Synthesis of calcium silicate hydrate/polymer complexes: Part I. Anionic and nonionic polymers

High molecular weight anionic polymers have been incorporated into the calc ium silicate hydrate (C-S-H) structure during precipitation of quasicrystal line CS-H from aqueous solution. The anionic polymers studied were poly(met hacrylic acid), poly(acrylic acid), and the sodium salt of poly(vinyl sulfo nic acid). Expansion of the interlayer spacing coupled with high-carbon con tents confirmed that the polymers intercalated between the layers. D-glucon ic acid behaves similarly. Intercalation characteristics strongly depended on both the type of polymer and Ca/Si molar ratio of C-S-H; intercalation r eached a maximum at an initial Ca/Si = 1.3 in all cases. Poly(vinyl alcohol ) was the only nonionic polymer among those studied that was incorporated i nto C-S-H. Evidence for interlayer intercalation is less definite. The C-S- H/polymer complexes were examined by Fourier transform infrared spectroscop y, Si-29 nuclear magnetic resonance magic angle spinning, and C-13 cross-po larization, magic angle spinning nuclear magnetic resonance spectroscopy.