unvulcanized

As the most desirable consequence, the ultrasonically devulcanized rubber can be reprocessed and revulcanized in a manner similar to that employed with unvulcanized elastomers.

The DSC thermograms of the unvulcanized samples based on the second heating scan performed between -80 and 20[degrees]C are shown on the left side of Figure 3 and the obtained [T.sub.g] values are summarized in Table 1.

Costs associated with cleaning method development and validation are minimal relative to those required for other processes where unvulcanized silicone-drug mixtures contact numerous surfaces of both mixing and fabrication equipment.

Among the topics are the basic concepts and behavior of rubber elasticity, characterizing structure in the science and technology of elastomers, the viscoelastic behavior of rubber and dynamics of blends, the rheological behavior and processing of unvulcanized rubber, vulcanization, reinforcing elastomers by particulate fillers, the science of rubber compounding, the strength of elastomers, the chemical modification of polymers, tire engineering, and recycling rubbers.

(82) A second, smaller, company to make rubber shoes appeared, as well as a workshop specializing in recapping old tires with imported "camelback." (83) The latter was an unvulcanized rubber compound, which was cemented onto the tire after the old tread had been buffed off and was then vulcanized onto the tire in a mold.

At around the same time Uniroyal was developing and launching its TPR, a host of competitive products began to appear, most of which were blends of unvulcanized EPM or EPDM elastomers with PP and/or PE.

In general, TPOs are produced by blending a thermoplastic such as polypropylene with an unvulcanized elastomer such as EPDM.

* RPA (rheology) is used to measure viscoelastic properties and process simulation of raw rubber, as well as unvulcanized rubber compounds.