1. Rheological Moifiers For Aqueous Solution Prepared by Intesar shawahin Sheren abu ali Instructor Mr.yaseen qawasmi

2. Introduction: Rheological modifers are materials which are used to modify the flow properties of fluid (liquid,suspensions,emulsions, creams,etc) Ingeneral materials which increase the viscosty of formulation\system are referred to as thickenes or rheological addititives

3. Why we use rheological modifiers Why we use rheological modifiers There are both marketing and technichal reasons for using rheological additives invarious products The first:consumer appeal :the users expect a thick product is more concentrated and richer than athin one The second:suspension stabilization in suspwnsions the rheological additives delay the separation soliod particales during storege The third:rheological addititives in fluid such as liquids and creams conter thixotropic prperties in order to improve their mobility during application and facilitate thease of spreading on surface

4. Types of rheological additives for aqueous solution:

5. Types of rheological additives for aqueous solution

6. Type of monomer distribution in polymers:

7. Representative sreletal structures of polymers

8. Rheological behavior of water soluble polymers: The polymers influnce the the rheological properties of fluid dneto acquiring alarge volume in solution as compared to the total of the molecular dimention of the repeating units The solution volume occupied by the solvated polymer chain is known as the hydrodynamic volume(hdv) Hdv is determined by polymer structural parameters polymer –solvent interaction polymer association or repulsions temp,eonc and mw

9. Non ionic synthetic polymers The water soluble synthetic nonioic polymers represent avastclass of polymers The nonionic polymers are generally compatible with anionic,nonionic amphoteric and eationic surfactants The nonionic polymers also have amuch better to lerance for electrolytes than the anionic polymers it may exhibit a cloud point behavior under go base or acid hydrolysis and may be unstable to harsh environments such as peroxide persultates or hypochlorite

10. Synthetic anionic polymers: Arepresentativ group of industrially important anionic polymers is as follows Poly(acrylic acid) Poly(methacrylic acid ) Poly(styrene sulfomic acid) polyacrylamidomethly (propane sulfonic acid) Poly(methyl vinyletherlmaleic anhydride)

11. The molecular structure of the anionic polymers can be tailored to allow significant conformational changes with bh,temb or added electrolytes The anionic polemers are general compatible with anionic and nonionic They can tolerate amoderate level of astorng oxidizing environment The anionic polemers usually ph and electrolyte sensitive and are incompatible with cationic materials

12. Synthtic cationic polemers: The synthetic polemers are of three types :ammonium(1,2,3and quaternary)sulfonium and phosphonium Of these the ammonium based polemers constitute alarg class of materials with diverse applications The copolymer of acrylamide and ammonium acrylate is used to build viseosity in rinse –cycle fabric softeners

13. Synthetic amphoteric polymers: These polymers exhibit both positive and negative charges on the same monomers or along the same backbone This class also include the inter polymer complex of polyanions and polycations The amphoteric polymers are highly soluble in water