Interface, glass/resin

Tooling Materials, Techniques, Tool Design , PLASTEC Rept 15 (1964) 7)WJ.Eakins, Glass/Resin Interface Patent Survey, Patent List, and General Bibliography , PLASTEC Rept 18 (1964) 8) A.E. Molzon, Electrical Pro-... 

Aqueous nitric and hydrochloric acids caused considerable reduction in tensile strength. Inorganic compounds are usually tested as aqueous solutions and it is very often the more dilute solutions which have the most deleterious effect upon glass-reinforced PPS. This is believed to be caused by the action of water, not the reagent, on the glass-resin interface. More will be said about this in the section on automotive uses. 

Enhanced interdiffusion and chemical bonding seem to be the most important mechanisms in formation of strong interfacial adhesion. On the other hand, reduced silane-resin polar interaction and increased hydrophobicity of the silane coatings are of major consequence in producing glass/resin interfaces resistant to degradation by water. 

W. A. Zisman, Surface chemistry of glass reinforced plastics, Symp. Glass-Resin Interface of Soc. Plastics Ind., 19th Annu. Exhib. and Conf., Chicago (Feb. 6, 1964). 

The highest mechanical strengths are usually obtained when the fibre is used in fine fabric form but for many purposes the fibres may be used in mat form, particularly glass fibre. The chemical properties of the laminates are largely determined by the nature of the polymer but capillary attraction along the fibre-resin interface can occur when some of these interfaces are exposed at a laminate surface. In such circumstances the resistance of both reinforcement and matrix must be considered when assessing the suitability of a laminate for use in chemical plant. Glass fibres are most commonly used for chemical plant, in conjunction with phenolic resins, and the latter with furane, epoxide and, sometimes, polyester resins. 

The situation is more complex when various other ingredients are added to PBT. Glass fibers, for instance, may lose adhesion from the resin due to the action of water on the glass-PBT interface, independent of the PBT-matrix reaction. This action will depend on specific contact conditions such as time, temperature and pH. In some instances, fiber-to-matrix adhesion can be recovered when the sample is dried, resulting in the recovery of some mechanical properties (if the PBT matrix is not too severely degraded). Other additives can introduce additional complications. 

Koenig, J.L.. Shih, P.T.K. (1971). Raman studies of the glass fiber-silane-resin interface. J. Colloid. Interface Sci. 36, 247-253. 

Figure lit shows the diffusion of dinitrophenol in aqueous solution into resin filled with 5% short glass fibres. The stain clearly follows the water up the fibre-resin interface. 

Mechanism of adhesion at the glass-fibre - resin interface... 

R Wong. Recent aspects of glass fiber-resin interfaces. J Adhesion 4 171-179, 1972. 

Fig. 4.37 SEM images of two glass filled composites with different adhesion properties are shown (A) is a composite with poor adhesion, as shown by the clean glass fiber surfaces resulting from failure at the fiber-resin interface (B) has holes where fibers with poor adhesion pulled out of the matrix (C) shows failure in the matrix and thus there is resin on the fiber surfaces also seen magnified in (D).

Figure 11.15 Fluorescent protein as a mechanophore at the fibre-epoxy resin interface in self-reporting fibre-reinforced composites, (a) The formation of microdamages promotes interfacial debonding between resin and fibre, therefore causing the protein to unfold and to lose its fluorescence. (b) Confocal fluorescence microscopy image of a damaged glass fibre-eYFP/epo>y composite, (c) Z-stack projection of confocal fluorescence microscopy images of a damaged carbon fibre-eYFP/ epoxy composite. (F yellow fluorescence channel, O overlay of fluorescence and transmission images).

R. Wong, Recent Aspects of Glass Fiber-Resin Interfaces , American Chemical Society, Division Organic Coatings and Plastic Chemistry 31, No. 2, Washington, DC (September 12-17,1971). 

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