New Possibilities in the Description of Overall Crystallization of Polymers

Abstract

Applications of the probabilistic model of spherulitic structure formation are demonstrated. The model permits prediction of the conversion of melt into spherulites in complicated crystallization conditions, including crystallization in a finite volume, in the presence of reinforcing fibers, and in a temperature gradient. The progression of interspherulitic boundary formation can also be described, thus giving insight into development of the spherulitic pattern. The predictions based on the model are verified by a computer simulation of the spherulitic structure formation. They are also in agreement with experimental data.The modeling of polymer crystallization during cooling of thick-walled products is also reported. The obtained information allows for the geometry of a product and its size to be related with a time and temperature range of polymer crystallization.

In‐process thermochemical analysis of in situ poly(ethylene glycol methacrylate‐co‐glycidyl methacrylate) monolithic adsorbent synthesis

“…The polymer growth phase occurs gradually in a layer‐by‐layer format from the bottom of the mold after the formation of the first nuclei to form globules, clusters of globules with pore interconnectivities to yield a single continuous piece. Avrami's isothermal crystallization equation was used to model the polymer growth phase because of its ability to predict the kinetics of polymer formation in a finite volume at isothermal and nonisothermal conditions as follows: where ξ 2 is the extent of AB l liquid transformation into the bulk solid polymer, k 2 ( T ) is the specific rate constant, f (ξ 2 ) is a function of the extent of the reaction and governs the kinetics of polymer growth, and r is the Avrami's constant, which typically ranges from 1 to 4. A value of r = 4 was chosen because the mechanism of polymethacrylate monolith formation is based on the sporadic formation of nuclei.…”

Dispersed phase morphology and fractionated crystallization of high-density polyethylene in PET/HDPE blends

“…SEM micrographs of the fractured surface and related distributions of sizes for PET/PE53K -PET/PE90K and PET/PE150K from top to bottom (28.6% of the particles have size larger than 10 µm in the case of PET/PE150K) theory since when the number of nuclei is lower, the probability that any point in the crystallizing space belongs to the transformed fraction is also reduced[37][38][39].Effect of a compatibilizer on the crystallization behavior of HDPE in PET/HDPE/E-GMA blendsThe effect of the addition of a compatibilizer on the HDPE crystallization was examined for PET/PE53K/E-GMA, PET/PE90K/E-GMA and PET/PE150K/E-GMA blends with composition 85/12.5/2.5. The DSC analysis shows that the crystallization behavior of the HDPE is influenced by adding the E-GMA random copolymer.…”