Mechanical and electrical properties of graphene-coated polyimide yarns improved by nitrogen plasma pre-treatment

2021 ◽  
pp. 004051752098410
Author(s):  
Chuanli Su ◽  
Fangbing Lin ◽  
Jinhua Jiang ◽  
Huiqi Shao ◽  
Nanliang Chen
Keyword(s):  
Plasma Treatment ◽  
High Performance ◽  
Mechanical Performance ◽  
Fiber Material ◽  
Dip Coating ◽  
Nitrogen Plasma ◽  
Extreme Condition ◽  
Graphene Coating ◽  
Conductivity Property ◽  
Pre Treatment

One-dimensional high-performance yarns with excellent conductivity and flexibility are of considerable interest in the energy and aerospace industries. However, how to achieve highly conductivity, excellent flexibility, extreme condition durability and high mechanical performance in one fiber material is still a great challenge using economically viable materials and synthesis technologies. Herein, we report electrically conductive yarns (modified polyimide (M-PI)/reduced graphene oxide (RGO) yarns) consisting of RGO coated on the surface of nitrogen plasma M-PI yarns, which are fabricated by combining the N2 plasma pre-treatment and repeated dip-coating and reducing technique. N2 plasma treatment is used to roughen the surface of the PI yarn and introduce functional groups, contributing to improve wettability, which can provide a stronger adhesion of the graphene coating. The dip-coating and reducing process was repeated 10 times to enhance the loading mass of RGO on the PI yarns, then M-PI/RGO yarns with better conductivity property can be obtained. The effects of N2 plasma treatment power and time on the M-PI yarns and M-PI/RGO yarns are investigated and discussed. The results demonstrate that the graphene layer is uniformly and densely coated on the PI yarn when being treated at 200 W for 8 min, and the conductivity of the M-PI/RGO yarn reaches 1.51 × 102 S/m. The M-PI/RGO yarn combine the advantages of RGO and PI yarns, retaining the mechanical properties and thermal stability of PI yarn while exploiting the conductive property of RGO. In addition, the enhanced adhesion between the PI yarn and graphene coating endows the composite yarns with excellent fastness and superior flexibility. This work describes an environmentally friendly, controllable and facile method to develop flexible and conductive functional graphene-coated PI yarns with high-performance properties.

STABILIZATION OF TUFF MATERIAL BY ELECTROSPINNING OF LOW AREAL WEIGHT TPU VEIL MATERIAL

2021 ◽  
Author(s):  
JOSEPH DEITZEL ◽  
DIRK HEIDER ◽  
ROGER CRANE ◽  
TEKIN OZDEMIR
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Complex Geometry ◽  
Fiber Material ◽  
Short Fiber ◽  
Continuous Fiber ◽  
Forming Process ◽  
Fiber Volume ◽  
Carbon Fiber Material

The Tailored Universal Feedstock for Forming (TuFF) material is an aligned, discontinuous carbon fiber material with high fiber volume fraction up to 63% and mechanical performance equivalent to continuous fiber, unidirectional composites. The short fiber material allows at least 40% in-plane extension during processing enabling metal-like forming approaches simplifying composites manufacturing significantly. Traditionally, TuFF preforms are produced at areal weight (AW) of ~8 grams per square meter (gsm), stacked and impregnated with thermoset or thermoplastic polymer to create prepreg followed by curing/consolidation in an autoclave or stamp forming process resulting in high-performance structural parts. Here, the impregnated TuFF prepreg can be handled the same way as traditional continuous fiber prepreg. In contrast, to enable liquid composite molding (LCM) processes with TuFF material, the unimpregnated (dry) short fiber TuFF preforms must be stabilized for handling and preforming purposes. This paper details an electrospun veil approach as shown in Figure 1 to stabilize the individual TuFF sheets while maintaining the in-plane extensibility for complex geometry parts. Electrospun TPU fibers are applied onto the TuFF surface and then consolidated via a combination of heating and pressure, formingtrials were carried out using the stabilized preforms and composites werefabricated using LCM. Tensile tests show ~90-95% property retention versus theunstabilized baseline. The approach allows fabrication of stabilized TuFF fabricsfor the first time enabling the use of LCM processes for complex geometry parts.

