Surface modification of ultrahigh molecular weight polyethylene by plasma‐induced in‐situ grafting with vinyl triethoxysilane

Abstract

Ultrahigh molecular weight polyethylene (UHMWPE) is an excellent material with high performance, but it is very difficult to covalently introduce functional groups on its surface owing to its inherently inert structure, which constrains its further application. In this study, vinyl triethoxysilane (VTEOS) containing hydrolysable alkoxyl groups was in situ grafted on UHMWPE by air plasma treatment. The plasma treatment conditions for VTEOS grafting were optimized. The structure of the modified UHMWPE was characterized with FTIR and XPS. The relatively high VTEOS content was obtained when the treating conditions were about 20 W, 125 Pa for 10 min. And FTIR results showed that the grafted structure on the surface was stable for long time duration in the ambient environment. After the treatment, the roughness of the surface increased and the water contact angle of the modified sample dropped to 47.5° from 92.8° of the unmodified one. TGA and XRD results indicated that plasma treatment would not change the bulk structure of UHMWPE greatly. Cell culture experiments showed that fibroblasts on the modified samples had notably high viability and proliferation rate with good adhesion shape. Hence, it might be an effective method to improve the surface properties of UHMWPE for biomedical applications by plasma-induced in-situ grafting with VTEOS. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 321-332, 2018.

Overview of sterilization methods for UHMWPE through surface analysis

“…11 The peak for CQO stretching at the band 1714 cm À1 indicates oxidation, which is high on surface level, but decays gradually into the sample's core 3,23 and has been associated with plasma treated UHMWPE. 4 Although the CPO sample showed oxidation bands, they were not intense enough to harm the bulk sample, as can be seen in the presented TGA and nanoscratch results.…”

“…10). 4 In this set, CPO surfaces showed mostly round shaped fibroblasts, indicating poor cellular adhesion. High resolution SEM images can be viewed in Fig.…”

“…[1][2][3] UHMWPE has a semicrystalline structure, with around half of polymeric chains organized in the form of crystalline lamellae and the other half in a crosslinked amorphous phase. 4 This feature is occasioned by its glass transition temperature T g = À80 1C and melting point T melt = 135 1C, both of which allow the unique viscosity. Furthermore, the amorphous behavior allows other ideal properties for biomedical use, such as chemical inertness, low friction coefficient and a low wear rate.…”

“…Furthermore, the amorphous behavior allows other ideal properties for biomedical use, such as chemical inertness, low friction coefficient and a low wear rate. 2,4,5 However, sterilization processes are mandatory, in order to eliminate microbial life before implantation. 2,6 Nowadays, there are several methods for sterilizing such materials such as ethylene oxide (EtO), 6 hydrogen peroxide plasma (HPP), steam autoclave (SA) and cold plasma oxidation (CPO)reflecting the lack of scientific consensus over which of the methods is best suiting, considering long-term effects on patients.…”

Investigating the crosslinking effects on surface characteristics of vinyltrimethoxysilane‐grafted moisture‐cured low‐density polyethylene/ethylene vinyl acetate blend

“…have published their research results on modification of LDPE with 2‐Hydroxyethyl Acrylate by a special grafting method and have utilized water CAM to study the polarity of grafted polymer. Meng et al . have investigated the surface modification of ultra‐high molecular weight PE (UHMWPE) via plasma‐induced in situ grafting with vinyltriethoxysilane and they have utilized various techniques such as X‐ray photoelectron spectroscopy (XPS), CAM, SEM, and so forth to characterize surface‐modified UHMWPE.…”