The Oretical Investigations As Bas Is For Anew Rehometer Which Measures The Non-liner Mechanical Properties Of Dolymeric Solutions Or Melts:

Mostafa Mohammed Yaseen El-bakery

For 10% commercial polystyrene solution in toluene the viscosityvalues of this solution are nearly independent of the angular velocity Q,Fig.( 6-13), . The first normal stress difference values measured by theeccentric spheres rheometer for the same solution are plotted in Fig.(6-14). In these curves , it is shown that the viscous curves are identicalfor£=0.6 and £=0.8 while in the case of viscoelastic curves the valuesare coincide very well for values of eccentricities up to s =0.6 .ConclusionThe new eccentric spheres rheometer based on the presenttheoretical work had been constructed . Two parameters of theviscoelastic fluids ; namely the shear viscosity f! and the first normalstress difference coefficient [a. 2 + 2a. I] can be determined by thisrheometer .A good fitting between the theoretical and the experimentaldata has been shown for the present work and this fitting is coincidewith the results in the texts. The high degree of symmetry of the presentset up and the absence of the serious end effects may be considered asan advantage of the present rheometer. The first problem of the presentset up is the small range of the eccentricities and its unacuracey . Thisunacuracy of the determination ofthe eccentricity had been avoided inthe present case by making two eccentricities in opposite directions andthen taking the average value .10% polystyrene In toluenel-I- 00000 E:=.8?(?(?(?(?( E:= .61 ~I’::,I’::,I’::,!’::J:” E:= .4’-. 00000 E:=.2I- l- ***** E:=zeroI-’- ~0»r>; ?( 9 ’X”~ 10 -1~o0, t:: I0’::, I’::, ’---/ 0 *l- I’::, I’::,>, I- +-’ * *(f) ’- 0 0 ~0(f) 10 -2 I=->’- r- 0Q) ’- s: I-