scholarly journals Identification of the Temperature Dependence of the Thermal Expansion Coefficient of Polymers

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3035
Author(s):  
Igor N. Shardakov ◽  
Aleksandr N. Trufanov
Keyword(s):  
Thermal Expansion ◽  
Temperature Change ◽  
Expansion Coefficient ◽  
Strain Response ◽  
Uv Curable ◽  
Change Rate ◽  
Heating And Cooling ◽  
Thermal Expansion Coefficients ◽  
Wide Range ◽  
Uniform Temperature Field

In this paper, we proposed an approach to study the strain response of polymer film samples under various temperature effects and note their corresponding effects. The advantages of the developed approach are determined by the fact that thin films of material are used as samples where it is possible to generate a sufficiently uniform temperature field in a wide range of temperature change rates. A dynamic mechanical analyzer was used for the experimental implementation of the above approach for two UV-curable polymers and one type of epoxy resin. Experimental results have shown that the thermal expansion coefficients for these polymers depend significantly not only on the temperature but also on its change rate. The strain response of the polymer to heating and cooling, with the same absolute values of the rate of temperature change, differs significantly, and this dissimilarity becomes stronger with its increasing. The results of thermomechanical experiments for massive samples on traditional dilatometer are shown to compare with the results for film samples. The discovered dependences of the temperature expansion coefficient on the temperature and its change rate can be used for mathematical modeling of thermomechanical processes arising during the operation of products made of polymers.

Measurement of thermal expansion coefficient of substrate GGG and its epitaxial layer YIG

1999 ◽  
Vol 14 (1) ◽  
pp. 2-4 ◽  
Author(s):  
Rui-sheng Liang ◽  
Feng-chao Liu
Keyword(s):  
Thin Film ◽  
Thermal Expansion ◽  
Single Crystal ◽  
Thermal Expansion Coefficient ◽  
Epitaxial Layer ◽  
Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
New Method ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

A new method is used in measuring the linear thermal expansion coefficients in composite consisting of a substrate Gd3Ga2Ga3O12 (GGG) and its epitaxial layer Y3Fe2Fe3O12 (YIG) within the temperature range 13.88 °C–32.50 °C. The results show that the thermal expansion coefficient of GGG in composite is larger than that of the GGG in single crystal; the thermal expansion coefficient of thick film YIG is also larger than that of thin film. The results also show that the thermal expansion coefficient of a composite consisting of film and its substrate can be measured by using a new method.

scholarly journals Twisted Fibers Can Have an Adjustable Thermal Expansion

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 456
Author(s):  
Donghua Yue ◽  
Liming Wei
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Carbon Fibers ◽  
Expansion Coefficient ◽  
Twist Angle ◽  
Capacitive Sensor ◽  
Model Calculations ◽  
Thermal Expansion Coefficients ◽  
Geometrical Features ◽  
Expansion Coefficients

In this paper, a device with high accuracy capacitive sensor (with the error of 0.1 micrometer) is constructed to measure the axial thermal expansion coefficent of the twisted carbon fibers and yarns of Kevlar. A theoretical model based on the thermal elasticity and the geometrical features of the twisted structure is also presented to predict the axial expansion coefficient. It is found that the twist angle, diameter and pitch have remarkable influences on the axial thermal expansion coefficients of the twisted carbon fibers and Kevlar strands, and the calculated results are in good agreement with experimental data. We found that, with the increase of the twist angle, the absolute value of the axial thermal expansion coefficient increases. For the Kevlar samples, the expansion coefficient will grow by about 46% when the twist angle increases from 0 to 25 degrees, while the carbon fiber samples will grow by about 72% when the twist angle increases from 0 to 35 degrees. The experimental measurements and the model calculations reveal important properties of the thermal expansion in the twisted structures. Most notably, the expansion of the strand during heating or cooling can be zero when the twist angle is around β = arcsin(αL/αT)^1/2, where β denotes twist angle of the strand and αL, αT are the longitute and the transverse thermal expansion coefficient of the strand, respectively. According to the present experiments and analyses, a method to control the axial thermal expansion coefficient of this new kind of twisted structure is proposed. Moreover, the mechanism of this tunable thermal expansion is discussed. Based on the model, a method that can be used to rectify the thermal expansion properties of the twist structures is established. This may be a new way of fabricating zero expansion composite materials in the future.

