Aziridine-Capped Poly(ethylene glycol) Brush Copolymers with Tunable Architecture as Versatile Cross-Linkers for Adhesives

Controlling adhesive and cohesive properties in a refined manner is paramount to developing high-performance adhesives. Therefore, developing and implementing cross-linkers have become a major focus in adhesive research, but most conventional cross-linkers are small molecules or oligomers with limited functionality. Herein, a brush copolymer consisting of varying lengths and densities of the aziridine-capped poly(ethylene glycol) (AzPEG) brush, termed P(AzPEG), is presented for use as a multifunctional polymeric cross-linker for carboxylate-containing acrylic adhesives. The density and length of the AzPEG brush, with respect to the total brush, are controlled conveniently by the concentration and molecular weight of the AzPEG acrylate monomer, respectively. In addition, the use of amphiphilic PEG also makes it possible for use in a variety of solvents. Using poly(EHA-co-AA) and poly(EHA-co-BA-co-MMA-co-AA-co-HEMA) as solvent and waterborne acrylic adhesives, respectively, their mechanical and adhesive properties are effectively controlled by P(AzPEG) with varying densities and lengths of the AzPEG brush without the need for a substantial change in concentration. These findings certainly show the advantages of brush copolymer-based cross-linkers for adhesives.