scholarly journals Basalt Fibre Composite with Carbon Nanomodified Epoxy Matrix under Hydrothermal Ageing

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 532
Author(s):  
Tatjana Glaskova-Kuzmina ◽  
Aldobenedetto Zotti ◽  
Anna Borriello ◽  
Mauro Zarrelli ◽  
Andrey Aniskevich
Keyword(s):  
Electrical Conductivity ◽  
Epoxy Matrix ◽  
Fibre Composite ◽  
Basalt Fibre ◽  
Electrically Conductive ◽  
Three Point Bending ◽  
Bending Mode ◽  
Before And After ◽  
Flexural Tests ◽  
Relative Change

This work aimed to investigate the effect of hybrid carbon nanofillers (e.g., carbon nanotubes/carbon nanofibers in the ratio 1:1 by mass) over the electrical and flexural properties for an epoxy matrix and corresponding basalt fibre reinforcing composite (BFRC) subjected to full-year seasonal water absorption. Hydrothermal ageing was performed by full immersion of the tested materials into distilled water according to the following model conditions (seasons). The mechanical properties were measured in three-point bending mode before environmental ageing and after each season. Upon environmental ageing, the relative change of flexural strength and elastic modulus of the epoxy and NC was within 10–15%. For nanomodified BFRCs, the slightly higher effect (approx. by 10%) of absorbed moisture on flexural characteristics was found and likely attributed to higher defectiveness (e.g., porosity, the formation of agglomerates etc.). During flexural tests, electrical resistance of the nanocomposites (NC) and BFRC/NC samples was evaluated. The electrical conductivity for UD BFRC/NC, before and after hydrothermal ageing, was by 2 and 3 times higher than for the NC, accordingly, revealing the orientation of electrically conductive nanoparticles and/or their agglomerates during lay-up manufacturing which was evaluated by the rules of the mixture. Based on all results obtained it can be concluded that the most potentially applicable for damage indication was UD BFRC/NC along fibres since full-year hydrothermal ageing improved its electrical conductivity by approx. 98% and, consequently, the ability to monitor damages was also enhanced.

scholarly journals Flexural Mechanical Characteristic of Sawdust and Chipwood Filled Epoxy Composites

2011 ◽  
Vol 471-472 ◽  
pp. 1064-1069 ◽  
Author(s):  
S. Hisham ◽  
A.A. Faieza ◽  
N. Ismail ◽  
S.M. Sapuan ◽  
M.S. Ibrahim
Keyword(s):  
Mechanical Performance ◽  
Natural Fiber ◽  
Fibre Composite ◽  
Fiber Composite ◽  
Untreated Wood ◽  
Test Method ◽  
Modulus Of Rupture ◽  
Three Point Bending ◽  
Wood Fibres ◽  
Flexural Tests

A study was conducted with the objective of gathering the information through flexural (three-point bending) testing. This research presents the testing results concerning the mechanical properties, modulus of elasticity (MOE) and modulus of rupture (MOR) of natural fiber reinforced composite. Resin were used as a matrix and untreated wood fibres contents 14% by weight as a filler treatment parameters to obtain better compatibility involving wood fibres Sawdust (SW) and Chipwood (CW) and epoxy. The feasibility of processing the composite prepared manually from waste wood and epoxy using open molding was investigated. The tests that have been conducted are in according to ASTM (D790-97) for flexural properties test method. Statistical analysis using ANOVA one way and two way showed that the differences of results obtained from those SW and CW fiber composite samples are significant, which confirm a very firm mechanical performance of the composites through flexural tests. This shows the producing a good quality of SW and CW fibre composite which maybe can use for furniture utilities.

Effect of Cu doping on the electrical Properties of ZnTe by Vacuum Thermal Evaporation

2018 ◽  
Vol 31 (3) ◽  
pp. 20
Author(s):  
Sarmad M. M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Hall Effect ◽  
Carrier Concentration ◽  
Hall Mobility ◽  
Cu Doping ◽  
Before And After ◽  
Hall Effect Measurements ◽  
Evaporation Technique ◽  
P Type

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but  decreases by increasing Cu concentration.

