Balata
Balata is a natural, hard, horn- like material that is plastic and rubbery when exposed to heat . The gutta-percha-like substance is obtained by drying the milky sap of the South American balata tree . In contrast to natural rubber , the dry juice has a high resin content of around 40% and contains around 45% rubber. The resin is also partially or completely removed for various applications. Like rubber, balata can be vulcanized .
The rubbery part of the balata consists of trans - polyisoprenes (polyterpenes), in contrast to the cis - isomers of natural rubber, i.e. a geometrically different, otherwise identical molecule .
Similar products are gutta-percha and chicle , which come from the milky sap of other plant species. In these, the polyisoprenes of the rubbery part have a trans- or mixed configuration. The guayule rubber from the guayule ( Parthenium argentatum ) is also used to a greater extent, here the polyisoprenes are cis -configured.
Like gutta-percha, raw balata has the shape of leather-like, elastic plates, brownish on the outside and gray-white on the inside. It becomes soft and plastic at around 50 ° C and melts at around 150 ° C. It is more durable in air than gutta-percha because it does not oxidize as quickly.
Vulcanized balata was widely used in the past to make golf balls ; today ionomers are mostly used for this . It serves as a cheap substitute for gutta-percha as well as for the production of drive belts and shoe soles etc.
literature
- Balata. In: Meyer's encyclopaedic lexicon . Volume 3, 1971, p. 394.
Web links
Individual evidence
- ↑ R. Hansel, O. Sticher, E. Steinegger: Pharmakognosie - Phytopharmazie. Volume 1, 6th edition, Springer, 1999, ISBN 978-3-662-09270-5 , p. 49.
- ^ Georg Frerichs, Georg Arends, Heinrich Zörnig: Hager's handbook of pharmaceutical practice. First volume, Springer, 1938, ISBN 978-3-642-88873-1 (reprint), p. 1416.
- ↑ Golf balls from 1600 to today on swisshickorygolf.ch, accessed on January 19, 2018.
- ↑ K. Kollmann, KH Bussmann, A. Dahl, G. Morchutt, B. Arp: Belt drives, chain drives, clutches: Lectures and contributions to the discussion at the “Drive Elements ” conference, Essen 1953 . Springer-Verlag, ISBN 978-3-663-02896-3 ( google.com ).