scholarly journals Enhanced Surface Energetics of CNT-Grafted Carbon Fibers for Superior Electrical and Mechanical Properties in CFRPs

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1432
Author(s):  
Arash Badakhsh ◽  
Kay-Hyeok An ◽  
Byung-Joo Kim
Keyword(s):  
Electrical Resistivity ◽  
Flexural Strength ◽  
Epoxy Resin ◽  
Weight Ratio ◽  
Chemical Vapor ◽  
Work Of Adhesion ◽  
Ductility Index ◽  
Reinforced Plastic ◽  
Surface Energetics ◽  
Growth Formation

Surface enhancement of components is vital for achieving superior properties in a composite system. In this study, carbon nanotubes (CNTs) were grown on carbon fiber (CF) substrates to improve the surface area and, in turn, increase the adhesion between epoxy-resin and CFs. Nickel (Ni) was used as the catalyst in CNT growth, and was coated on CF sheets via the electroplating method. Surface energetics of CNT-grown CFs and their work of adhesion with epoxy resin were measured. SEM and TEM were used to analyze the morphology of the samples. After the optimization of surface energetics by catalyst weight ratio (15 wt.% Ni), CF-reinforced plastic (CFRP) samples were prepared using the hand lay-up method. To validate the effect of chemical vapor deposition (CVD)-grown CNTs on CFRP properties, samples were also prepared where CNT powder was added to epoxy prior to reinforcement with Ni-coated CFs. CFRP specimens were tested to determine their electrical resistivity, flexural strength, and ductility index. The electrical resistivity of CNT-grown CFRP was found to be about 9 and 2.3 times lower than those of as-received CFRP and CNT-added Ni-CFRP, respectively. Flexural strength of CNT-grown Ni-CFRP was enhanced by 52.9% of that of as-received CFRP. Interestingly, the ductility index in CNT-grown Ni-CFRP was 40% lower than that of CNT-added Ni-CFRP. This was attributed to the tip-growth formation of CNTs and the breakage of Ni coating.

Characterization of the SiCf/SiC Composite Fabricated by the Whisker Growing Assisted CVI Process

2005 ◽  
Vol 287 ◽  
pp. 200-205 ◽  
Author(s):  
Ji Yeon Park ◽  
S.M. Kang ◽  
Weon Ju Kim ◽  
Woo Seog Ryu
Keyword(s):  
Flexural Strength ◽  
Chemical Vapor ◽  
Pyrolytic Carbon ◽  
Chemical Vapor Infiltration ◽  
Interlayer Thickness ◽  
Filling Time ◽  
The Matrix ◽  
Sic Whiskers

To obtain a dense SiCf/SiC composite by the chemical vapor infiltration (CVI) process, whisker growing before matrix filling was applied, which is called the whisker growing assisted CVI process. The whisker growing and matrix filling processes were carried out using MTS (CH3SiCl3) and H2 as source and diluent gases, respectively. Tyranno-SATM was used as a reinforced substrate. Characterizations of SiC whisker grown during the in situ whisker growing process have been investigated. The weight gain rates with the matrix filling time and the density of composites was measured. The flexural strength with the thickness of the pyrolytic carbon (PyC) interlayers has been evaluated. b-SiC whiskers with many stacking faults were grown well in the Tyranno SATM fabrics. Tyranno-SA/SiC composite with a PyC interlayer thickness of 150 nm had a flexural strength of 610 MPa and the density of 2.71 g/cm3.

scholarly journals Micromechanical Modeling of Flexural Strength for Epoxy Polymer Concrete

2017 ◽  
Vol 09 (08) ◽  
pp. 1750117 ◽  
Author(s):  
Dongpeng Ma ◽  
Yiping Liu ◽  
Nanli Zhang ◽  
Zhenyu Jiang ◽  
Liqun Tang ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Epoxy Resin ◽  
Epoxy Polymer ◽  
Resin Content ◽  
Micromechanical Modeling ◽  
Polymer Concrete ◽  
Flexural Performance ◽  
Micromechanics Models ◽  
Strong Adhesion ◽  
Good Agreement

