Ebonite method

A modified ebonite method was developed [134] to study the interfaces associated with polymer tire cords. Hre 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 is of interest in tire... 

In summary, the ebonite method can be used routinely for polymer blends or composite specimens, such as tire cords, where hardening. 

Fig. 4.14 TEM micrographs of sectioned industnal tire cords are prepar by the ebonite method to enhance the contrast of the various structures and to harden the adhesive and the rubber for sectioning. Fiber cross sections, two adhesive layers (RFL) and the rubber (R) are shown by TEM.

The study of phase size and compatibility requires that the different phases be observed, distinct from one another, and that there is minimum distortion in the polymers. However, multiphase polymers often cannot be stained or sectioned uniformly. There are composite structures that are combinations of soft rubbers, coatings and oriented fibers which caimot be stained with a single staining agent and the sections may be deformed or distorted, limiting both observation and interpretation. The ebonite method was developed by Smith and Andries [111] to stain and uniformly harden polymers. 

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. 

Basic to the microscopical examination of polymeric systems is the need to cut thin sections, and this is called the science of microtomy. But before soft rubber specimens can be microtomed they must be hardened in some manner. The two methods used in this study are the freezing, or cyro, method, and chemical hardening of unsaturated rubbers with molten sulfur, called the ebonite method. 

In this section, all of the micrographs except Figure 23 have been taken on samples that have been hardened using the ebonite method and microtomed with an ultramicrotome. 

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