-matrix adhesion in short fiber-rubber composites is always a field of extensive research. If the fibers are not bonded properly with the rubber matrix, fibers will shde past each other under tension deforming the matrix, thereby reducing the strength properties. In the case of short fiber-reinforced rubber composites, loads are not directly applied to the fibers, but are apphed to the matrix. To obtain a high-performance composite, the load must be effectively transferred to the fibers, which is possible only when the fiber-matrix interphase is sufficiently strong. In addition, the adhesion between the fiber and the matrix should be such that the failure occurs in the matrix rather than at the interphase [92]. 

Jayaraman, K. and Reifsnider, K.L, (1993). The interphase in unidirectional fiber reinforced epoxies effect on residual thermal stresses. Composites. Sci. Technol. 47, 119-129. 

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. 

The chemical composition of the composite constituents and the interphase is not limited to any particular material class. There are metal-matrix, ceramic-matrix, and polymer-matrix composites, all of which find industrially relevant applications. Similarly, reinforcements in important commercial composites are made of such materials as steel. E-glass, and Kevlar . Many times a bonding agent is added to the fibers prior to compounding to create an interphase of a specified chemistry. We will describe specific component chemistries in subsequent sections. 

Despite the emphasis on favorable interactions between the matrix and reinforcement and compound formation between them, it may be beneficial in certain circumstances for the interaction between the two primary constituents to be relatively weak. This is especially true in ceramic-ceramic composites, where both constituents are brittle, and the only way to impart some ductility on the composite is for the interphase to fail gracefully —that is, for the fibers to actually pull out of the matrix in a controlled manner. Optimization of the interphase properties in advanced composites is currently the focus of much research. 

Overall the surface chemical composition of the reinforcing fibers or the adherends is chemically quite different from the bulk composition of these materials. Specific interactions between epoxies and these surfaces without cognizance of the different surface chemistries can lead to erroneous conclusions about the epoxy-surface bonding or interphase structure. 

The primer chosen for this investigation consisted of an equimolar mixture of phenyl- and amino-functional silanes, suggested as a potential superior primer for aluminum/epoxy adhesive joints [7], The amino-functional silane is known to be effective as an adhesion promoter for fiber-reinforced composite materials [1, 2] as well as for epoxy/metal adhesive joints [8, 9] and provides for strong chemical interaction between the adhesive and primer, while the phenyl functional silane should reduce the overall concentration of polar, hydrophilic functional groups in the interphase region and at the same time maintain or improve the ability of the resin and primer to interpenetrate due to its structural similarity to the adhesive resin. 

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