Swelling behavior and thermal stability of poly(methylmethacrylate) crosslinked by the oxozirconium cluster Zr4O2(methacrylate)(12)

A new isomer of the oxozirconium cluster Zr4O2(methacrylate)(12) was obtained by reaction of zirconium butoxide with an excess of methacrylic acid, Contrary to the known isomer, the structure is centrosymmetric with a planar, rhombic Zr-4 core, Copolymerization with a 56-207-fold excess of methlylmethacrylate results in cluster-crosslinked poly(methylmethacrylate) that swells in ethyl acetate but does not dissolve. The solvent uptake during smelling decreases and the thermal stability improves with an increasing portion of the cluster.