Fibre-matrix adhesion

Scholtens, B. J. R. and Brackman, J. C., Influence of the film former on fibre-matrix adhesion and mechanical properties of glass-fibre reinforced thermoplastics, J. Adhes., 52, 115 (1995). 

Fragmentation Test. The problem of determining fibre-matrix adhesion has received considerable attention. Tlie analysis using the fragmentation of a model system is considered to constitute the best solution. 

This load is transmitted through the interface from the matrix to the fibre and, as originally described by Kelly and Tyson (2), the fibre breaks into small fragments until a limiting fragment size /c is reached (Figure 3). Knowledge of /c enables one to determine the shear resistance of the interface that is, the capacity of the interface to transfer the stress from the matrix to the fiber. This shear resistance of the interface, x, is therefore a direct measurement of fibre-matrix adhesion. 

Determination of Fibre-Matrix Adhesion. The average shear strength x and maximum shear strength Xmax at the fibre-matrix interface CZ, 22) are given by... 

It is observed that the fibre-matrix adhesion increases, whatever the nature of the epoxy, from the untreated to the oxidized and coated fibers. For instance, in the case of resin II, the increase is 70 to 80% when die coated fiber 3 is used. 

Inverse gas chromatography at infinite dilution appears to be a powerful tool for studying the surface properties of carbon fibres and polymer matrices. The use of alkane probes and acid/base probes allows the characterization of the surfaces in terms of their London dispersive component of surface energy and their acid/base or acceptor/donor characteristics. A strong correlation was obtained between fibre-matrix adhesion, measured by a destructive fragmentation technique, and the level of acid base interactions calculated from the chromatographic analysis. 

Since silica particles appear to give rise to better durabilities than metakaolin, and poly(vinyl acetate) was previously shown to exhibit better fibre-matrix adhesion than poly(vinyl alcohol) [5], a... 

Rovings coated with the mixture PVAc/Silicol P/cement in the ratio 20 40 40 do not exhibit improved fibre-matrix adhesion (Figure 9A). However, the residual tensile strength of 1082 N after... 

The major factors that govern the properties of short-fibre thermoplastic composites are fibre volume fraction, fibre dispersion, fibre aspect ratio and length distribution, fibre orientation and fibre-matrix adhesion. Each of these parameters is briefly discussed below. 

It has also been found that moisture absorbance of the natural fibre-polymer composite can be prevented if the fibre-matrix adhesion is optimized [15, 24]. Indeed, whereas composites based on standard PP and cellulosic fibres displayed high water content at the interphase, due to the presence of microcavities, the encapsulation of the fibres with MAPP decreased the water sensitivity of the composites in terms of both the water uptake and its diffusion coefficient [25], as shown in Fig. 19.9. 

Strength of glass fibre/NR composites can be improved by modification of NR and glass fibre. Modified NR can also give higher strength and better adhesion properties. Modification of glass fibre helps to improve the fibre/matrix adhesion. It is discussed very shortly in this section. 

Figure 9.13 Schematic of the interphase region between fiber and matrix. Source Reprinted with permission from Herrera-Franco PJ, Drzal LT, Comparison of methods for the measurement of fibre/matrix adhesion in composites, Composites, 23, 2,1992. Copyright 1992, Elsevier.

King JA, Buttry DA, Adams DF, Development and evaluation of surface treatments to enhance the fibre matrix adhesion in PAN based carbon fibre liquid crystal polymer composites 2. Electrochemical treatments, Polym Composites, 14(4), 301-307, 1993. 

Interactions and Properties of Composites a) Fibre-Matrix Adhesion Measurements. 

PLASMA ENHANCED CVD OF AROMATICS SURFACE TREATMENT OF CARBON FIBRES TO OPTIMIZE FIBRE/MATRIX ADHESION... 

There are several methods to improve fibre/matrix adhesion. 

Plasma treatment with benzene monomer, with pyridine monomer as well as with aniline monomer led to an improvement of interlaminar shear strength of 5 to 12 % in epoxy resin composites. The highest improvement in ILSS tests on epoxy composites was achieved by treatment of the fibres in a benzene/argon/air plasma. This treatment led also to better values of 38 % in flexural strength and the edge fibre elongation increased to 41 %. The reason for the improvement of the fibre matrix adhesion lies... 

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