Determination of nanoparticles elasticity moduli in the epoxy composite using homogenization models

2018 ◽  
Author(s):  
A. A. Filippov ◽  
V. M. Fomin
Keyword(s):  
Epoxy Composite ◽  
Elasticity Moduli

scholarly journals Electrodeposition of 4-Benzenesulfonic Acid onto a Graphite-Epoxy Composite Electrode for the Enhanced Voltammetric Determination of Caffeine in Beverages

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Leonardo de A. Furtado ◽  
Mariana C. de O. Gonçalves ◽  
Carlos V. M. Inocêncio ◽  
Edilson M. Pinto ◽  
Daniela de L. Martins ◽  
...  
Keyword(s):  
Composite Electrode ◽  
Epoxy Composite ◽  
Reference Method ◽  
Diazonium Salts ◽  
Composite Electrodes ◽  
Wave Voltammetry ◽  
Linear Behaviour ◽  
Chromatographic Procedure ◽  
Kinetics Of

Caffeine is widely present in food and drinks, such as teas and coffees, being also part of some currently commercialized medicines, but despite its enhancement on several functions of human body, its exceeding use can promote many health problems. In order to develop new fast approaches for the caffeine sensing, graphite-epoxy composite electrodes (GECE) were used as substrate, being modified by different diazonium salts, synthetized as their tetraflouroborate salts. An analytical method for caffeine quantification was developed, using sware wave voltammetry (SWV) in Britton–Robinson buffer pH 2.0. Detection limits for bare electrode and 4-benzenesulfonic modified electrode were observed circa 145 µmol·L−1 and 1.3 µmol·L−1, respectively. The results have shown that the modification shifts the oxidation peaks to lower potential. Kinetics of the reaction limited by diffusion was more expressive when caffeine was added to the solution, resulting in decreases of impedance, characterized by lower Rct. All results for caffeine determination were compared to a reference chromatographic procedure (HPLC), showing no statistical difference. Analytical parameters for validation were suitably determined according to local legislation, leading to a linear behaviour from 5 to 150 µmol·L−1; precision of 4.09% was evaluated based on the RDC 166/17, and accuracy was evaluated in comparison with the reference method, with recovery of 98.37 ± 2.58%.

Determination of the Directional Dependent In-Plane Thermal Conductivity of K63B12 Pitch-Fiber/Epoxy Composite

2004 ◽  
Author(s):  
Jessica N. McClay ◽  
Peter Joyce ◽  
Andrew N. Smith
Keyword(s):  
Thermal Conductivity ◽  
Thermal Management ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Fiber Composite ◽  
Fiber Volume ◽  
State Technique ◽  
Fiber Composite Materials

Measurements of the in-plane thermal conductivity and the directional dependence of Mitsubishi K63B12 pitch-fiber/Epoxy composite from Newport Composites are reported. This composite is being explored for use in the Avanced Seal Delivery System for effective thermal management. The thermal conductivity was measured using a steady state technique. The experimental results were then compared to a model of the thermal conductivity based on the direction of the fibers. These estimates are based on the properties of the constituent materials and volume of fibers in the sample. Therefore the density and the fiber volume fraction were experimentally measured. The thermal conductivity is clearly greatest in the direction of the fibers and decreases as the fibers are rotated off axis. In the case of pitch fiber composite materials, the contribution of the fibers to the thermal conductivity dominates. The experimental data clearly followed the correct trends; however, the measured values were 25% to 35% lower than predicted.

scholarly journals Generation of R-Curve from 4ENF Specimens: An Experimental Study

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
V. Alfred Franklin ◽  
T. Christopher
Keyword(s):  
Composite Materials ◽  
Fracture Energy ◽  
Epoxy Composite ◽  
Beam Theory ◽  
Fiber Direction ◽  
Crack Growth Resistance Curve ◽  
Aerospace Applications ◽  
Delamination Toughness ◽  
Theory Solution

The experimental determination of the resistance to delamination is very important in aerospace applications as composite materials have superior properties only in the fiber direction. To measure the interlaminar fracture toughness of composite materials, different kinds of specimens and experimental methods are available. This article examines the fracture energy of four-point end-notched flexure (4ENF) composite specimens made of carbon/epoxy and glass/epoxy. Experiments were conducted on these laminates and the mode II fracture energy, GIIC, was evaluated using compliance method and was compared with beam theory solution. The crack growth resistance curve (R-curve) for these specimens was generated and the found glass/epoxy shows higher toughness values than carbon/epoxy composite. From this study, it was observed that R-curve effect in 4ENF specimens is quite mild, which means that the measured delamination toughness, GIIC, is more accurate.

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