Studies of Elastomer Oxidation via Thermal Analysis

1999 ◽  
Vol 72 (1) ◽  
pp. 165-173 ◽  
Author(s):  
D. J. Burlett

Abstract Elastomers are used in many industrial applications because of their remarkable toughness and elasticity. However, the source of these properties is also a weakness, in that loss of properties via oxidation is an important factor in their selection. Thermoanalytical techniques, such as differential scanning calorimetry (DSC), provide useful tools for the characterization of the stability of elastomers. DSC can not only be used to determine oxidative induction times under isothermal conditions but can also be used to determine apparent overall activation energies of the oxidation process. An evaluation of these techniques is made and the technique is used to compare the oxidation susceptibility of polybutadienes of different microstructure. The results of these DSC scans are interpreted in terms of the chemistry of the oxidation process using FTIR results.

2018 ◽  
Vol 39 (4) ◽  
pp. 21
Author(s):  
Gilbert Bannach ◽  
Rafael R. Almeida ◽  
Luis G. Lacerda ◽  
Egon Schnitzler ◽  
Massao Ionashiro

Several papers have been described on the thermal stability of the sweetener, C12H19Cl3O8 (Sucralose). Nevertheless no study using thermoanalytical techniques was found in the literature. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC) and infrared spectroscopy, have been used to study the thermal stability and thermal decomposition of sweetener.


2017 ◽  
Vol 53 (2) ◽  
pp. 107-114 ◽  
Author(s):  
M. Voncina ◽  
M. Petric ◽  
P. Mrvar ◽  
J. Medved

The AM60 alloy was thermodynamically examined using chemical analysis, thermodynamic calculation made by ThermoCalc program, ?in situ? thermal analysis and differential scanning calorimetry (DSC), whereas the microstructure constituents were confirmed using optical and scanning electron microscopy (SEM). At the eutectic temperature of 437 ?C the equilibrium solubility of Al in Mg is 12.6 wt. % Al. On the boundaries of the primary Mg grains the intermetallic compound of Al12Mg17 is precipitating according to the solvus line of the Mg-Al phase diagram. Solidification of the AM60 alloy has been investigated using ?in situ? simple thermal analysis. The investigation of solidification has been taking place by evaluation of the cooling curves in connection with metallographic examinations, differential scanning calorimetry and thermodynamic calculations. All defects, nonmetallic inclusions and intermetallic compounds that occur in investigated AM60 alloy were identified.


1990 ◽  
Vol 204 ◽  
Author(s):  
M. Speciale ◽  
C. La Rosa ◽  
D. Grasso ◽  
A. Porto ◽  
P. Lanza ◽  
...  

ABSTRACTThe curing of a commercial ethoxymethyl-phosphosiloxane at different temperatures and under various gas ambients was characterised using NMR, thermoanalytical techniques, and FTIR spectroscopy. DSC (Differential Scanning Calorimetry) and DTG (Differential Thermo Gravimetry) were employed to characterize the reactions that occur during thermal treatments in O2 or N2 atmospheres. FTIR spectroscopy and CP (Cross Polarization) 133C - NMR were used to detect the presence of the hydroxyl and organic groups in the cured samples. The experimental results identified three different temperatures (400,580,700°C) that define important stages of the curing reaction. In particular, for annealing at temperatuires up to 580°C in 02, DSC, DTG and FTIR spectra showed the elimination of the organic groups. However, when the annealing was carried out in N2 up to 700°C, these groups are retained.


2013 ◽  
Vol 432 ◽  
pp. 413-417 ◽  
Author(s):  
Li Ming Zhang ◽  
Zhi Ying Hu ◽  
Li Hu Yan ◽  
Run Liu Li ◽  
Cheng Wei Cao ◽  
...  

In order to improving the stability and bioavailability of tea polyphenols (TP), the TP/starchinclusion complex(TPSIC) was prepared by adding TP to starch slurry during gelatinization, and its TPreleasing behaviorswas investigated. The formation of inclusion complex was confirmed by powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The TPSIC showed a characteristic of V-type crystallinity and a looser gel matrix. The encapsulation increased the stability of TP and generated a good releasing behavior after enzymatic erosion. The lower releasing rate indicated that the prepared inclusion complexes had good retention ability and effectively reduced the releasing rate of TP. The releasing rate of TPSIC increased with the increase of TP concentration.


2008 ◽  
Vol 33 (3) ◽  
pp. 13-18 ◽  
Author(s):  
C. Beninca ◽  
I. M. Demiate ◽  
L. G. Lacerda ◽  
M. A. S. Carvalho Filho ◽  
M. Ionashiro ◽  
...  

Unprocessed native starches are structurally too weak and functionally too restricted for application in today's advanced food technologies. Processing is necessary to engender a range of functionality. Naturals or natives starches can be modified by using several methods physical, chemical, enzymatic or combined, according industrial purposes. In this work, native corn starch was hydrolyzed by hydrochloric acid solution and investigated by using thermoanalytical techniques (thermogravimetry - TG, differential thermal analysis - DTA and differential scanning calorimetry - DSC), as well as optical microscopy and X-ray diffractometry. After acid treatment at 30 and 50°C, a decrease of gelatinization enthalpy (ΔHgel) was verified. Optical microscopy and X-ray diffractometry allowed us to verify the granules contorn and rugosity typical of cereal starches.


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