Effect of side-chain length of succinic anhydride on coefficient of thermal expansion behavior of epoxy resins

2006 ◽  
Vol 55 (11) ◽  
pp. 1289-1295 ◽  
Author(s):  
Fan-Long Jin ◽  
Mijeong Han ◽  
Soo-Jin Park
Keyword(s):  
Thermal Expansion ◽  
Chain Length ◽  
Epoxy Resins ◽  
Succinic Anhydride ◽  
Coefficient Of Thermal Expansion ◽  
Side Chain ◽  
Side Chain Length ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior

Thermal Expansion Behavior and Characteristic of SiCp/Al Composites

2011 ◽  
Vol 287-290 ◽  
pp. 658-661 ◽  
Author(s):  
Xian Liang Zhou ◽  
Duo Sheng Li ◽  
Ai Hua Zou ◽  
Xiao Zhen Hua ◽  
Zhi Guo Ye ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Size Range ◽  
Coefficient Of Thermal Expansion ◽  
Pure Aluminum ◽  
Annealing Process ◽  
Ceramic Mold ◽  
Range Space ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior ◽  
Al Matrix

SiCp/Al composites were fabricated by ceramic mold freedom infiltration and pressureless infiltration, respectively. The microstructure and phases are analyzed by metallurgical microscope and coefficient of thermal expansion of SiCp/Al composites were tested by thermal dilatometer. The results show that SiCp/Al composites are compact and uniform. SiC particles were dispersed uniformly in Al matrix, and SiCp segregation was not found in composites. Under a certain SiCp size range, space between SiCp decreases with decreasing of SiCp size, and CTE of SiCp/Al composites also decreases with decreasing of particles size. Compared with CTE of composite with pure aluminum as matrix, CTE of composite with ZL101 as matrix is less. Under the annealing process, CTE of SiCp/Al composites with ZL101 as matrix is less than that with the solution and aging, which indicated that its dimensional stability of resisting to temperature fluctuation is better, and thermal expansion behavior and characteristic of SiCp/Al composites are also better.

scholarly journals Evaluation of the coefficient of thermal expansion of human and bovine dentin by thermomechanical analysis

2012 ◽  
Vol 23 (1) ◽  
pp. 03-07 ◽  
Author(s):  
Murilo Baena Lopes ◽  
Zhuoqun Yan ◽  
Simonides Consani ◽  
Alcides Gonini Júnior ◽  
Anderson Aleixo ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Third Molar ◽  
Weight Changes ◽  
Incisor Tooth ◽  
Test Environment ◽  
Material Interface ◽  
Human Teeth ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior

The mismatch of thermal expansion and contraction between restorative materials and tooth may cause stresses at their interface, which may lead to microleakage. The present work compared the coefficient of thermal expansion (CTE) with the thermomechanical behavior of human and bovine teeth and determined if the CTE is a suitable parameter to describe tooth behavior. Fifteen human third molar and 15 bovine incisor tooth slices (6×5×2 mm) were allocated to 3 groups according to the test environment: G1 - room condition, G2 - 100% humidity, G3 - desiccated and tested in dry condition. Each specimen was weighed, heated from 20 to 70ºC at 10ºC min−1 and reweighed. The CTE was measured between 20 and 50ºC. Fresh dentin (human -0.49% ± 0.27, bovine -0.22% ± 0.16) contracted on heating under dry condition. Under wet conditions, only human teeth (-0.05% ± 0.04) showed contraction (bovine 0.00% ± 0.03) accompanied by a significantly lower (p<0.05) weight loss than in dry specimens (human 0.35% ± 0.15, bovine 0.45% ± 0.20). The desiccated dentin expanded on heating without obvious weight changes (0.00% ± 0.00). The CTE found was, respectively, in dry, wet and dissected conditions in ºC-1: human (-66.03×10-6, -6.82×10-6, 5.52×10-6) and bovine (-33.71×10-6, 5.47×10-6, 4.31×10-6). According to its wet condition, the dentin showed different CTEs. The thermal expansion behavior of human and bovine dentin was similar. A simple evaluation of the thermal expansion behavior of tooth structure by its CTE value may not be appropriate as a meaningful consideration of the effects on the tooth-material interface.

scholarly journals Effects of added SiO2 nanoparticles on the thermal expansion behavior of shape memory polymer nanocomposites

2018 ◽  
Vol 30 (1) ◽  
pp. 32-44 ◽  
Author(s):  
Mohammad Javad Mahmoodi ◽  
Mohammad Kazem Hassanzadeh-Aghdam ◽  
Reza Ansari
Keyword(s):  
Thermal Expansion ◽  
Shape Memory ◽  
Polymer Nanocomposites ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Shape Memory Polymer ◽  
Polymer Nanocomposite ◽  
Thermal Expansion Behavior ◽  
Interphase Region ◽  
Expansion Behavior

In this study, a unit cell–based micromechanical approach is proposed to analyze the coefficient of thermal expansion of shape memory polymer nanocomposites containing SiO2 nanoparticles. The interphase region created due to the interaction between the SiO2 nanoparticles and shape memory polymer is modeled as the third phase in the nanocomposite representative volume element. The influences of the temperature, volume fraction, and diameter of the SiO2 nanoparticles on the thermal expansion behavior of shape memory polymer nanocomposite are explored. It is observed that the coefficient of thermal expansion of shape memory polymer nanocomposite decreases with the increase in the volume fraction up to 12%. Also, the results reveal that with the increase in temperature, the shape memory polymer nanocomposite coefficient of thermal expansion linearly increases. The role of interphase region on the thermal expansion response of the shape memory polymer nanocomposite is found to be very important. In the presence of interphase, the reduction in nanoparticle diameter leads to lower coefficient of thermal expansion for shape memory polymer nanocomposite, while the variation of nanoparticles diameter does not affect the coefficient of thermal expansion in the absence of interphase. Based on the simulation results, the shape memory polymer nanocomposite coefficient of thermal expansion decreases as the interphase thickness increases. In addition, the contribution of interphase coefficient of thermal expansion to the shape memory polymer nanocomposite coefficient of thermal expansion is more significant than that of interphase elastic modulus.

