Synthesis, characterisation and elektrorheological properties of pol (2-acrylamido-2-methyl-1-propane sulfonic acid)

SYNTHESIS, CHARACTERISATION AND ELECTRORHEOLOGICAL PROPERTIES OF POLY(2- ACRYLAMIDO-2-METHYL-1 -PROPANE SULFONIC ACİD) (M. Sc. Thesis) Haşim YILMAZ GAZİ UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY FEBRUARY 1999 ABSTRACT Considerable scientific and industrial interest is currently being focused on a class of materials known as electrorheological (ER) fluids. These fluids display remarkable behavior, being able to convert rapidly and repeatedly from a fluid to a solid when an electric field is applied or removed. In this study, poly(2-acrylamido-2-methyl-1 -propane sulfonic acid), (PAMPS), was synthesised using potassium persulfate, (K2S2O8), radicalic initiator. Polymer synthesis was characterized by elemental analysis, FTIR, 1H and 13C NMR spectroscopy, end group analysis and viscostiy measurements. Molecular mass of PAMPS was determined as 36 000 g/mol and 35 000 g/mol from end group analysis and viscometric measurement respectively. Lithium salt of PAMPS, (PAMPS-Li), was prepared by hydrolysis. Particle size of PAMPS-Li was determined by dynamic light scattering, (DLS), as 40 um. Suspensions of PAMPS-Li salt at various concentrations were prepared in silicone oil, mineral oil, dioctylphthalate, (DOP), tri octyltrimellilate, (TOTM), insulating oils. Electrorheological, (ER), properties of these suspensionsIV were investigated at various shear rate, (y), shear stress, (t) and electric field strengths, (E). Maximum ER activity was observed with the 33% (m/m) suspension of PAMPS-Li in the silicone oil. Excess shear stress was found to increase with increasing particle concentration and electric field strength. Between the suspensions prepared at various concentrations in silicone oil. ER activity was found to decrease with increasing temperature at low shear rates. Those suspensions were shown a shear-thinning visco-efastic behaviour. Science code Key Words Number of Pages Supervisor 405 Poly(2-acrylamido-2-methyl-1 -propane sulfonic acid), Electrorheological suspensions, Electrorheological fluids. 105 Assoc. Prof. Dr. Halil İbrahim ÜNAL