Dear Friend,

Please read the following instruction and also, check the paper as link below.

http://pubs.acs.org/doi/full/10.1021/cm991174m

In this Communication, we report preliminary results on the cross-linking of poly(methyl methacrylate) by the oxozirconium methacrylate cluster Zr6(OH)4O4(OMc)12 (1). In a series of recently described crystalline oxozirconium methacrylate clusters,4 1 had the closest structural similarity to zirconia. It consists of a Zr6O4(OH)4 core in which the faces of a Zr6 octahedron are alternatively capped by μ3-O and μ3-OH groups. The cluster can be considered the smallest possible piece of tetragonal zirconia wrapped by methacrylate ligands. Three of them chelate the zirconium atom at one triangular face, while the remaining nine bridge the other edges. Inspection of the crystal structure of 1 shows that the double bonds of the methacrylate ligands should be fully accessible for chemical reactions.

Just a simple note: 

 (Poly methyl methacrylate acid) does not exist as such. Either there is PMMA which is poly(methyl methacrylate) or poly(methacrylic acid). Another possibility is to have a copolymer of methyl methacrylate & methacrylic acid.

The second & the third, above, can be cross-linked but the process is not easy.As for PMMA, I do not think that there will be inter-chain or intra-chain cross-linking done on it until there is a moeity on each chain "that can be made by free radicals" followed by joining the moeities to each other by suitable molecules. 

Hi, by the use of MBA crosslinker.