190 likes | 325 Views
Workshop series 2013 SJU-AAPS Student Chapter St. John’s University Oct. 10 2013, 5:00 PM. Rheometer. Tapan Parikh St. John’s University, Queens, New York E-mail: tapan.parikh05@stjohns.edu; Phone : 718-990-8087. References.
E N D
Workshop series 2013 SJU-AAPS Student Chapter St. John’s University Oct. 10 2013, 5:00 PM Rheometer Tapan Parikh St. John’s University, Queens, New York E-mail: tapan.parikh05@stjohns.edu; Phone: 718-990-8087
References • Webinar Presentation: Viscoelasticity- Creep and Oscillatory Rheology. Plog, J,11th July 2013. (Thermo Scientific website) • Rotational Rheometery. Brno, 28- 29th march 2012- school of rheology.www.malvern.com (Malvern Instruments website) • Rheometer. www.tainstruments.com (TA Instruments website) • Viscoelastic properties of polymers. Ferry, J. John Wiley & Sons, 3rd 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
Instrumental: Rheometer Environmental test chamber Upper Plate Discovery Hybrid HR2 Rheometer Lower Plate 5
Working Principle Strain Shear stress Shear Viscosity (Pa. S)= Shear stress / Shear rate = (G*) (Time) 6
Rheological profiles of copolymers KOLLIDON VA 64 SOLUPLUS Tan(δ) 109°C Tan(δ) 123°C 15
Applications • Melt extrusion • Strength of gel • Die swell • Time dependent properties, e.g. coating 16