scholarly journals Effect of Cellulose Reducing Ends on the Reinforcing Capacity of Powdered Cellulose in Polypropylene Composites

2019 ◽  
Vol 3 (4) ◽  
pp. 98
Author(s):  
Mohammadali Azadfar ◽  
Max R. Graham ◽  
Michael P. Wolcott
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Tests ◽  
Powdered Cellulose ◽  
Polypropylene Composites ◽  
Melt Compounding ◽  
Absorption Band Intensity ◽  
Ductile Behavior ◽  
Air Circulation ◽  
Scanning Electron

Powdered cellulose-reinforced (20 wt%) polypropylene composites were prepared by melt compounding and subsequent injection moldings. We assessed the effect of cellulose reducing ends on the capacity of powdered cellulose to reinforce polypropylene composites after seven days exposure to air circulation during the conditioning of samples. Tensile tests on the composites were performed at 5.08 mm/min. Fourier transform infrared spectroscopy revealed some changes that occurred within the composites by demonstrating a practical decrease in –C=O (1744 cm−1) absorption band intensity. A thermogravimetric analysis indicated differences within the thermal behavior of the prepared composites, showing a higher onset of degradation. Scanning electron microscopy of the fracture areas, together with load–extension curves, further characterized the development of interfacial cellulose/matrix adhesion as well as the brittle and ductile behavior of the composites. The results indicate that the thermal and tensile properties of powdered cellulose/polypropylene are improved by decreasing the amount of cellulose reducing ends in the system.

scholarly journals Polymeric Composites Based on Polyurea Matrix Reinforced with Carbon Nanotubes

2017 ◽  
Vol 54 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Maria Adina Vulcan ◽  
Celina Damian ◽  
Paul Octavian Stanescu ◽  
Eugeniu Vasile ◽  
Razvan Petre ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

This paper deals with the synthesis of polyurea and its use as polymer matrix for nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT). Two types of materials were obtained during this research, the first cathegory uses the polyurea as matrix and the second one uses a mixture between epoxy resin and polyurea. The nanocomposites were characterized by Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM) and Tensile Tests .The elastomeric features of nanocomposites were highlighted by the results which showed low value of Tg. Also higher thermal stability with ~40oC compared with commercial products (M20) were observed, but lower mechanical properties compared to neat polyurea.

scholarly journals What Is Considered a Variation of Biomechanical Parameters in Tensile Tests of Collagen-Rich Human Soft Tissues?—Critical Considerations Using the Human Cranial Dura Mater as a Representative Morpho-Mechanic Model

Medicina ◽  
2020 ◽  
Vol 56 (10) ◽  
pp. 520
Author(s):  
Johann Zwirner ◽  
Mario Scholze ◽  
Benjamin Ondruschka ◽  
Niels Hammer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Soft Tissue ◽  
Dura Mater ◽  
Soft Tissues ◽  
Tensile Tests ◽  
Interquartile Range ◽  
Tissue Structure ◽  
Mechanical Parameters ◽  
Scanning Electron

Background and Objectives: Profound knowledge on the load-dependent behavior of human soft tissues is required for the development of suitable replacements as well as for realistic computer simulations. Regarding the former, e.g., the anisotropy of a particular biological tissue has to be represented with site- and direction-dependent particular mechanical values. Contrary to this concept of consistent mechanical properties of a defined soft tissue, mechanical parameters of soft tissues scatter considerably when being determined in tensile tests. In spite of numerous measures taken to standardize the mechanical testing of soft tissues, several setup- and tissue-related factors remain to influence the mechanical parameters of human soft tissues to a yet unknown extent. It is to date unclear if measurement extremes should be considered a variation or whether these data have to be deemed incorrect measurement outliers. This given study aimed to determine mechanical parameters of the human cranial dura mater as a model for human soft tissues using a highly standardized protocol and based on this, critically evaluate the definition for the term mechanical “variation” of human soft tissue. Materials and Methods: A total of 124 human dura mater samples with an age range of 3 weeks to 94 years were uniformly retrieved, osmotically adapted and mechanically tested using customized 3D-printed equipment in a quasi-static tensile testing setup. Scanning electron microscopy of 14 samples was conducted to relate the mechanical parameters to morphological features of the dura mater. Results: The here obtained mechanical parameters were scattered (elastic modulus = 46.06 MPa, interquartile range = 33.78 MPa; ultimate tensile strength = 5.56 MPa, interquartile range = 4.09 MPa; strain at maximum force = 16.58%, interquartile range = 4.81%). Scanning electron microscopy revealed a multi-layered nature of the dura mater with varying fiber directions between its outer and inner surface. Conclusions: It is concluded that mechanical parameters of soft tissues such as human dura mater are highly variable even if a highly standardized testing setup is involved. The tissue structure and composition appeared to be the main contributor to the scatter of the mechanical parameters. In consequence, mechanical variation of soft tissues can be defined as the extremes of a biomechanical parameter due to an uncontrollable change in tissue structure and/or the respective testing setup.

