Penyerapan Air Resin Akrilik Polimerisasi Panas Setelah Ditambahkan Serbuk Nanopartikel Serat Batang Pisang Barangan (Musa acuminata Colla) yang Dialkalisasi dan Diwarnai

Abstract

Water absorption is one of the material properties that causes dimensional changes in heat-cured acrylic resin, affecting the stability and aesthetics of dentures. The addition of natural fibers, such as banana stem fibers (Musa acuminata Colla), as a reinforcing agent in acrylic resin is expected to improve its physical and mechanical properties. This study aims to analyze the differences in water absorption of cured acrylic resin after the addition of alkali-treated and dyed banana stem fiber nanopowder at concentrations of 0.5%, 1%, and 1.5% by weight. The research specimens consisted of heat- acrylic resin discs with a diameter of 50 ± 1 mm and a thickness of 0.5 ± 0.05 mm. A total of 40 specimens (n=10 per group) were divided into four groups: Without fiber addition, 0.5% fiber powder by weight, 1% fiber powder by weight, and 1.5% fiber powder by weight, added to the acrylic resin powder. The fibers were extracted from banana stems, alkali-treated with 5% NaOH at 25°C for 1 hour, dyed with 15% red dragon fruit extract, ground, dried, and processed using ball milling. The acrylic mixture was then placed into molds and cured. Water absorption was measured using the formula according to ISO No. 1567:1999. The mean and standard deviation values of water absorption for Groups I, II, III, and IV were 5.32±2.18 μg/mm³, 4.73±2.40 μg/mm³, 4.50±3.21 μg/mm³, and 2.11±2.15 μg/mm³, respectively. Statistical analysis using one-way ANOVA showed a significant difference in water absorption among the groups after the addition of banana stem fiber nanopowder at concentrations of 0.5%, 1%, and 1.5% by weight, with a p-value of 0.038 (p<0.05). Post hoc analysis revealed significant differences (p<0.05) between Group I and Group IV (p = 0.007), Group II and Group IV (p = 0.026), and Group III and Group IV (p = 0.041). Thus, it can be concluded that the higher the concentration of fiber powder added to the acrylic resin powder, the lower the water absorption value. The 1.5% by weight concentration was found to be the best in achieving the lowest water absorption value.