Surface modification of ultra‐high‐molecular‐weight polyethylene. I. Characterization and sintering studies

Abstract

ABSTRACT:We performed surface modification of ultrahigh-molecular-weight polyethylene (UHMWPE) through chromic acid etching with the aim of improving the performance of UHMWPE's composites with poly(ethylene terephthalate) fibers. In part I of this study, we evaluated the effects of chemical modification on the surface properties of UHMWPE with X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements. The thermal properties, rheology, and sintering behavior of the modified UHMWPE were compared to those of the base material. XPS and FTIR analysis confirmed the presence of carboxyl and hydroxyl groups on the surface of the modified powders. The substitution of polar groups into the backbone of the polymer decreased its contact angles with water and hexadecane and increased its surface energy, as evidenced by contact angle measurements. The modified UHMWPE was more crystalline than the base resin and less prone to thermal degradation. Although the rheological properties were virtually identical, the modified powders sintered more readily, presumably due to their higher surface energy, which suggested enhanced processability by compression molding.

Surface modification of ultra‐high molecular weight polyethylene fibers by chromic acid

“…After modification, a new contribution appears at 288.9 eV (shown in Fig. b), which can be assigned to carbon atoms having a total of three bonds to oxygen atoms as present in carboxyl groups (―COOH) …”

Irradiation grafting of methyl methacrylate monomer onto ultra‐high‐molecular‐weight polyethylene: An experimental design approach for improving adhesion to bone cement

“…Depending on the surface crystalline morphology, highly complex rootlike cavities may form on the etched surface, which results in dramatic improvements in the wettability and bondability. In addition to the introduction of polar functional groups to the surface of the polymer, chromic acid preferentially etches the amorphous regions of the samples 11, 13, 15. Chemical etching was performed before irradiation for 30 min at room temperature.…”

“…In the previous studies,11–13 we examined the surface characteristics of UHMWPE oxidized with chromic acid and the graft copolymerization of MMA monomer onto UHMWPE and acid‐etched UHMWPE using a preirradiation method in air. The presence of polar functional groups on the surface of a modified UHMWPE increases the surface tension and wettability of the polymer and may provide sites for chemical or physical interactions with bone cement.…”

Facile preparation of a crosslinked hydrophilic UHMWPE membrane

“…Regarding the unique morphology of filter media with particles and sintering procedures, commercial products are also mainly doped with inorganic particles or organic modifiers to improve their hydrophilicity, while maintaining their good mechanical properties. However, as mentioned before, the performance is unsustainable, as the modifier will leach out during operation . Other modification methods are also not suitable for commercial UHMWPE filters due to the very high molecular weight (> 1 million) and relatively inert surface of UHMWPE.…”

“…However, as mentioned before, the performance is unsustainable, as the modifier will leach out during operation. [29][30][31][32][33][34][35] Other modification methods are also not suitable for commercial UHMWPE filters due to the very high molecular weight (> 1 million) and relatively inert surface of UHMWPE. To solve this problem, a facile one-pot crosslinkingsintering technique is presented with a UHMWPE flat membrane as a model.…”