THE EFFECT OF POLYMER IN STEEL FIBER REINFORCED CEMENT COMPOSITES
Three kinds of polymers, polymethylaarylate emulsion (PAE) , polyvinyl formal solution (PV-FO),styrene acrylate copolymer emulsion(SA) are chosen to study the effect of polymer in steel fiber reinforced cement composites (SFRCC). The experimental results shonw that the bonding properties in SFRCC are remarkably im proved after the addition of three kinds of polymer. The inter facial handing strength is obroiously enhanced with the addition of polymer contents, and is gradually steady or cut down slightly when the polymer content ercesses 15%. In the meantime,the toughness of SFRCC is greatly advanced when the polymers are doped. At last, the effect mechanism of polymer in SFRCC is put forward
Most theories about macromolecular crowding focus on two ideas: the macromolecular nature of the crowder and entropy. For proteins, the volume excluded by the crowder favors compact native states over expanded denatured states, enhancing protein stability by decreasing the entropy of unfolding. We tested these ideas with the widely used crowding agent Ficoll-70 and its monomer, sucrose. Contrary to expectations, Ficoll and sucrose have approximately the same stabilizing effect on chymotrypsin inhibitor 2. Furthermore, the stabilization is driven by enthalpy, not entropy. These results point to the need for carefully controlled studies and more sophisticated theories for understanding crowding effects.