The Mechanical Properties of Organic Modified Epoxy Resin

2020 ◽  
Vol 43 (3) ◽  
pp. 10-14
Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Epoxy Resins ◽  
Mechanical Tests ◽  
Organic Modification ◽  
Three Point Bending ◽  
Modified Epoxy

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.

scholarly journals Mechanical Properties and Corrosion Resistance of TiAl6V4 Alloy Produced with SLM Technique and Used for Customized Mesh in Bone Augmentations

2021 ◽  
Vol 11 (12) ◽  
pp. 5622
Author(s):  
Nicola De Angelis ◽  
Luca Solimei ◽  
Claudio Pasquale ◽  
Lorenzo Alvito ◽  
Alberto Lagazzo ◽  
...  
Keyword(s):  
Sem Analysis ◽  
Bone Augmentation ◽  
Specific Test ◽  
Chemical Action ◽  
Three Point Bending ◽  
Custom Made ◽  
Manufacturing Techniques ◽  
Mechanical Properties And Corrosion ◽  
Flexural Tests ◽  
Applied Stresses

Bone augmentation procedures represent a real clinical challenge. One option is the use of titanium meshes. Additive manufacturing techniques can provide custom-made devices in titanium alloy. The purpose of this study was to investigate the material used, which can influence the outcomes of the bone augmentation procedure. Specific test samples were obtained from two different manufacturers with two different shapes: surfaces without perforations and with calibrated perforations. Three-point bending tests were run as well as internal friction tests to verify the Young’s modulus. Test samples were placed in two different buffered solutions and analyzed with optical microscopy. A further SEM analysis was done to observe any microstructural modification. Three-point flexural tests were conducted on 12 specimens. Initial bending was observed at lower applied stresses for the perforated samples (503 MPa) compared to non-perforated ones (900 MPa); the ultimate flexural strength was registered at 513 MPa and 1145 MPa for perforated and non-perforated samples, respectively. Both microscopic analyses (optical and SEM) showed no significant alterations. Conclusions: A normal masticatory load cannot modify the device. Chemical action in the case of exposure does not create macroscopic and microscopic alterations of the surface.

Polypyrrole/PU hybrid hydrogels: electrically conductive and fast self-healing for the potential application in body-monitor sensor

2021 ◽  
Author(s):  
Zhanyu Jia ◽  
Guangyao Li ◽  
Juan Wang ◽  
shouhua Su ◽  
Jie Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Potential Application ◽  
Self Healing ◽  
Electrically Conductive ◽  
Sensor Application ◽  
Hybrid Hydrogels ◽  
Health Monitor

Conductivity, self-healing and moderate mechanical properties are necessary for multifunctional hydrogels which have great potential in health-monitor sensor application. However, the combination of electrical conductivity, self-healing and good mechanical properties...

scholarly journals P157 Potential benefit of intravenous immunoglobulin in connective tissue disease associated interstitial lung diseases

Rheumatology ◽  
2021 ◽  
Vol 60 (Supplement_1) ◽  
Author(s):  
Vasilis Kouranos ◽  
Lauren V Host ◽  
Corrado Campochiaro ◽  
Athol Wells ◽  
Christopher P Denton ◽  
...  
Keyword(s):  
Lung Function ◽  
Connective Tissue ◽  
Lung Diseases ◽  
Immunosuppressive Treatment ◽  
Interstitial Lung Diseases ◽  
Ivig Treatment ◽  
Before And After ◽  
Predicted Values ◽  
Relative Change ◽  
Median Change