scholarly journals Effect of Plasma-Treatment of Interleaved Thermoplastic Films on Delamination in Interlayer Fibre Hybrid Composite Laminates

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2834
Author(s):  
Salvatore Giacomo Marino ◽  
Florian Mayer ◽  
Alexander Bismarck ◽  
Gergely Czél
Keyword(s):  
Plasma Treatment ◽  
Composite Laminates ◽  
High Performance ◽  
Oxygen Plasma ◽  
Mechanical Performance ◽  
Hybrid Composites ◽  
Acrylonitrile Butadiene Styrene ◽  
Tensile Tests ◽  
Oxygen Plasma Treatment ◽  
Engineering Structures

Safe, light, and high-performance engineering structures may be generated by adopting composite materials with stable damage process (i.e., without catastrophic delamination). Interlayer hybrid composites may fail stably by suppressing catastrophic interlayer delamination. This paper provides a detailed analysis of delamination occurring in poly(acrylonitrile-butadiene-styrene) (ABS) or polystyrene (PS) film interleaved carbon-glass/epoxy hybrid composites. The ABS films toughened the interfaces of the hybrid laminates, generating materials with higher mode II interlaminar fracture toughness (GIIC), delamination stress (σdel), and eliminating the stress drops observed in the reference baseline material, i.e., without interleaf films, during tensile tests. Furthermore, stable behaviour was achieved by treating the ABS films in oxygen plasma. The mechanical performance (GIIC and σdel) of hybrid composites containing PS films, were initially reduced but increased after oxygen plasma treatment. The plasma treatment introduced O-C=O and O-C-O-O functional groups on the PS surfaces, enabling better epoxy/PS interactions. Microscopy analysis provided evidence of the toughening mechanisms, i.e., crack deflection, leading plasma-treated PS to stabilise delamination.

scholarly journals Polymer/Iron-Based Layered Double Hydroxides as Multifunctional Wound Dressings

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1130
Author(s):  
Mariana Pires Figueiredo ◽  
Ana Borrego-Sánchez ◽  
Fátima García-Villén ◽  
Dalila Miele ◽  
Silvia Rossi ◽  
...  
Keyword(s):  
Drug Release ◽  
High Performance ◽  
Mechanical Performance ◽  
Release Kinetics ◽  
Wound Dressings ◽  
In Vitro Drug Release ◽  
Improved Performance ◽  
Double Hydroxide ◽  
Double Hydroxides

This work presents the development of multifunctional therapeutic membranes based on a high-performance block copolymer scaffold formed by polyether (PE) and polyamide (PA) units (known as PEBA) and layered double hydroxide (LDH) biomaterials, with the aim to study their uses as wound dressings. Two LDH layer compositions were employed containing Mg2+ or Zn2+, Fe3+ and Al3+ cations, intercalated with chloride anions, abbreviated as Mg-Cl or Zn-Cl, or intercalated with naproxenate (NAP) anions, abbreviated as Mg-NAP or Zn-NAP. Membranes were structurally and physically characterized, and the in vitro drug release kinetics and cytotoxicity assessed. PEBA-loading NaNAP salt particles were also prepared for comparison. Intercalated NAP anions improved LDH–polymer interaction, resulting in membranes with greater mechanical performance compared to the polymer only or to the membranes containing the Cl-LDHs. Drug release (in saline solution) was sustained for at least 8 h for all samples and release kinetics could be modulated: a slower, an intermediate and a faster NAP release were observed from membranes containing Zn-NAP, NaNAP and Mg-NAP particles, respectively. In general, cell viability was higher in the presence of Mg-LDH and the membranes presented improved performance in comparison with the powdered samples. PEBA containing Mg-NAP sample stood out among all membranes in all the evaluated aspects, thus being considered a great candidate for application as multifunctional therapeutic dressings.

