scholarly journals Superficial morphology and mechanical properties of in vivo aged orthodontic ligatures

2013 ◽  
Vol 18 (3) ◽  
pp. 107-112 ◽  
Author(s):  
Glaucio Serra Guimarães ◽  
Liliane Siqueira de Morais ◽  
Margareth Maria Gomes de Souza ◽  
Carlos Nelson Elias
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Strength Test ◽  
Test Method ◽  
Test Results ◽  
Tensile Strength Test ◽  
Oral Environment ◽  
Scanning Electron

INTRODUCTION: The degradation of elastic ligatures in the oral environment results in the need of periodic replacement to maintain the optimal force during the orthodontic treatment. The purpose of this study was to perform a clinical prospective randomized study of the degradation of orthodontic elastomeric ligatures in the oral environment by scanning electron microscopy (SEM) and tensile strength test. METHOD: Two hundred elastic ligatures were randomly selected and placed around the brackets of 5 volunteers and removed in groups of 10, at different times (1, 2, 3, and 4 weeks). The control group was performed by another fifty ligatures which were not submitted to the oral degradation. The analyses were done by scanning electron microscopy (SEM) and strength mechanical test. RESULTS: The tensile strength test results showed reduction in the ultimate strength values after four weeks ageing in the oral environment and no statistical difference in the yield strength values (p < 0.05). The orthodontic elastomeric ligatures surface was significantly degraded in the oral cavity after four weeks. The elastomeric degradation began in the first week when the increase in the roughness could be detected just in some areas. Afterwards, the surface became gradually rougher and, after 4 weeks, it was totally rough with some crack areas. CONCLUSIONS: The elastic ligatures aged in the oral environment showed higher superficial degradation and lower loss of mechanical properties after the maximum experimental period.

scholarly journals Analysis of PLA Composite Filaments Reinforced with Lignin and Polymerised-Lignin-Treated NFC

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2174
Author(s):  
Diana Gregor-Svetec ◽  
Mirjam Leskovšek ◽  
Blaž Leskovar ◽  
Urška Stanković Elesini ◽  
Urška Vrabič-Brodnjak
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Glassy State ◽  
Nanofibrillated Cellulose ◽  
Dynamic Mechanical Properties ◽  
Initial Modulus ◽  
Surface Modified ◽  
Scanning Electron

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.

scholarly journals Effect of Annealing Process on the Mechanical Properties of X70 Pipeline Steel

2018 ◽  
Vol 186 ◽  
pp. 02001
Author(s):  
Teng-wei Zhu ◽  
Cheng-liang Miao ◽  
Zheng Cheng ◽  
Zhipeng Wang ◽  
Yang Cui ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Annealing Temperature ◽  
Pipeline Steel ◽  
Annealing Process ◽  
X70 Pipeline Steel ◽  
Grain Sizes ◽  
Scanning Electron

The influence of the mechanical properties of X70 pipeline steel under different annealing temperature was studied. The corresponding microstructure was investigated by the Field Emission Scanning Electron Microscopy. The results showed that the yield strength and the tensile strength both experienced from rise to decline with the increase of annealing temperature. The grain sizes were coarse and a large amount of cementite precipitated due to preserving temperature above 550 °, which induced matrix fragmentation and deteriorate the -10 ° DWTT Toughness. There were little changes on the microstructure and mechanical properties when the annealing temperature was under 500 °.

Analysis of Applicability of the Hollow Carbon Fibres for Self-Repairing Composites

2012 ◽  
Vol 729 ◽  
pp. 246-251 ◽  
Author(s):  
Sándor Kling ◽  
Tibor Czigány
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Tensile Tests ◽  
Single Fibre ◽  
Internal Diameter ◽  
Carbon Fibres ◽  
Hollow Carbon ◽  
Scanning Electron

The geometry and mechanical properties of solid and hollow carbon fibres were investigated by light-and scanning electron microscopy, and by single fibre tensile tests. The hollowness factor of fibres was determined by their external and internal diameter. The tensile strength was determined by single fibre tensile break tests. It was shown that the bigger the diameter of the fibres the lower the mechanical properties is. It was found that the hollow carbon fibres are suitable for preparation of a self-repairing composite with the advantage over other solutions because of their geometrical and mechanical properties.