Abstract Background/Aims  Intravenous immunoglobulin (IVIg) confers significant benefit in range of connective tissue diseases (CTD) including inflammatory myopathy (IM) of which interstitial lung diseases (ILD) are a major complication. This study aimed to assess the efficacy of IVIg on pulmonary involvement in refractory active CTD including systemic sclerosis (SSc). Methods  All patients with CTD-ILD confirmed on HRCT either with IM or SSc overlap myositis who did not achieve satisfactory clinical response to standard immunosuppressive agents and subsequently received regular IVIg infusions for IM were retrospectively identified. Serial lung function tests and immunosuppressive treatment regimen 9-12 months prior and 9-12 months after repeat courses of IVIg were recorded. Progressive ILD was considered when, despite immunosuppressive treatment, a relative FVC decline≥10% and/or relative DLco decline ≥15% were identified during the 9-12 months preceding IVIg treatment. The significance of median DLco and FVC percentage relative change to IVIg treatment was assessed by Wilcoxon signed-rank test. Results  22 patients (mean age 50.5±13.1 years old) with IM-ILD treated with IVIg were identified. ILD occurred in association with IM in 10 patients, overlap SSc myositis in another 11 patients, while one had mixed connective tissue disease with myositis. Lung function results were available for 19/22 (86%). Eight patients (42.1%) were found to have progressive ILD(four with IM and four with overlap SSc-myositis). The median change in FVC% predicted and DLco% predicted in the 9-12 months before and after IVIg treatment is presented in Table 1. There was a significant difference in the DLco% predicted rate of relative change before and after IVIg treatment (p = 0.035) for the overall cohort. However, no differences in lung function were observed in the rate of relative change between patients with IM and patients with SSc myositis overlap. Significant improvement in DLco% predicted values was identified in the subgroup analysis of patients with progressive ILD(p = 0.012). P157 Table 1:The median change in FVC and DLco% predicted values prior and after the IVIg treatmentPatients with myositis related ILD9-12 months before IVIg treatment (relative change)9-12 months after IVIg treatment (relative change)p-valueAll (n = 19)FVC % predicted-3.8 (-54.4 - 14.6)2.1 (-33 - 33.7)0.145DLco % predicted-9.2 (-60.7 - 9.2)-2.3 (-26 - 41.9)0.035PM/DM (n = 10)FVC % predicted-1.8 (-20.2 - 14.6)0.8 (-33 - 30.9)0.401DLco % predicted-9.6 (-60.7 - 9.2)-2.4 (-26 - 41.9)0.093SSc-PM/DM overlap (n = 11)FVC % predicted-6 (-54.4 - 10.6)3.4 (-19.9 - 33.7)0.139DLco % predicted-10.8 (-47.1 - 2.5)4.2 (-22.7 - 16.8)0.173Progressive ILD (n = 8)FVC % predicted-14.5 (-54.4 - 14.6)5.7 (-11.9 - 33.7)0.123DLco % predicted-25.3 (-60.6 - -14.1)12 (-2.3 - 41.9)0.012 Conclusion  IVIg may be an effective rescue therapy in the prevention of further lung function decline in refractory myositis and SSc overlap in particular in subgroups with progressive ILD. Future studies to determine its role in CTD-ILD are warranted. Disclosure  V. Kouranos: None. L.V. Host: None. C. Campochiaro: None. A. Wells: None. C.P. Denton: None. V.H. Ong: None. E. Renzoni: None.

scholarly journals Electrically Conductive Networks from Hybrids of Carbon Nanotubes and Graphene Created by Laser Radiation

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1875
Author(s):  
Alexander Yu. Gerasimenko ◽  
Artem V. Kuksin ◽  
Yury P. Shaman ◽  
Evgeny P. Kitsyuk ◽  
Yulia O. Fedorova ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Laser Irradiation ◽  
Flexible Electronics ◽  
Threshold Energy ◽  
Wavelength Region ◽  
Hybrid Nanostructures ◽  
Graphene Sheets ◽  
Electrically Conductive ◽  
Walled Carbon Nanotubes

A technology for the formation of electrically conductive nanostructures from single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and their hybrids with reduced graphene oxide (rGO) on Si substrate has been developed. Under the action of single pulses of laser irradiation, nanowelding of SWCNT and MWCNT nanotubes with graphene sheets was obtained. Dependences of electromagnetic wave absorption by films of short and long nanotubes with subnanometer and nanometer diameters on wavelength are calculated. It was determined from dependences that absorption maxima of various types of nanotubes are in the wavelength region of about 266 nm. It was found that contact between nanotube and graphene was formed in time up to 400 fs. Formation of networks of SWCNT/MWCNT and their hybrids with rGO at threshold energy densities of 0.3/0.5 J/cm2 is shown. With an increase in energy density above the threshold value, formation of amorphous carbon nanoinclusions on the surface of nanotubes was demonstrated. For all films, except the MWCNT film, an increase in defectiveness after laser irradiation was obtained, which is associated with appearance of C–C bonds with neighboring nanotubes or graphene sheets. CNTs played the role of bridges connecting graphene sheets. Laser-synthesized hybrid nanostructures demonstrated the highest hardness compared to pure nanotubes. Maximum hardness (52.7 GPa) was obtained for MWCNT/rGO topology. Regularity of an increase in electrical conductivity of nanostructures after laser irradiation has been established for films made of all nanomaterials. Hybrid structures of nanotubes and graphene sheets have the highest electrical conductivity compared to networks of pure nanotubes. Maximum electrical conductivity was obtained for MWCNT/rGO hybrid structure (~22.6 kS/m). Networks of nanotubes and CNT/rGO hybrids can be used to form strong electrically conductive interconnections in nanoelectronics, as well as to create components for flexible electronics and bioelectronics, including intelligent wearable devices (IWDs).

