scholarly journals Mechanical Properties of Glass-Based Geopolymers Affected by Activator and Curing Conditions under Optimal Aging Conditions

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 502
Author(s):  
Tai-An Chen
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Glass Powder ◽  
Weight Ratio ◽  
Polymeric Materials ◽  
Curing Temperature ◽  
Curing Conditions ◽  
Positive Effects ◽  
Aging Conditions ◽  
Optimal Values

Inorganic polymeric materials react slowly at room temperature and therefore, usually require high-temperature curing. This study determined the correlation between temperature and duration in high-temperature curing. The results revealed optimal values for each alkali equivalent of an activator (weight ratio of Na2O/glass powder), curing temperature, and curing duration. Increasing the curing duration and curing temperature had positive effects when the alkali equivalent was lower than the optimal percentage. However, over-curing resulted in the visible cracking of the specimens. Furthermore, despite being initially high, the compressive strength of specimens gradually diminished after standing in air. To ensure the durability of glass-based geopolymers, the curing temperature and duration should not exceed 70 °C, and 1 day, respectively.

scholarly journals Mechanical properties of glass-based geopolymer affected by activator and curing conditions under the optimal aging conditions

2021 ◽  
Author(s):  
Tai-An Chen
Keyword(s):  
High Temperature ◽  
Weight Ratio ◽  
Polymeric Materials ◽  
High Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Curing Conditions ◽  
Positive Effects ◽  
Optimal Value ◽  
Aging Conditions

Inorganic polymeric materials react slowly at room temperature and as a result usually require high-temperature curing. This study used the Arrhenius equation to analyze the correlation between curing temperature and curing duration during high-temperature curing. The test results show that optimal values exist for each alkali equivalent of the activator (weight ratio of Na2O/glass powder), curing temperature, and curing duration. Extending the curing duration and increasing the curing temperature have positive effects when the alkali equivalent is lower than the optimal value. However, over-curing results in invisible cracking in the specimens. Furthermore, despite exhibiting high strength initially, the strength of specimens gradually diminishes after standing in air. To ensure the durability of glass-based geopolymer, the curing temperature should not exceed 70℃, and the curing duration should be less than one day.

scholarly journals Investigation of Fatigue Behavior of ABS and PC-ABS Polymers at Different Temperatures

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1818
Author(s):  
Andrea Mura ◽  
Alessando Ricci ◽  
Giancarlo Canavese
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Working Condition ◽  
Fatigue Behavior ◽  
Polymeric Materials ◽  
Cyclic Loads ◽  
Structural Components ◽  
Working Temperature ◽  
Different Temperatures ◽  
Positive Effect

Plastics are widely used in structural components where cyclic loads may cause fatigue failure. In particular, in some applications such as in vehicles, the working temperature may change and therefore the strength of the polymeric materials. In this work, the fatigue behavior of two thermoplastic materials (ABS and PC-ABS) at different temperatures has been investigated. In particular, three temperatures have been considered representing the working condition at room temperature, at low temperature (winter conditions), and high temperature (summer conditions and/or components close to the engine). Results show that high temperature have big impact on fatigue performance, while low temperatures may also have a slight positive effect.

Influence of Curing Temperature on Metakaolin-Based Geopolymers

2014 ◽  
Vol 775-776 ◽  
pp. 210-215
Author(s):  
Danúbia Lisbôa da Costa ◽  
Romualdo Rodrigues Menezes ◽  
Gelmires Araújo Neves ◽  
Sandro Marden Torres
Keyword(s):  
Room Temperature ◽  
Industrial Wastes ◽  
Curing Temperature ◽  
Inorganic Polymers ◽  
Flexural Test ◽  
X Ray Diffraction ◽  
Curing Conditions ◽  
X Ray ◽  
Natural Minerals ◽  
Application Potential

Geopolymers, also known as inorganic polymers, are aluminosilicates with cementing characteristics that have great application potential. They are produced by the alkaline activation of aluminosilicates precursors such as industrial wastes, calcined clays, natural minerals, among others and have their properties intimately associated to characteristics of the precursor materials and curing conditions. In this sense, this study aims to evaluate the mechanical behavior of geopolymers obtained from metakaolin according to the curing temperature. The geopolymerization was reached by the mixture of metakaolin with NaOH and the curing of the specimens was held at room temperature, 60°C and 100°C. The specimens were characterized by X-ray diffraction, mercury intrusion porosimetry, and SEM. The mechanical strength was determined by flexural test. The results show that the process of geopolymerization suffers a direct influence of the curing temperature used.

