On oxygen plasma‐treated polypropylene interfaces with air, water, and epoxy resins. II. Epoxy resins

Abstract

SYNOPSISXPS, SEM, SSIMS, FTIR-ATR, water-in-air, and air-in-water contact angle measurements have been used to unambiguously characterize the locus of failure of PP/epoxy joints. In the case of untreated PP, the fracture has been found adhesive, whereas in oxygen plasmatreated PP, it is cohesive, within bulk P P , but close to the modified PP-bulk PP interface.The smoothness of fracture surfaces allowed us to exclude mechanical interlocking effects. Shear-strength measurements showed that the mechanical strength of the joint was improved by plasma treatment. Preliminary thermal equilibration of the plasma-treated PP sample and changes in the curing cycle of the epoxy resin did not change either the locus of failure or the shear strength of the joint. The reason is probably because the number of polar functions left at the surface after thermal equilibration is sufficient to induce adhesion. The mechanical strength of the PP surface layer may be the determining factor. Fracture energy calculations showed that the observed locus of failure is the same as predicted on the basis of surface energy considerations.

Poly(2‐oxazoline)‐derived Contact Biocides: Contributions to the Understanding of Antimicrobial Activity

“…Prior to the tests of antimicrobial activity, the surface energies of the (compound) PP plates were determined from contact angle measurements employing the test liquids water and diiodomethane [for pE 100‐25 n A 25 n ( n = 0–4)] and ethylene glycol and diiodomethane [for pN 100‐25 n A 25 n ( n = 0–3)] (Figure 2). All surface energies were in the range of 25–33 mN ·m −1 (PP had a surface energy of 28.5 mN ·m −1 in good agreement with literature data),39 indicative of neither pronouncedly hydrophobic nor hydrophilic character. Based upon these measurements, the wettability of all compound plates was classified as suitable for the application of the compound materials as substitutes for PP‐based devices.…”

Competitive Adsorption of Monoclonal Antibodies and Nonionic Surfactants at Solid Hydrophobic Surfaces

“…The aim of the present study was to gain further insight into the blocking properties of polysorbate 80 (PS80) toward the adsorption of mAbs onto solid hydrophobic interface. Specifically, it is the intention to relate this data of model surfaces (water contact angle from 85° to 90°) to polymers such as polyethylene, polypropylene, and polyvinylchloride used in the production of infusion bags (water contact angles from 87° to 104°) . To this purpose, the adsorption kinetics of two model mAbs in the presence and absence of the commonly used surfactant PS80 were studied.…”

Regulation of polyurethane hemocompatibility and endothelialization by tethered hyaluronic acid oligosaccharides

“…Surface modification methods are usually based on radiofrequency-generated gas plasmas [29], but the plasma-treated surfaces become unstable upon exposure to air and experience rapid changes in their surface characteristics. Moreover, functional groups introduced by plasma treatment may leach from the material surface following exposure to aqueous solutions, leading to a reduction in the reproducibility and efficacy of subsequent modification steps [33]. Thus, in the present work, PU functionalization was achieved via bulk incorporation of branched polyethylenimine (PEI), thereby generating highly aminated materials that could be modified via a variety of synthetic schemes.…”