Modification of Chitosan as Chemical Admixture for Cement Pastes

Document Type : Original Article

Authors

1 Institute of Chemical and Biological Technologies, Satbayev University, 22 Satpayev Street, 050013 Almaty, Kazakhstan

2 School of Chemical Engineering, Kazakh-British Technical University, Almaty, Kazakhstan

3 School of Chemical and Biological Technologies, Satbayev University, 22 Satpayev Street, 050013 Almaty, Kazakhstan

4 School of Energy, Construction and Environment, Faculty of Engineering, Environment & Computing, Sir John Laing Building, JL138, Coventry University, Coventry, CV1 2HF

Abstract

Three different composition ratios of chitosan-g- acrylic acid, P[Ch-g-AA] were prepared in the presence of potassium persulphate as an initiator using free radical technique. The grafted copolymers were characterized through FT-IR, TGA, DSC, and SEM. The results showed that these grafted copolymers have a single glass transition indicating that these copolymers can form a miscible phase. The P[Ch-g-AA] exhibit thermal stability. SEM of the grafted copolymers showed no phase separation, when compared with the pure Ch. The effect of grafted copolymers on the physico-mechanical properties of cement pastes was investigated. The addition of water mixed with grafted copolymer to the cement, improves properties of cement pastes. As the ratios of AA in the grafted copolymer increases, the water-to-cement (WC) ratio, setting time as well as water absorption decreases. While The compressive strength was sharply increased at nearly all hydration ages.

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