The Experts below are selected from a list of 54 Experts worldwide ranked by ideXlab platform
Michael H Santare - One of the best experts on this subject based on the ideXlab platform.
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influence of Resin properties on interlaminar shear strength of glass epoxy mwnt hybrid composites
Composites Part A-applied Science and Manufacturing, 2011Co-Authors: V C S Chandrasekaran, Suresh G Advani, Michael H SantareAbstract:Samples of glass fiber epoxy composites made with Resin containing 0.5 wt.% multiwall carbon nanotubes (MWNTs) have shown enhanced interlaminar shear strength relative to unmodified epoxy when evaluated using compression shear test. Improvement in the interlaminar shear strength (ILSS) of the composites can be due to an increase in the matrix shear strength or an increase in the fiber–matrix interface strength or both. In this work, we conducted tests to assess the relative contributions of the matrix shear properties and the glass fiber–epoxy interface to the ILSS enhancement. Samples of reinforced matrix were prepared by dispersing 0.5% MWNT by weight in epoxy. Both the reinforced Resin and neat Resin Control samples were subjected to identical ultrasonic agitation. Shear properties of the neat epoxy film and the MWNT reinforced epoxy film were investigated using a shear punch tests on miniature specimens (6.4 mm diameter, 0.5 mm thick). The strength of the fiber–matrix interface for both modified and unmodified matrix was also characterized using the microdroplet test. The results show that the change in ILSS is primarily due to the contribution from the strengthening of the fiber matrix interface and not from a change in the matrix shear strength.
Lippo V J Lassila - One of the best experts on this subject based on the ideXlab platform.
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short glass fiber reinforced restorative composite Resin with semi inter penetrating polymer network matrix
Dental Materials, 2007Co-Authors: Sufyan Garoushi, Lippo V J LassilaAbstract:Abstract Objectives The purpose of this study was to investigate the reinforcing effect of short E-glass fiber fillers on some mechanical properties of dental composite Resin with interpenetrating polymer network (IPN)-polymer matrix. Materials and methods Experimental composite Resin was prepared by mixing short fibers (3 mm in length) with a fraction of 22.5 wt% and IPN-Resin 22.5 wt% with silane treated silica filler 55 wt% using high speed mixing machine. Test specimens (2 mm × 2 mm × 25 mm) and (9.5 mm × 5.5 mm × 3 mm) were made from the experimental composite (FC) and conventional particulate composite Resin (Control, Z250, 3M-ESPE). The test specimens ( n = 6) were either dry stored or water stored (37 °C for 30 days) before the mechanical tests. Three-point bending test was carried out according to ISO 10477 and compression loading test was carried out using a steel ball (O3.0 mm) with speed of 1.0 mm/min until fracture. Degree of monomer conversion (DC %) of both composites was determined by FTIR spectrometry. Water sorption and solubility of specimens were also measured. Scanning electron microscopy was used to evaluate the microstructure of the composite. Results ANOVA revealed that experimental fiber composite had statistically significantly higher mechanical performance of flexural strength (210 MPa) and compressive load-bearing capacity (1881 N) ( p Significance The use of short fiber fillers with IPN-polymer matrix yielded improved mechanical performance compared to conventional restorative composite.
Eugenio Brambilla - One of the best experts on this subject based on the ideXlab platform.
