Influence of the Temperature of Crystallization on the Melting of Crystalline Rubber

1941 ◽  
Vol 14 (3) ◽  
pp. 544-545 ◽  
Author(s):  
Norman Bekkedahl ◽  
Lawrence A. Wood
Keyword(s):  
Mechanical Properties ◽  
Crystalline Material ◽  
X Ray Diffraction ◽  
Volume Increase ◽  
X Ray ◽  
Different Temperatures ◽  
Quantitative Results ◽  
Rate Of Heating ◽  
One Year ◽  
Time Required

Abstract Data presented in this communication show an instance in which melting of a crystalline material is very much dependent on the temperature at which the crystals have been formed. It is well known that many substances in which crystallization is relatively slow can be crystallized at different temperatures in a range below the melting point, but no effect of the crystallization temperature on the temperature of melting seems to have been previously reported. The quantitative results for crystalline rubber, the material under investigation, are shown in Figure 1. The crystallization of unvulcanized rubber in the unstretched state has been found to occur at temperatures between about −40° C and 13° C. The time required for crystallization is about one year at 13° C, about ten days at 0° C, and a few hours at −20° C. Below −40° C the mobility is presumably insufficient for the formation of crystals. Crystallization and fusion are accompanied by changes in volume, heat capacity, light absorption, birefringence, x-ray diffraction, and mechanical properties such as hardness. The volume decreases about 2.5 per cent on crystallization, and the magnitude of the change is little influenced, if at all, by the temperature. Fusion, as measured by the volume increase, is found to be independent of the rate of heating, and to occur over a range of five or ten degrees.

The Effects of Austempering Temperature and Time on Mechanical Properties of Ductile Cast Iron Grade FCD450

2020 ◽  
Vol 856 ◽  
pp. 92-98
Author(s):  
Janthira Chantarach ◽  
Rungsinee Canyook
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Low Temperature ◽  
Impact Toughness ◽  
Ductile Cast Iron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Austempering Temperature ◽  
Iron Grade

The purpose of the study was to inspect microstructure, mechanical properties and impact toughness of ductile cast iron grade FCD450 produced by austempering process. The study focused on austempering parameter, which effected impact toughness of material at low temperature. The FCD450 was initially temperature austenized at 885°C (1625˚F) for 2 hours. Austempering was carried out at three different temperatures of 271°C (520˚F), 313°C (560˚F) and 357°C (675˚F). The austempering temperature were varied at 1.5, 2.5 and 3.5 hours. X-ray diffraction was showed that the austempered ductile cast iron (ADI) microstructure consists of austenite and ferrite. The results showed that when austempered at 357°C (675˚F) for 2.5 hours has highest hardness and impact energy at low temperature. The dimple ductile fracture of ADI fracture surfaces was revealed by scanning electron microscope (SEM).

Synthesis of Porous Ti2SnC from TiH2-Sn-TiC/Graphite Powders in Tube Furnace

2014 ◽  
Vol 602-603 ◽  
pp. 130-133 ◽  
Author(s):  
Zheng Yang Li ◽  
Li Bo Wang ◽  
Guo Cai Zhong ◽  
Sai Sai Li ◽  
Ai Guo Zhou
Keyword(s):  
Mechanical Properties ◽  
Carbon Source ◽  
Tube Furnace ◽  
X Ray Diffraction ◽  
Porous Sample ◽  
Max Phases ◽  
X Ray ◽  
Porous Ti ◽  
Different Temperatures ◽  
Ternary Carbides

Titanium tin carbide (Ti2SnC) is a member a MAX phases, which are ternary carbides or nitrides with layered structure. Ti powders are normally used as Ti source to synthesize Ti2SnC. In this paper, TiH2, a relative cheaper Ti source, was used to synthesize Ti2SnC. Ti2SnC was synthesized from TiH2/Sn/TiC or TiH2/Sn/graphite powders by a tube furnace at different temperatures under Ar atmosphere. From the analysis of X-ray diffraction results, the lowest temperature to synthesize Ti2SnC was 1000 °C. Ti2SnC content increased with temperature, and high purity Ti2SnC was fabricated at 1200 °C. From scanning electron microscopy, as-synthesized Ti2SnC from TiH2/Sn/TiC was with plate-like structure. However, for Ti2SnC from graphite as carbon source, there was some stripe microstructure. Some large pores existed between the Ti2SnC particles. The existence of the pores make the mechanical properties of Ti2SnC block significantly reduced, its compressive strength was only 0.483 MPa or 0.35 MPa respectively for samples synthesized from TiC or graphite as carbon source. The low mechanical properties make the porous sample easy to be broken as powders.

