Application of Thermogravimetric-Fourier Transform Infrared (TG-FTIR) Coupling Technology in the Study of PA6 Pyrolysis
Tianjin Port East Technology Co., Ltd. Applied Analysis Department
Abstract
PA6), is a semi-transparent or opaque milky white granule characterized by thermoplastic properties, light weight, high toughness, chemical resistance, and durability. It is commonly used in automotive parts, mechanical components, electronic and electrical products, and engineering accessories. PA6 is a class of polymers containing repeating structural units of amide groups on the macromolecular chain; its thermal degradation mechanism is of significant importance for flame retardancy research.
1. Experimental Methods
1.1 Samples and Instruments
PA6 (Nylon 6, granules, manufactured by BASF, Germany, industrial grade)
FTIR-850
Heated gas chamber and conveyor line accessories
TG 209 F1(NETZSCH GmbH)
1.2 Experimental Procedure Setup
1.2.1 TGA Settings
The atmosphere is30ml/minhigh-purity nitrogen
ThermogravimetryThe starting temperature for the analysis is30℃, to warm uprate10℃/minrise to700℃。
1.2.2 canTemperature Settings for the Heating Chamber and Conveyor Line
The temperature at the transmission line interface is200℃
The temperature of the transmission line is210℃
The temperature of the heated gas chamber is210℃
1.2.3 FTIR-850 Setup
Resolution:4cm-1, Measurement range4000-400cm-1。
1.3 ExperimentMethod
After 30 minutes of ventilation,FTIR-850Enable continuous data collection in the software, with a collection interval of1 min, SelectWaitingtrigger。
Take onePA6granulesPlace the sample in the crucible, then press1.2Run the configured experimentTGA与FTIR。
2 ExperimentResults and Discussion
Figure 1 TG curveand the graph of its first derivative
From the figure1. Yes, you canIt can be seen that,PA6atN2The thermal decomposition process in this atmosphere has only one weight loss band, with the temperature range for thermal weight loss primarily occurring between360—490℃，DTG curveThere is only one zero-gravity peak, located at450℃（43min) or so, the rate of thermal degradation reaches its maximum, indicating thatMade of PA6Thermal degradation is a one-step process, achieved byFTIR can be used toA study of the gases produced during the pyrolysis process.
Figure 2 43minPA6Thermal degradation gas-phase productsFTIR spectrum
43minutes3000-2800cm-1,2400-2300cm-1,1800-1700cm-1reaches its peak at this point, which is consistent withDTG curveExactly the same.As shown in Figure 2As can be seen,On the 29th00cm-1AppendixA strong absorption peak has recently appeared; analysis indicates that it isAlkyl and CO2the absorption peak, whereas1710.88cm-1The strong absorption peak observed should be that of the amide group,928 cm-1和961cm-1The absorption peak corresponds to the amideIV的CONHTransformationVibrational absorption peak. Combined with PA6'sBased on the main-chain structure, it can be inferred that the above absorption peaks are caused by oligomers of lactam formed following the degradation of the main chain.。1500 cm-1NearbyH2Oabsorption peak，2300cm-1NearbyCO2absorption peak, indicating that the gaseous products at this point contain water and carbon dioxide.
As can be seen from the results above,TG-FTIR couplingTechnology is a useful tool for studying the thermal degradation behavior or mechanisms of polymers.