Surface Modification and Adhesion Mechanism of Isotactic Polypropylene with Low-Energy Electron-Beam Treatments

Abstract

Recently, smaller-size electron-beam (EB) accelerators have offered EB irradiation in laboratory systems. Therefore, polymer surface treatments with low-energy EB have been developed in the past years. For high adhesion strength, low-energy EB treatment is also a promising method in comparison to plasma surface treatment. In the plasma treatment, the mechanism of the effect on the adhesion properties has been proved and the excess treatments led to the formation of a weak boundary layer and reduction of adhesion strength. In contrast, the low-energy EB possesses high penetration ability. In this work, we focused on the surface treatments of isotactic polypropylene (it.PP) with low-energy EB irradiation for adhesion. The dependence of adhesion strength on the absorbed dose of electron beam was evaluated, and the mechanism of electron beam on the adhesion properties was investigated from various perspectives of surface properties and morphology. Compared to that of plasma-treated it.PP, the adhesion strength of it.PP with electron-beam irradiation increased drastically. We proved that the radical was generated in the substrates after electron-beam treatments and would form covalent bonds between adhesives and substrates, which achieved higher adhesion than plasma treatments. In addition, the electron beam reached effectively a deep region from the top surface of the substrates and provided larger adhesion strength.

Investigation of Interfacial Water Accumulation between Polypropylene Thin Film and Si Substrate by Neutron Reflectivity

“…Weak bonding at the interface adversely affects the various properties of PP-based nanocomposites and metal/resin bonding materials, such as mechanical properties, gas permeability, and thermal conductivity. Therefore, various conventional surface treatments of PP, such as cold plasma treatment, low-energy electron-beam treatment, ion-beam irradiation, and so on, − have been explored to archive strong bonding between the PP and metals or other polymeric materials. These surface treatments improve the adhesion between PP and metal surfaces. − …”

Electron beam irradiation treatment of textiles materials: a review

“…This owes to the fact that the plasma treatment process occurs near the surface. Moreover, the systemic plasma treatment for adhesion characteristics was indicated that the excess treatments result in creating a poor boundary layer and reducing the adhesion strength [37][38][39]. In the textile modification, unlike other radiation methods such as plasma [40,41], corona charges [42], or microwave radiation, [43] it was reported that the e-beam penetration occurred in the entire volume of the fibers, as well as, affected the whole portions of the fiber substructure [36,44,45].…”

Enhanced dielectric and energy storage properties of polypropylene by high‐energy electron beam irradiation

“…In previous studies, the influence of electron beam irradiation on the molecular structure, crystallization, rheology, and mechanical properties of PP has been investigated in detail. [26][27][28][29] For example, Helmut Münstedt's group investigated the rheological properties and molecular structure of electron-beam irradiated PP. The results showed that irradiation reduced the molecular weight of PP due to chain scission.…”

“…Furthermore, the free radicals were formed for the electron‐beam irradiated PP, which formed covalent bonds and improved interfacial strength between substrates and adhesives. [ 27 ] M. Stephan's group irradiated PP in a molten state with electron‐beam. Compared with solid‐state irradiation, a higher branching degree was achieved under the molten state irradiation process.…”