Rayon-natural rubber composite

The effect of the HRH system on adhesion is further illustrated by the micrographs (Figures 7-11) of the same rayon-natural rubber composite with and without HRH. Figures 7-9 show a thin section of the composite without HRH stretched to various elongations with the force applied parallel to the direction of orientation. Many voids form as the strain is increased owing to fiber-matrix bond failures. Both the number and size of voids increase with increasing strain. 

The most common textile bonding compositions are, of course, the RFL (resorcinol-formaldehyde-latex) dips used to adhere tire carcass rubber to cord reinforcing members. A typical RFL composition calls for a latex terpolymer of styrene-butadiene-vinyl pyridine as well as the resorcinol and hexamethylene tetramine. Some natural rubber latex or regular SBR latex may also be added. The R F resin which forms in situ is able to react chemically with rayon by methylol etherification of the cellulose s hydroxyls. Similar reaction is likely with the amide groups of nylon fibers as shown in Figure 7. 

Textile fibers (cotton, silk, wool, hair, rayon, nylon, polyester, aramid, etc.) Structural materials (lumber, composites, poly(oxymethylene), PVC, nylon, etc.) Rastios (polyethylene, polypropylene, polytetrafluoroethylene, polyoxide, etc.) Adhesives (glues, epoxies, polyvinyl alcohol, synthetic rubber, segmented polyurethanes, etc.) Biological materials (the basic molecules, carbohydrates, proteins, and DNA)... 

Short fibres of glass, rayon, aramid, asbestos and cellulose as reinforcing fillers, have been broadly used in rubber industries due to their high modulus, high strength and low creep. In recent years especially, natural fibres such as jute fibre, cellulose fibre, " coir fibre," " sisal fibre," " etc. have been also widely used in NR composites because they are enviromnental friendly, cheap, abundant and renewable. However, natural fibres also have some disadvantages such as moisture absorption, quality variations, low thermal stability and poor compatibility with the hydrophobic polymer matrix. 

A modified ebonite method was developed [113] to study the interfaces associated with polymer tire cords. Tire cords composed of PET, rayon or nylon fibers are generally bonded to rubber with a resorcinol-formaldehyde-latex (RFL) adhesive. The nature of the interfaces are of interest in tire cord studies. OSO4 may be used to stain and harden the RFL, but the soft rubber is not affected by this treatment, and, in fact, it forms a barrier to stain penetration. The ebonite reaction hardens the rubber and hardens and stains the RFL while maintaining the geometrical integrity of the composite. 

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