Ryoichi Kinoshita

Development of the simultaneous thermal analysis/X-ray scattering measurement system

A new simultaneous DSC/X-ray measurement system was developed for the purpose of combining X-ray scattering data and calorimetric data. The DSC/X-ray measurement system was equipped with a conventional wide-angle X-ray diffractometer (WAXD). The phase transition behavior of pure hexatriacontane was measured by the DSC/WAXD, both on heating and cooling. The accuracy and reproducibility of the simultaneous DSC/X-ray instrument were comparable with the conventional DSC.

Thermal degradation of polyesters by simultaneous TG-DTA/FT-IR analysis

A combination system of thermogravimetric/differential thermal analysis (TG-DTA) and Fourier-transform infrared absorption spectroscopy (FT-IR) was described. This simultaneous TG-DTA/FT-IR technique gave spectroscopic and weight loss information about the thermal degradation process of engineering polyesters; poly(ethylene terephthalate)(PET) and poly(butylene terephthalate)(PBT). The evolved gases from PET were benzoic acid, carbon dioxide and carbon monoxide, while those from PBT were terephthalic acid esters and benzoic acid esters.ZusammenfassungEs wird ein kombiniertes System aus TG-DTA und FT-IR beschrieben. Mit dieser simultanen TG-DTA/FT-IR-Technik wurden spektroskopische und Massenverlustangaben über die thermische Zersetzung technisch wichtiger Polyester, namentlich von Poly(ethylenterephthalat) (PET) und Poly(Butylenterephthalat) (PBT) ermittelt. Die aus PET freigesetzten Gase waren Benzoesäure, Kohlendioxid und Kohlenmonoxid, die aus PBT freigesetzten Gase hingegen Terephthalsäureester und Benzoesäureester.

Kinetic analysis of the thermal decomposition of polyesters by simultaneous TG-DTA/FT-IR

Abstract The thermal decompositions of poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) were measured by a simultaneous TG-DTA/FT-IR system. Two kinds of data, FT-IR spectra and the specific gas profiles (SGP), were collected as a function of temperature, in addition to the TG-DTA data. Evolved gas analysis was carried out in terms of specific gas profiles (SGP) at the specific absorption band. Kinetic analysis was performed on both the TG and SGP curves obtained at various heating rates, and the activation energy estimated from the TG curves was in agreement with that obtained from the SGP curves of the aromatic esters of PBT. In the case of PET, the activation energy obtained from the TG curves was an average of that calculated from the SGP curves for the aromatic esters and carbon dioxide.

TG-DTA/FT-IR method for analyzing thermal decomposition mechanism of polyesters

An attempt to estimate the thermal decomposition mechanism of polymers using the simultaneous TG-DTA/FT-IR system was summarized. The library search of FT-IR spectra at various temperatures and of the subtraction spectrum obtained by subtracting the spectra at different temperatures were used to determine the types of evolved gases from poly(ethylene terephthalate) and poly(butylene terephthalate) at given stages of decomposition. The quantitative analysis of evolved gases was carried out using the specific gas profiles at the specific absorption band. The kinetic parameters were estimated from both TG and spectroscopic curves measured at various heating rates.ZusammenfassungMittels eines simultanen TG-DTA/FT-IR Systemes wurde ein Versuch zur Abschätzung des Mechanismus der thermischen Zersetzung von Polymeren unternommen und beschrieben. Zur Bestimmung des Types flüchtiger Substanzen, die in bestimmten Stadien der Zersetzung aus Poly(ethylen-terephthalat) und Poly(butylen-terephthalat) entstehen, wurden die FT-IR-Spektren bei verschiedenen Temperaturen und die Differenzspektren aus Subtraktion der Spektren bei verschiedenen Temperaturen in einem Spektrenverzeichnis gesucht. Die quantitative Analyse der freigesetzten Gase wurde unter Verwendung der spezifischen Gasprofile an den spezifischen Absorptionsbanden durchgeführt. Die kinetischen Parameter wurden anhand der TG-und der spektroskopischen Kurven für verschiedene Temperaturen geschätzt.

Kinetic analysis of the isothermal crystallization of an n-alkane and polyethylene observed by simultaneous DSC/FT-IR/WAXD measurement

Abstract The isothermal crystallization process of n-hexatriacontane (C36H74) and high-density polyethylene (HDPE) was observed by simultaneous DSC/FT-IR and DSC/WAXD measurements. For C36H74, the formation of the trans-conformation and the crystallization exothermic peak of the hexagonal phase from the melt were observed at the same time. The absorption band due to the rocking mode vibration of the methylene group was split at the transformation from the hexagonal phase to the modified monoclinic phase. In the case of HDPE, the formation of the trans-conformation started before the observation of the crystallization exothermic peak. When the crystallization exothermic peak was observed, about 60% of trans-conformation was already formed. The conformational transition from the gauche-form to the trans-form was recognized as a phenomenon occurring before the crystal growth of HDPE.

New applications of the automatic thermal analysis system

Abstract The Automatic Thermal Analysis System has been developed because of the recent demand for improved efficiency of thermal analysis. The system is able to automate heating and cooling measurements for differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and TMA/SS (stress, strain control TMA) over a wide temperature range. A program-controlled liquid nitrogen gas cooling system is used with the same capabilities (reproducibility, noise level, etc.) for cooling and heating measurements. As a result of this automation, not only has the efficiency of thermal analysis work improved, but the following new applications have been made possible: (1) specific heat capacity measurement for DSC in cooling mode; and (2) characterization of plastic samples during cycle heating and cooling for TMA and DSC.