نتایج جستجو برای: thermal degradation

تعداد نتایج: 362694  

2008
D. BRAUN

A survey is given of the recent advances in the study of and the present knowledge of the thermal degradation of polyvinyl chloride. The sites for initiation of the thermal degradation, the mechanism of the dehydrochiorination, the discolouration of PVC by heat and the influence of plasticizers on the rate of degradation are discussed.

2003
T. D. Bradley A. Ball S. E. Harding J. R. Mitchell

Information about the thermal degradation of guar gum has been obtained from the time dependence of the viscosity at high temperatures measured using a slit viscometer. The viscosity is related to the molecular weight using previously published relations between the zero shear specific viscosity and the coil overlap parameter in conjunction with the appropriate Mark-Houwink equation. Unlike ani...

2014
P. E Sánchez-Jiménez L. A. Pérez-Maqueda

Combined kinetic analysis has been applied for the first time to the thermal degradation of polymeric materials. The combined kinetic analysis allows the determination of the kinetic parameter from the simultaneous analysis of a set of experimental curves recorded under any thermal schedule. Besides, the method does not make any assumption about the kinetic model or activation energy and allows...

2016
Dieter Brüggemann Sylvain Quoilin

The design of efficient Organic Rankine Cycle (ORC) units for the usage of industrial waste heat at high temperatures requires direct contact evaporators without intermediate thermal oil circuits. Therefore, the thermal stability of high-temperature working fluids gains importance. In this study, the thermal degradation of hexamethyldisiloxane (MM) is investigated in an electrically heated tube...

Journal: :Bioresource technology 2012
Matheus Poletto Ademir J Zattera Maria M C Forte Ruth M C Santana

The influence of wood components and cellulose crystallinity on the thermal degradation behavior of different wood species has been investigated using thermogravimetry, chemical analysis and X-ray diffraction. Four wood samples, Pinus elliottii (PIE), Eucalyptus grandis (EUG), Mezilaurus itauba (ITA) and Dipteryx odorata (DIP) were used in this study. The results showed that higher extractives ...

Journal: :Journal of agricultural and food chemistry 2003
Minh Thuy Nguyen Indrawati M Hendrickx

Stability of folic acid and 5-methyltetrahydrofolic acid in phosphate buffer (0.2 M; pH 7) toward thermal (above 65 degrees C) and combined high pressure (up to 800 MPa)/thermal (20 up to 65 degrees C) treatments was studied on a kinetic basis. Residual folate concentration after thermal and high pressure/thermal treatments was measured using reverse phase liquid chromatography. The degradation...

2011
M. Aminuddin U. Nazim I. Ahmad

Light and temperature have considerable effect on the degradation of piroxicam in aqueous solutions. The pH and acetate buffer ions also affect the degradation process. The apparent first-order rate constants for the photochemical and thermal degradation of piroxicam have been determined as 2.04-10.01 and 0.86-3.06×10(-3) min(-1), respectively. The first-order plots for the degradation of pirox...

2013
Przemysław Zalewski Judyta Cielecka-Piontek Piotr Garbacki Anna Jelińska Marta Karaźniewicz-Łada

The stability-indicating LC assay method was developed and validated for quantitative determination of cefcapene pivoxil in the presence of degradation products formed during forced degradation studies. An isocratic RP-HPLC method was developed with a Lichrospher RP-18 (250 mm × 4.6 mm, 5 μm) column and the mobile phase composed of 45 volumes of acetonitrile and 55 volumes of mixture composed o...

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