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A growing number of PDA nanoparticles were adhered on the CF surface, presumably associated with the emergence of PDA agglomerates as the PDA deposited time increases. PDA injections were the ideal PDA sized time for fiber and matrix interlocking, according to the researcher. The introduction of PDA increased the chemical reaction and mechanical interlocking between fiber and matrix. The tensile strength of PDA 24 h sized CF increased by 26. 7 percent, 65. 6%, and 163. 6%, respectively, compared to unsized CF.
Source link: https://europepmc.org/article/PPR/PPR531486
Ambient cured wet layup carbon fiber reinforced epoxy composites that are used extensively in the repair of infrastructure and structural components can be exposed to elevated temperature conditions for extended stretches of time from hours to days as a result of thermal variations. Mechanical studies show that tensile and short beam shear properties are not adversely affected by the highest temperatures of exposure determined in this study. Transitions in failure modes are linked through microscopy to damage progression both at the level of fiber-matrix interface quality and through the bulk resin, particularly at the inter-layer level. The changes in glass transition temperature determined by differential scanning calorimetry may be related to thresholds that reveal changes in the mechanisms of damage.
Source link: https://europepmc.org/article/MED/35890731
For the external confinement, the present research examines these two key aspects: considering natural fibers and epoxy binder modification to improve ductile behavior, i. e. On plain concrete cylinders, various strength tests were conducted using sisal, basalt, carbon, and hybrid sisal-basalt FRP systems with different FRP layer thicknesses. Compared to unconfined specimens, those strengthened with MWCNT-converted hybrid FRP wraps containing sisal and basalt fibers saw increases of 114% and 87 percent in load carrying capability and energy absorption, as a result of the inherent rigidity of hybrid fibers and epoxy conversion. MWCNT's hybrid sisal-basalt FRP confidant specimens had superior properties and the low strength of natural FRP confinement could be increased by epoxy modification, according to the MWCNT's reports.
Source link: https://europepmc.org/article/MED/35706939
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