A vinyl monomer of the structure R—B—Ar(—CHCH₂)_n (1) in which Ar is an aromatic ring (arylene group); n is an integer 0, in particular one or two; B is a bridge structure; R is a (C_2-30)-hydrocarbon group carrying two or more protected or unprotected hydroxy groups. The monomer is characterized in that B comprises a chain of atoms linking R to Ar and consisting of 1-10 atoms selected from carbons and the heteroatoms ether oxygen, thioether sulphur or amino nitrogen, with the proviso that the terminal atom in B which is attached to R is one of the heteroatoms. A method for producing a polymer support matrix in which the vinylmonomer is one of the monomeric units. The support matrix as such is also claimed. The preferred method for producing the support matrices involves suspension polymerisation, the preferred form of matrix is beads. The matrix is cross-linked ##STR1##