(a) Principal dimensions of the RMS800 and the CPP2 rheometers. Signals: Forces Fi, Fo, torques Mi, Mo. In the RMS800, only Fi and Mi were measured. Ri is exclusively used for this geometry. (b) Principal dimensions of CPP3 rheometer cell. Signals: Forces F1, F2, torque M = M1. R1 and R2 are exclusively used for this geometry. F3 is not measured.
Comparison of forces F acting on different partitions, calculated for N1 and N2 given in the figure and the following geometries (see Fig. 1 ): CPP2: Ri = 6 mm. CPP3: R1 = 3 mm, R2 = 6 mm. 6 < R < 8 mm is the radius of the sample. Dotted lines: CPP2, solid lines: CPP3. To reduce confusion, Fi and Fo are used for the CPP2, F1 and F2 for the CPP3 only. Note that Fi = F1 + F2.
Setup of partition P1 of the CPP3 rheometer cell. F film heater, G glass foam, F1 normal force module, M torque module. Principal dimension: 2R1 = 6 mm.
Setup of partition P2 of the CPP3 rheometer cell. AF auxiliary frame, BR base ring, DS disk springs, F film heater, G glass foam, F2 normal force modules, H height and tilt adjustment. Principal dimension: 2R2 = 12 mm.
Assembly: Partition P1 in green, partition P2 in yellow, support structure in grey. A adapter plate to MCR300, AF auxiliary frame, B baseplate (thermostatted), BR base ring, C Thermocoax®, DS disk springs, F film heaters, F1, F2 normal force modules, G glass foam, M torque module, P3 partition 3 (in light blue, nonmeasuring), S centering and height adjustment of P3, T tubular casing.
Start-up viscosity η of PDMS 04A006 at 30 °C. The total strain during shear is 40. The sample size of all samples is R = 9 ± 0.1 mm. Each test has been repeated twice and from a fresh sample. η0(t) is calculated from the linear RTS (Table IV ). The shear rate in (s−1) is indicated in the figure.
Steady state values of η, Ψ1, and −Ψ2, determined at a strain of γ ≈ 15. η0(t) and Ψ1 0(t) are calculated from the RTS with Eqs. (2) and (3) . The Gleissle mirror relations [ Gleissle (1980) ] were applied to η( ) and Ψ1( ) with κ = 2.2 to get η(1/ ) and Ψ1(κ/ ). −Ψ2 0(t) is a second order polynomial fit to −Ψ2(κ/ ).
(a) Start-up first normal stress coefficient Ψ1 of PDMS 04A006 at 30 °C. Shear rate 6 s−1. This corresponds to Wi ≈ 1. The total strain during shear is 40. The solid circles with error bars are calculated with the RMS800 method [ Schweizer (2002) ]. (b) Start-up negative second normal stress coefficient −Ψ2.
List of partitioned plate rheometers.
Specifications of the CPP3 rheometer cell.
Characteristics of the sample PDMS 04A006.
Linear viscoelastic RTS of PDMS 04A006 at 30 °C.
Axial compliance effects in the CPP3 cell. Common parameters: Cone angle α 0.15 rad, axial stiffness Ka = 2 N/μm, τd = 0.2 s, axial response time ta = 6πRη/Kaα3 [ Hansen and Nazem (1975) ]. If ta/τd ≥ 0.3, axial compliance effects are expected in the transient regime.
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