TY - JOUR
T1 - Improving fracture toughness of dental nanocomposites by interface engineering and micromechanics
AU - Chan, K. S.
AU - Lee, Y. D.
AU - Nicolella, D. P.
AU - Furman, B. R.
AU - Wellinghoff, S.
AU - Rawls, R.
N1 - Funding Information:
This work was supported by National Institutes of Health through Grant No. P01DE11688. The authors are thankful for the contributions of the GTE (Bis-GMA, TEGDMA, and Bis-EMA) monomers by Esstech Corp., Essington, PA 19029, USA, and the filler particles by Schott Glas GmbH, Landshut, Germany. Technical assistance by Mr. Donald E. Moravits, SwRI, in performing fracture testing and AFM is acknowledged. Clerical assistance by Ms. A. Matthews at SwRI in the preparation of this manuscript is acknowledged.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/8
Y1 - 2007/8
N2 - The fracture toughness of dental nanocomposites fabricated by various methods of mixing, silanization, and loadings of nanoparticles had been characterized using fatigue-precracked compact-tension specimens. The fracture mechanisms near the crack tip were characterized using atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The near-tip fracture processes in the nanocomposties were identified to involve several sequences of fracture events, including: (1) particle bridging, (2) debonding at the poles of particle/matrix interface, and (3) crack deflection around the particles. Analytical and finite-element methods were utilized to model the observed sequences of fracture events to identify the source of fracture toughness in the dental nanocomposites. Theoretical results indicated that silanization and nanoparticle loadings improved the fracture toughness of dental nanocomposites by a factor of 2-3 through a combination of enhanced interface toughness by silanization, crack deflection, as well as crack bridging. A further increase in the fracture toughness of the nanocomposites can be achieved by increasing the fracture toughness of the matrix, nanofilled particles, or the interface.
AB - The fracture toughness of dental nanocomposites fabricated by various methods of mixing, silanization, and loadings of nanoparticles had been characterized using fatigue-precracked compact-tension specimens. The fracture mechanisms near the crack tip were characterized using atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The near-tip fracture processes in the nanocomposties were identified to involve several sequences of fracture events, including: (1) particle bridging, (2) debonding at the poles of particle/matrix interface, and (3) crack deflection around the particles. Analytical and finite-element methods were utilized to model the observed sequences of fracture events to identify the source of fracture toughness in the dental nanocomposites. Theoretical results indicated that silanization and nanoparticle loadings improved the fracture toughness of dental nanocomposites by a factor of 2-3 through a combination of enhanced interface toughness by silanization, crack deflection, as well as crack bridging. A further increase in the fracture toughness of the nanocomposites can be achieved by increasing the fracture toughness of the matrix, nanofilled particles, or the interface.
KW - Dental nanocomposites
KW - Fracture toughness
KW - Interface engineering
KW - Toughening mechanisms
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U2 - 10.1016/j.engfracmech.2006.07.013
DO - 10.1016/j.engfracmech.2006.07.013
M3 - Article
AN - SCOPUS:34047242217
VL - 74
SP - 1857
EP - 1871
JO - Engineering Fracture Mechanics
JF - Engineering Fracture Mechanics
SN - 0013-7944
IS - 12
ER -