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In present work curing kinetics of UV-initiated cationic photo-polymerization of EPICLON series epoxy resin HP-820 and key cure process parameters, such as the extent of cross-linking and conversion, polymerization rate and the order of reactions have been studied by Photo-Differential Scanning Calorimetry (DPC). Different kinetics analysis results, including enthalpy of the reaction, induction time,...
A bipolar plate for polymer electrolyte membrane fuel cells (PEMFC) was prepared from epoxy/graphite compounds with various carbon nanotube (CNT) using press molding process. In order to decide the cure condition of temperature and time, differential scanning calorimetry (DSC) analysis was carried out and the data was introduced to Kissinger expression and isoconversional expression to get kinetic...
A generalized hybrid modeling is proposed to estimate the chemical shrinkage and modulus evolutions at arbitrary temperatures. Using the existing curing kinetics modeling, a theoretical formulation is developed to provide a mathematical relationship between the evolution properties at arbitrary temperatures and those obtained at a reference temperature. The evolution properties at the reference temperature...
The challenge of this work is to prepare ceramics in the form of powders crystallized type Na2-2xA2xPbP2O7 (A = Li, K, Ag and 0 < x < 1) by the method glass. These different compositions will be characterized by different techniques such as X-ray diffraction, spectroscopy FTIR and thermal analyses ATD, ATG and DSC to determine their local structures. Indeed, the absorption bands appeared in...
Insulation liquids are mainly used in oil filled transformers for their cooling and insulating properties. Besides a testing of electrical properties, there is also important to monitor oxidation stability and activation energy as the factors which can decide on an application possibility of the insulating liquid. The main aim of this paper is to describe the influence of temperature aging on the...
In this report we present the synthesis of two kinds of epoxy-curable diazo-coupling phenol novolac derivatives which gives rise to high crosslinking densities with reduced free volumes and tie-up the molecular segments and insert bulky substituent such as aromatic groups by inflammable N element. The synthetic procedure and material characteristics are discussed, and the flame retardancy and thermostability...
Silicon-containing epoxy resin (CNE-Si) was synthesized from diphenylsilandiol (DPSD) and ortho-cresol novolac epoxy resin using SnCl2 as catalyst. The chemical structure of CNE-Si prepared in this paper was characterized by 1H-NMR and FTIR. The thermal stability was analyzed by TGA. The result showed that the -Si- group enhanced the thermal stability of the epoxy resin. The curing kinetics of the...
Water treeing is considered to be the main mechanism limiting the service time for polymeric cables with wet design. Water trees do not grow at a low relative humidity (RH) and therefore the RH in the insulation should be kept as low as possible for as long as possible. A system of polymeric outer sheaths can be designed to slow down the transport of water into the high voltage insulation system....
Differential scanning calorimetry (DSC) was used to study the formation of MgB2 from amorphous boron powder and MgH2/Mg powder. The B and powder mixture demonstrated that forms near 600degC with an estimated activation energy of 239 kJ/mole. The B and Mg powder mixture has an additional low temperature reaction near 425degC that is initiated by Mg(OH)2 decomposition. Similar effects can be duplicated...
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