Rheopexy, viscosity measurements

The time dependent steady shear viscosity of neat PLA and a series of intercalated nanocomposites are shown in Fig. 3.17. ° Steady-shear viscosity measurements were conducted at 175°C using 25 mm diameter cone and plate geometry with a cone angle of 0.1 rad. The shear-viscosity of PLACNs is enhanced considerably at all shear rates with time, and at a fixed shear rate increases monotonically with increasing MMT content. On the other hand, all intercalated nanocomposites exhibited strong rheopexy behaviour, and this behaviour becomes prominent at low shear rate (= 0.001 s ), while pure PLA exhibited a time independent viscosity at all shear rates. With increasing shear rates, the shear viscosity attains a plateau after a certain time (indicated by the arrows in Fig. 3.17), and the time required to attain this plateau decreases with... 

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