000			01420nam a2200181Ia 4500
008			220216s9999 xx 000 0 und d
100			_aEhabe E E
245		0	_aFactors affecting the estimation of dirt content in raw natural rubber
260			_bIndian Journal of Natural Rubber Research _c2001
300			_a30-35
520			_aWide variations have been observed in dirt content values from identical raw natural rubber smaples 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.
650			_aDirt content
650			_aNatural rubber
650			_aRaw rubber
650			_aTechnical specification
700			_aSainte-Beuve J
942			_cJS
999			_c59236 _d59236