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Thermal Decomposition Kinetics (thermal + decomposition_kinetics)

Distribution by Scientific Domains
Chemistry66%

Selected Abstracts

Synthesis and Thermal Decomposition Kinetics of the Complex of Samarium p -Methylbenzoate with 1,10-Phenanthroline

CHINESE JOURNAL OF CHEMISTRY, Issue 1 2007
Jian-Jun Zhang
Abstract The complex [Sm(p -MBA)3phen]2 (p -MBA, p -methylbenzoate; phen, 1,10-phenanthroline) was prepared and characterized by elemental analysis, IR and UV spectra. The thermal decomposition process of [Sm(p - MBA)3phen]2 was studied under a static air atmosphere by TG-DTG and IR techniques. Thermal decomposition kinetics was investigated employing a newly proposed method, together with the integral isoconversional non-linear method. Meanwhile, the thermodynamic parameters (,H,, ,G, and ,S,) were also calculated. The lifetime equation at mass-loss of 10% was deduced as ln ,=,24.7825+18070.43/T by isothermal thermogravimetric analysis. [source]

Surface modification of PHBV films with different functional groups: Thermal properties and in vitro degradation

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2010
Yu Ke
Abstract Polyacrylamide was photografted on solution-cast poly(3-hydroxybutyric acid- co -3-hydroxyvaleric acid) (PHBV) films (amide-PHBV), on which amide groups were transformed into amine groups through Hofmann degradation reaction (amine-PHBV), followed by collagen coupling reaction to prepare collagen-modified PHBV (collagen-PHBV). Amide-, amine-, and collagen-PHBV had higher water absorption and d -spacing values than PHBV, and melting temperatures and enthalpies decreased in the order of collagen-PHBV < amine-PHBV < amide-PHBV < PHBV. Thermal decomposition kinetics of PHBV component in the films has been investigated by means of nonisothermal thermogravimetric and derivative thermogravimetric studies. Applying the Avrami-Erofeev equation with index of 2/5 as the probable kinetic function, the suitable activation energy was calculated by the Friedman method through linear fitting (correlation coefficient > 0.98). The activation energy of PHBV was lower than that of amide-PHBV but higher than that of amine- and collagen-PHBV. Being incubated in phosphate-buffered saline at 37°C, the modified PHBV films showed more weight loss than PHBV during 360 days; however, pH of degradation fluids was nearly neutral as the initial pH was recorded at 7.2. The modified PHBV films with different functional groups may provide an improved biodegradation rate for various cytocompatible biomaterials constructs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

Thermal decomposition kinetics of poly(nButMA- b -St) diblock copolymer synthesized by ATRP

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2009
Adnan KurtArticle first published online: 8 JUN 200
Abstract The reaction mechanism of decomposition process and the kinetic parameters of the poly(n -butyl methacrylate-b-styrene), poly(nButMA-b-St), diblock copolymer synthesized by atom transfer radical polymerization (ATRP) were investigated by thermogravimetric analysis (TGA) at different heating rates. TGA curves showed that the thermal decomposition occurred in one stage. The apparent activation energies of thermal decomposition for copolymer, as determined by the Kissinger's, Flynn,Wall,Ozawa and Tang methods, which does not require knowledge of the reaction mechanism (RM), were 112.52, 116.54, and 113.41 kJ/mol, respectively. The experimental results were compared with master plots, in the range of the Doyle approximation. Analysis of experimental results suggests that in the conversion range studied, 3,18%, the actual RM is an A2 sigmoidal type. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]

Synthesis and Thermal Decomposition Kinetics of the Complex of Samarium p -Methylbenzoate with 1,10-Phenanthroline

CHINESE JOURNAL OF CHEMISTRY, Issue 1 2007
Jian-Jun Zhang
Abstract The complex [Sm(p -MBA)3phen]2 (p -MBA, p -methylbenzoate; phen, 1,10-phenanthroline) was prepared and characterized by elemental analysis, IR and UV spectra. The thermal decomposition process of [Sm(p - MBA)3phen]2 was studied under a static air atmosphere by TG-DTG and IR techniques. Thermal decomposition kinetics was investigated employing a newly proposed method, together with the integral isoconversional non-linear method. Meanwhile, the thermodynamic parameters (,H,, ,G, and ,S,) were also calculated. The lifetime equation at mass-loss of 10% was deduced as ln ,=,24.7825+18070.43/T by isothermal thermogravimetric analysis. [source]

Synthesis and thermal decomposition reaction kinetics of complexes of [Sm2(m -ClBA)6(phen)2],·,2H2O and [Sm2(m -BrBA)6(phen)2],·,2H2O

INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 2 2007
Jian Jun Zhang
Complexes of [Sm2(m -ClBA)6(phen)2],·,2H2O and [Sm2(m -BrBA)6(phen)2],·,2H2O (m -ClBA = m -chlorobenzoate, m -BrBA = m -bromobenzoate, and phen = 1,10-phenanthroline) were prepared and characterized by elemental analysis and IR spectra. The thermal decomposition processes of the two complexes were studied by means of TG,DTG and IR techniques. Their thermal decomposition kinetics were investigated from the analysis of the TG and DTG curves by jointly using a new method proposed by us and a newly nonlinear isoconversional integral method. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 39: 67,74, 2007 [source]

3,3,6,6,9,9-Hexaethyl-1,2,4,5,7,8-hexaoxacyclononane at 296 K

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009
Jorge Cerna
The title molecule (diethyl ketone triperoxide, DEKTP), C15H30O6, is a cyclic triperoxide closely related to triacetone triperoxide (TATP), one of the most unstable explosives known. However, the stability of DEKTP is ca 20,50 times greater than that of TATP. DEKTP crystallizes with two molecules in the asymmetric unit, with virtually identical geometry. The cyclononane core is stabilized in a twisted boat,chair conformation (approximate D3 symmetry), very close to that previously described for TATP. The explanation for the safe thermal behaviour of DEKTP compared with TATP should thus not be sought in the molecular dimensions, but rather in the thermal decomposition kinetics. [source]