Aromatic maleimides and methods of using the same

A photopolymerizable composition comprising a photopolymerizable compound comprising at least one ethylenically unsaturated double bond and a photoinitiator comprising an ortho-substituted N-aromatic maleimide of the Formula (I) ##STR13## wherein:

• R.sub.1 is selected from the group consisting of CX.sub.3, COOR, COR, CN, SR, N(R).sub.2, R.sub.8, X, and MI;
• R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are independently selected from the group consisting of H, CX.sub.3, COOR, COR, OR, CN, SR, N(R).sub.2, R.sub.8, X, and MI;
• R.sub.6 and R.sub.7 are independently selected from the group consisting of H, lower alkyl, and halide;
• X is halide with the proviso that when R.sub.1 is halide, at least one of R.sub.2, R.sub.3, R.sub.4, and R.sub.5 is CX.sub.3, COOR, COR, OR, CN, SR, N(R).sub.2, or MI;
• R is selected from the group consisting of H, lower alkyl, cycloalkyl, and aryl;
• R.sub.8 is selected from the group consisting of lower alkyl, cycloalkyl, and aryl, with the proviso that when R.sub.1 is lower alkyl, at least one of R.sub.2, R.sub.3, R.sub.4, and R.sub.5 is CX.sub.3, COOR, COR, OR, CN, SR, N(R).sub.2, or MI and further R.sub.1 is not benzyl, or R.sub.8 is a spacer group connecting at least two compounds of Formula (I) to form a di- or multi-functional maleimide, said spacer group selected from the group consisting of:
• ##STR14## and ##STR15## wherein Y and Z are each independently selected from C2 to C10 alkylene, m is an integer from 1 to 10, and n is an integer from 1 to 10;
• and
• MI is ##STR16## wherein R.sub.6 and R.sub.7 are as defined above.