An Adhesion Improvement of Low-Density Polyethylene to Aluminum through Modification with Functionalized Polymers

Abstract

An interfacial adhesion improvement between low-density polyethylene (LDPE) and aluminum (Al) foil is an important challenge in designing multilayered packaging (TetraPak packaging type) due to insufficient inherent adhesion between both untreated materials. Therefore, extra adhesive layers are often used. The hydrophobic character of LDPE is responsible for poor adhesion to Al and can result in delamination. This study deals with the comparative study of the bulk modification of LDPE with various commercially available adhesive promoters with different chemical compositions to increase LDPE’s adhesive characteristics and ensure good adhesion in LDPE/Al laminates. A copolymer of ethylene and methacrylic acid; a terpolymer of ethylene, maleic anhydride, and acrylic ester; or maleated PE were used as adhesive promoters, and their effect on adhesion improvement of LDPE to Al was investigated. The best adhesion improvement was observed in LDPE-modified samples with maleated PE, while 0.1 wt.% additive content significantly increased peel resistance (from zero to 105 N/m). An additional increase in additive content (0.5 wt.%) in LDPE led to stronger adhesion forces than the cohesion forces in Al foil. Adding 0.5 wt.% of maleated PE into LDPE improved the LDPE/Al laminates’ adhesion and can be applied in multilayered lamination applications.

Characterization of Molecular Interactions in the Bondline of Composites from Plasma-Treated Aluminum and Wood

“…The results of Žigon et al [13] showing that the plasma-treated aluminum and beech wood surfaces bonded with PVAc withstand significantly higher shear forces than untreated surfaces were explained on a molecular level in this work. Plasma treatment improves the surface properties of both the wood and the aluminum to interact better with the PVAc.…”

“…In the case of plasma-treated aluminum, a large part of the surface serves as the contact area, which leads to many intermolecular interactions. This can also explain the increase in shear forces from 4.45 MPa for untreated aluminum to 7.54 MPa [13] for plasmatreated aluminum. Accordingly, PVAc could potentially replace more expensive adhesives like epoxy or polyurethane.…”

“…Furthermore, the materials were treated with plasma before bonding. This results in an increase in shear To improve the performance of such bonded materials, there are many studies that focus on the chemical modification of the adhesive [12,13]. On the other hand, the metal surface can also be modified to improve the adhesive properties.…”

A method for manufacturing a mechanically strong and durable hybrid structure of polyethylene–hydroxyapatite composite and titanium alloy

“…It is suggested that these chemical interactions may occur between the maleic anhydride groups of the compatibilizer HDPE‐ g ‐MAH presented in the polymer composite and the oxide layer on the metal surface. This argument is based on three main aspects: (i) PE‐ g ‐MAH is widely employed as an effective adhesive layer in polymer–metal laminated packaging 19 ; (ii) hybrid overlap joints produced using neat HDPE exhibited a threefold reduction in ULSF, measuring 331 ± 72 N; and (iii) HA particles in the HDPE–HA composite are not expected to directly affect the adhesion with the Ti6Al4V substrate. This is because, in the injection molding of polymer composites, a thin, filler‐free polymer skin is formed on the surface of the composite part, preventing contact between the HA particles and the metal surface during injection overmolding of HDPE–HA/Ti6Al4V hybrid joint.…”