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Method for determining coefficient of thermal expansion

A technology of thermal expansion coefficient and measurement method, applied in the direction of thermal expansion coefficient of materials, etc., can solve problems such as large difference in results, complex and expensive instruments, and inability to prepare bulk samples

Active Publication Date: 2014-04-09
SHENZHEN INST OF ADVANCED TECH CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It is very difficult to directly measure the strain of carbon nanomaterials as a function of temperature
So far, the relationship between the strain of carbon nanomaterials and temperature has been mainly determined by theoretical calculations. However, the results predicted by various theoretical models vary greatly. It is still unclear whether carbon nanomaterials will expand or contract when heated at room temperature.
The experimental measurement method that has been developed now is mainly to measure the change of grain size with temperature through X-ray diffraction. This method has high precision, but the measurement sample is small, the measurement speed is slow, and the instrument is complicated and expensive.
Similarly, a large number of solvent-based polymer slurries used in the semiconductor industry are finally processed into thin films, and regular-shaped bulk samples cannot be prepared. To measure the thermal expansion coefficient of these materials, it is necessary to develop a more concise and efficient measurement method

Method used

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  • Method for determining coefficient of thermal expansion

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0140] Determination of Thermal Expansion Coefficient of Bisphenol A Type Epoxy Resin

[0141] 1. Place a single alumina fiber in a heating table, place the heating table on an optical microscope stage, and heat the alumina fiber between 22°C and 142°C with a step length of 10°C, using Renishaw2000 to pull The Raman system measures the Raman spectra at different temperatures, and collects the Raman spectra of the alumina fibers at different temperatures with 633nm laser excitation, and obtains 13 first Raman spectral values. Among them, the R1 peaks of alumina fibers at 295K and 415K are as follows image 3 shown. Take 13 temperature values ​​of 22°C, 32°C, 42°C, 52°C, 62°C, 72°C, 82°C, 92°C, 102°C, 112°C, 122°C, 132°C and 142°C as the abscissa, and use the corresponding The 13 first Raman spectrum values ​​of 13 are used as the ordinate, and the 13 temperature values ​​and 13 corresponding first Raman spectrum values ​​are linearly fitted, and the linear diagram is as follo...

Embodiment 2

[0148] Determination of the thermal expansion coefficient of carbon nanotubes

[0149] 1. Place the single-walled carbon nanotubes in a heating stage, place the heating stage on the stage of an optical microscope, and heat the carbon nanotubes between 22°C and 162°C with a step length of 10°C, using Renishaw2000 to pull The Raman system uses 633nm laser excitation to collect Raman spectra of carbon nanotubes at different temperatures, and obtains 15 first spectral values. With 15 temperature values ​​of 22°C, 32°C, 42°C, 52°C, 62°C, 72°C, 82°C, 92°C, 102°C, 112°C, 122°C, 132°C, 142°C, 152°C and 162°C As the abscissa, with the corresponding 15 first spectral values ​​as the ordinate, the 15 temperature values ​​and the 15 corresponding first spectral values ​​are linearly fitted, and the linear diagram is as follows Figure 9 As shown, the linear relationship is ω G’ =2643-0.029T. Determine χ from this linear relationship F , the values ​​are listed in Table 1;

[0150] 2....

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Abstract

The invention relates to a method for determining a coefficient of thermal expansion. The method comprises the steps of determining a spectral peak movement amount of a to-be-detected sample caused by the variation of unit temperature to be recorded as ChiF; mixing the detected sample and polymer to obtain a mixture, and ultrasonically dispersing the mixture to obtain a composite material; determining a second spectral value of the composite material under a surface strain value by utilizing a strain determining device and a spectral system, linearly fitting the surface strain value and the second spectral value, determining the spectral peak movement quantity of the detected sample, which is caused by the unit strain and is parallel to the strain direction to be recorded as SO; determining the spectral peak movement amount of the detected sample in the composite material caused by the unit temperature variation by utilizing the spectral system to be recorded as ChiC; calculating the coefficient of the thermal expansion of the detected sample according to the following formula if the coefficient alpha E of the polymer is known: alpha F=alpha E-(ChiC-ChiF) / SO. The method is simple, convenient in determination and capable of rapidly and accurately determining the coefficient of the thermal expansion of the detected sample.

Description

technical field [0001] The invention relates to the technical field of material parameter measurement, in particular to a method for measuring thermal expansion coefficient. Background technique [0002] Carbon nanomaterials, such as carbon nanotubes and graphene, have broad application prospects due to their excellent physical and chemical properties. For situations where the temperature changes greatly during material processing or under working conditions, if the thermal expansion coefficient of the carbon nanomaterial and the substrate in contact with it does not match, residual stress will occur, and in severe cases, interface slip or peeling will occur between the two phases. However, the measurement of the thermal expansion coefficient of carbon nanomaterials has always been a problem that plagues academic and industrial circles. [0003] The coefficient of linear thermal expansion describes the ratio of the elongation of a material to the original length caused by a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N25/16
Inventor 孙蓉邓立波张国平
Owner SHENZHEN INST OF ADVANCED TECH CHINESE ACAD OF SCI
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