Properties of poly(acrylic acid)/modified starch compositions applied as a new polymeric binders
Polimery 2015, No 3, 179
The selected physicochemical properties of water-thinnable poly(acrylic acid)/sodiumsalt of carboxymethyl starch (PAA/CMS-Na) compositions — new environmentally friendlypolymer binding agents — were investigated as a function of time. The aqueous compositionPAA/CMS-Na was stored in closed vessels in a cooling chamber at 10 °C. During thethree-month storage period the changes of coloration, viscosity, wetting angle onquartz glass, structure and size distribution of the binding agent particles werestudied. On this basis, the stability of the binder properties was preliminarilyevaluated. Additionally, the moulding sands containing an aqueous composition PAA/CMS-Naas a binder (stored for a week or three months) were prepared, hardened and subjectedto the bending strength tests. It was found, that after three months of storageunder conditions resembling those found in a foundry the new binder did not loseits properties as a binding agent for the moulding sand.