scholarly journals SCAFFOLD FROM MICRO ELECTROSPUN POLYLACTIDE ACID AND WET CHEMICAL HYDROTHERMAL REACTION HYDROXY APATITE USED FOR BIOMEDICAL APPLICATION

2020 ◽  
Vol 31 (01) ◽  
Author(s):  
NGUYEN THAI HOA ◽  
PHAM TRUNG KIEN ◽  
HUYNH DAI PHU
Keyword(s):  
Mechanical Performance ◽  
Hydrothermal Reaction ◽  
Biomedical Application ◽  
Fiber Surface ◽  
Average Diameter ◽  
Hydroxy Apatite ◽  
Before And After ◽  
Wet Chemical ◽  
Polylactide Acid ◽  
Compressional Strength

Polylactic acid (PLA) microfibrous composite scaffolds having hydroxy apatite (HA) particles in the fibers were prepared by electrospinning of PLA and wet chemical hydrothermal reaction HA with average diameter of 8.13 µm. The fibers were compressed in mould into bulk scaffolds. Microscopy characterizations confirmed integration of the crystalline HA and PLA fibers in both before and after compression. The morphology, porosity of scaffolds were examined by scanning electron microscope (SEM). The HA content were observed by SEM and determined by Thermogravimetry Analysis (TGA). Agglomeration gradually appeared and increased on the fiber surface along with the increase of HA concentration. The fiber diameter also increased with the HA concentration. Mechanical property of scaffold was examined by compressional strength test. The scaffold prepare for bone substitute implant application with suitable mechanical performance and morphology.

Processing and characterization of thermoplastic nanocomposite fibers of hot melt copolyamide and carbon nanotubes

2017 ◽  
Vol 31 (3) ◽  
pp. 359-375 ◽  
Author(s):  
Paulina Latko-Durałek ◽  
Kamil Dydek ◽  
Michał Sobczakand ◽  
Anna Boczkowska
Keyword(s):  
Carbon Nanotubes ◽  
Mechanical Performance ◽  
Fiber Surface ◽  
Average Diameter ◽  
Multifunctional Composites ◽  
Adhesive Properties ◽  
Multi Walled Carbon Nanotubes ◽  
Nanocomposite Fibers ◽  
Walled Carbon Nanotubes ◽  
Hot Melt

In this study, thermoplastic nanocomposite fibers based on hot melt copolyamide and multi-walled carbon nanotubes (MWCTs) were fabricated with a two-step approach. In the first step, a masterbatch containing 20 wt% MWCTs was diluted by pure hot melts to produce nanocomposite pellets with 2, 4, and 6 wt% MWCTs. In the second step, nanocomposite fibers were extruded and drawn from the fabricated pellets. The selected processing conditions resulted in fibers with an average diameter of 80 μm. Rheological behavior of hot melt copolyamide changes dramatically after the addition of carbon nanotubes (CNTs). Crystallinity content expressed by enthalpy of melting is higher in the fibers than in the pellets. Microscopic examination shows that MWCTs are randomly oriented in the direction of the extrusion. The mechanical performance of the fibers shows decreased elongation at break for fibers with MWCTs and an increase in Young’s modulus. A strong influence of fiber surface quality on mechanical properties was also indicated. Thermoplastic nanocomposites fibers with MWCTs, based on hot melt copolyamide, are a new group of materials that can be applied as multifunctional composites for aviation, automotive, military, medical and electronic industries due to their adhesive properties, low melting range as well as electrical properties.

scholarly journals Mechanical Performance of Glass-Based Geopolymer Matrix Composites Reinforced with Cellulose Fibers

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2395 ◽  
Author(s):  
Gianmarco Taveri ◽  
Enrico Bernardo ◽  
Ivo Dlouhy
Keyword(s):  
Fly Ash ◽  
Mechanical Performance ◽  
Fiber Surface ◽  
Cellulose Fiber ◽  
Maximum Effect ◽  
Matrix Composites ◽  
Curing Conditions ◽  
Chevron Notch ◽  
Geopolymer Matrix ◽  
Mechanical Performances

Glass-based geopolymers, incorporating fly ash and borosilicate glass, were processed in conditions of high alkalinity (NaOH 10–13 M). Different formulations (fly ash and borosilicate in mixtures of 70–30 wt% and 30–70 wt%, respectively) and physical conditions (soaking time and relative humidity) were adopted. Flexural strength and fracture toughness were assessed for samples processed in optimized conditions by three-point bending and chevron notch testing, respectively. SEM was used to evaluate the fracture micromechanisms. Results showed that the geopolymerization efficiency is strongly influenced by the SiO2/Al2O3 ratio and the curing conditions, especially the air humidity. The mechanical performances of the geopolymer samples were compared with those of cellulose fiber–geopolymer matrix composites with different fiber contents (1 wt%, 2 wt%, and 3 wt%). The composites exhibited higher strength and fracture resilience, with the maximum effect observed for the fiber content of 2 wt%. A chemical modification of the cellulose fiber surface was also observed.

