Factors affecting the estimation of dirt content in raw natural rubber
2001
Ehabe, Ejolle Eugène | Sainte-Beuve, Jérôme
Wide variations have been observed in dirt content values from identical raw natural rubber samples in different laboratories using similar test procedures. Factors investigated in this study ranged from the physical nature and concentration of the peptiser employed to heat transfer during dissolution of raw natural rubber in the solvent. Rubbers of latex grade, as against those of cuplump, required longer heating before the formation of clear homogeneous solutions. After a critical duration of dissolution, prolonged heating led to the formation of a macrogel that remained insoluble in most nonpolar hydrocarbon solvents. This macrogel seemed to have been in part responsible for the poor repeatability of dirt values. The duration of swelling in white spirit, before heating, affected the formation of insoluble fractions, though this seemed to vary with the time of introduction of the rubber into the mixture. (Résumé d'auteur)
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