Structure and mechanical properties of Ni/Ti multilayered composites produced by accumulative roll-bonding process

2019 ◽  
Vol 54 (8) ◽  
pp. 1119-1126
Author(s):  
Mohammad Mokhles ◽  
Morteza Hosseini ◽  
Habib Danesh-Manesh ◽  
Seyed Mojtaba Zebarjad
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Accumulative Roll Bonding ◽  
Tensile Tests ◽  
Total Elongation ◽  
Uniaxial Tensile ◽  
Roll Bonding ◽  
Multilayered Composites ◽  
Scanning Electron

This research studies the structure and mechanical properties of Ni/Ti multilayered composites produced from commercial pure Ni and Ti foils by accumulative roll-bonding technique. To investigate these properties, scanning electron microscopy, Vickers microhardness, and uniaxial tensile tests were conducted at different processing cycles. Studies showed that in terms of structure, Ni and Ti layers maintain their continuity even up to 10 cycles of accumulative roll-bonding. Moreover, the energy-dispersive spectroscopy in scanning electron microscopy detected no deformation induced diffusion or reactive interfacial zones. It was found that by increasing the accumulative roll-bonding cycles, tensile and yield strengths as well as the hardness of the composite enhance and the total elongation reduces continuously.

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.

scholarly journals Preparation and Properties of Bacterial Cellulose/Alginate Blend Bio-Fibers

2011 ◽  
Vol 6 (3) ◽  
pp. 155892501100600 ◽  
Author(s):  
Shuai Zhang ◽  
Jin Luo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Bacterial Cellulose ◽  
Tensile Tests ◽  
Intermolecular Hydrogen Bonds ◽  
Scanning Electron

LiOH/urea/thiourea aqueous systems have been successfully applied to the dissolution of bacterial cellulose (BC) and alginate (AL) to prepare blend fibers. Morphology, compatibility and mechanical properties of the blend fibers were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and tensile tests. The analyses indicated a good miscibility between alginate and bacterial cellulose, because of the strong interaction from the intermolecular hydrogen bonds. The mechanical properties of BC/AL blend fibers were significantly improved by introducing bacterial cellulose.

scholarly journals Solidification, Microstructure and Mechanical Properties of Mg-2.8Nd-1.5Gd-0.5Zn-0.5Zr Cast Alloy with Erbium Addition

2018 ◽  
Vol 202 ◽  
pp. 01001
Author(s):  
R. Ahmad ◽  
A.M.M. Elaswad ◽  
M. Z. Hamzah ◽  
N. R. Shahizan
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Cast Alloy ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Microstructure Analysis ◽  
Cooling Curve ◽  
Scanning Electron

The thermal parameters of Mg-2.8Nd-1.5Gd-0.5Zn-0.5Zr cast alloy with 0.25 wt.% of erbium (Er) were evaluated by the computer-aided cooling curve thermal analysis(CA CCTA), whereas the microstructure analysis was investigated by the optical microscope and scanning electron microscopy. Results from the cooling curve and microstructure analysis showed that Er altered the grain size of the alloys. In addition, the grain size was reduced by approximately 19.6% with the addition of Er. Scanning electron microscopy results showed that Er formed an Mg-Zn-Nd-Er phase which distributed along the grain boundaries. Furthermore, the mechanical properties were investigated by hardness and tensile tests with Er addition. The addition of 0.25 wt.% of Er significantly improved the ultimate tensile strength and yield strength. In addition, the hardness value of Mg-2.8Nd-1.5Gd-0.5Zn-0.5Zr increased by 13.9% with Er addition.

