Which effect will be dominant depends on whether devitrification of the rigid amorphous chains takes place, during the allotted time.
However, devitrification of the rigid fraction of the amorphous chains, trapped in the polymer-particle interphase, above a critical annealing temperature, was observed to lead to improved kinetics of isothermal crystallization, for compositions below the percolation threshold.
(formation of crystalline phases during firing)
Venugopal (1979) reported that the rhyolite contains plagioclase, alkali feldspar, and embayed quartz phenocrysts set in a partially sericitized, aphanitic groundmass; a late phase of devitrification
is indicated by oval patches of radiating plagioclase scattered throughout the finer groundmass.
One thus achieves a longer time scale of drug's devitrification
Forces acting on the solid-bed in a single-screw extruder are directly proportional to the coefficient of dynamic friction for temperatures less than the melting or devitrification temperature of the polymer.
For temperatures less than the melting or devitrification temperature an implicit finite difference technique was used to predict the polymer-metal interface temperature based on the measured metal temperature and the amount of heat generated by friction at the interface (7).
Below the melting or devitrification temperature the shear stresses are determined by a frictional mechanism.
g] because the devitrification
of the network enables the crosslink reaction to proceed to completion.
ii) The devitrification of both phases favors the mobility of materials and thus allows the mass transfer.
Moreover, DSC has showed that postcured samples reach the complete conversion and, therefore, this peak is not associated to some devitrification effect.
The second peak is attributed to devitrification (24), which occurs when the cure temperature exceeds the ultimate glass transition of the material.
The algorithm closely follows the chemically controlled part of the curing and successfully reproduces structural phenomena like the vitrification and devitrification (see, for example, the knee corresponding to the vitrification-devitrification sequence in dynamic runs at very slow heating rates and the final degree of cure under isothermal conditions).
This upturn is due to the onset of devitrification of the polymer, caused by the long time between measurements at each temperature--approximately 18 min.
As mentioned previously, this upturn is associated with the onset of devitrification in the polymer system under the oxidative conditions of the analysis.