Microstructures and Mechanical Properties of Melt Spinning Spandex

2014 ◽  
Vol 1048 ◽  
pp. 36-40
Author(s):  
Wei Lai Chen ◽  
Lin Yan Wan ◽  
Hong Qin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Melt Spinning ◽  
Scanning Electron

Microstructures and mechanical properties of melt spinning spandex were studied in this article.Cross section and longitudinal surface were observed and analyzed by JSM-5610LV scanning electron microscopy. Q2000 DSC differential scanning calorimeter was used to test the glass transition temperature and melting temperature which indicated glass transition temperature is about 44°C and melting temperature is about 200°C. We employed JSM-5610LV scanning electron microscopy to observe adhesion of melt spinning spandex with nylon filament after different time and temperature processing. It concluded that after 150°C90s、160°C60s、160°C90s、170°C30s heat treatment, the adhesive of melt spinning spandex with nylon is good. At the same time,tensile strength and elastic properties of melt spinning spandex which was processed under different time and temperature were tested, tensile strength and elastic recovery of melt spinning spandex after160°C 90s heat treatment is the best.

Effect of Nanocellulose Loading on Tensile Properties of Nitrile Rubber

2017 ◽  
Vol 264 ◽  
pp. 112-115
Author(s):  
Erfan Suryani Abdul Rashid ◽  
Wageeh Abdulhadi Yehye ◽  
Nurhidayatullaili Muhd Julkapli ◽  
Sharifah Bee O.A. Abdul Hamid
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Tensile Test ◽  
Tensile Properties ◽  
Mechanical Performance ◽  
Butadiene Rubber ◽  
Fracture Surfaces ◽  
Scanning Electron

Nanocellulose (NCC) is incorporated into nitrile butadiene rubber (NBR) latex with the composition 0 to 5 phr using dipping method. Mechanical properties of NBR/NCC composites using tensile test was used to characterize their mechanical performance and the fracture surfaces post tensile test were studied. The tensile strength of NBR/NCC composites increase significantly with the addition of nanocellulose. This could be anticipated due to the presence of Van der Waals interaction between hydrophilic natures of nanocellulose with hydrophobic of NBR consequently limits the tearing propagation. The result was supported with the fracture surfaces morphology viewed under Fourier Emission Scanning Electron Microscopy (FESEM).

scholarly journals Simultaneous Improvement in the Tensile and Impact Strength of Polypropylene Reinforced by Graphene

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Li Juan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Fracture Surface ◽  
Impact Strength ◽  
Melt Blending ◽  
Elongation At Break ◽  
Morphological Behavior ◽  
Scanning Electron

The nanocomposites of polypropylene (PP)/graphene were prepared by melt blending. The effects of the dosage of graphene on the flow and mechanical properties of the nanocomposites were investigated. The morphologies of fracture surfaces were characterized through scanning electron microscopy (SEM). The graphene simultaneous enhanced tensile and impact properties of nanocomposites. A 3.22% increase in tensile strength, 39.8% increase in elongation at break, and 26.7% increase in impact strength are achieved by addition of only 1 wt.% of graphene loading. The morphological behavior indicates the fracture surface of PP/graphene is more rough than that of pure PP.

Effect of Hydroentanglement on Structures and Properties of Wet-Laid Paper Sheets

2019 ◽  
Vol 821 ◽  
pp. 201-205
Author(s):  
Chao Deng ◽  
Xian Gyu Jin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Air Permeability ◽  
Water Absorbency ◽  
Structures And Properties ◽  
Before And After ◽  
Properties Of Materials ◽  
Scanning Electron

In this work, pulp/lyocell wet-laid paper sheets have been consolidated by hydroentanglement techniques. Scanning electron microscopy has been used to evaluate the structures of wet-laid paper sheets before and after hydroentanglement. Wet tensile strength along longitudinal (preferential) and transverse directions show the effect of hydroentanglement techniques on the mechanical properties of wet-laid paper sheets. In addition, the air permeability and water absorbency properties of materials have been evaluated. The results show that the structures of wet-laid paper sheets become fluffy and fiber entanglements increase after consolidation. The wet tensile strength values of wet-laid paper sheets at the longitudinal and transverse directions are increased by 109.0% and 78.7%, respectively after hydroentanglement. The air permeability and water absorbency of wet-laid paper sheets are increased by 957.6% and 137.0%.

