Effects of surface treatments on the adhesion between PEEK and silicone polymer.

STATEMENT OF PROBLEM: Polyetheretherketone (PEEK) material can be used as a prosthetic scaffold to repair bone defects, but the inert surface of PEEK limits the application of this polymer material on prosthetic scaffolds.

PURPOSE: The purpose of this in vitro study was to investigate the effects of different surface treatments on the bond strength between PEEK and medical-grade silicone polymer.

MATERIAL AND

METHODS

Forty PEEK specimens were randomly assigned to 1 of 5 groups. The experimental groups consisted of D-PEEK, B-PEEK, S-PEEK, and BS-PEEK, which were sequentially treated with DMSO, sodium borohydride (NaBH4), 98% concentrated H2SO4, and a combination of concentrated sulfuric acid and sodium borohydride, respectively. Group P-PEEK served as the untreated control. Scanning electron microscopy was used to observe the PEEK surface morphology, and X-ray photoelectron spectroscopy was performed to analyze changes in the surface functional groups before and after the modification. Each treated PEEK group was bonded to medical-grade silicone polymer using silicone adhesive (n=8), and adhesion strength was assessed with a universal testing machine. One-way analysis of variance tests was used to analyze the data (α=.05).

RESULTS

Surface etching was evident in the B-PEEK, S-PEEK, and BS-PEEK groups; visible pores appeared on the S-PEEK and BS-PEEK surfaces. The root mean square values of the bond strength deviations between PEEK and silicone polymer showed significant differences among the various groups (P<.001), with the BS-PEEK group exhibiting the highest mean ±standard deviation bond strength (2.58 ±0.46 MPa). Significant differences in contact angles were found among the various groups (P<.001), with S-PEEK exhibiting the highest surface energy (42.6 ±2.1 mN/m). No surface modifications showed cytotoxicity.

CONCLUSIONS

Sulfonation and NaBH4 treatments significantly enhance the adhesion strength between silicone polymer and PEEK. Sulfonation followed by NaBH4 treatment produces a substantial increase in bond strength between silicone polymer and PEEK.