JPH0731141B2 - Differential scanning calorimeter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential scanning calorimetry (DSC) device which is a kind of thermal analysis device.
In particular, it is characterized by the data processing of the measurement data.

[0002]

2. Description of the Related Art A differential scanning calorimeter is equipped with a differential scanning calorimeter for measuring a heat flow rate while increasing a sample temperature, and a data processor for calculating a specific heat of a sample from measured data of the differential scanning calorimeter. ing. When comparing and comparing DSC curves of different samples or DSC curves of the same type of sample that were measured under different measurement conditions, the sample masses of those measurement data are usually different, so the DSC curve may be expanded. The heat flow value is adjusted to a common scale by reducing it. As this conversion method, a method in which a value obtained by simply dividing the heat flow rate value Q (ordinate of the DSC curve) by the sample mass is adopted as the normalized heat flow rate value is generally used. This is usually called standardization of data.

[0003]

The peak height of the DSC curve is not originally proportional to the sample mass, and the amount obtained by simply dividing the heat flow rate value by the sample mass is still an amount dependent on the sample mass. . Specifically, the peak of the DSC curve measured on a sample with a small mass and normalized per unit mass is more relative to the peak of the DSC curve measured on a sample with a larger mass and normalized per unit mass. It tends to be overestimated. Therefore, the method of simply dividing the heat flow rate value by the sample mass does not achieve normalization. It is an object of the present invention to provide a differential scanning calorimeter which has a data processing function and can properly standardize and output a DSC curve.

[0004]

[Means for Solving the Problems] A sample mass m, an apparatus constant R, a heating rate α, a specific heat c, a latent heat of transition ΔH ₀ , a peak height h of a DSC curve, a half width w, and an area S are as follows. There is a relationship of (1) to (3).

[0005]

[Equation 4]

[Equation 5]

[Equation 6] S = mΔHo (3)

Of these, m, R and α are known values,
Since h, w, and S can be obtained by actual measurement, c and ΔH ₀ can be calculated, which allows the sample mass m and the peak height h to be calculated.
Can be obtained. The peak height h ₀ per unit mass can be obtained from this relational expression, and the heat flow rate Q can be calculated by the ratio between the peak height h ₀ and the peak height h of the DSC curve of the measured data.
If is standardized, the correct standardization is performed.

The present invention is shown in FIG. 2 is a differential scanning calorimeter that measures the heat flow rate Q while raising the sample temperature,
The data processing device that calculates the specific heat of the sample from the measurement data of the differential scanning calorimeter 2 includes a data memory 4, a sample characteristic value calculation unit 6, a normalization unit 8 and an output unit 10. The data memory 4 stores the actual measurement data from the differential scanning calorimeter 2. The sample characteristic value calculator 6 calculates at least two of the peak height h, the peak half width w, and the peak area S of the DSC curve from the data stored in the data memory 4, and the calculated value and the values are input in advance. Using the temperature rising rate α, the device constant R and the sample mass m, the specific heat c and the transition latent heat ΔH ₀ of the sample are calculated according to the above equations (1) to (3). The normalization unit 8 uses the calculated specific heat c, the transition latent heat ΔH ₀ , the temperature rising rate α, the device constant R, and the sample mass m which are input in advance, and uses the above equation (1) to calculate the peak height h per unit mass. Calculate ₀ . The output unit 10 calculates the ratio h ₀ / h of the calculated peak height h ₀ per unit mass and the actually measured peak height h.
Then, the measured heat flow rate value Q is standardized, and the standardized DSC curve is output as Q ₀ = Q · h ₀ / h.

[0008]

2 and 3 show an example of the operation of the present invention.
The device constant R is a thermal resistance between the sample part and the heat source, which is a value specific to the DSC device used and is previously input to the data processing device. The heating rate α is a set value,
The sample mass m is a measured value, and both are input to the data processing device. When the measurement is started, the heat flow rate value Q is fetched as actual measurement data with respect to temperature or time and is stored in the data memory. When the measured data is plotted, a DSC curve as shown in FIG. 3 (A) is obtained.