Thermal expansion coefficients of a binary alloy Ni80Zr20 at elevated temperatures

1984 ◽  
Vol 17 (5) ◽  
pp. 359-360
Author(s):  
S. K. Shadangi ◽  
U. K. Shadangi ◽  
S. C. Panda
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Elevated Temperatures ◽  
Intermetallic Phase ◽  
Lattice Parameter ◽  
Solid Solution Phase ◽  
Linear Variation ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The Debye–Scherrer pattern of the alloy Ni80Zr20 clearly shows the presence of a nickel solid-solution phase along with a new intermetallic phase Ni23Zr6, which seems to be isostructural with the Co23Zr6 phase. The thermal expansion coefficient of the Ni23Zr6 phase has been investigated in the temperature range 1003–1493 K. Linear variation of lattice parameter with temperature has been observed. The thermal expansion coefficient remains almost constant throughout this temperature interval.

Analyzing Hysteresis and Thermal Expansion Coefficient of M40/AZ91D during Thermal Cycling

2017 ◽  
Vol 898 ◽  
pp. 890-897
Author(s):  
Mei Hui Song ◽  
Yu Zhang ◽  
Yan Chun Li ◽  
Guo Qin Chen ◽  
Zi Yang Xiu
Keyword(s):  
Thermal Expansion ◽  
Thermal Cycling ◽  
Temperature Change ◽  
Residual Strain ◽  
Coefficient Of Thermal Expansion ◽  
Internal Heat ◽  
Impregnation Method ◽  
Change Rate ◽  
Temperature Range ◽  
Temperature Change Rate

In this work, AZ91D composite reinforced with M40 fiber was prepared by pressure impregnation method. Expansion behaviors of M40/AZ91D composite were studied with thermal expansion instrument in 25-150 °C and 25-150 °C temperature ranges of internal heat circulation, and then analyzed the influence law of hysteresis, residual strain and coefficient of thermal expansion (CTE) by different temperature change rate. The results revealed that residual stress and strain in process of pressure impregnation would lead to strain hysteresis and residual strain of composite in thermal cycling. At the same time, the CTE of the composites decreased with the increase of cycle times. Residual strain of the composite went up with the rise of temperature changed rate of the thermal cycling and CTE decreased with temperature change rate ascending in the 25-150°C temperature range. The CTE of the composites decreased with the increase of temperature during the heating process, which cut down with the increase of temperature in process of heating and cooling in the 25-495°C temperature range.

scholarly journals Thermal expansion coefficient of few-layer MoS2 studied by temperature-dependent Raman spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhongtao Lin ◽  
Wuguo Liu ◽  
Shibing Tian ◽  
Ke Zhu ◽  
Yuan Huang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Negative Thermal Expansion ◽  
Thermal Parameter ◽  
Temperature Dependent ◽  
Bending Vibrations ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

AbstractThe thermal expansion coefficient is an important thermal parameter that influences the performance of nanodevices based on two-dimensional materials. To obtain the thermal expansion coefficient of few-layer MoS2, suspended MoS2 and supported MoS2 were systematically investigated using Raman spectroscopy in the temperature range from 77 to 557 K. The temperature-dependent evolution of the Raman frequency shift for suspended MoS2 exhibited prominent differences from that for supported MoS2, obviously demonstrating the effect due to the thermal expansion coefficient mismatch between MoS2 and the substrate. The intrinsic thermal expansion coefficients of MoS2 with different numbers of layers were calculated. Interestingly, negative thermal expansion coefficients were obtained below 175 K, which was attributed to the bending vibrations in the MoS2 layer during cooling. Our results demonstrate that Raman spectroscopy is a feasible tool for investigating the thermal properties of few-layer MoS2 and will provide useful information for its further application in photoelectronic devices.

