Bound rubber toluene extraction

Bound rubber - The bound rubber content was measured with toluene as solvent [48,49]. The nonvulcanized samples (0.2 g) were cut into small pieces and put into a steel-wire basket of very fine mesh, which was immersed in 100 mL of toluene at room temperature for 72 h. The solvent was renewed after 24 h. The extracts were collected and left for 24 h in air and 24 h in vacuo at 105°C to evaporate the solvent. The amount of bound rubber (BdR) is expressed as the percentage of the total polymer content in the compound. 

According to a JSR patent Nd-catalysis allows for the polymerization of BD in the presence of carbon black. By this method a BR/carbon black master batch is obtained. The master batch technology eliminates time and energy consuming mixing of carbon black and rubber [340,341]. According to this patent the content of bound rubber (amount of rubber which can be extracted from a carbon black/rubber mixture with an appropriate solvent, e.g. toluene) is increased and vulcanizate properties are improved. 

In laboratory practice, a small sample of rubber is extracted with solvent (usually toluene) at room temperature for a specified period of time (1 week) and the percentage of bound rubber, Rb, is calculated from the equation ... 

A way to infer the activity of a filler toward an elastomer is to measure so called bound rubber. When an uncured elastomer-filler mixture is extracted with a solvent (e.g., toluene), then the gel-tike elastomer, which is bound to filler, cannot be dissolved, whereas the rest of the elastomer is soluble and is extracted away from the gel-tike mixture. The more the bound rubber, the more active the filler is assumed to be. 

Bound Rubber Content from Toluene Extraction Kinetic Method... 

It was found that the value of mean molecular weight of original Indian rubber present in the fraction soluble in toluene was equal approximately to 1,188,000 units. Ozonization of the Indian rubber in latex with the attachment of 0.8-1.0 mass % of ozone reduced mean molecular weight up to 990,000-993,000 units, that is, to the value that approximately corresponded to the working viscosity of mechanically plasticized mbber with Mooney viscosity equal to 50-55 units. Dependence of the change of molecular mass for the ozonizated mbber on the amount of the bound ozone is presented in Table 13.1. In all of the samples of modified polymers extracted from the ozonizated Indian mbber latex content of the carbonyl and carboxyl functional groups regularly increased with an increase of... 

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