Influence of Nanoclay Concentration on the CO2 Diffusion and Physical Properties of PMMA Montmorillonite Microcellular Foams

• Published in: Industrial & engineering chemistry research Vol. 50; no. 24; pp. 13819 - 13824
• Main Authors: Realinho, Vera, Antunes, Marcelo, Martínez, Antonio B, Velasco, José I
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 21.12.2011
• Subjects: Applied sciences; Chemical engineering; Exact sciences and technology; Materials and Interfaces; Montmorillonite; Foam; Diffusion; Physical properties; Carbon dioxide
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie201532h

Microcellular foams of poly(methyl methacrylate) with variable concentrations of an organically modified montmorillonite, oMMT (2.5–10 wt %), were prepared using a supercritical CO2 dissolution physical foaming process. Particular importance was given to the analysis of the influence of the montmorillonite on the CO2 desorption behavior out of the several nanocomposites. The saturation concentration of CO2 was found to be two times higher in the nanocomposites when compared to the pure PMMA and a comparative analysis of the desorption curves showed that a higher concentration of CO2 remained in the nanocomposites for long times when compared to PMMA, except for the 10 wt % oMMT nanocomposite. Also, the incorporation of oMMT promoted the formation of submicrometric foams with much lower cell sizes and higher cell densities. With increasing the amount of oMMT, the glass transition temperature of PMMA decreased in both the solids and foams and important improvements were observed regarding the specific elastic moduli of the foams, demonstrating the mechanical reinforcement effect of oMMT.