Influence of plasma pretreatment of polypropylene on the adhesion with aluminium: An Auger spectroscopic study

“…The addition to polymer chains of sticker groups, which can interact with the solid surface strongly by forming hydrogen, covalent, or ionic bonds, is an efficient and widely used strategy to modify the adhesive strength. A specific application of this method in industry is the improvement of the adhesion properties of polyolefins either by functionalizing the surface chains through different treatments, − such as corona discharge, high-temperature oxidation, flame treatments, and chromic acid etching, or by using copolymers containing polar functional groups. The cohesive strength of the polymer depends on the density and the primary and secondary structure of the materials, i.e., the conformation and organization of the individual polymer chains and the degree of crystallinity within the interphase.…”

Section: Introductionmentioning

confidence: 99%

Polymer−Solid Interfaces: Influence of Sticker Groups on Structure and Strength

1998

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A model polymer−solid interface, aluminum- (Al-) carboxylated polybutadiene (cPBD), was designed to investigate the influence of the sticker group (−COOH) on the fracture energy (G IC). A model polymer, cPBD, was synthesized through high-pressure carboxylation of polybutadiene (PBD) and contained −COOH randomly distributed along the length of the polymer chains. T-peel tests were used to evaluate the interfacial fracture energy. The effect of the concentration of the sticker groups (φ) on the fracture energy was examined, and a critical concentration (φc), around 3 mol %, was found to give a maximum bonding strength, which was an order of magnitude stronger than the same interface without sticker groups. The fracture energy of Al−cPBD−Al interfaces increased over a range of 10−1000 min annealing time, t, which is much longer than the characteristic relaxation time of PBD at room temperature. The fastest adhesion occurred for sticker group concentrations at φc, whereas chains with sticker groups at φc ± 1% required much longer surface rearrangement times. The dynamics of adhesion was found to be comparable to time-dependent surfaces restructuring, using dynamic contact angle studies. Many of these results could be understood from a self-consistent lattice model developed by Theodorou, which we used to investigate how the sticker groups affect the structure of the interfacial chains. Sticker groups were found to have a strong tendency to segregate to the solid surface, resulting in a large concentration gradient near the solid surface. This phenomenon, together with the extremely slow surface restructuring process of cPBD chains, which relax like tethered chains, partially accounts for the long time dependence of the fracture energy of Al−cPBD−Al interfaces. Modeling also showed that the chain shape and the chain connectivity close to the solid surface was modified. With increasing concentration of sticker groups, the flatness of the chains near the solid substrate decreased at first and then increased, indicating an optimum concentration for efficient chain connectivity within the interfaces. These modeling results predicted a critical concentration of sticker groups for optimum bonding in the sense of cohesive strength, agreeing well with experimental results.

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Characterization of Surfaces, Interfaces, and Thin Films of Organic Materials

Zhang

2006

Materials Science and Technology

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Influence of plasma pretreatment of polypropylene on the adhesion with aluminium: An Auger spectroscopic study

Cited by 14 publications

References 8 publications

Surface modification of polyethylene powder by nitrogen and ammonia low pressure plasma in a fluidized bed reactor

Surface modification of polyethylene powder by nitrogen and ammonia low pressure plasma in a fluidized bed reactor

Polymer−Solid Interfaces: Influence of Sticker Groups on Structure and Strength

Characterization of Surfaces, Interfaces, and Thin Films of Organic Materials

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