Measurement Principle of Glass Thermal Expansion Coefficient and Technology Application of DIL402PC Dilatometer

2014 ◽  
Vol 983 ◽  
pp. 251-256
Author(s):  
Yan Hua Sun ◽  
Dong Qing Zhang ◽  
Fei Wu ◽  
Kai Sun
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
It Use ◽  
Standard Samples ◽  
Technology Application ◽  
Wide Range ◽  
System Check ◽  
Coefficient Of Linear Expansion ◽  
Accuracy And Repeatability

The paper introduces the measuring principle of glass thermal expansion coefficient. It expresses the features and advantages of the linear variable differential transformer measuring principle by comparing the thermal expansion coefficient measurement methods analysis. Meanwhile, the paper introduces DIL402PC dilatometer measuring devices and measurement procedures. It use standard samples to execute thermal expansion instrument system check from the accuracy and repeatability. The result shows thermal expansion coefficient of linear expansion instrument bias of DIL402PC dilatometer is within the error range of the theoretical value. The process proves it has a wide range of applications.

The Alloy Design of Metallic Interconnector of Solid Oxide Electrolyte Fuel Cell (SOFC)

2007 ◽  
Vol 561-565 ◽  
pp. 1617-1620
Author(s):  
Ian Bo Chen ◽  
Shuang Shii Lian ◽  
Chia Ying Li ◽  
Wei Ja Shong ◽  
Ruey Yi Lee
Keyword(s):  
Thermal Expansion ◽  
Fuel Cell ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Low Cost ◽  
Melting Furnace ◽  
Solid Oxide ◽  
Temperature Oxidation ◽  
Thermal Expansion Coefficients ◽  
Metallic Interconnector

This study is intended to reduce the difference of thermal expansion coefficient between metallic interconnector and solid electrolyte of SOFC (Solid Oxide Fuel Cell) without sacrificing of electrical conductivity. Fe-Cr alloys have been chosen as candidate materials due to its merit of low cost and high temperature oxidation resistance. Different amount of alloys element and compositions have been varied to optimize the properties by method of alloys design with aid of thermodynamics software Thermal-Cal. Phase diagrams of multi-components alloys have been drawn to predict the possible stable phases formed in the investigated metals. An arc melter and plasma melting furnace were used to melt the investigated alloys. The measurements of thermal expansion coefficients and electrical conductivities are carried out with TMA and ASR resistance instrument. The results indicate that the Fe-10Cr alloy exhibits the smallest thermal expansion coefficient among the alloys, while Fe-16Cr has a lowest electrical resistance .

Research on the Apparent Thermal Expansion Coefficient of Concrete Subject to Freeze-Thaw Cycles and Chloride Salt Attack

2012 ◽  
Vol 446-449 ◽  
pp. 3304-3310 ◽  
Author(s):  
Zhen Di Wang ◽  
Yan Yao ◽  
Ling Wang
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Chloride Salt ◽  
Absolute Value ◽  
Freeze Thaw ◽  
Heating And Cooling ◽  
Water To Cement Ratio ◽  
Temperature Rate ◽  
Concrete Matrix

The aim of the research is to determine the strain-temperature rate and investigate the apparent thermal expansion coefficient of three kinds of concrete (ATEC). The strain of concrete with the dimension of 100mm×100mm×100mm subject to freeze-thaw cycles and chloride salt attack were measured using an embedded strain gauge. The ATEC was calculated from the strain-temperature rate using linear regression. The results show that the absolute value of ATEC of specimen saturated by 3.5 wt. % chloride salt solution was reducing with the progress of freeze-thaw cycles. However, the ATEC of the dried specimen subject to heating and cooling is independent from water to cement ratio, and approximately maintains the same level during the whole heating and cooling cycle, and the ATEC of air-entrained specimen is constant within 20 cycles. Overall, deterioration of concrete matrix can be evaluated by apparent thermal expansion coefficient besides weight loss and dynamic elastic modulus.