Sintering Effects on Mechanical Properties of Hydroxyapatite-Titanium Dioxide (HA-TiO2) Composites

2006 ◽  
Vol 309-311 ◽  
pp. 355-358 ◽  
Author(s):  
Faik N. Oktar ◽  
Onur Meydanoglu ◽  
Gültekin Göller ◽  
Simeon Agathopoulos ◽  
G. Rocha ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Dioxide ◽  
Diffraction Analysis ◽  
Compression Strength ◽  
Bovine Bone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Densification Behaviour ◽  
Different Temperatures

Composites of bovine bone derived HA with 5 wt% and 10 wt% of TiO2 were sintered at different temperatures. Their characterization comprised measurements of density, microhardness, and compression strength together with SEM observations and X-ray diffraction analysis. Better densification behaviour was achieved at higher sintering temperatures. The highest microhardness value was measured in the samples sintered at 1300°C. The best compressive strengths of the samples containing 5% and 10% TiO2 were obtained after sintering at 1300°C and 1200°C, respectively.

scholarly journals Effect of silver nanoparticless in the structure and mechanical properties of mullite/Ag cermets

2019 ◽  
Vol 51 (2) ◽  
pp. 175-187
Author(s):  
Gabriela Téllez-Arias ◽  
José Miranda-Hernández ◽  
Oscar Olea-Mejía ◽  
J. Lemus-Ruiz ◽  
Eduardo Terrés
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Different Temperatures ◽  
Confocal Scanning ◽  
Confocal Scanning Microscopy ◽  
Scanning Electron

The objective of this work was to study the influence of the addition of silver nanoparticles in the microstructure of mullite at two different temperatures of sintering (1500 and 1600?C), in order to decrease the porosity and increase the density as well better the hardness and fracture toughness. The microstructural characteristics were studied by scanning electron microscopy, confocal scanning microscopy and X-ray diffraction. Mullite/Ag cermets with homogenous microstructure were and a fracture toughness of 2.42 MP??m1/2.

scholarly journals DENSIFICATION AND MECHANICAL PROPERTIES OF FeMn13-TiC COMPOSITE FABRICATED BY PULSED ELECTRIC CURRENT SINTERING PROCESS

2018 ◽  
Vol 24 (4) ◽  
pp. 273 ◽  
Author(s):  
Khanh Quoc Dang ◽  
Quang Anh Hoang ◽  
Hiep Van Tran ◽  
Minh Cong Nguyen ◽  
Hao Van Pham ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Electric Current ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pulsed Electric Current ◽  
Different Temperatures

In the present work, FeMn13-40 wt.% TiC composite was fabricated by Pulsed Electric Current Sintering (PECS) process at different temperatures between 990 and 1020<sup>o</sup>C under a pressure of 60 MPa with a holding time of 5 min in the vacuum. Phases identification was done using the X-ray diffraction. The relative density, microstructure and hardness of the samples were characterized. The results showed that the relative density of FeMn13-TiC composite increased with the increase of sintering temperature. The highest relative density (96.19%) and the hardness (70.54 HRC) of the sample were achieved by PECS process, namely sintering at the temperature of 1020<sup>o</sup>C under the applied pressure of 60 MPa for 5 min.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

scholarly journals Enhancement of Chloroprene/Natural/Butadiene Rubber Nanocomposite Properties Using Organoclays and Their Combination with Carbon Black as Fillers

