Two‐component acrylic structural adhesive initiated by tributylborane for untreated PET adhesion

In order to improve the adhesion strength of acrylic adhesive to untreated poly(ethylene terephthalate) (PET) substrate, two‐component acrylic structural adhesives initiated by tributylborane were prepared. The effects of acrylic monomers, elastomers, decomplexers, and oligomers on the adhesion properties of two‐component acrylic structural adhesive were investigated in sequence. It is found that the shear strength on PET of adhesives toughened by acrylonitrile–butadiene–styrene copolymer and carboxyl‐terminated butadiene–acrylonitrile copolymer is higher than that of commercial adhesives Dp8010NS and Loctite 3030. A tailored oligomer was synthesized from hydroxyl propyl–terminated polydimethylsiloxane and 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate. It is also noticed that premature failure usually takes place in the lap shear test samples due to the brittleness of the acrylic adhesive, except in the sample of adhesive modified by tailored oligomer. Excellent adhesion to the PET substrate is achieved by this adhesive modified by tailored oligomer, with a lap shear strength above 11 MPa and T‐peel strength up to 5.34 N/mm. Additionally, the resulting adhesive is qualified for the structural bonding of PET materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46612.