Adhesive bonding systems having adherence to low energy surfaces

A polymerizable composition for bonding a low surface energy substrate to a similar or different substrate, comprising:

• a) at least one free-radically polymerizable monomer component,
• b) an effective amount of an initiator system for initiating polymerization of the free-radically polymerizable monomer, said initiator system comprising:
• alkylated borohydride or tetraalkyl borane metal or ammonium salts comprising formula VI below:
• wherein R10 is C1-C10 alkyl,
• R11 and R12, which may be the same or different, are selected from the group consisting of H, D, C1-C10 alkyl, C3-C10 cycloalkyl, phenyl, phenyl-substituted C1-C10 alkyl and phenyl-substituted C3-C10 cycloalkyl, provided that any two of R10-R12 may optionally be part of a carbocyclic ring,
• R13 is H, D or C1-C10 alkyl, and
• M+ is a metal ion or a quaternary ammonium ion comprising formula VII below
• wherein R14-R17, which may be the same or different, are selected from the group consisting of C1-C10 alkyl, C2-C10 alkenyl, C3-C10 cycloalkyl, aryl, C1-C10 alkylaryl, aryl C1-C10 alkyl and aryl C1-C10 cycloalkyl, provided that any two of R14-R17 may be part of an optionally unsaturated carbocyclic ring;
• and
• c) a polymerizable siloxane reactive with the free-radically polymerizable monomer component.