Gutta percha solution

Fig. 17b. Reduced osmotic pressure c for gutta-percha solutions in toluene ( ) and in carbon tetrachloride (o) ...

Benzol and oil of turpentine dissolve gutta-percha partially when cold, but almost completely by heat. One part of tho gutta requires for its solution from four to six parts of oil of turpentine. Bisulphide of earboii and chloroform dissolve it cold, and by cither of these solvents it may be obtained pure in the manner already described. 

By mixing only two per cent, of chloride of sulphur, or ouly fifteen per cent, of the other substances, with the sirupy solution of gutta-percha, a compound is obtained which does not materially differ from guttapercha in Ite properties. 

In a similar manner, articles may be coated With transformed gutta-percha, by dipping them first into a sirupy solution of gutta-percha in bisulphide of carbon, and afterwards plunging them into a bath consisting of two to ten parts of chloride of sulphnr dissolved in ono hundred parte of bichloride of carbon,... 

If the articles subjected to these processes are of such a nature that they would be damaged by the acid vapors formed during the operation, the patentees state that carbonate of soda should be mixed with the solution of gutta-percha, in quantity sufficient to neutralize the acid formed. 

Gutta percha has a lower water absorption than natural rubber and is a good dielectric. It is dissolved by carbon disulphide, chloroform and benzene but alkaline solutions and dilute acids do not affect it. It is destroyed by nitric acid and charred by warm concentrated sulphuric acid but resists hydrofluric acid. 

With the notable exceptions of natural rubber and gutta-percha, almost all naturally occurring polymers are optically active. Historically, interest in optically active synthetic polymers has focused on modeling natural polymers, interpreting the conformational properties of macromolecules in solution, and investi-... 

This type of crystallisation was first suggested by Storks in 1938. He made films of gutta percha 27 nm thick by evaporation from solution. Electron diffraction showed that the films were composed of large crystallites with the chain axes normal to the plane of the film. The only possibility was that the chains folded back and forth upon themselves, so that adjacent segments were parallel and in crystal register. 

Becanse of its thermoplastic character, gutta percha cannot be sterilized by heating. Instead, where disinfection is necessary, a dilute solution of sodium hypochlorite (typically 5%) should be used. 

Before the advent of infra-red analysis, natural rubber (and gutta percha) was identified by the Weber test which involved bromination. The rubber was reacted with bromine to form a dibromide which was then treated with a solution of phenol in carbon tetrachloride. A violet colouration of the residue developed after gentle boiling of the mixture. (This test also gives positive results for synthetic polyisoprenes and butyl rubber.)... 

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