Influence of aggressive environmental aging on mechanical and thermo-mechanical properties of Ultra Violet (UV) Cured in Place Pipe liners

Ultraviolet light cured-in-place pipe is a popular trenchless rehabilitation technology used to repair existing buried pipelines without soil excavation. A polymer composite liner is manufactured directly in the field. After curing is complete, the new liner is placed in service to convey flowing water. Long-term water exposure has the potential to degrade the fiber reinforced cured-in-place pipe liners. Like other composites, liner hygrothermal stability could be a major challenge, especially for undercured materials. The objective of this study was to investigate the effect of aggressive environmental conditions such as water, salt solution, and simulated concrete pore solution at 50℃ on cured-in-place pipe liner mechanical and thermo-mechanical performance. Liners were exposed to aqueous solutions ranging from a typical exposure environment to a very aggressive alkaline environment. Cured-in-place pipe liner samples were collected from New York storm sewer installation sites. Specimens were assessed for the degree of curing as determined by differential scanning calorimetry and TGA. Samples were then immersed in aforementioned solutions for investigating the stability of the liners as a function of degree of cure. Both interlaminar shear strength and thermo-mechanical properties significantly differed based on the degree of cure. Cured-in-place pipe liner mechanical and thermo-mechanical properties were significantly impacted by water, salt, and pore solutions exposure. Long-term exposure to salt and alkaline environments may have a detrimental effect on the performance of cured-in-place pipe liners and desires additional scrutiny.

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Electrospun PCL Patches with Controlled Fiber Morphology and Mechanical Performance for Skin Moisturization via Long-Term Release of Hemp Oil for Atopic Dermatitis

Membranes ◽

10.3390/membranes11010026 ◽

2020 ◽

Vol 11 (1) ◽

pp. 26

Author(s):

Sara Metwally ◽

Daniel P. Ura ◽

Zuzanna J. Krysiak ◽

Łukasz Kaniuk ◽

Piotr K. Szewczyk ◽

...

Keyword(s):

Mechanical Properties ◽

Atopic Dermatitis ◽

Mechanical Performance ◽

Antibacterial Properties ◽

Skin Condition ◽

Fiber Morphology ◽

Suitable Material ◽

Hemp Oil ◽

Skin Moisture

Atopic dermatitis (AD) is a chronic, inflammatory skin condition, caused by wide genetic, environmental, or immunologic factors. AD is very common in children but can occur at any age. The lack of long-term treatments forces the development of new strategies for skin regeneration. Polycaprolactone (PCL) is a well-developed, tissue-compatible biomaterial showing also good mechanical properties. In our study, we designed the electrospun PCL patches with controlled architecture and topography for long-term release in time. Hemp oil shows anti-inflammatory and antibacterial properties, increasing also the skin moisture without clogging the pores. It can be used as an alternative cure for patients that do not respond to traditional treatments. In the study, we tested the mechanical properties of PCL fibers, and the hemp oil spreading together with the release in time measured on skin model and human skin. The PCL membranes are suitable material as patches or bandages, characterized by good mechanical properties and high permeability. Importantly, PCL patches showed release of hemp oil up to 55% within 6 h, increasing also the skin moisture up to 25%. Our results confirmed that electrospun PCL patches are great material as oil carriers indicating a high potential to be used as skin patches for AD skin treatment.

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Effect of toughened polyamide-coated carbon fiber fabric on the mechanical performance and fracture toughness of CFRP

Journal of Composite Materials ◽

10.1177/0021998321999458 ◽

2021 ◽

pp. 002199832199945

Author(s):

Jong H Eun ◽

Bo K Choi ◽

Sun M Sung ◽

Min S Kim ◽

Joon S Lee

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Photoelectron Spectroscopy ◽

Mechanical Performance ◽

Epoxy Composites ◽

Scanning Calorimetry ◽

Internal Damage ◽

Impact Tests ◽

Flexural Tests ◽

The Impact

In this study, carbon/epoxy composites were manufactured by coating with a polyamide at different weight percentages (5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%) to improve their impact resistance and fracture toughness. The chemical reaction between the polyamide and epoxy resin were examined by fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy. The mechanical properties and fracture toughness of the carbon/epoxy composites were analyzed. The mechanical properties of the carbon/epoxy composites, such as transverse flexural tests, longitudinal flexural tests, and impact tests, were investigated. After the impact tests, an ultrasonic C-scan was performed to reveal the internal damage area. The interlaminar fracture toughness of the carbon/epoxy composites was measured using a mode I test. The critical energy release rates were increased by 77% compared to the virgin carbon/epoxy composites. The surface morphology of the fractured surface was observed. The toughening mechanism of the carbon/epoxy composites was suggested based on the confirmed experimental data.