Epoxy polymer concrete (EPC) has been widely used in civil engineering nowadays due to its excellent mechanical properties and advantages in processing. In this paper, a modeling study has been carried out on the flexural performance of EPC. Two classic micromechanics models, i.e. rule of mixture and Mori-Tanaka method, are introduced to predict the flexural strength of EPC with various epoxy resin contents. The comparison shows that the parallel model based on the rule of mixture attains a good agreement with the measured results when the epoxy resin content is sufficiently high to achieve strong adhesion between the aggregate and the epoxy resin. In contrast, the Mori–Tanaka method with the failure criterion dominated by the weakest phase fails to give acceptable prediction due to the unsuitability of its basic assumptions to EPC, particularly when the epoxy resin content is at relatively high levels.

scholarly journals Effects of zinc acetate and cucurbit[6]uril on PP composites: crystallization behavior, foaming performance and mechanical properties

e-Polymers ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 491-499 ◽  
Author(s):  
Yuhui Zhou ◽  
Li He ◽  
Wei Gong
Keyword(s):  
Impact Strength ◽  
Flexural Strength ◽  
Zinc Acetate ◽  
Crystallization Behavior ◽  
Cell Structure ◽  
Weight Ratio ◽  
Crystallization Rate ◽  
Sem Images ◽  
Improvement Effect ◽  
Lower Temperature

AbstractIn this study, polypropylene (PP) foams were prepared with 1.0 wt% of cucurbit[6]uril (Q[6]), zinc acetate (Zn(Ac)2), Zn@Q[6] (a supramolecular compound synthesized from Q[6] and Zn(Ac)2), or a mixture of Zn(Ac)2 and Q[6] (weight ratio of 1:1) through injection molding in the presence of a chemical blowing agent, azodicarbonamide. The effect of the additions on the crystallization behavior and foaming performance of PP and the mechanical characterizations of the foaming samples were determined. The results showed that the additions can change the crystallization type from homogeneous to heterogeneous, increase the crystallization rate and shrink the size but increase the density of spherulites. Among the additions, Q[6] most significantly altered the crystallization properties. Scanning electron microscopy (SEM) images revealed that the PP foaming performance can be improved by Zn(Ac)2 addition at a lower temperature (175°C); however, further increasing the temperature had an undesirable effect. Q[6] exhibited the optimum foaming improvement effect on PP in a wide temperature range (175–195°C). Adding nanoparticles also enhanced the tensile properties, flexural strength and impact strength of foaming PP at low temperatures. However, with increasing temperature, the poor cell structure demonstrated undesirable effects in terms of tensile strength, flexural strength and impact strength.

scholarly journals Development of Coffee Biochar Filler for the Production of Electrical Conductive Reinforced Plastic

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1916 ◽  
Author(s):  
Mauro Giorcelli ◽  
Mattia Bartoli
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Black ◽  
Epoxy Resin ◽  
Resin Composites ◽  
Powder Form ◽  
Coffee Waste ◽  
Reinforced Plastic ◽  
Epoxy Resin Composites

In this work we focused our attention on an innovative use of food residual biomasses. In particular, we produced biochar from coffee waste and used it as filler in epoxy resin composites with the aim to increase their electrical properties. Electrical conductivity was studied for the biochar and biochar-based composite in function of pressure applied. The results obtained were compared with carbon black and carbon black composites. We demonstrated that, even if the coffee biochar had less conductivity compared with carbon black in powder form, it created composites with better conductivity in comparison with carbon black composites. In addition, composite mechanical properties were tested and they generally improved with respect to neat epoxy resin.

