JPH0640070B2 - Fourier transform infrared spectrophotometer measuring device with differential scanning calorimeter - Google Patents

Description

The present invention relates to a Fourier transform infrared spectrophotometric (FTIR) measuring apparatus equipped with a differential scanning calorimeter (hereinafter DSC) and a reflection type infrared microscope. .

[Prior Art] The purpose of FTIR is to obtain an infrared absorption spectrum similarly to a conventional infrared spectrophotometer (dispersive IR). That is, in the dispersion type IR, the light emitted from the light source is applied to the sample and then introduced into the spectroscope, and the spectrum is obtained by dispersing the light into a monochromatic light by the diffraction grating. Instead, an interferometer is used to generate interference light and apply it to the sample.

In the case of FTIR, an interference waveform called an interferogram is obtained instead of a spectrum signal obtained directly from the detector. This is a waveform obtained by reciprocating the moving mirror of the interferometer back and forth. In order to obtain a spectrum from the obtained interferogram, mathematical calculation called Fourier transform is necessary. The computer calculates this at high speed.

On the other hand, thermal analysis has hitherto been mainly used for measurement for research and development, but nowadays, a test standard using thermal analysis has been established, and practical application, that is, quality control and process control at the production site. It has become an era when it is used for acceptance inspection of materials.

In that field, we have started with polymers, glass, ceramics,
It covers a wide range of fields including metals, gunpowder, semiconductors, pharmaceuticals, and foods.

Two types of (A) heat-flux type and (B) heat-compensating type have been incorporated into the DSC, but at present, the heat-flux type is widely used.

In the heat flux DSC, a sample and a reference substance are placed on a metal plate (generally constantan, which is a thermocouple material) connected to a heating furnace that is a heat sink, and the temperature difference between the sample and the reference substance is measured. There is. Since the difference in the amount of heat flowing into the sample and the reference substance from the heat sink is proportional to the temperature difference between the sample and the reference substance, the heat flow rate (mJ / sec) is indirectly measured by measuring the temperature difference. You are doing it.

In the heat flux DSC, since the sample and the reference material are installed in a heating furnace with a good temperature distribution, noise due to temperature fluctuations in the heating furnace and noise due to changes in convection are extremely small. Since it is stable, highly sensitive measurement is possible.

On the other hand, in the heat-compensated DSC, a micro-heater that can separately heat the sample and the reference substance is provided to raise and lower both of them at a constant speed, and at that time, the temperature difference between the sample and the reference substance is always zero. Thus, the amount of power supplied to the micro heater is controlled. This difference in power supply (mJ / se
c) is stored.

In the heat compensation type DSC, the heat capacity of the holder and the micro-heater is small, so that the temperature followability is good, and the thermal resistance from the heater to the sample is small, so that the peak is sharp and the so-called peak resolution is excellent.

Regardless of which method is used, the DSC has the feature of being able to quantitatively handle data, such as high measurement accuracy of calorific value and specific heat measurement.

However, care must be taken not to decompose the sample, because it is not suitable for measuring decomposition reactions.

The sample for DSC measurement may have any form such as film, fiber or particle, and the sample amount may be as small as several mg.

According to the measurement chart, for example, in the case of polyetheretherketone (PEEK), the glass transition point (endotherm) at 142.4 ° C, the low temperature crystallization point (exothermic) at 176.1 ° C,
There is a melting point (endotherm) at 340.8 ° C. The heat of crystallization is
The heat of fusion is 97.5 mJ and the heat of fusion is 150.2 mJ. These amounts of heat are obtained from the peak area, but the DSC signal is integrated with time in the data processing.

By directly connecting the DSC and FTIR, it is possible to simultaneously measure the change in the amount of heat of the sample and the infrared spectrum when the temperature is raised or lowered.

In the conventional DSC / FTIR measurement, the cell portion of the DSC has a structure capable of transmitting infrared light, and the infrared spectrum is measured by a transmission infrared microscope.

[Problems to be Solved by the Invention] In the conventional method, since the cell part of the DSC has a structure capable of transmitting infrared light, the measurable sample is
There was a problem that it was limited to something like a transparent film. Many samples to be subjected to DSC measurement are in powder form, and it is difficult to measure the infrared spectrum of these samples by a transmission method.