scholarly journals ESTIMATIVA DO COEFICIENTE DE EXPANSÃO TÉRMICA DE MISTURAS DE ÓLEO DIESEL E ÓLEO DE SOJA RESIDUAL

e-xacta ◽  
2013 ◽  
Vol 6 (1) ◽  
pp. 67
Author(s):  
César Augusto Canciam
Keyword(s):  
Thermal Expansion ◽  
Regression Analysis ◽  
Linear Regression ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Alternative Energy ◽  
Linear Regression Analysis ◽  
Diesel Oil ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

<p align="justify">A utilização de óleos vegetais residuais como fonte de energia alternativa vem ganhando espaço investigativo no Brasil, principalmente na produção de biocombustíveis e de misturas combustíveis com óleo diesel. O presente trabalho teve por objetivo estimar o coeficiente de expansão térmica de misturas de óleo diesel (OD) e óleo de soja residual (OSR) a partir da modelagem matemática de dados da massa específica em função da temperatura. As misturas estudadas foram: mistura 1 (25% OSR + 75% OD), mistura 2 (50% OSR + 50% OD) e mistura 3 (75% OSR + 25% OD). O intervalo de temperatura considerado foi de 25 a 90ºC. Para a estimativa do coeficiente de expansão térmica foi realizada uma análise de regressão linear. Os valores do coeficiente de expansão térmica encontrados foram 7,7508 x 10-4ºC-1 (para a mistura 1), 8,3355 x 10-4ºC-1 (para a mistura 2) e 8,2249 x 10-4ºC-1(para a mistura 3). Nas análises de regressão linear, os coeficientes de correlação foram próximos da unidade, indicando que para cada mistura a correlação é classificada como muito forte. A ausência na literatura de valores do coeficiente de expansão térmica para misturas OD + OSR dificultou a comparação com os valores encontrados.</p><p align="justify">Abstract</p><p align="justify">The use of residual vegetable oils as an alternative energy source is gaining momentum investigative in Brazil, mainly in the production of biofuels and blends with Diesel oil. This study aimed to estimative the thermal expansion coefficient of mixtures of Diesel oil (DO) and residual soybean oil (RSO) from the mathematical modeling of data of specific weight as a function of temperature. The mixture 1 (25% RSO + 75% DO), mixture 2 (50% RSO + 50% DO) and mixture 3 (75% RSO + 25% DO) were studied. The temperature range considered was 25 to 90ºC. A linear regression analysis was performed to estimative the values of the thermal expansion coefficient. The thermal expansion coefficients were 7.7508 x 10-4 ºC-1 (for the mixture 1), 8.3355 x 10-4 ºC-1 (for the mixture 2) and 8.2249 x 10-4 ºC-1 (for the mixture 3). In linear regression analysis, the correlation coefficients were close to unity, indicating that the correlation for each mixture is classified as very strong. The absence in the literature of the thermal expansion coefficients of the mixtures DO + RSO made it difficult the comparing with the values found.</p>

Implications of Stress Dependency of the Thermal Expansion Coefficient on Thermal Buckling

1992 ◽  
Vol 114 (2) ◽  
pp. 189-192 ◽  
Author(s):  
C. W. Bert ◽  
C. Fu
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Temperature Dependent ◽  
Elastic Coefficient ◽  
Wide Range ◽  
Mechanics Analysis ◽  
Thermoelastic Solid ◽  
Stress Dependent ◽  
Stress Dependency

A thermosolid mechanics analysis based on sound thermodynamic and mechanical principles is derived for a thermoelastic solid in which the elastic coefficient is temperature-dependent, and thus the TEC (thermal expansion coefficient) must be stress-dependent. The theory is applied to the case of slender elastic members with full axial restraint and subjected to a uniform increase in temperature. Numerical results are presented for a wide range of materials and slenderness ratios.

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