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Streptococcus mutans adherence and biofilm formation on experimental composites containing dicalcium phosphate dihydrate nanoparticles
Journal of Materials Science: Materials in Medicine, 2017Co-Authors: Andrei C. Ionescu, Sebastian Hahnel, Gloria Cazzaniga, Marco Ottobelli, Roberto Ruggiero Braga, Marcela Charantola Rodrigues, Eugenio BrambillaAbstract:This study aimed at evaluating bacterial adhesion and biofilm formation on Resin-based composites (RBC) including dicalcium phosphate dihydrate nanoparticles (nDCPD). Methods: Specimens were prepared from experimental RBCs with BisGMA/TEGDMA Resin matrix including 20 vol% of either nDCPD (nDCPD-RBC), TEGDMA-functionalized nDPCD (F-nDCPD-RBC) or silanized silica (SiO_2-RBC). Neat Resin blend (Control-Resin), conventional nanohybrid RBC (Control-RBC) and human enamel were used for reference. Characterization of the specimens included surface roughness (SR), surface free energy (SFE), chemical surface composition (EDS, XPS), and buffering ability of a pH = 4.00 solution. Streptococcus mutans adherence was assessed after 2 h; biofilm formation was simulated for 48 h using a bioreactor. Adherent, viable biomass was determined using tetrazolium salt assay (MTT). Results: nDCPD-RBC yielded highest roughness and showed higher polar and lower disperse component to total SFE. EDS and XPS indicated higher amounts of calcium and phosphate on the surface of nDCPD-RBC than on F-nDCPD-RBC. nDCPD buffered the acidic solution to 5.74, while functionalization almost prevented buffering (pH = 4.26). F-nDCPD-RBC reduced adherence and biofilm formation in comparison to nDCPD-RBC. Regardless of functionalization, biofilm formation on nDCPD-containing RBCs was not significantly different from SiO_2-RBC. Control-Resin, Control-RBC, and enamel surfaces showed similar adherence values as F-nDCPD-RBC, but lower biofilm formation compared to both nDCPD-containing RBCs. In conclusion, the incorporation of nDCPD did not minimize S. mutans adherence and biofilm formation as a function of the materials´ surface properties. However, results observed for the buffering capacity indicated that optimized formulations of biomimetic RBCs may be useful for modulating their interaction with microorganisms. Graphical Abstract
V C S Chandrasekaran - One of the best experts on this subject based on the ideXlab platform.
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influence of Resin properties on interlaminar shear strength of glass epoxy mwnt hybrid composites
Composites Part A-applied Science and Manufacturing, 2011Co-Authors: V C S Chandrasekaran, Suresh G Advani, Michael H SantareAbstract:Samples of glass fiber epoxy composites made with Resin containing 0.5 wt.% multiwall carbon nanotubes (MWNTs) have shown enhanced interlaminar shear strength relative to unmodified epoxy when evaluated using compression shear test. Improvement in the interlaminar shear strength (ILSS) of the composites can be due to an increase in the matrix shear strength or an increase in the fiber–matrix interface strength or both. In this work, we conducted tests to assess the relative contributions of the matrix shear properties and the glass fiber–epoxy interface to the ILSS enhancement. Samples of reinforced matrix were prepared by dispersing 0.5% MWNT by weight in epoxy. Both the reinforced Resin and neat Resin Control samples were subjected to identical ultrasonic agitation. Shear properties of the neat epoxy film and the MWNT reinforced epoxy film were investigated using a shear punch tests on miniature specimens (6.4 mm diameter, 0.5 mm thick). The strength of the fiber–matrix interface for both modified and unmodified matrix was also characterized using the microdroplet test. The results show that the change in ILSS is primarily due to the contribution from the strengthening of the fiber matrix interface and not from a change in the matrix shear strength.
Sufyan Garoushi - One of the best experts on this subject based on the ideXlab platform.
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short glass fiber reinforced restorative composite Resin with semi inter penetrating polymer network matrix
Dental Materials, 2007Co-Authors: Sufyan Garoushi, Lippo V J LassilaAbstract:Abstract Objectives The purpose of this study was to investigate the reinforcing effect of short E-glass fiber fillers on some mechanical properties of dental composite Resin with interpenetrating polymer network (IPN)-polymer matrix. Materials and methods Experimental composite Resin was prepared by mixing short fibers (3 mm in length) with a fraction of 22.5 wt% and IPN-Resin 22.5 wt% with silane treated silica filler 55 wt% using high speed mixing machine. Test specimens (2 mm × 2 mm × 25 mm) and (9.5 mm × 5.5 mm × 3 mm) were made from the experimental composite (FC) and conventional particulate composite Resin (Control, Z250, 3M-ESPE). The test specimens ( n = 6) were either dry stored or water stored (37 °C for 30 days) before the mechanical tests. Three-point bending test was carried out according to ISO 10477 and compression loading test was carried out using a steel ball (O3.0 mm) with speed of 1.0 mm/min until fracture. Degree of monomer conversion (DC %) of both composites was determined by FTIR spectrometry. Water sorption and solubility of specimens were also measured. Scanning electron microscopy was used to evaluate the microstructure of the composite. Results ANOVA revealed that experimental fiber composite had statistically significantly higher mechanical performance of flexural strength (210 MPa) and compressive load-bearing capacity (1881 N) ( p Significance The use of short fiber fillers with IPN-polymer matrix yielded improved mechanical performance compared to conventional restorative composite.