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Paper Information

Journal:   IRANIAN POLYMER JOURNAL (ENGLISH)   May-June 2004 , Volume 13 , Number 3; Page(s) 241 To 246.
 
Paper: 

THE EFFECT OF MOLECULAR WEIGHT ON THE BEHAVIOUR OF STEP-GROWTH HYDROPHOBICALLY MODIFIED ETHOXYLATED URETHANE (S-G HEUR) END-CAPPED WITH DODECYL ALCOHOL

 
 
Author(s):  BARMAR M.*, BARIKANI M., KAFFASHI B.
 
* DEPARTMENT OF POLYURETHANE, FIBERS AND ADVANCED POLYMERIC MATERIALS, IRAN POLYMER AND PETROCHEMICAL INSTITUTE,TEHRAN, I.R. IRAN
 
Abstract: 

Associative thickeners are an important group of polymers often used to control the rheological properties of aqueous systems. One class of these polymers is hydrophobically modified ethoxylated urethane (HEUR). In this research, the influence of hydrophilic sizes of HEURs on the rheology of their aqueous solutions was studied. For this purpose, two model thickeners of HEUR polymers were synthesized by step-growth polymerization of poly (ethylene oxide) (PEO) with dicyclohexylmethane diisocyanate (H12MDI). At first, the prepolymers were produced with different molecular weights by changing the molar ratios of the initial reactants. Then, S-G HEUR model thickeners were produced via reacting of the prepared isocyanate terminated prepolymers with monofunctional dodecyl alcohol. In this way, two polyurethane based model thickeners were obtained with different molecular weights arising from various hydrophilic lengths. The response of these S-G HEUR thickeners in aqueous solutions to both steady shear and oscillatory shear was determined. Considerable increases in thickening efficiency as decreasing molecular weight of model thickeners were observed. Also dynamic measurements verified the results obtained from the steady state measurements about the effect of molecular weight on the viscoelastic properties of aqueous S-G HEUR solutions

 
Keyword(s): S-G HEUR, HYDROPHILE, HYDROPHOBE, ASSOCIATION, STEADY SHEAR VISCOSITY, OSCILLATORY
 
References: 
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