Search Results

You are looking at 1 - 10 of 14 items for :

  • All content x
Clear All

the safe passage of the effluent from the TG through the FT-IR. The addition of software in the FT-IR that allows the collection of a series of sequential infrared spectra completes the basic package. A TG/FT-IR experiment is really two separate

Restricted access

coupled with Fourier transformed infrared (FT/IR). It was reported the TG-FT/IR pyrolysis experiment at low heating rates of biomass samples (wheat straw, tobacco) and pyrolysis yield was evaluated [ 3 ]. It was investigated palm oil waste, are the major

Restricted access

Abstract  

Thermogravimetry coupled with Fourier transform infrared spectroscopy (TG/FT-IR) was used to investigate the stabilizing action of 3-(2,4-dibromophenylazo)-9-(2,3-epoxypropane)carbazole on the degradation of poly(vinyl chloride) (PVC). It was found that this secondary stabilizer increases the initial temperature of hydrogen chloride evolution (the main process responsible for PVC decomposition), thereby allowing its application for novel PVC systems with enhanced thermal stability. The application of TG/FT-IR technique for study of the thermal properties of polymeric materials offers additional characterization options in comparison with thermogravimetry, if used alone.

Restricted access

Abstract  

Thermogravimetric analysis (TG) provides information regarding mass changes in the sample resulting from heat treatment under controlled environment. However, it does not provide any chemical information regarding the gases evolved during the thermal degradation. Using FT-IR spectrometry in combination with TG, it is often possible to identify the evolved gases, and also monitor their evolution profiles during thermal degradation. In this study, we present the TG/FT-IR combined analysis of incineration and pyrolysis of some common plastics such as high density polyethylene (HDPE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polystyrene (PS). This study demonstrates the utility of such combined analysis in providing useful information regarding the use of thermal treatment for recycling or incineration.

Restricted access

thermoanalytical investigations (TG-FT-IR) is it possible to gain insight into the problematics surrounding the carbonate formation of La(OH) 3 and the resulting influence on the thermal transformation [ 12 ]. Experimental Lanthanum

Restricted access

Abstract  

A series of blends of poly(vinyl chloride) (PVC) and polyaniline (PANI) was prepared by solution casting and investigated by methods of thermal analysis, namely thermogravimetric analysis (TG), coupled with Fourier transform infrared spectroscopy (TG-FT/IR) and differential scanning calorimetry (DSC). It was found that the thermal stability of this polymer system depends on the composition of blend; the main product of prevailing PVC decomposition process — hydrogen chloride — seems to play specific role during degradation since it can react with PANI structures, characterized by different protonation degree.

Restricted access

Abstract  

Although thermogravimetric analysis (TG) has become an indispensable tool for the analysis and characterization of materials, its scope is limited as no information is obtained about the qualitative aspects of the evolved gases during the thermal decomposition. For processes involving mass loss, a powerful technique to provide this missing information is Fourier transform infrared spectroscopy (FT-IR) in combination with TG. It supplies a comprehensive understanding of thermal events in a reliable and meaningful way as data are obtained from a single sample under the same conditions. The coupling TG/FT-IR is used in fuel analysis for the identification of residual volatiles, to determine their sequence of release and to resolve thermogravimetric curves. In this work, the usefulness of TG/FT-IR for characterizing middle distillate fuel residues is illustrated with some typical examples of recent application. A Bio-Rad FTS 25 FT-IR spectrometer coupled with a TA Instruments TGA 2950 thermogravimetric analyzer was used for data aquisition. The results obtained demonstrate the utility of this combined technique in determining the decomposition pathway of tarry materials at various stages of pyrolysis, thereby allowing new insights into the complex thermal behaviour of hydrocarbon residual systems.

Restricted access

Abstract  

Thermal analysis methods are well-established techniques in research laboratories of pharmaceutical industry. The robustness and sensitivity of instrumentation, the introduction of automation and of reliable software according to the industrial needs widened considerably the areas of applications in the last decade. Calibration of instruments and validation of results follow the state of the art of cGMP as for other analytical techniques. Thermal analysis techniques are especially useful for the study of the behavior of the poly-phasic systems drug substances and excipients and find a unique place for new delivery systems. Since change of temperature and moisture occur by processing and storage, changes of the solid state may have a considerable effect on activity, toxicity and stability of compounds. Current requirements of the International Conference of Harmonisation for the characterization and the quantitation of polymorphism in new entities re-enforce the position of thermal analysis techniques. This challenging task needs the use of complementary methods. Combined techniques and microcalorimetry demonstrate their advantages. This article reviews the current use of thermal analysis and combined techniques in research and development and in production. The advantage of commercially coupled techniques to thermogravimetry is emphasized with some examples.

Restricted access

Abstract  

The polycondensation reactions between 4,4′-[sulphonyl bis(p-benzoyl)(p-phenyleneoxy)]dibenzoic acid (I) andp-phenylenediamine (II), 1,5-diaminonaphthalene (III), 4,4′-sulphonyldianiline (IV), 4,4′-diaminodiphenylsulphide (V) 4,4′-methylenedianiline (VI) and 4,4′-oxydianiline (VII) to form aromatic polyamides containing sulphone, ether and ketone linkages were attempted by a solid-solid interaction route. A stoichiometric 1∶1 molar ratio of solid reactants was dynamically heated directly in a TG/DSC apparatus, and simultaneous TG/FT-IR was performed to interpret the mechanism of reaction. The results suggest that the polycondensation is dependent on the diamine used. The formation of polyamide was successful when I interacted with II, III, VI and VII. The interaction with IV and V was in part successful because partial decarboxylation of the diacid, made unstable by the diamine, occurred before the condensation reaction.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Eveline De Robertis, Gabriela F. Moreira, Raigna A. Silva, and Carlos A. Achete

-8539(96)01777-1 . 27. Berbenni , V , Marini , A , Bruni , G , Zerlia , T . TG/FT-IR: an analysis of the conditions affecting the combined TG/spectral response . Thermochim Acta . 1995 ; 258 : 125 – 133 . 10

Restricted access