Study of Transcrystallization in Polymer Composites

1989 ◽  
Vol 170 ◽  
Author(s):  
Benjamin S. Hsiao ◽  
J. H. Eric
Keyword(s):  
Thermal Conductivity ◽  
Free Energy ◽  
Carbon Fiber ◽  
Plasma Treatment ◽  
Polymer Composites ◽  
High Performance ◽  
Interfacial Strength ◽  
Fiber Surface ◽  
Semicrystalline Polymers ◽  
First Case

AbstractTranscrystallization of semicrystalline polymers, such as PEEK, PEKK and PPS, in high performance composites has been investigated. It is found that PPDT aramid fiber and pitch-based carbon fiber induce a transcrystalline interphase in all three polymers, whereas in PAN-based carbon fiber and glass fiber systems, transcrystallization occurs only under specific circumstances. Epitaxy is used to explain the surface-induced transcrystalline interphase in the first case. In the latter case, transcrystallization is probably not due to epitaxy, but may be attributed to the thermal conductivity mismatch. Plasma treatment on the fiber surface showed a negligible effect on inducing transcrystallization, implying that surface-free energy was not important. A microdebonding test was adopted to evaluate the interfacial strength between the fiber and matrix. Our preliminary results did not reveal any effect on the fiber/matrix interfacial strength of transcrystallinity.

Comparative studies of nitrogen plasma and argon plasma treatment on the strength of PBO fibre reinforced high-temperature resistant thermoplastic composite

2021 ◽  
pp. 095400832098729
Author(s):  
K Sudheendra ◽  
Jennifer Vinodhini ◽  
M Govindaraju ◽  
Shantanu Bhowmik
Keyword(s):  
Contact Angle ◽  
High Temperature ◽  
Plasma Treatment ◽  
Sessile Drop ◽  
Dynamic Contact Angle ◽  
Argon Plasma ◽  
Film Surface ◽  
Fibre Surface ◽  
Nitrogen Plasma ◽  
Thermoplastic Composite

The study involves the processing of a novel poly [1, 4-phenylene-cis-benzobisoxazole] (PBO) fibre reinforced high-temperature thermoplastic composite with polyaryletherketone (PAEK) as the matrix. The PBO fibre and the PAEK film surface was modified using the method of argon and nitrogen plasma treatment. The investigation primarily focuses on evaluating the tensile properties of the fabricated laminates and correlating it with the effect of plasma treatment, surface characteristics, and its fracture surface. A 5% decrease in tensile strength was observed post argon plasma treatment while a 27% increase in strength was observed post nitrogen plasma treatment. The morphology of the failure surface was investigated by scanning electron microscopy and an interfacial failure was observed. Furthermore, the effect of plasma on the wettability of PBO fibres and PAEK film surface was confirmed by the Dynamic Contact Angle analysis and sessile drop method respectively. FTIR spectral analysis was done to investigate the effect of plasma treatment on the chemical structure on the surface. The results of the wettability study showed that the argon plasma treatment of the fibre surface increased its hydrophobicity while nitrogen plasma treatment resulted in the reduction of contact angle.

scholarly journals Durability Study on High-Performance Fiber-Reinforced Mortar under Simulated Wastewater Pipeline Environment

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3781
Author(s):  
Tianyu Wang ◽  
Yahong Zhao ◽  
Baosong Ma ◽  
Cong Zeng
Keyword(s):  
Mass Loss ◽  
Pore Volume ◽  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Economic Losses ◽  
Structural Deterioration ◽  
Simulated Wastewater ◽  
Corrosive Environments

