Polymer-cement and polymer-alite interactions in hardening of cement-polymer composites

Article presents the results of investigations on the mutual interactions between ethylene vinyl acetate (EVA) redispersible powders and hydrating Portland cement as well as elite. Influence of EVA powder on liquid phase composition was investigated. Liquid phase was squeezed out of hardened cement and cement polymer pastes using special pressure mould. The results showed that the presence of EVA powder significantly alters liquid phase composition. Acetate ions are present in pore solution of polymer modified pastes in concentration up to 0.9 M after 21 days of curing. Polymer hydrolysis influence also the properties of polymer films. FTIR investigations showed that for EVA modified pastes bands at 1744 cm(-1) and 1250 cm(-1) has become more sharpen, the half-width is decreased comparing to spectra of pure EVA copolymer. It suggests that the structure of copolymer tends to organize. Organisation of structure is caused by alkaline hydrolysis of copolymer and replacement of acetate groups by hydroxyl ones. As literature data indicates, changes in structure of copolymer influence the physiochemical properties of polymeric films e.g. permeability and strength.