Utilization of Waste Packaging Glass as Progressive Filler in Polymer Anchor Material Based on Epoxy Resin

2019 ◽  
Vol 887 ◽  
pp. 40-47
Author(s):  
Tomáš Žlebek ◽  
Jakub Hodul ◽  
Rostislav Drochytka
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Epoxy Resin ◽  
High Strength Concrete ◽  
Chemical Resistance ◽  
Negative Impact ◽  
High Strength ◽  
Pull Out ◽  
Pull Out Strength ◽  
Packaging Glass

The work deals with the use of waste glass to the polymer anchor material based on epoxy resin, primarily for anchoring to a high strength concrete (HSC). The main aim was to use the largest possible amount of the waste packaging glass by reducing the amount of epoxy resin, which is an expensive material and its production has a negative impact on the environment. Within the experimental verification, the influence of waste packaging glass fraction 0–0.63 mm on the final properties of the polymer anchoring material was observed. To determine the optimal formulation compressive strength, flexural strength, chemical resistance, shrinkage and pull-out test were performed. Based on the evaluation of the results the optimal percentage of filling was determined, when the polymer anchor material showed high strengths, minimal shrinkage, good chemical resistance, optimal consistency for anchoring into the HSC and high anchor bolt pull-out strength.

scholarly journals The Submillimeter Telescope - A Status Report

1994 ◽  
Vol 140 ◽  
pp. 66-67
Author(s):  
R. N. Martin ◽  
J. W. M. Baars
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
Weight Ratio ◽  
High Strength ◽  
Modern Technology ◽  
Status Report ◽  
Atmospheric Conditions ◽  
Max Planck ◽  
Reinforced Plastic ◽  
Secondary Support ◽  
Night And Day

SummaryThe Max-Planck-Institut für Radioastronomie, Bonn and the Steward Observatory of the University of Arizona, Tucson are collaborating on the construction and operation of a dedicated submillimeter facility. The Submillimeter Telescope (SMT) is a 10 m diameter reflector surrounded by a corotating enclosure. The instrument is an alt-azimuth mounted f/13.8 Cassegrain homology telescope with two Nasmyth and bent Cassegrain foci. The SMT will have diffraction limited performance at a wavelength of 300 μm. and an operating overall figure accuracy of 15 μm rms. The primary and secondary reflector surfaces are constructed out of aluminum-core, carbon-fiber-reinforced-plastic (CFRP) face sheet sandwich panels. The primary reflector backup structure and secondary support are fabricated from CFRP structural members. This modern technology provides both the means for reaching the required precision of the SMT for both night and day operation (basically because of the low coefficient of thermal expansion and high strength-to-weight ratio of CFRP) and a potential route for the realization of lightweight telescopes of even greater accuracy in the future. The SMT will be the highest accuracy radio telescope ever built.The SMT is located at an altitude of 3180 m on Emerald Peak (Mt. Graham) 120 km northeast of Tucson in southern Arizona. Measurements indicate that atmospheric conditions allow submillimeter observations during about 40% of the time in winter months. The telescope is placed in a co-rotating enclosure of novel design. The enclosure fits tightly around the telescope, with the focus flanges extending from the elevation bearings into the receiver rooms of the enclosure. A flat tertiary mirror is used to direct the beam through either of the two elevation bearings. Thus, we are able to mount receivers directly on the telescope while maintaining laboratory type conditions in the access area surrounding the receivers. On the “facility instrument” side, several receivers can be operated simultaneously.

Quasi-static and dynamic mechanical thermal performance of date palm/glass fiber hybrid composites

2020 ◽  
pp. 152808372095803
Author(s):  
Abderrazek Merzoug ◽  
Bachir Bouhamida ◽  
Zouaoui Sereir ◽  
Abderrezak Bezazi ◽  
Ali Kilic ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Glass Fiber ◽  
Date Palm ◽  
Hybrid Composites ◽  
Weight Ratio ◽  
Fiber Surface ◽  
Damping Factor ◽  
Dynamic Mechanical ◽  
Naoh Solution ◽  
Composite Glass