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Initial properties and ageing behaviour of pineapple leaf and palm fibre as reinforcement for polypropylene

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705715598356 ◽

2016 ◽

Vol 30 (2) ◽

pp. 174-195 ◽

Cited By ~ 4

Author(s):

Rungsima Chollakup ◽

Haroutioun Askanian ◽

Florence Delor-Jestin

Keyword(s):

Mechanical Properties ◽

Cost Effective ◽

Tensile Tests ◽

Natural Fibre ◽

Thermal Ageing ◽

Second Step ◽

Scanning Calorimetry ◽

Ultraviolet Exposure ◽

Palm Fibre

In the furniture, automotive and contruction industries, there is increased demand for cost-effective and lightweight biocomposites. The objective of this work was to develop new natural fibre-based composites with specific properties. Palm and pineapple leaf fibres were chosen in association with polypropylene (PP). The first step was to investigate the effect of these natural fibres as reinforcement for PP. The evolution of chemical structure and crystallinity was proposed with infrared spectroscopy measurements and differential scanning calorimetry thermograms, respectively. The assessments of mechanical properties with tensile tests and melt viscoelastic behaviour were also investigated. The study enabled to distinguish the influence of fibre content. The second step in our work was to assess the composite durability after ultraviolet exposure or thermal ageing. The oxidation level was calculated. The long-term evolution of thermal and mechanical properties was also proposed. As a result, the PP/pineapple leaf composite revealed a promising biocomposite.

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The Influence of Sub-Zero Conditions on the Mechanical Properties of Polylactide-Based Composites

Materials ◽

10.3390/ma13245789 ◽

2020 ◽

Vol 13 (24) ◽

pp. 5789

Author(s):

Olga Mysiukiewicz ◽

Mateusz Barczewski ◽

Arkadiusz Kloziński

Keyword(s):

Mechanical Properties ◽

Room Temperature ◽

Mechanical Performance ◽

Mechanical Analysis ◽

Uniaxial Tensile ◽

Uniaxial Tensile Test ◽

Mechanical And Thermal Properties ◽

Scanning Calorimetry ◽

Linseed Cake ◽

Static Mechanical

Polylactide-based composites filled with waste fillers due to their sustainability are a subject of many current papers, in which their structural, mechanical, and thermal properties are evaluated. However, few studies focus on their behavior in low temperatures. In this paper, dynamic and quasi-static mechanical properties of polylactide-based composites filled with 10 wt% of linseed cake (a by-product of mechanical oil extraction from linseed) were evaluated at room temperature and at −40 °C by means of dynamic mechanical analysis (DMA), Charpy’s impact strength test and uniaxial tensile test. It was found that the effect of plasticization provided by the oil contained in the filler at room temperature is significantly reduced in sub-zero conditions due to solidification of the oil around −18 °C, as it was shown by differential scanning calorimetry (DSC) and DMA, but the overall mechanical performance of the polylactide-based composites was sufficient to enable their use in low-temperature applications.

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Effect of Kenaf Alkalization Treatment on Morphological and Mechanical Properties of Epoxy/Silica/Kenaf Composite

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.35.22743 ◽

2018 ◽

Vol 7 (4.35) ◽

pp. 258 ◽

Cited By ~ 9

Author(s):

Che Nor Aiza Jaafar ◽

Muhammad Asyraf Muhammad Rizal ◽

Ismail Zainol

Keyword(s):

Mechanical Properties ◽

Sodium Hydroxide ◽

Mechanical Performance ◽

Flexural Modulus ◽

Charpy Impact ◽

Charpy Impact Test ◽

Curing Temperature ◽

Curing Process ◽

Scanning Calorimetry ◽

Kenaf Fiber

The mechanical performance of silica modified epoxy at various concentration of sodium hydroxide for surface treatment of multi-axial kenaf has been analyzed. Epoxy resin with amine hardener was modified with silica powder at 20 phr and toughened by treated kenaf fiber that immerses in various concentrations of sodium hydroxide (NaOH) ranging from 0% to 9% of weight. The composite was analyzed through differential scanning calorimetry (DSC) to ensure complete curing process. The mechanical properties of the composites were analyzed through flexural test, Charpy impact test and DSC to ensure the complete curing process. DSC analysis results show epoxy sample was completely cured at above 73°C that verifies the curing temperature for preparation for the composite. Hence, 3% NaOH treated composite exhibits the best mechanical properties, with 10.6 kJ/m2 of impact strength, 54.1 MPa of flexural strength and 3.5 GPa of flexural modulus. It is due to the improvement of fiber-matrix compatibility. Analysis by SEM also revealed that a cleaner surface of kenaf fiber treated at 3% NaOH shown cleaner surface, thus, in turn, improve surface interaction between fiber and matrix of the composite. The composites produced in this work has high potential to be used in automotive and domestics appliances.

