Workshop series 2013 SJU-AAPS Student Chapter St. John’s University Oct , 5:00 PM Tapan Parikh St. John’s University, Queens, New York Phone: Rheometer

References Webinar Presentation: Viscoelasticity- Creep and Oscillatory Rheology. Plog, J,11 th July (Thermo Scientific website) Rotational Rheometery. Brno, th march school of rheology. (Malvern Instruments website) Rheometer. (TA Instruments website) Viscoelastic properties of polymers. Ferry, J. John Wiley & Sons, 3 rd edition 1

Rheology “Study of flow of matter in liquid state as well as soften solid state in which material responds as a plastic rather than deforming elastically in response to applied force.” * –Viscosity (measure of resistance to deformation) –Elasticity (tendency of solid material to return to original shape after deformation) Rheometer * Schowalter (1978) Mechanics of non-newtonian fluid pergamon 2

Types of rheometer Shear stress/ shear strain based Capillary rheometer Rotational cylinder –Cone and plate (homogenous sample) –Plate and plate (heterogeneous sample) Extensional stress based e.g. Rheoten (fiber spinning) Capillary break 3

Typical shear rate ranges 4

Instrumental: Rheometer Lower Plate Upper Plate Environmental test chamber 5 Discovery Hybrid HR2 Rheometer

Working Principle Strain Shear stress Shear Viscosity (Pa. S)= Shear stress / Shear rate = (G*) (Time) 6

Principle of oscillatory measurement 7

Step 1. Amplitude sweep 8

Step 2. Frequency sweep 9

Step 3. Oscillatory measurement 10

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Rheological profiles of copolymers Tan(δ) 109°C Tan(δ) 123°C SOLUPLUS KOLLIDON VA 64 15

Applications Melt extrusion Strength of gel Die swell Time dependent properties, e.g. coating 16