scholarly journals Multi-material braids for multifunctional laminates: conductive through-thickness reinforcement

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Caroline O’Keeffe ◽  
Laura Rhian Pickard ◽  
Juan Cao ◽  
Giuliano Allegri ◽  
Ivana K. Partridge ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fibre ◽  
Electromagnetic Interference ◽  
Design Tool ◽  
Electrically Conductive ◽  
Current Collection ◽  
Wide Range ◽  
Predictive Design ◽  
The Right ◽  
Metal Wires

AbstractConventional carbon fibre laminates are known to be moderately electrically conductive in-plane, but have a poor through-thickness conductivity. This poses a problem for functionality aspects that are of increasing importance to industry, such as sensing, current collection, inductive/resistive heating, electromagnetic interference (EMI) shielding, etc. This restriction is of course more pronounced for non-conductive composite reinforcements such as glass, organic or natural fibres. Among various solutions to boost through-thickness electrical conductivity, tufting with hybrid micro-braided metal-carbon fibre yarns is one of the most promising. As a well-characterised method of through thickness reinforcement, tufting is easily implementable in a manufacturing environment. The hybridisation of materials in the braid promotes the resilience and integrity of yarns, while integrating metal wires opens up a wide range of multifunctional applications. Many configurations can be produced by varying braid patterns and the constituting yarns/wires. A predictive design tool is therefore necessary to select the right material configuration for the desired functional and structural performance. This paper suggests a fast and robust method for generating finite-element models of the braids, validates the prediction of micro-architecture and electrical conductivity, and demonstrates successful manufacturing of composites enhanced with braided tufts.

Investigate of Electrical Conductivity of Shape-Memory Polymer Filled with Carbon Black

2008 ◽  
Vol 47-50 ◽  
pp. 714-717 ◽  
Author(s):  
Xin Lan ◽  
Jin Song Leng ◽  
Yan Ju Liu ◽  
Shan Yi Du
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Shape Memory ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Recovery Process ◽  
Thermomechanical Properties ◽  
Electrically Conductive ◽  
New System

A new system of thermoset styrene-based shape-memory polymer (SMP) filled with carbon black (CB) is investigated. To realize the electroactive stimuli of SMP, the electrical conductivity of SMP filled with various amounts of CB is characterized. The percolation threshold of electrically conductive SMP filled with CB is about 3% (volume fraction of CB), which is much lower than many other electrically conductive polymers. When applying a voltage of 30V, the shape recovery process of SMP/CB(10 vol%) can be realized in about 100s. In addition, the thermomechanical properties are also characterized by differential scanning calorimetery (DSC).

Heterogeneous Preparation of Cellulose/Ag/Polyaniline Conductive Composite and its Electrical Property

2012 ◽  
Vol 182-183 ◽  
pp. 254-258
Author(s):  
Zhong Li Zhao ◽  
Zun Li Mo ◽  
Zhong Yu Chen
Keyword(s):  
Electrical Conductivity ◽  
Electrical Property ◽  
Conductive Network ◽  
High Electrical Conductivity ◽  
Electrically Conductive ◽  
Conductive Composite

Cellulose/Ag/polyaniline conductive composite with rather excellent electrical conductivity was heterogeneously synthesized in this paper. The UV-Vis analysis indicated that homogeneous nanoAg particles deposited on the surface of cellulose in the form of globe particles. They offered some electrons to polyaniline chains. This behavior resulted to the facts that more polyaniline embedded on cellulose and an integrated electrically conductive network formed. Consequently, the high electrical conductivity of the composite was observed. The value was 3.48 S/cm, which was higher two magnitudes than the electrical conductivity of cellulose/polyaniline composite (2.15×10-2S/cm), and even was higher than the electrical conductivity of pure polyaniline (0.142 S/cm). This paper provided a facile method for the preparation of cellulose/Ag/ polyaniline composite with favorable electrical conductivity.

Sign in / Sign up

Export Citation Format

Share Document