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Mechanical performance of HMA-2 modified with purified and unpurified carbon nanotubes and nanofibers

Ingeniería e Investigación ◽

10.15446/ing.investig.v37n2.58649 ◽

2017 ◽

Vol 37 (2) ◽

pp. 99-106

Author(s):

Mario Rodrigo Rubio ◽

Duván Julián Martínez ◽

Carlos Enrique Daza ◽

Fredy Alberto Reyes

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Elastic Modulus ◽

Mechanical Performance ◽

Resilient Modulus ◽

Type Ii ◽

Dynamic Characterization ◽

Traffic Loads ◽

Nickel Copper

The present study evaluates the mechanical performance of a Hot Mix Asphalt – Type II (HMA-2) modified with carbon nanotubes and carbon nanofibers (CNTF). CNTF were made by means the Catalytic Vapor Deposition (CVD) technique at 700° C using a Nickel, Copper and Aluminum (NiCuAl) catalyst with a Cu/Ni molar relation of 0,33. In order to properly assess HMA-2 performance, three different mixtures were analyzed: 1) HMA-2 modified with purified CNTF; 2) HMA-2 modified with non-purified CNTF and, 3) a Conventional HMA-2 (control). Samples manufactured in accordance with the Marshall Mix Design were tested in the laboratory to study rutting, resilient modulus (Mr) and fatigue. In addition to the aforementioned dynamic characterization, the effect of CNTF purification on the asphalt mixture’s mechanical properties was analyzed. In short, a comparative study was designed to determine whether or not CNTF should be purified before introduction into the HMA-2. This investigation responds to the growing demand for economical materials capable of withstanding traffic loads while simultaneously enhancing pavement durability and mechanical properties. Although purified CNTF increased HMA-2 stiffness and elastic modulus, non-purified CNTF increased the asphalt mixture’s elastic modulus without considerable increases in stiffness. Thus, the latter modification is deemed to help address fatiguerelated issues and improve the long-term durability of flexible pavements.

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The mechanical performance of the laminated aluminum-epoxy/glass fiber composites containing halloysite nanotubes: An experimental investigation

Journal of Industrial Textiles ◽

10.1177/1528083720960735 ◽

2020 ◽

pp. 152808372096073

Author(s):

Marwa A Abd El-baky ◽

Mohamed A Attia

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Tensile Strain ◽

Mechanical Performance ◽

Flexural Modulus ◽

Halloysite Nanotubes ◽

Interlaminar Shear Strength ◽

Plane Shear ◽

Bearing Strength ◽

Interlaminar Shear

In this study, the effect of different weight percentages (wt. %) of halloysite nanotubes (HNTs) on the mechanical performance of glass laminate aluminum (Al) reinforced epoxy (GLARE) was investigated. GLARE (3/2) laminates with quasi-isotropic lay-up, [Al/[(0°/90°)/(45°/−45°)]s/Al/[(0°/90°)/(45°/−45°)]s/Al] filled with 0, 0.25, 0.5, 1, 2 and 3 wt. % of HNTs were fabricated using hand lay-up followed by compression molding. To explore the effect of HNTs on the mechanical properties, tensile, flexural, in-plane shear, interlaminar shear, bearing and impact tests were conducted. Results demonstrated that the inclusion of 1 wt. % of HNTs into GLARE leads to maximum improvements of 35.67, 8.50, 28.85, 50.47, 50.27, 30.43, 23.73, 72.08, 30.74, and 51.52% in tensile strength, tensile strain, Young's modulus, modulus of toughness, flexural strength, flexural strain, in-plane shear strength, interlaminar shear strength, bearing strength, and impact strength, respectively, compared to pristine GLARE. An enhancement of 38.89% in the flexural modulus was attained by adding 0.5 wt. % of HNTs to GLARE compared to pristine GLARE. The tensile strength, tensile strain, modulus of toughness, flexural strength, flexural modulus, flexural strain, in-plane shear strength, and interlaminar shear strength of GLARE filled with 3 wt. % of HNTs are 0.91, 0.88, 0.91, 0.91, 0.71, 0.83, 0.85, and 0.91 times those of the original GLARE. But Young’s modulus, bearing strength, and impact strength are 1.10, 1.15 and 1.20 times those of the original GLARE. To investigate the fracture mechanism, field emission scanning electron microscope (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX) were used. The microscopic images revealed that adding HNTs lead to the improvement in the interaction between the epoxy matrix and glass fiber, thereby improving the mechanical properties.