scholarly journals CHARACTERISTIC OF XONOTLITE SYNTHESIZED BY HYDROTHERMAL REACTION USING RICE HUSK ASH AND ITS APPLICATION TO ABSORB CHROME (III) SOLUTION

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Trung Kien Pham ◽  
Tran Ngo Quan
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Hydrothermal Reaction ◽  
Mekong Delta ◽  
Molar Ratio ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Xrf Scanning ◽  
Before And After ◽  
Chrome Iii

In this paper, we report on synthesizing xonotlite, calcium silicate hydrate (CSH), via a hydrothermal reaction using rice husk from the Mekong Delta, Vietnam. The rice husks were burnt at 1000 °C for 3 h. Grey rice husk ash was collected, then mixed with Ca(OH)2 at a Ca/Si molar ratio of 1 : 1. This was followed by a hydrothermal reaction at 180 °C for 24 h and 48 h to obtain the xonotlite mineral. Before and after adsorption, 3-mm xonotlite pellets were thoroughly characterized using X-ray diffractometry (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and ultraviolet-visible (UV-VIS) spectroscopy. This material has potential application in chromium(III) removal during a chrome-plating process. The adsorption efficiency of the 3-mm pellet samples reached more than 76 % after 12 h.

scholarly journals MECHANICAL CHARACTERIZATION OF PA 12 AND HDPE PIPES BEFORE AND AFTER AGING IN WATER AT TWO DIFFERENT TEMPERATURES

2021 ◽  
Vol 9 (1) ◽  
pp. 248-256
Author(s):  
J.A. dos Santos ◽  
R.C. Tucunduva ◽  
J.R.M. D’Almeida
Keyword(s):  
High Density Polyethylene ◽  
Mechanical Performance ◽  
High Density ◽  
Effect Of Temperature ◽  
Polyamide 12 ◽  
Polyethylene Pipes ◽  
Before And After ◽  
Different Temperatures ◽  
Deterioration Process ◽  
Combined Action

Polymer pipes are being widely used by many industrial segments. Although not affected by corrosion, the mechanical performance of these pipes can be reduced due to exposure to temperature, UV radiation and by contact with various fluids. Depending on the deterioration process, embrittlement or plasticization may occur, and the service life of the pipe can be severely reduced. In this work, the combined action of temperature and water upon the mechanical performance of polyamide 12 and high-density polyethylene pipes is evaluated. Destructive and non-destructive techniques were used and the performance of both materials was compared. Both polymers were platicized by the effect of water. However, for high density polyethylene the effect of temperature was more relevant than for polyamide. This behavior was attributed to the dependence of the free volume with the markedly different glass transition temperature of the polymers and the temperatures of testing.

scholarly journals ID: 1038 Hydrothermal synthesis of carbon nanodots from millets for cancer cells imaging

2017 ◽  
Vol 4 (S) ◽  
pp. 116
Author(s):  
Quang Ngo Khoa ◽  
Tran Thi Xuan Thuy ◽  
Che Thi Cam Ha
Keyword(s):  
Hydrothermal Synthesis ◽  
Cancer Cells ◽  
Biomedical Application ◽  
Average Diameter ◽  
Optical Measurements ◽  
Carbon Nanodots ◽  
Excitation Wavelength ◽  
Economical Method ◽  
Potential Applications ◽  
Multicolor Fluorescence

We presented a green, simple and economical method to synthesize carbon nanodots (C-dots) from millets using hydrothermal synthesis route. The obtained C-dots have average diameter ranging from 6 to 8 nm. Optical measurements showed the formation of hydroxyl, carbonyl/carboxyl, amino functional groups on the particle surfaces, resulting in their high hydrophilicity and bioconjugation. After treatment with C-dots, human cervical and lung cancer cells became bright and exhibited multicolor fluorescence under different excitation wavelength. The achievement demonstrated potential applications of fluorescent C-dots in the field of biomedical application, especially in diagnostic disease techniques.

scholarly journals Research on Mechanical Performance & Behaviour of Geopolymer Concrete Subjected to Elevated Temperatures