Computational modeling and relevance of numerical convergence for the investigation of thermal expansion behavior for aluminium hybrid composites

2016 ◽  
Vol 05 (02) ◽  
pp. 1650007
Author(s):  
S. A. Mohan Krishna ◽  
T. N. Shridhar ◽  
L. Krishnamurthy
Keyword(s):  
Silicon Carbide ◽  
Thermal Expansion ◽  
Hybrid Composites ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Expansivity ◽  
Numerical Convergence ◽  
Thermal Expansion Behavior ◽  
Al 6061 ◽  
Expansion Behavior ◽  
Wide Range

The thermal characterization and analysis of composite materials has been increasingly important in a wide range of applications. The coefficient of thermal expansion (CTE) is one of the most important properties of metal matrix composites (MMCs). Since nearly all MMCs are used in various temperature ranges, measurement of CTE as a function of temperature is necessary in order to know the behavior of the material. In this research paper, the evaluation of CTE or thermal expansivity has been accomplished for Al 6061, silicon carbide and graphite hybrid MMCs from room temperature to [Formula: see text]C. Aluminium-based composites reinforced with silicon carbide and graphite particles have been prepared by stir casting technique. The thermal expansivity behavior of hybrid composites with different percentage compositions of reinforcements has been investigated. The results have indicated that the thermal expansivity of different compositions of hybrid MMCs decrease by the addition of graphite with silicon carbide and Al 6061. Empirical models have been validated for the evaluation of thermal expansivity of composites. Numerical convergence test has been accomplished to investigate the thermal expansion behavior of composites.

Thermal Expansion Behavior of Alloyed Pearlitic Flake Graphite Cast Irons

1986 ◽  
Vol 108 (4) ◽  
pp. 358-364
Author(s):  
M. C. Rukadikar ◽  
G. P. Reddy
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Melting Furnace ◽  
Steel Scrap ◽  
Electric Melting ◽  
Flake Graphite ◽  
Cast Irons ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior ◽  
Nickel Copper

Precise understanding of thermal expansion behavior of flake graphite cast irons is essential to know the thermal fatigue resistance of these irons when used for elevated temperature application like diesel engine components, ingot moulds, hot mill rolls, glass moulds, dies, etc. Twenty-three pearlitic flake graphite irons having identical base compositions (levels of sulfur, manganese, phosphorus, dissolved gases, and trace elements) having two levels of carbon (3.93 percent and 3.00 percent) and alloyed with elements such as molybdenum, vanadium, chromium, tin, nickel, copper, antimony, and aluminum were produced by carburizing steel scrap in an electric melting furnace. Thermal expansion behavior of all these irons were studied with the help of a dilatometer to determine the influence of graphite morphology and chemical composition. It is seen from the results that thermal contraction of flake graphite irons follows a different path during cooling than the thermal expansion path followed during heating. Further increase in graphitic carbon and coarseness of graphite tend to lower the coefficient of thermal expansion. Additions like molybdenum/copper at high level help in reducing thermal expansion; higher content of tin/antimony/aluminum/silicon tend to increase it while chromium/nickel/copper at low level have no effect. The present investigation has thus provided information regarding thermal expansion/contraction behavior of twenty-three flake graphite irons having almost all commonly used alloying elements.

scholarly journals Experimental Study on Thermal Expansion Behavior of Concrete under Three-Dimensional Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhipeng Yu ◽  
Fan Zhang ◽  
Xiao Ma ◽  
Fujian Yang ◽  
Dawei Hu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Stress State ◽  
Coefficient Of Thermal Expansion ◽  
Three Dimensional ◽  
Test System ◽  
True Triaxial Test ◽  
Underground Engineering ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior

Concrete is widely used in underground engineering and bears three-dimensional stress transmitted by overlying load. When a fire occurs, the thermal expansion of concrete structure under such stress state is different from that under stress-free state. For this purpose, a self-developed real-time high-temperature true triaxial test system was applied to investigate the thermal expansion behavior of concrete under three-dimensional stress state. The thermal expansion strain of concrete under the three-dimensional stress undergoes strain increasing and strain stabilizing stages. At 600°C, the maximum thermal expansion strain of concrete under the three-dimensional stress is 0.75%. The average coefficient of thermal expansion of concrete under three-dimensional stress condition was then calculated, and its value reaches the minimum of 8.68 × 10−6/°C at 200°C and the maximum of 13.41 × 10−6/°C at 500°C. Comparing the coefficient of thermal expansion of concrete under stress-free condition given by Eurocode, it is found that the three-dimensional stress has an obvious restraint on the thermal expansion of concrete. The research results can provide theoretical basis for the stability analysis of underground engineering concrete structures under high-temperature environment.

scholarly journals Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1789
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

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