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Effect of Long-term Service on Microstructure and Mechanical Properties of NiCrMoV Steel Welded Joint

MATEC Web of Conferences ◽

10.1051/matecconf/201926903012 ◽

2019 ◽

Vol 269 ◽

pp. 03012

Author(s):

Manjie Fan ◽

Peng Wang ◽

Qixing Sun

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Welded Joint ◽

Welding Process ◽

Turbine Rotor ◽

Optical Microscope ◽

Turbine Plant ◽

Nicrmov Steel ◽

Service Conditions

The influences of prolonged service on microstructure evolution and mechanical properties of NiCrMoV steel welded joint in an ex-service welded steam turbine rotor were investigated. The welded rotor had been operated for 22 years since 1991. The specimens for the present study were taken from the location where the temperature was as high as 230°C. The optical microscope (OM) showed that even after long-term service, there were no obvious defects such as creep cavities, cracks found in the microstructure of the whole welded joint after such a long term service. The microstructure was uniform and no obvious grain coarsening was observed. However some black strip-shaped zones were found in base metal and heat affected zone (HAZ). The distribution of hardness across the welded joints showed no anomalies. The results of tensile strength and fracture toughness tests demonstrated that the welded joint still exhibited excellent. Mechanical performance after long-term service, indicating that the welding process of Shanghai Turbine Plant was reliable and stable. With the improvement of forging and welding qualities and improved heat treatment furnaces with more accurately controlled temperature, it is reasonable to assume that the current large low-pressure (LP) welded rotors are definitely safe to operate under similar service conditions for designed life.

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Cure kinetics and autoclave-pressure dependence on physical and mechanical properties of woven carbon/epoxy 8552S/AS4 composite laminates

Polymers and Polymer Composites ◽

10.1177/09673911211028413 ◽

2021 ◽

pp. 096739112110284

Author(s):

Abd Baghad ◽

Khalil El Mabrouk ◽

Sébastien Vaudreuil ◽

Khalid Nouneh

Keyword(s):

Mechanical Properties ◽

Composite Laminates ◽

Treatment Time ◽

Physical And Mechanical Properties ◽

Cure Kinetics ◽

Void Content ◽

Scanning Calorimetry ◽

Microstructure And Mechanical Properties ◽

The Matrix ◽

Interlaminar Shear

The final mechanical properties of composite laminates are highly dependent on their curing cycles in the autoclave. During this cycle, the temperature, pressure, vacuum, and treatment time will influence the quality of manufactured parts. The void content is considered the most harmful defects in carbon/epoxy laminates since they weaken the matrix-dominated mechanical properties such as interlaminar shear and compressive strengths. In the present work, differential scanning calorimetry is used to characterize the influence of time/temperature on the behavior of the epoxy resin. Then, a series of [0/90/−45/+45]s laminates composites are autoclave-cured under various applied pressures to evaluate their impact on microstructure and mechanical properties. The interlaminar shear modulus, interlaminar shear strength, laminate compressive modulus, and laminate compressive strength at room and operating engine temperature were measured. The correlation between microstructure and mechanical properties was also studied. The mechanical properties of manufactured carbon/epoxy laminates are found to be dependent on pressure and microstructure. These results are explored to establish an optimal autoclave pressure route that would minimize porosity without counterbalancing mechanical properties.

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PEEK filament characteristics before and after extrusion within fused filament fabrication process

Journal of Materials Science ◽

10.1007/s10853-021-06652-0 ◽

2022 ◽

Author(s):

Cleiton André Comelli ◽

Richard Davies ◽

HenkJan van der Pol ◽

Oana Ghita

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Extrusion Process ◽

X Ray Diffraction ◽

Fused Filament Fabrication ◽

Scanning Calorimetry ◽

Fast Scanning Calorimetry ◽

Transmission Electron ◽

Before And After ◽

History Of

AbstractThe heating and extrusion process in fused filament fabrication (FFF) is significantly shorter than the conventional extrusion process where longer heating times and significant pressure are applied. For this reason, it is important to understand whether the crystal history of the feedstock is fully erased through the FFF process and whether the FFF process can be tailored further by engineering the crystallization of the feedstock filaments. In this context, a methodology for evaluating the influence of morphology and mechanical properties on different feedstock and extruded filaments is proposed. Filaments with three different PEEK 450G crystalline structures (standard crystallinity, drawn filament and amorphous filament) were selected and evaluated, before and after free extrusion. The resulting morphology, crystallinity and mechanical properties of the extruded filaments were compared against the feedstock properties. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential and fast scanning calorimetry (DSC/FDSC) and tensile test were the techniques used to evaluate the materials. The results showed clear differences in the properties of the feedstock materials, while the analysis of the extruded filaments points to a homogenization of the resulting material producing mostly similar mechanical properties. However, the use of the drawn filament highlighted a statistically significant improvement in crystallinity and mechanical performance, especially in strain values. This conclusion suggests the innovative possibility of improving the quality of manufactured parts by tailoring the microstructure of the feedstock material used in the FFF process. Graphical abstract

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