Microbond techniques

Biro, D.A., McAlea, P.K. and Deslandes, Y. (1991). Application of the microbond technique characterization of carbon fiber-epoxy interfaces. Potym. Eng. Sci. 37, 1250-1256. 

McAlea, K.P. and Besio, G.J. (1988). Adhesion between polybutylene terephthalate and E-glass measured with a microbond technique. Polym. Composites, 9, 285 290. 

Biro D A, Pleizier G and Deslandes Y (1993) Appheation of the microbond technique. IV. Improved fiber-matrix adhesion by RF plasma treatment of organic fibers, J Appl Polym Sci 47 883-894. Sheu G S and Shyu S S (1994) Stuface properties and interfacial adhesion studies of aramid fibers modified by gas plasmas. Compos Sci Technol 52 489-497. 

Fig. 3. Schematic representation of the fiber pull-out and microbond techniques showing geometrical parameters,...

The microbond technique was analyzed by Naim [56] and more recently by Scheer and Naim [57]. In the first paper, a variational mechanics analysis of the stresses in the microbond specimen was completed. In the second paper, a new, more complete shear-lag analysis was presented. The proposed shear-lag result for analyzing the microbond test results is given by the equation in terms of the force of debonding ... 

The following experimental procedure can be used to measure the interfacial shear strength by means of the microbond technique for a thermosetting resin matrix. 

Fig. 5. Apparatus used to perform the microbond technique showing details of the microvise used to hold the microdrop while a load is applied on the fiber.

Single fiber fragmentation technique Ksi/MPa (IJd) Microindentation technique Ksi/MPa Microbond technique Ksi/MPa... 

The major advantages of the pull-out and microbond techniques can be summarized as follows (1) the value of force at the moment of debonding can be measured (2) these techniques can be used for almost any fiber-matrix combination. 

Direct measurement of the interfacial adhesion between a fibre and a resin matrix using the microbond technique. 

Three test methods, the fragmentation, pull-out and microbond methods, were used to analyse the micromechanics for carbon fibre/epoxy composites and Raman spectroscopy was used to determine the variation of fibre strain with position along a carbon fibre in a resin. It was demonstrated that the latter technique was capable of revolutionising interpretation of composite micromechanics and the different micromechanical test methods. In particular, it was shown that the technique could be used to distinguish between elastic deformation, interfacial debonding and shear yielding of the matrix at the interface. 19 refs. (FRC 94, Institute of Materials, Newcastle, March 1994)... 

For an extended review on current trends to characterize the fiber/matrix interphase as well as both direct and less direct methods for measuring the interfacial level of adhesion, the reader is referred to the work of Herrera-Franco and Drzal [34]. In this work, apart from the four methods and techniques already discussed (SFP, CLP, SFF, and microbond), all others have not been applied for lignocellulosic fibers. 

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