Free-radically polymerizable crosslinker, curable composition, and adhesive therefrom

A free-radically polymerizable crosslinker composed of divalent segments Z represented by the formula

• wherein each divalent segment Z is respectively directly bonded to:
• i) two secondary N atoms, each further directly bonded to a divalent segment Z or an X group,
• ii) two tertiary N atoms, each further directly bonded to p additional divalent segments Z and (2−p) X groups, wherein p is 0, 1, or 2;
• or
• iii) a secondary N atom further directly bonded to:
• one additional divalent segment Z or an X group;
• and a tertiary N atom further directly bonded to p additional divalent segments Z and (2−p) X groups,
• wherein each R1 independently represents an alkylene group having from 1 to 4 carbon atoms,
• wherein each n independently represents a positive integer, and
• wherein each X group is independently represented by the formula:
• wherein each L independently represents a covalent bond, O, S, NR1, or a divalent linking group having from 2 to 8 carbon atoms and up to 3 oxygen atoms, and
• wherein each R2 is independently a free-radically polymerizable group selected from vinyloxy, methacryloxy, allyloxy, vinylaryl having from 8 to 12 carbon atoms, and 2-propenylaryl having from 9 to 13 carbon atoms,
• with the proviso that no two of O, S, or N atoms in the X group are adjacent
• wherein the free-radically polymerizable crosslinker has a number average molecular weight of from 4000 to 54000 grams per mole as measured by gel permeation chromatography at 40° C. versus a polystyrene standard.