From this DSC curve, at least two of the peak height h, peak half width w, and peak area S shown in FIG. 3B are automatically calculated. Using the input or set R, α, m and the calculated h, S, w, the specific heat c and the latent heat of transition ΔH _{0 are} calculated from the relationships of the equations (1) to (3).
Is calculated.

Next, as shown in FIG.
In equation (1), those set values or input values and calculated values c, ΔH
₀ is substituted, and the peak height h ₀ when the sample mass m is 1 is calculated. When plotting the measurement data again, the heat flow rate value Q measured by the ratio h ₀ / h of the normalized peak height h ₀ and the measured peak height h was normalized to Q ₀ , 3 (D) is output. Q ₀
= Q · h ₀ / h.

[0011]

EXAMPLE FIG. 4 shows an example. Differential scanning calorimeter 2
The data processing device for processing the actual measurement data is realized by, for example, a personal computer. The data processing device is provided with a CPU 12, and the CPU 12 has a ROM 1 holding a data processing program via a bus 14.
6, a RAM 18, a CRT 20, a keyboard 22, a plotter 24, etc. are connected, and an A / D converter 26 is provided for converting the measurement data from the differential scanning calorimeter 2 into a digital signal and loading it into the CPU 12. .

The data processing device is not limited to a general-purpose personal computer, but may be a microcomputer system having such a function. 1 and 4, the data memory 4 corresponds to the RAM 18, and the sample characteristic value calculation unit 6 and the normalization unit 8 include the CPU 12 and the ROM 1.
6 and the RAM 18. The output unit 10 corresponds to the plotter 24.

[0013]

INDUSTRIAL APPLICABILITY In the present invention, rather than simply dividing the DSC actual measurement data by the sample mass, the specific heat and the transition latent heat are calculated from the actual measurement data, and the relational expression (1) representing the relationship between the peak height and various conditions and measured values is obtained. ) Was used to calculate the peak height per unit mass, and the DSC curve was standardized based on this, so strict standardization of different samples and different data obtained under various measurement conditions should be performed. Will be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing the present invention.

FIG. 2 is a flowchart showing an example of the operation of the present invention. (A)-(D) in FIG. 2 are (A)-(next) in FIG.
It corresponds to (D).

FIG. 3 is a diagram showing a procedure of data processing according to the operation of FIG.

FIG. 4 is a block diagram showing an example.

[Explanation of symbols]

 2 Differential scanning calorimeter 4 Data memory 6 Sample characteristic value calculation unit 8 Normalization unit 10 Output unit

Claims (1)

[Claims] 1. A data processing apparatus comprising: a differential scanning calorimeter for measuring a heat flow rate Q while increasing a sample temperature; and a data processing device for calculating a specific heat of a sample from measurement data of the differential scanning calorimeter. Is a data memory that stores the actual measurement data from the differential scanning calorimeter, and at least two of the peak height h, the peak half width w, and the peak area S of the DSC curve are calculated from the data stored in this data memory. A sample characteristic for calculating the specific heat c and the latent heat of transition ΔH ₀ of the sample according to the following equations (1) to (3) using the calculated value, the temperature rising rate α, the device constant R, and the sample mass m which are input in advance. Value calculator, calculated specific heat c, transition latent heat ΔH ₀
Also, using the temperature rising rate α, the device constant R and the sample mass m which are input in advance, a normalization unit for calculating the peak height h ₀ per unit mass by the following formula (1), and the calculated unit mass per unit mass and normalizing the measured heat flow value Q by the ratio h ₀ / h of the peak height h ₀ and the measured peak height h of the Q ₀ = Q · h
An output unit for outputting a DSC curve standardized as ₀ / h, a differential scanning calorimeter. [Equation 1] [Equation 2] [Equation 3] S = mΔHo (3)