Effect of Curing Regimes on Metakaolin Geopolymer Pastes Produced from Geopolymer Powder

2012 ◽  
Vol 626 ◽  
pp. 931-936 ◽  
Author(s):  
Liew Yun Ming ◽  
Kamarudin Hussin ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Mohammed Binhussain ◽  
Luqman Musa ◽  
...  
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Solidification Process ◽  
Curing Temperature ◽  
Alkali Concentration ◽  
Strength Development ◽  
Curing Time ◽  
Curing Conditions ◽  
Metakaolin Geopolymer ◽  
Geopolymer Paste

The properties of metakaolin geopolymer paste are affected by the alkali concentration, the initial raw materials, solidification process, and amount of mixing water as well as the curing conditions. This study aimed to investigate the effect of curing temperature (room temperature, 40°C, 60°C, 80°C and 100°C) and curing time (6h, 12h, 24h, 48h and 72h) on the geopolymer pastes produced from geopolymer powder. The results showed that curing at room temperature was unfeasible. Heat was required for the geopolymerization process, where strength increased as the curing temperature was increased. Moderate elevated curing temperature favored the strength development of geopolymer pastes in comparison with those treated with extreme elevated curing temperature. When geopolymer paste was subjected to extreme elevated curing temperature, shorter curing time should be used to avoid deterioration in strength gain. Similarly, longer curing time was recommended for moderate elevated curing temperature. The microstructure of geopolymer paste cured at moderate curing temperature showed obvious densification of structure. In contrast, the structure formed was weak and less compact at very high elevated curing temperature.

Effect of Temperature on Tensile Properties of Vulcanized Rubber

1934 ◽  
Vol 7 (2) ◽  
pp. 371-386
Author(s):  
A. A. Somerville ◽  
W. F. Russell
Keyword(s):  
High Temperature ◽  
Tensile Properties ◽  
Room Temperature ◽  
Point Of View ◽  
Effect Of Temperature ◽  
Curing Conditions ◽  
Vulcanized Rubber ◽  
Before And After ◽  
Temperature Test ◽  
Better Than

Abstract The tensile properties and tear resistance of a large number of commercial inner tubes, before and after aging by different methods, are studied at 0°, 25°, and 100° C. A number of uncured bus-truck tube stocks are also studied from the point of view of their capacity to withstand high temperatures. The effect of testing rubber at 100° C. as compared with room temperature is discussed; how some compounds collapse at 100° C., while others have tensile properties equal to, or better than those at 25°, is shown. The effect of testing artificially aged specimens at 100° C., as well as at 25° C., is discussed; the high-temperature test may reveal conditions of deterioration and overcure that are not noticeable in the 25° tests. The compounding and curing conditions that lead to high tensile properties at 100° C., as well as those which cause inferior quality, are discussed.

scholarly journals Synthesis, characterization and properties of phthalonitrile-etherified resole resin

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 500-509
Author(s):  
Dayong Zhang ◽  
Xiaohui Liu ◽  
Xuefeng Bai ◽  
Yinyin Zhang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Weight Loss ◽  
High Temperature ◽  
Room Temperature ◽  
Curing Temperature ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Bonding Properties ◽  
New Type

AbstractA new type of phthalonitrile-etherified resole resin (PNR) was synthesized from resole resin and 4-nitrophthalonitrile. The differential scanning calorimetry results showed that the curing temperature of PNR is lower than that of phthalonitrile resin. Excellent thermal stability and bonding properties were obtained after curing at 220°C. TGA showed that in air, the temperature of 5% weight loss (T5%) of the cured PNR was 446°C, approximately 41°C higher than that of resole resin (RS), and the char yield at 800°C increased from 4% for RS to 33% for PNR. The shear strengths of PNR at room temperature and high temperature were increased by 8% and 133%, respectively, over those of RS, and after aging at 350°C for 2 h, these values were increased by 262% and 198%, respectively, over those of RS. Its excellent curing behavior, heat resistance and high bonding strength show that PNR can be used as a high temperature-resistant adhesive.

