The binder-burnout kinetics of poly(vinyl) butyral from BaTiO 3 multilayer ceramic capacitors with platinum metal electrodes were analyzed by combining thermogravimetric analysis with infrared spectroscopy. The rate of weight loss was accelerated when both BaTiO 3 and platinum metal were present, and the presence of both metal and ceramic enhanced the production of CO 2 . The activation energy and preexponential factor were determined by analysis of the weightloss data with a first-order kinetics model. Then, the decomposition kinetics were incorporated into a coupled heat-and mass-transport model to predict pressure increases as a function of the heating cycle. The heating cycles determined in this manner then were used to evaluate the yield of capacitors 1.3-3.8 cm long and 0.3-1.3 cm high. The optimum yield was realized at an aspect ratio (height:length) of 1:3.
A TG/FTIR system was used to identify the products of thermal oxidative degradation of PVB, and also to elucidate the mechanism of degradation. This technique is useful in the kinetic analysis of fast reactions such as polymer degradation, unlike the use of a TG/GC/FTIR system, in which long retention times are needed to separate the products. A computer resolution method based on a pattern recognition technique is proposed to resolve the dynamic mixture IR spectra of the degradation products. A four‐component synthetic mixture was used to evaluate the performance of the resolution algorithm and was found to be accurate within ±5%. The method was then applied to PVB degradation. The dynamic information of PVB thermal oxidative degradation obtained by resolving the mixture IR spectra was used to elucidate the reaction mechanism and to determine the kinetic parameters. Results showed that PVB degradation in air took place at a temperature 50K lower and the overall activation energy dropped from 338 kJ/mole (in nitrogen) to 200 kJ/mole (in air) compared with the degradation in a nitrogen atmosphere.
Kinetic models for the thermal degradation of
poly(vinylbutyral) PVB/Al2O3 and
PVB/AlN
composites, based on weight loss and evolved gas analysis (EGA), are
presented. TG (sample
weight loss) and FT-IR (mixture gas spectra) data were measured to
elucidate the kinetic models
using isothermal and nonisothermal approaches. The mixture IR
spectra at each time or
temperature were resolved using a least-mean-square (LMS) algorithm to
obtain the dynamic
information for each major volatile product formed during the
degradation process. The kinetic
results using isothermal and nonisothermal approaches showed excellent
agreement. Activation
energies of PVB thermal degradation are ∼300 kJ/mol in nitrogen and
∼200 kJ/mol in air for
pure PVB and ∼100 kJ/mol for PVB/Al2O3 and
PVB/AlN in nitrogen. The polymer residues at
different isothermal treatments were subjected to DRIFTS spectra, and
the carbon content of
the residual samples was analyzed using a Leco analyzer.
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