CaCO₃–Polymer Nanocomposite Prepared with Supercritical CO₂

Abstract

A novel process for generation of a CaCO 3 –polymer nanocomposite with a controlled three-dimensional shape was developed. Specifically, a nanocomposite with a high CaCO 3 content was produced by introducing supercritical CO 2 into a polymer matrix containing Ca ions. A mixture of poly(vinyl alcohol), Ca acetate, and poly(acrylic acid) was poured into a mold, the mold was placed in an autoclave, and CO 2 was introduced to precipitate CaCO 3 within the polymer matrix. Laser Raman spectroscopy and transmission electron microscopy showed that this process produced a nanocomposite containing highly dispersed CaCO 3 (aragonite) nanoparticles. The flexural strength of the nanocomposite was larger than the flexural strengths of limestone and CaCO 3 produced by hydrothermal hot pressing. The use of supercritical CO 2 facilitated CO 2 dissolution, which resulted in rapid precipitation of CaCO 3 in the polymer matrix. The above-described process has potential utility for fixation of CO 2 .