The acid–alkaline-inducd corrosive environments inside wastewater concrete pipelines cause concrete structural deterioration and substantial economic losses all over the world. High-performance concrete/mortar (HPC) was designed to have better resistance to corrosive environments, with enhanced service life. However, the durability of HPC in wastewater pipeline environments has rarely been studied. A high-performance mortar mixture (M) reinforced by supplemental materials (including fly ash and silica fume) and polyvinyl alcohol (PVA) fibers, together with a mortar mixture (P) consisting of cement, sand and water with similar mechanical performance, were both designed and exposed to simulated wastewater pipeline environments. The visual appearance, dimensional variation, mass loss, mechanical properties, permeable pore volume, and microstructure of the specimens were measured during the corrosion cycles. More severe deterioration was observed when the alkaline environment was introduced into the corrosion cycles. Test results showed that the M specimens had less permeable pore volume, better dimensional stability, and denser microstructure than the P specimens under acid–alkaline-induced corrosive environments. The mass-loss rates of the M specimens were 66.1–77.2% of the P specimens after 12 corrosion cycles. The compressive strength of the M specimens was 25.5–37.3% higher than the P specimens after 12 cycles under corrosive environments. Hence, the high-performance mortar examined in this study was considered superior to traditional cementitious materials for wastewater pipeline construction and rehabilitation.

scholarly journals Demonstration of epitaxial growth of strain-relaxed GaN films on graphene/SiC substrates for long wavelength light-emitting diodes

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ye Yu ◽  
Tao Wang ◽  
Xiufang Chen ◽  
Lidong Zhang ◽  
Yang Wang ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Light Emitting Diodes ◽  
Nitrogen Plasma ◽  
Biaxial Stress ◽  
Organic Chemical ◽  
Graphene Surface ◽  
Light Emitting ◽  
Long Wavelength ◽  
Pre Treatment ◽  
Wavelength Light

AbstractStrain modulation is crucial for heteroepitaxy such as GaN on foreign substrates. Here, the epitaxy of strain-relaxed GaN films on graphene/SiC substrates by metal-organic chemical vapor deposition is demonstrated. Graphene was directly prepared on SiC substrates by thermal decomposition. Its pre-treatment with nitrogen-plasma can introduce C–N dangling bonds, which provides nucleation sites for subsequent epitaxial growth. The scanning transmission electron microscopy measurements confirm that part of graphene surface was etched by nitrogen-plasma. We study the growth behavior on different areas of graphene surface after pre-treatment, and propose a growth model to explain the epitaxial growth mechanism of GaN films on graphene. Significantly, graphene is found to be effective to reduce the biaxial stress in GaN films and the strain relaxation improves indium-atom incorporation in InGaN/GaN multiple quantum wells (MQWs) active region, which results in the obvious red-shift of light-emitting wavelength of InGaN/GaN MQWs. This work opens up a new way for the fabrication of GaN-based long wavelength light-emitting diodes.

Effect of Ions Substitution on Nanospace La-Fe-O Catalytic Properties for Simultaneous Removal of NOx and Soot

2013 ◽  
Vol 740 ◽  
pp. 565-569
Author(s):  
Xiao Xiao Meng ◽  
Mao Xiang Jing ◽  
Feng Lin He ◽  
Xiang Qian Shen
Keyword(s):  
High Performance ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Dip Coating ◽  
Exhaust Emission ◽  
Simultaneous Removal ◽  
Microstructural Characteristics ◽  
Coating Method ◽  
Citrate Gel Process ◽  
Dip Coating Method

The catalysts La0.8K0.2FeO3(LKFO), La0.8K0.2Fe0.7Mn0.3O3(LKFMO) and La0.8K0.2Fe0.67Mn0.3Pt0.03O3(LKFMPO) were prepared by the citrate-gel process and the catalyst-coated honeycomb ceramic devices were prepared by the citrate-gel assisted dip-coating method. All the catalysts have a high performance on the simultaneous removal of NOxand soot at a temperature range of 200 to 400°C under the practical diesel exhaust emission. The obvious catalytic improvement is largely due to the effects of ions substitution, pore structure and microstructural characteristics of the catalysts. The catalytic performance order is LKFMPO > LKFMO > LKFO. Among them the LKFMPO catalyst shows the best catalytic properties, especially in the removal of NOx, with a maximum conversion rate of NOx(21.2%).

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