2019 ◽  
Vol 8 (2S8) ◽  
pp. 883-887
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Geopolymer Concrete ◽  
Sem Images ◽  
Before And After ◽  
Alkaline Conditions ◽  
Compressive Strength Of Concrete

The investigative studies on mechanical performance & behaviour, of Geopolymer Concrete (GPC) before and after the exposure to elevated temperatures (of 200 0 C -1000 0 C with an increment of 100 0 C). Indicate that the GPC Specimens Exhibited better Compressive strength at higher temperatures than that of those made by regular OPC Concrete with M30 Grade. The chronological changes in the geopolymeric structure upon exposure to these temperatures and their reflections on the thermal behaviour have also been explored. The SEM images indicate GPC produced by fly ash , metakaolin and silica fume, under alkaline conditions form Mineral binders that are not only non-flammable and but are also non-combustible resins and binders. Further the Observations drawn disclose that the mass and compressive strength of concrete gets reduced with increase in temperatures.

scholarly journals Biocompatibility of Nanoporous TiO2Coating on NiTi Alloy Prepared via Dealloying Method

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jin Huang ◽  
Junqiang Wang ◽  
Xiangdong Su ◽  
Weichang Hao ◽  
Tianmin Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Shape Memory ◽  
Biomedical Application ◽  
Niti Alloy ◽  
Treatment Method ◽  
Niti Shape Memory Alloy ◽  
Contact Method ◽  
Biological Compatibility ◽  
Before And After ◽  
Niti Shape Memory Alloys

This paper investigated the biocompatibility of nanoporous TiO2coating on NiTi shape-memory alloy (SMA) prepared via dealloying method. Our previous study shows that the dealloying treatment at low temperature leads to 130 nm Ni-free surface titania surface layer, which possesses good bioactivity because of the combination of hydroxyl (OH−) group in the process of dealloying treatment simultaneously. In this paper, the biological compatibility of NiTi alloy before and after dealloying treatment was evaluated and compared by direct contact method with dermal mesenchymal stem cells (DMSCs) by the isolated culture way. The interrelation between the biological compatibility and surface change of material after modification was systematically analyzed. As a consequence, the dealloying treatment method at low temperature could be of interest for biomedical application, as it can avoid sensitization and allergies and improve biocompatibility of NiTi shape-memory alloys. Thus it laid the foundation of the clinical trials for surface modification of NiTi memory alloy.

SUB-MICROSCALE SPECKLE PATTERN CREATION ON SINGLE CARBON FIBERS FOR IN-SITU DIC EXPERIMENTS

2021 ◽  
Author(s):  
KARAN SHAH ◽  
GENE YANG ◽  
MOHAMMAD EL LOUBANI ◽  
SUBRAMANI SOCKALINGAM ◽  
DONGKYU LEE
Keyword(s):  
Carbon Fibers ◽  
Fiber Strength ◽  
Glass Fibers ◽  
Speckle Pattern ◽  
Fiber Surface ◽  
Average Diameter ◽  
Sputter Deposition ◽  
Image Correlation ◽  
Longitudinal Tensile Strength ◽  
Fiber Breaks

High performance carbon and glass fibers are widely used as reinforcements in composite material systems for aerospace, automotive, and defense applications. Modifications to fiber surface treatment (sizing) is one of the ways to improve the strength of fibers and hence the overall longitudinal tensile strength of the composite. Single fiber tensile tests at the millimeter scale are typically used to characterize the effect of sizing on fiber strength. However, the characteristic length-scale governing the composite failure due to a cluster of fiber breaks is in the micro-scales. To access such micro-scale gage-lengths, we aim to employ indenters of varying radii to transversely load fibers and use scanning electron microscope (SEM) with digital image correlation (DIC) to measure strains at these lengthscales. The use of DIC technique requires creation of a uniform, random, and high contrast speckle pattern on the fiber surface such as that shown in Figure 1. In this work, we investigate the formation of sub-microscale speckle pattern on carbon fiber surface via sputter deposition and pulsed laser deposition techniques (PLD) using Gold-Palladium (Au-Pd) and Niobium-doped SrTiO3 (Nb:STO) targets respectively. Different processing conditions are investigated for both sputter deposition: sputtering current and coating duration, and PLD: number of pulses respectively to create sub-micron scale patterns viable for micro-DIC on both sized and unsized carbon fibers. By varying the deposition conditions and SEM-imaging the deposited patterns on fibers, successful pattern formation at sub-micron scale is demonstrated for both as-received sized and unsized IM7 carbon fibers of average diameter 5.2 μm via sputter deposition and PLD respectively.

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