Title: Gutta-Percha
CAS Registry Number: 9000-32-2
Literature References: The purified, coagulated, milky exudate of various trees of the genus Palaquium, Sapotaceae. Habit. Malayan Archipelago. Extensive review: Williams, Econ. Bot. 18, 5-26 (1964). Defined as a trans isomer of rubber. Rubber has a repeat period of 8.2 Å, whereas a-gutta-percha has 8.7 Å and b-gutta-percha has 4.8 Å. The short period of b-gutta-percha identifies it almost uniquely as an all-trans polyisoprene.
Properties: Becomes pliable at 25-30°, plastic at 60°. mp 100° (partial dec). On exposure to air and sunlight, it absorbs oxygen and becomes brittle. Insol in water; partially sol in hot alcohol; 90% or more dissolves in chloroform, carbon disulfide, petr ether, oil of turpentine. Keep under water and protected from light.
Melting point: mp 100° (partial dec)
Use: Insulator in electrotechnics, as dental cement; in orthopedics for fracture splints; manuf surgical instruments; covering golf balls. |