Virgin rubber

Jacob C, De P.P., Bhowmick A.K., and De S.K. Recycling of EPDM waste. II. Replacement of virgin rubber by ground EPDM vulcanizates in EPDM/PP thermoplastic elastomeric composition, J. Appl. 

Li, S., Lamminmaki, J., and Hanhi, K., Improvement of mechanical properties of rubber compounds using waste rubber/virgin rubber, Polym. Eng. Sci., 45, 1239, 2005. 

Figure 19a, b compares the storage modulus as well as tan 8 for various nanocomposites prepared from EVA rubber having 50% vinyl acetate content and loaded with MWCNT, as a function of temperature [162]. Throughout the experimental temperature range of —35 to 20°C, the storage moduli show steady increase from the virgin rubber with the increase in MWCNT level (see Fig. 19a). For example, there is...

Various rubber products can be manufactured using rubber from scrap tires to replace some or all of the virgin rubber or other material in the product. Tires may be either split, punched, or stamped to yield shapes suitable for fabrication, or the tires may be processed to crumb size to make new products, usually by mixing with other materials. 

Rubber Reclaim. For the traditional rubber "reclaim," crumb rubber is mixed with water, oil, and chemicals and heated under pressure, thus rupturing the carbon-sulfur bonds that cross-link the molecular matrix. The resulting partially devulcanized rubber may be formed into slabs or bales and shipped to manufacturers who process and vulcanize it for use as an alternative to virgin rubber to use in tires or to make mats and other rubber products. 

The samples of surface devulcanized reclaimed rubber made in this series of experiments were then compounded with a blend of virgin rubbers and cured. The blends were made by mixing 20 parts per 100 parts of rubber (phr) of the surface devulcanized reclaimed rubber samples with 70phr of Plioflex 1712 SBR, 30 phr of Budene 1254 polybutadiene rubber, about 9 phr of aromatic oil, about 70 phr of carbon black, about 2 phr of stearic acid, about 4 phr of wax, about 1 phr of accelerator, about 2 phr of zinc oxide, about 1.5 phr of sulfur, and about Iphr of antioxidant. The Plioflex 1712 has a bound styrene content of about 28.5% and was oil extended with about 37.5% of an... 

As can be seen from Table 6, the physical properties of some of the cured blends made with the surface devulcanized reclaimed rubber crumb samples were equivalent to those made with only virgin rubber. For instance, the 100% modulus, 300% modulus, and percent elongation measured in Examples 19 and 20 were very similar to those found in the control using only virgin rubber (the series labeled None ). 

If the virgin rubber was considered as a potential matrix for the scrap rubber, the fine particles of this rubber waste has also been tested as an additive in polymers. Various examples following this way are examined. 

E. Bilgili, A. Dybek, H. Arastoopour, and B. Bernstein. 2003. New recycling technology compression molding of pulverized rubber waste in the absence of virgin rubber. J. Elastomers Plastics. 35 235-56. 

Mandal N., S. Das Gupta, and R. Mukhopadhyay. 2002. Regenerated carbon black from scrap rubber products and its use in virgin rubber compound. Proceed. Conf. Prague Paper 89, p. 11. 

The tire is a complicated composite product consisting of tread, undertread, carcass, innerliner, bead, and sidewall. Many different types of rubber and carbon black reinforcement are used in manufacturing tires. Therefore, GRT is a blend of various rubbers and carbon blacks. Accordingly, in using GRT powder and devulcanized GRT in new tire manufacturing, many factors should be considered. Evidently, scrap tire powder can be used as a filler for virgin rubbers and devulcanized GRT can be used in blends with virgin rubbers. This market consumed approximately 1.354 x 10 tons of scrap tire rabber in 2009 (US Scrap Tire Markets, 2009). 

Extensive studies on the ultrasonic devulcanization of rubbers and some preliminary studies on ultrasonic decrosslinking of crosslinked plastics were carried out [83-122]. It was shown that this continuous process allows one to recycle various types of rubbers and thermosets. As a most desirable consequence, ultrasonically devulcanized rubber becomes soft, therefore making it possible for this material to be reprocessed, shaped, and revulcanized in very much the same way as the virgin rubber. This new technology has been used successfully in the laboratory to devulcanize a ground tire rubber (GRT)... 

---