Abbas, Hina
(2022)
Characterization of fiber reinforced
nanohybrid dental composites from
agricultural biowaste using kenaf
fiber.
Masters thesis, Universiti Sains Malaysia.
Abstract
Background: Fiber reinforced composite was introduced due to development
of new biomaterials, technological advancements, and more effective treatment
approaches. Aims of the study: This study aimed to determine the bonding mechanism
between kenaf fibers and nanohybrid dental composite derived from agricultural
biowaste. The kenaf fiber reinforced composite was investigated for flexural and
compressive strength. The features of fractured surface of the flexural specimens were
also assessed. Materials and method: Preparation of kenaf fiber reinforced composite
was done using the treated silica from rice husk and kenaf cellulose. The kenaf
cellulose was processed and treated using tetraethyl orthosilicate (TEOS) sol gel.
Fourier- transform infrared spectroscopy (FTIR) and scanning electron microscopy
(SEM) were used to investigate the treated kenaf cellulose. Six specimens were
prepared for each group; composite groups A, B, C, D, E, F, G with 0%, 1% untreated,
2% untreated, 1% treated, 2% treated kenaf cellulose, Neofil and ever-X composite
respectively. For compressive and flexural strength tests, specimens were formed
using stainless steel molds with dimensions of 6mm x 4mm and 25mm x 2mm x 2mm,
respectively. After light curing using a light cure unit (Elipar Deep cure L, 3M, USA)
for 40 seconds, the specimens were tested using an Instron Universal Testing Machine
(Shimadzu, Japan). SEM was used to examine the fractured flexural strength samples.
Results: SEM showed the average diameter of treated kenaf fibers was 7.4μm
whereas the average length of treated kenaf fibers was 537μm. The FTIR results suggested formation of chemical bonds between the kenaf cellulose and silica from
TEOS sol gel. For flexural and compressive strength tests, one way ANOVA showed
there was statistically significant difference (P<0.05) between all groups. The
nanohybrid composite incorporated with treated kenaf cellulose resulted in comparable
compressive strength with the commercial Neofil composite and no improvement for
flexural strength. SEM analysis showed smoother fiber surface with presence of lesser
voids and gaps between matrix and kenaf fiber which suggested enhanced interfacial
bonding. Conclusion: Surface treatment of the kenaf cellulose improved the bonding
mechanism in the kenaf reinforced nanohybrid composite. Adaptation between surface
treated kenaf fiber and composite matrix contributed to improvement in compressive
strength of fiber reinforced composite.
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