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The chemical analysis of the Ebonite is more difficult than that one of the vulcanised rubber ordinary, because it less attacked from dissolvents.

The used unrefined elastic rubber is constituted from hydrocarbons of the rubber, humidity, from therefore said resin, from nitrogenous substances, mineral substances, etc the varied composition much to second of the botanical origin, the origin, the way of collection and preparation; and it can introduce, especially in wild rubbers, also in the same quality, remarkable oscillations employee from varied circumstances.

The unrefined rubber can contain much variable humidity amount of usual the commercial grades contains them from to 8% approximately of humidity, but such hour the amount is much greater one, and can, in some case of the poorest qualities, to arrive to 40%.

The mineral substances, when the rubber is not frammista to sand, clay, etc, for effect of bad preparation or swindle, are present in small amount; the top qualities (Parà, and of plantation) leave 0,05-0,5% of ashes, the other aboriginal qualities (Cearà hardly, Mangabeira, Negrohead, rubbers Africans and Asians) leave some of usual from 1 5%.

On the goodness of a rubber it influences particularly its content in resinose substances, and is the much best one at least are I rendered some. The percentage of these in rubbers flock is most variable, and in the some poorest types it is much elevating. The qualities Asian rubber currents of plantation contain some: Crespi pales 1,8-3%; Sheets (sheets) 2,5-3%; Filled with smoke sheets (smoked sheets) 2,5-3-5% of rendered some. The top qualities Americans (Adorn fine) contain from 3 to 3,5% of resin; the qualities Americans more currents (Ceara scraps), etc contain some of usual in greater amount 3-5%, such hour until 12%; the guayule of Mexico, much poor quality 13-18%.Le good quality Africans contains variable resin amounts from 3 to 10%, but the inferior qualities can contain more from 20 to 40% and. The aboriginal Asian rubbers of good quality (Borneo, Assam, and analogous) contain of resin usual 5-15%, but those poorest ones can conteneme a lot more, as an example the Pontianak until to 70%.

The content in nitrogenous substances in the top qualities does not exceed 2- 3% in the running qualities can vary from 4 to 15% approximately.

The essential member and more important for the property of the product are the pure rubber, whose varied percentage in inverse way to the impurities over cited: therefore the rubber of plantation over 90-95%; the top qualities Americans contain some around to 90% (with to one sure insoluble rubber amount), the other qualities of the southern America from 70 to 90%; guayule 75% approximately; the qualities aboriginal Africans and Asians currents 60- 85%.