Abstract: Objective To study the effect of different surface pretreatments to high-strength glass fibers on the mechanical properties of glass fiber reinforced resin composite posts. Methods Glass fibers were divided into 4 groups for different surface treatments: no surface pretreatment; 450℃ calcination; etching with 10% HCl for 1 h after 450 ℃ calcination; etching with 10% HCl for 3 h after 450 ℃ calcination. All groups of glass fibers were immersed in KH570 solution before they were mixed into resin matrix, and then they were light -cured within a special mold to prepare the FRC posts. The flexure modulus, flexure strength and fracture load of FRC specimens were measured by universal mechanical testing machine. Statistical analysis was carried out with one-way analysis of variance (ANOVA) and the SNK tests(α=0.05). After three-point flexural bending test, the cross-section surface of FRC and the fracture surface of FRC were observed by a field emission scanning electron microscope (SEM). Results Different surface pretreatments of glass fibers affect the mechanical properties of FRC posts. FRC posts composed of glass fibers that were treated by 450 ℃ calcination and silanization presented the best overall performance, with flexure modulus (37.70±1.46) GPa; flexure strength (737.00±25.51) MPa; flexure load (196.53±6.80) N, which showed significant difference compared with other groups(P＜0.05)．Conclusion Glass fibers treated by 450 ℃ calcination and silanization could significantly improve the properties of FRC specimens.

Key words: glass fiber, surface pretreatment, light-cured resin, mechanical property