Influence of synthetic polymers on the mechanical properties of hardened β-calcium sulfate hemihydrate plasters

• Hydrophilic properties of assayed polymers are proportional to the water absorption.
• All assayed polymers enhanced water absorption at concentrations higher than 0.2%.
• The mechanical strengths enhancing happened with acceleration of initial hydration.
• The decrease of mechanical strengths happened with retard of the hydration.

Polymers have been used to modulate mechanical strengths and water absorption of construction or modeling materials as like gypsum. To understand the structure–performance relationship of polymers in hydration and properties of gypsum plaster, several designed carboxyl polyether sulfonates were investigated with comparison of some commercial polymers. It is found that bending strength of the hardened β-hemihydrate plaster is inversely proportional to number of carboxyl groups in the polymer that retards hydration. The mechanical strengths enhancement is coincident with acceleration of initial hydration, while decrease of mechanical strengths happened with retard of the hydration.

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