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1085
Author(s):  
Patricia Castaño-Rivera ◽  
Isabel Calle-Holguín ◽  
Johanna Castaño ◽  
Gustavo Cabrera-Barjas ◽  
Karen Galvez-Garrido ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
High Performance ◽  
Rubber Matrix ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rubber Blends ◽  
Ft Ir ◽  
Chloroprene Rubber

Organoclay nanoparticles (Cloisite® C10A, Cloisite® C15) and their combination with carbon black (N330) were studied as fillers in chloroprene/natural/butadiene rubber blends to prepare nanocomposites. The effect of filler type and load on the physical mechanical properties of nanocomposites was determined and correlated with its structure, compatibility and cure properties using Fourier Transformed Infrared (FT-IR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and rheometric analysis. Physical mechanical properties were improved by organoclays at 5–7 phr. Nanocomposites with organoclays exhibited a remarkable increase up to 46% in abrasion resistance. The improvement in properties was attributed to good organoclay dispersion in the rubber matrix and to the compatibility between them and the chloroprene rubber. Carbon black at a 40 phr load was not the optimal concentration to interact with organoclays. The present study confirmed that organoclays can be a reinforcing filler for high performance applications in rubber nanocomposites.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

scholarly journals The Potential for Natural Stones from Northeastern Brazil to Be Used in Civil Construction

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 440
Author(s):  
Fabiana Pereira da Costa ◽  
Jucielle Veras Fernandes ◽  
Luiz Ronaldo Lisboa de Melo ◽  
Alisson Mendes Rodrigues ◽  
Romualdo Rodrigues Menezes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Resistance ◽  
Mechanical Analysis ◽  
Northeastern Brazil ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Agents ◽  
Natural Stones

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.

scholarly journals Functional Bionanocomposite Fibers of Chitosan Filled with Cellulose Nanofibers Obtained by Gel Spinning

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1563
Author(s):  
Sofia Marquez-Bravo ◽  
Ingo Doench ◽  
Pamela Molina ◽  
Flor Estefany Bentley ◽  
Arnaud Kamdem Tamo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Cellulose Nanofibers ◽  
Microstructural Characterization ◽  
Fiber Formation ◽  
Fiber Direction ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
Gel Spinning ◽  
X Ray

Extremely high mechanical performance spun bionanocomposite fibers of chitosan (CHI), and cellulose nanofibers (CNFs) were successfully achieved by gel spinning of CHI aqueous viscous formulations filled with CNFs. The microstructural characterization of the fibers by X-ray diffraction revealed the crystallization of the CHI polymer chains into anhydrous chitosan allomorph. The spinning process combining acidic–basic–neutralization–stretching–drying steps allowed obtaining CHI/CNF composite fibers of high crystallinity, with enhanced effect at incorporating the CNFs. Chitosan crystallization seems to be promoted by the presence of cellulose nanofibers, serving as nucleation sites for the growing of CHI crystals. Moreover, the preferential orientation of both CNFs and CHI crystals along the spun fiber direction was revealed in the two-dimensional X-ray diffraction patterns. By increasing the CNF amount up to the optimum concentration of 0.4 wt % in the viscous CHI/CNF collodion, Young’s modulus of the spun fibers significantly increased up to 8 GPa. Similarly, the stress at break and the yield stress drastically increased from 115 to 163 MPa, and from 67 to 119 MPa, respectively, by adding only 0.4 wt % of CNFs into a collodion solution containing 4 wt % of chitosan. The toughness of the CHI-based fibers thereby increased from 5 to 9 MJ.m−3. For higher CNFs contents like 0.5 wt %, the high mechanical performance of the CHI/CNF composite fibers was still observed, but with a slight worsening of the mechanical parameters, which may be related to a minor disruption of the CHI matrix hydrogel network constituting the collodion and gel fiber, as precursor state for the dry fiber formation. Finally, the rheological behavior observed for the different CHI/CNF viscous collodions and the obtained structural, thermal and mechanical properties results revealed an optimum matrix/filler compatibility and interface when adding 0.4 wt % of nanofibrillated cellulose (CNF) into 4 wt % CHI formulations, yielding functional bionanocomposite fibers of outstanding mechanical properties.

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