An object of the present invention is to provide a DSC / FTIR device that can measure even a powder sample by measuring an infrared spectrum by a reflection method.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following constitution. That is, the present invention comprises a differential scanning calorimeter and a Fourier transform infrared spectrophotometer attached with a reflectometer infrared microscope, the detection unit of the differential scanning calorimeter is installed on the sample stage of the infrared microscope, A Fourier transform infrared spectrophotometer with a differential scanning calorimeter characterized in that a window plate made of an infrared spectrum transmitting material is provided on the upper portion of the sample cup of the cell part of the scanning calorimeter to transmit infrared rays by the reflection method. It is a measuring device.

[Operation] The present invention relates to FTIR and DS equipped with a reflection infrared microscope.
The detection part of the DSC is installed on the sample stage of the infrared microscope, and the cell part of the DSC transmits infrared rays by the reflection method so that the infrared spectrum can be measured by the reflection method. By providing a window plate made of infrared spectrum transmitting material, for samples whose molecular structure or crystal structure changes with temperature change,
The calorific value change and infrared spectrum of the sample can be measured simultaneously.

In the present invention, the window plate made of the infrared transmitting material is B
It is preferably a crystal plate made of aF ₂ and having an inert gas flow hole. This is because the BaF ₂ crystal plate has an excellent function of transmitting infrared rays by the reflection method. Alternatively, a KBr crystal plate or the like can be used, but water management is troublesome.

The provision of the inert gas flow hole is to prevent the thermal decomposition of the sample by flowing N ₂ gas or helium gas to the sample.

[Examples] The present invention will be described in more detail with reference to the following examples.
The present invention is not limited to the following examples.

FIG. 1 and FIG. 2 show one embodiment of the present invention, showing a DSC detector installed on the stage of an infrared microscope. That is, the detection unit 4 of the DSC
Is installed on the sample stage 6 of the infrared microscope 1, and the DS
A window plate 9 made of an infrared spectrum transmitting material is provided on the upper portion of the sample cup of the cell portion 8 of C for transmitting infrared rays by the reflection method.

The detection part of the DSC is installed so that the optical axis of the infrared microscope is at the center of the aluminum cell (sample cell 8) on the sample side as shown in FIG. Before starting the DSC measurement, KBr powder is put in the sample cell 8 as a reference of the infrared spectrum and measured. Next, the sample cell 8 containing the powder sample and the reference cell 7 containing the reference substance were placed on the thermocouple plate 12, and Ba with a vent was provided.
Cover with the window plate 9 of F ₂ and start the DSC measurement. The infrared spectrum can be measured continuously at the same time as the DSC measurement is started, or can be performed at any time in any temperature range.

The BaF ₂ window plate 9 was prepared by slicing a BaF ₂ crystal. Two pieces having a diameter of 29 mm, a thickness of 2 mm, and an inert gas flow hole having a diameter of 1 mm were provided.

[Advantages of the Invention] The present invention relates to FTIR and DS equipped with a reflection infrared microscope.
Directly connected to C, the detection part of the DSC is installed on the sample stage of the infrared microscope, and the cell part of the DSC transmits infrared rays by the reflection method so that the infrared spectrum can be measured by the reflection method. By providing a window plate made of an infrared spectrum transmitting material, it is possible to efficiently measure the heat quantity change and infrared spectrum of the sample at the same time for the sample whose molecular structure or crystal structure changes with temperature change. It was possible to achieve the remarkable effect.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention. 1: Infrared microscope 2: Objective mirror 3: Detector 4: DSC detector 5: DSC heating furnace 6: Sample stage 7: Reference cell 8: Sample cell 9: BaF ₂ window plate 10: Objective mirror 11: Vent hole 12: Thermocouple plate

Claims (1)

[Claims] 1. A differential scanning calorimeter and a Fourier transform infrared spectrophotometer equipped with a reflection infrared microscope, wherein the detection unit of the differential scanning calorimeter is installed on a sample stage of the infrared microscope. A Fourier transform infrared spectrophotometer with a differential scanning calorimeter characterized in that a window plate made of an infrared spectrum transmitting material is provided on the upper portion of the sample cup of the cell part of the scanning calorimeter to transmit infrared rays by the reflection method. measuring device.