Rubber compounding short fibers

Short fiber incorporated rubber compounds can be processed in a way similar to that of conventional mbber compounds. Proper dispersion of the fiber in the rubber matrix is the primary objective. 

An important application for rubber modified polyester resins is in short-fiber reinforced molding compounds. Specific applications within the automotive industry include grill-opening panels and various car and truck body panels. Rubber modified vinyl ester resins are used as adhesives and as primer coatings for storage tanks. 

Extensive reviews on short fibers-reinforced elastomers have been published by Goettler and Shen, ° and more recently by Rajeev. Table 7.11 is a list of selected published works on natural fiber-filled rubber composites, sorted by rubber type. Only vulcanizable rubbers were considered in preparing the table thermoplastic rubber and rubber-plastics blends were omitted. As can be seen most grades of conventional elastomers have been considered with quite a large variety of natural fibers. Natural Rubber, SBR, and EPDM compounds have received much attention, as expected with respect to their industrial importance. A bonding system is us in most cases, with resin types (i.e. resorcinol-formaldehyde, resorcinol-hexamethylenetetramine, sil-ica-resorcinol-hexamethylenetetramine) the most frequent ones. 

Expectedly quantitative results vary considerably from one fiber-rubber system to another, and other compounding ingredients may induce additional effects (positive or negative). The qualitative effects are completely in line with the expected role of short fibers, in agreement with micromechanic considerations (see Section 7.2). Certain authors have used well established micromechanic approaches, e.g., Voigt and Reuss averages (Equations 7.1 and 7.2), and Halpin-Tsai equations (Equation 7.5) to consider the effects on short natural fibers in rubber compounds. ... 

M.A. Lopez Manchado, M. Arroyo. Short fibers as reinforcement of rubber compounds. Polym. Compos., 23 (4), 666-673,2002. 

Reinforcements. Both the resole and novolac compounds use a broad array of reinforcements to meet the demands of the market place wood flour, cotton flock, minerals, chopped fabric. Teflon, glass fibers (long and short), nylon, rubber, and kevlar. Asbestos, which had been a widely used filler in many thermosetting compotmds, has been replaced over the past 20 years with glass fiber-reinforced phenolic compounds in many applications. 

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