Propargyloligosilazane matrixed composite for high temperature material combining polymer and ceramic properties

2021 ◽  
Vol 19 (3) ◽  
pp. 277-285
Author(s):  
Lixin Xuan ◽  
Diansen Li ◽  
Mingcun Wang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Room Temperature ◽  
Laminate Composite ◽  
Crosslinking Agent ◽  
Curing Temperature ◽  
High Yield ◽  
Thermosetting Resin ◽  
Thermal Curing ◽  
Carbon Fabric

Abstract A new single-phased thermosetting resin (propargyloligosilazane, POSZ) was prepared through Hofmann alkylation of oligosilazane with propargylbromide; the propargyl content in POSZ was controlled by monitoring the amount of propargylbromide in synthesis. The characterizations showed that POSZ has ideal rheology during material processing, the thermal curing temperature could be lowered when isocyanate was used as crosslinking agent, and the thermally cured POSZ can be pyrolyzed into anti-oxidative ceramic at a high yield of >70%. For POSZ-matrixed carbon-fabric laminate composite, it possessed high mechanical properties and retained the original shape with the increase of temperature as high as 800 °C. The POSZ-matrixed laminate has the mechanical properties combining polymer character at room temperature and ceramic character at high temperature, and it will find many prospective high temperature applications in need of polymer and ceramic properties simultaneously.

Effect of Cuing Conditions on the Microstructural Characteristics of Complex Binders

2013 ◽  
Vol 756-759 ◽  
pp. 29-32
Author(s):  
Xiang Li ◽  
Jian Jun Yan ◽  
Hua Quan Yang
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Room Temperature ◽  
Hydration Degree ◽  
Microstructural Characteristics ◽  
Early Hydration ◽  
Cement Pastes ◽  
Curing Conditions ◽  
Microstructure Characteristics ◽  
Micro Morphology

The microstructure characteristics of complex binders under two curing conditions were studied by observing the micro-morphology, analyzing the pore character and means of spectrum test. The results showed that high temperature curing improved the pore structure formed in the early hydration period and reduced the porosity and the coarse pores in pastes. More hydration products were generated on the surface of fly ash particles that made the microstructure of pastes more denser than cured in room temperature. However, high temperature curing had insignificant influence on the CaO/SiO2 ratio of C-S-H gel in pastes and contributed little to the improvement of the later hydration degree and microstrcture of fly ash-cement pastes.

Precipitate coarsening during hot-compression testing of NiAl + 2 at.% Nb

1986 ◽  
Vol 44 ◽  
pp. 598-599
Author(s):  
W. M. Sherman ◽  
K. M. Vedula
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Weight Ratio ◽  
Constant Strain Rate ◽  
Hot Compression ◽  
Compression Testing ◽  
Second Phase ◽  
Precipitate Coarsening ◽  
High Temperature Mechanical Properties ◽  
Ordered Intermetallic

The strength to weight ratio and oxidation resistance of NiAl make this ordered intermetallic, with some modifications, an attractive candidate to compete with many superalloys for high temperature applications. Recent studies have shown that the inherent brittleness of many polycrystalline intermetallics can be overcome by micro and macroalloying. It has also been found that the high temperature mechanical properties of NiAl can be enhanced through the addition of Nb by powder metallurgical techniques forming a dispersed second phase through interdiffusion in a polycrystalline matrix. A drop in the flow stress is observed however in a NiAl-2 at.% Nb alloy after 0.2 % strain during constant strain rate hot compression testing at 1025°C. The object of this investigation was to identify the second phase and to determine the cause of the flow stress drop.

ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

2019 ◽  
pp. 56-66
Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Titanium Carbide ◽  
Temperature Dependence ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Thermodynamic Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Analysis Data ◽  
Thermal Excitation

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

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