Fracture Characteristics of Vacuum Diffusion Bonded TA2 Titanium to 1Cr18Ni9Ti Stainless Steel Joint with Nb+Ni Interlayers

2009 ◽  
Vol 620-622 ◽  
pp. 399-402 ◽  
Author(s):  
Jing Long Li ◽  
Li Peng Huo ◽  
Fu Sheng Zhang ◽  
Jiang Tao Xiong ◽  
Wen Ya Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Electron Microscope ◽  
Intermetallic Compound ◽  
Pure Titanium ◽  
Strength Test ◽  
Fracture Characteristics ◽  
Tensile Strength Test ◽  
Scanning Electron

Pure titanium TA2 and 1Cr18Ni9Ti stainless steel were vacuum diffusion bonded using Nb + Ni foils as interlayers, where Nb foil was adjacent to TA2 and Ni foil adjacent to 1Cr18Ni9Ti. The samples were heated to a temperature of 800°C at a pressure of 10 MPa and kept for 60 min, and then to a temperature of 900°C at a pressure of 1 MPa and kept for 30 min. The mechanical properties of the joint were characterized by the tensile strength test. The average tensile strength of the joints was about 398 MPa. The fracture characteristics of the joint were investigated using scanning electron microscope. The fracture of tensile test samples occurred in the Ni3Nb intermetallic compound formed in the interlayers.

Effects of Rare Earth on Microstructure and Mechanical Properties of Al-3.2Mg Alloy

2015 ◽  
Vol 817 ◽  
pp. 192-197
Author(s):  
Xin Zhang ◽  
Ze Hua Wang ◽  
Ze Hua Zhou ◽  
Jian Ming Xu ◽  
Zhao Jun Zhong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Tensile Strength ◽  
Rare Earth ◽  
Second Phase ◽  
Phase Precipitation ◽  
X Ray ◽  
Scanning Electron

A series of Al-3.2Mg alloys with addition of 0~1.6 wt.% rare earth (Ce and La) were prepared. The microstructure of as-cast Al-3.2Mg alloys was investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and the tensile strength was measured. The results indicated that the addition of rare earth elements refined grain size and secondary dendrite arm spacing (SDAS), and the tensile strength was affected by means of the second-phase precipitation and the grain boundary. Accordingly, the ductility of Al-3.2Mg alloys reduced with the increasing of RE addition due to the more second-phase formation.

scholarly journals PENGARUH LIMBAH ABU PEMBAKARAN BIOMASSA KELAPA SAWIT TERHADAP SIFAT-SIFAT FISIKA DAN MEKANIK HIGH IMPACT POLYSTYRENE

2015 ◽  
Vol 4 (3) ◽  
pp. 23-28
Author(s):  
Fadhilla Asyri ◽  
Kartini Noor Hafni ◽  
A. Haris Simamora
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Impact Strength ◽  
Specific Gravity ◽  
Physical And Mechanical Properties ◽  
High Impact ◽  
Elongation At Break ◽  
Scanning Electron

This study aims was to determine the effect of palm oil fuel ash (POFA) composite as filler on the physical and mechanical properties of high impact polystyrene (HIPS) composites. The research methodology included preparation of raw materials, treatment POFA (hydration process of POFA), mixing using tumbler and then extruder, molding composite specimens, and testing. The variables used were weight ratio of HIPS with 140 mesh POFA at 95/5; 92.5/7.5; 90/10. The composites were tested by Fourier Transform Infrared (FTIR), ash content, specific gravity, tensile strength, elongation at break, impact strength, hardness test, and Scanning Electron Microscopy (SEM). The results of FTIR characterization shows the formation of –OH bonding that was suspected as Si-OH or Si-hydrat. Results of physical and mechanical properties of the composites shows that increase of the filler composition in HIPS-POFA composites until the ratio of 90/10, increase the specific gravity to 7.2% of the original, tensile strength did not change significantly to 28.4 MPa, elongation at break decreased to 2.7%, impact strength decreased to 3.183 KJ/m2, and the hardness increased to 110.5, and Scanning Electron Microscopy (SEM) test show the transformation of POFA structure on treated POFA and intercalation between the matrix and POFA.

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