نتایج جستجو برای: thermal degradation
تعداد نتایج: 362694 فیلتر نتایج به سال:
Polyaniline (PANI) nanocomposite has been successfully prepared in aqueousmedia by the chemical polymerization of aniline with ammonium peroxydisulphateas an initiator in the presence of a steric stabilizer such as sodium dodecylbenzenesulfonate(DBSNa), Poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol)(PVA), poly(ethylene glycol) (PEG) and hydroxypropylcellulose (HPC). Thechemical structure, m...
Thermal degradation of poly(lactic acid) (PLA), a biodegradable and bioabsorbable polyester, has been investigated under inert atmosphere using both isothermal and dynamic heating regimes.. Two kinetic models, one for isothermal and the other for dynamic heating regims were used to fit the experimental data. It has been demonstrated that the thermal degradation of PLA is a one-stage process wit...
We propose the use of thin Ag film deposition to remedy the degradation of near-infrared (NIR) absorption of black Si caused by high-temperature thermal annealing. A large amount of random and irregular Ag nanoparticles are formed on the microstructural surface of black Si after Ag film deposition, which compensates the degradation of NIR absorption of black Si caused by thermal annealing. The ...
The thermal degradation of three polymeric peroxides of styrene monomers with substituents in the para position was studied at various temperatures (65, 75, 85, and 95°C). A continuous distribution model was used to evaluate the rate coefficients for the random-chain and chain-end scission degradation from the evolution of molecular weight distributions with time. The activation energy determin...
Thermo-gravimetric analyses of three cellulosic substances, namely, microcrystalline and amorphous cellulose, and treated Japanese cypress (JC) sawdust were carried out in this study. The thermal degradation temperature of crystalline cellulose decreased with increasing ball-milling time, while that of amorphous cellulose barely changed. However, small differences in the derivative thermo-gravi...
In this paper investigates an energetic imidazolium ionic liquid plasticizer (ILP) effect on the degradation kinetics of nitrocellulose, which is a important component of double based solid propellants. For better comparison and evaluation, diethyl phthalate (DEP) plasticizer, which has a structure similar to ILP, was also evaluated. Heat of combustion analysis was performed to evaluate the en...
In this work, the relationship between cellulose crystallinity, the influence of extractive content on lignocellulosic fiber degradation, the correlation between chemical composition and the physical properties of ten types of natural fibers were investigated by FTIR spectroscopy, X-ray diffraction and thermogravimetry techniques. The results showed that higher extractive contents associated wi...
Anthocyanins are food colourants with strong antioxidant activities, but poor thermal stability limits their application in neutral foods. In the present study, impacts of yeast mannoproteins on the thermal stability of anthocyanins were studied at pH 7.0. The degradation of anthocyanins at 80 and 126 °C followed first order kinetics, and the addition of mannoproteins reduced the degradation ra...
This paper reports novel methods for accelerated ageing tests, with comparative reliability between them for stresses applied on power RF LDMOS: Thermal Shock Tests (TST), Thermal Cycling Tests (TCT), High Voltage Drain (HVD) and coupling thermal and electrical effects under various conditions. The investigation findings obtained after various ageing tests show the degradation and the device’s ...
The thermal degradation behavior and pyrolysis kinetic models of wood flour (WF)/PVC composites before and after adding chitosan were studied using thermogravimetry (TGA) and nine common kinetic model functions (f(α)). The results indicated that the thermal degradation temperature of WF/PVC composites was delayed to a higher value after adding chitosan. The first-order reaction order (L1) model...
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