000			01944nam a2200385Ia 4500
008			220216s9999 xx 000 0 und d
100			_aGupta B R
245		0	_aRheological and die swell behaviour of natural rubber melts
260			_bIndian Journal of Natural Rubber Research _c1989
300			_a38-46
520			_aStudies on rheological and die swell behaviour of natural rubber melts were carried out in aDavenport Capillary Rheometer. Two types of rubber, a Standard Malaysian Rubber (SMR-L) and a viscosity stabilised form of SMR (SMR CV-70) were masticated in a two-roll mill at 50 degree C for different time invervals. The extent of mastication is expressed as plasticity, measured from Wallace rapid plastimeter. Both type of rubbers have shown pseudoplastic behaviour with the value of Non-Newtonian index, n, varying between 0.1675 and 0.2695 under different levels of mastication. Die swell increases with plasticity and shear stress, but decreases with increasing levels of mastication. The value of non-Newtonian index first decreases with plasticity and then increases. The apparent viscosity is found to decrease with the rate of shear and the extent of mastication. It is also established that the power-law model describes the behaviour of both masticated and unmasticated rubber.
650			_aApparent viscosity
650			_aApparent viscosity
650			_aDie swell
650			_aDie swell
650			_aExtrusion rheometer
650			_aExtrusion rheometer
650			_aMastication
650			_aMastication
650			_aNatural rubber
650			_aNatural rubber
650			_aPlasticity
650			_aPlasticity
650			_aRate of shear
650			_aRate of shear
650			_aRheology
650			_aRheology
650			_aShear stress
650			_aShear stress
650			_aSMR-CV
650			_aSMR-CV
650			_aSMR-L
650			_aSMR-L
942			_cAR
999			_c47105 _d47105