The present work reports an experimental study on the thermal and mechanical properties of hybrid composites obtained from Petiole Date Palm Fiber (PDPF)/Glass fiber (GF) as reinforcement and vinylester resin (VE). In order to improve the fiber/matrix adhesion, palm fibers were alkali treated with 5% NaOH solution for 24 h–72h. SEM and ATR-FTIR analysis revealed that the 48 h treatment of PDFP with NaOH solution led to rough fiber surface. Vacuum assisted resin transfer molding (VARTM) system was used to produce four hybrid composites (30PDPF/0GF, 20PDPF/10GF, 10PDPF/20GF and 0PDPF/30GF) where the weight ratio of total fiber reinforcement was kept 30%. The treated palm fibers were arranged as a nonwoven mat and placed between woven glass fabrics. Tensile, flexural, dynamic mechanical thermal analysis (DMTA), and thermogravimetric (TGA) were carried out to evaluate the performance of the hybrid composites. The flexural strength and modulus for pure PDPF composite were found to be 60 MPa and 3.87 GPa respectively. Addition of 20%wt glass fiber led an increase in the thermal stability and an enhancement in the tensile and flexural strength by 71.72% and 74.51%, respectively compared to pure PDPF composite. However, the incorporation of 10% of PDPF increases the damping factor from 0.2 for the composite glass/VE to 0.54 for the hybrid 10PDPF/20GF. According to findings of this study, PDPF based composites can be used as non-structural parts in automotive and boat industries.

scholarly journals Electrical Resistivity of Ni–Fe Wires Coated with Sn Using low-Pressure Chemical Vapor Deposition

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 317
Author(s):  
Jun-Hyun Kim ◽  
Jeong Geun Bak ◽  
Chang-Koo Kim
Keyword(s):  
Electrical Resistivity ◽  
Chemical Vapor Deposition ◽  
Electron Scattering ◽  
Vapor Deposition ◽  
Deposition Temperature ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Reaction Products ◽  
Irregular Shapes ◽  
Pressure Chemical

In this study, we demonstrated that the deposition of Sn on Ni–Fe wires using low-pressure chemical vapor deposition (LPCVD) can be used to control the electrical resistivity of the wires. Furthermore, the effect of the deposition temperature on the resistivity of the Ni–Fe wires was investigated. The resistivity of the Sn-deposited Ni–Fe wires was found to increase monotonically with the deposition temperature from 550 to 850 °C. Structural and morphological analyses revealed that electron scattering by Ni3Sn2 and Fe3Sn particulates, which were the reaction products of LPCVD of Sn on the surface of the Ni–Fe wires, was the cause of the resistivity increase. These coalesced particulates displayed irregular shapes with an increase in the deposition temperature, and their size increased with the deposition temperature. Owing to these particulate characteristics, the Sn content increased with the deposition temperature. Furthermore, the temperature dependency of the Sn content followed a pattern very similar to that of the resistivity, indicating that the atomic content of Sn directly affected the resistivity of the Ni–Fe wires.

Preparation and Curing Behaviour of N-Phenylmaleimide-Styrene-Maleic Anhydride Copolymer/o-Cresol Formaldehyde Epoxy Resin Composite System

2013 ◽  
Vol 646 ◽  
pp. 30-33
Author(s):  
Meng Yi Xu ◽  
Liang Zhou ◽  
Mei Juan Yin ◽  
Ai Qiong Kong
Keyword(s):  
Thermal Stability ◽  
Epoxy Resin ◽  
Composite System ◽  
High Dielectric Constant ◽  
Resin Composite ◽  
Weight Ratio ◽  
Dissipation Factor ◽  
Epoxy Resin Composite ◽  
Maleic Anhydride Copolymer ◽  
High Dielectric

Epoxy resin was used as the dielectric ink with some undesirable properties, such as a high dielectric constant, high dissipation factor and low thermal stability, In this paper, a NSMA/OCFEP.system were prepared, and the properties and curing behavior of the NSMA/ OCFEP system were intensively studied. Theoretical analysisi on the curing process of the system showed that when the weight ratio is 2.0:1.0, the best thermal stability is achieved.

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