Effects of Aluminum Oxide on Combustion Behavior of Intumescent Fire-Retarded Polypropylene Composites

2011 ◽  
Vol 120 ◽  
pp. 598-602
Author(s):  
Shan Hu ◽  
Hui Jing ◽  
Jun Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aluminum Oxide ◽  
Oxygen Index ◽  
Al2o3 Content ◽  
Reaction Products ◽  
Limiting Oxygen Index ◽  
Polypropylene Composites ◽  
Melamine Phosphate ◽  
Scanning Electron

The melamine phosphate (MP) was synthesized from melamine and phosphate acid. Aluminum oxide (Al2O3) was added into the MP during its synthesis. Fourier transform infrared spectroscopy (FTIR) was used to characterize the reaction products. The composites were prepared from polypropylene (PP) and intumescent flame retardant (IFR) additives of MP and pentaerythritol (PER). The effect of Al2O3 content on the properties of the composites was investigated by the limiting oxygen index (LOI), thermogravimetry (TG) and scanning electron microscopy (SEM). The results indicated that the LOI value of the composites could be enhanced obviously with suitable content of Al2O3. When the Al2O3 content was 6 wt% in MP, the LOI value increased to 35.5% from 31.0% for the composite without Al2O3, the amount of residual char at 600°C increased from 8.9 wt% to 13.9 wt%.

scholarly journals Influence of Processing Method on the Mechanical and Electrical Properties of MWCNT/PET Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
O. Rodríguez-Uicab ◽  
A. May-Pat ◽  
F. Avilés ◽  
P. Toro ◽  
M. Yazdani-Pedram
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Processing Method ◽  
Multiwalled Carbon ◽  
Electrical Percolation ◽  
Melt Compounding ◽  
Mechanical And Electrical Properties ◽  
Electrical Percolation Threshold ◽  
Scanning Electron

Multiwalled carbon nanotube (MWCNT)/polyethylene terephthalate (PET) composites were prepared by three processing methods: direct extrusion (DE), melt compounding followed by extrusion (MCE), and dispersion of the MWCNTs in a solvent by sonication followed by extrusion (SSE). The mechanical properties of the MWCNT/PET composites processed by MCE increased with 0.1 wt% MWCNTs with respect to the neat PET. The electrical percolation threshold of MWCNT/PET composites processed by DE and MCE was ~1 wt% and the conductivity was higher for composites processed by MCE. Raman spectroscopy and scanning electron microscopy showed that mixing the MWCNTs by melt compounding before extruding yields better dispersion of the MWCNTs within the PET matrix. The processing method assisted by a solvent resulted in matrix plasticization.

Shape Memory Effect and Superelasticity of an Equiatomic Ti-Ni Alloy with Surface Sulfide Layers

2006 ◽  
Vol 510-511 ◽  
pp. 262-265
Author(s):  
Tae Hyun Nam ◽  
Shin Goo Hur ◽  
Jae Hwa Lee ◽  
Gyu Bong Cho
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Tensile Tests ◽  
Constant Load ◽  
Ni Alloy ◽  
Memory Characteristics ◽  
Scanning Electron ◽  
Start Temperature

Shape memory characteristics and superelasticity of an equiatomic Ti-Ni alloy with surface sulfide layers were investigated by means of thermal cycling tests under constant load, tensile tests, and scanning electron microscopy. Martensitic transformation start temperature (Ms) increased by sulfidation, which is ascribed to a compressive stress imposed by surface sulfide layers. Surface sulfide layers were found to make transformation elongation be small when their thickness was less than 5 ㎛. This is ascribed to the fact that the surface sulfide layers were not detached from substrates and constrained martensitic transformation. When thickness of the surface sulfide layers was 35 ㎛, transformation elongation was not affected by them because they were detached during transformation. Superelastic recovery decreased by the sulfide layers when their thickness was about 5 ㎛, while it did not change when the thickness was about 35 ㎛.

Effect of Boron and Titanium Addition on the Hot Ductility of Low-Carbon Nb-Containing Steel

2015 ◽  
Vol 34 (8) ◽  
Author(s):  
Wei-Jian Liu ◽  
Jing Li ◽  
Cheng-Bin Shi ◽  
Xiang-Dong Huo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tensile Tests ◽  
Hot Ductility ◽  
Low Carbon ◽  
Titanium Addition ◽  
Intragranular Ferrite ◽  
Transmission Electron ◽  
Scanning Electron

AbstractThe effect of boron and titanium addition on the hot ductility of Nb-containing steel was investigated using hot tensile tests. The fracture surface and the quenched longitudinal microstructure were examined by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that both steel samples had the similar change from 1,100°C to 700°C. The hot ductility of Nb-containing steel with boron and titanium addition was higher than the steel without boron and titanium in the temperature range of 900–750°C. Because the formation of intergranular ferrite was inhibited by solute boron segregating on the grain boundary, the formation of TiN changed the distribution of Nb- and boron-containing precipitates and improved the amount of intragranular ferrite.

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