Density Fluctuations during the Early Stages of Polymer Crystallization: An Overview

Abstract

The present work provides a critical review of polymer crystallization studies using SALS; experimental methods, analysis techniques, observations and their relations with respect to other techniques are discussed. Furthermore, the fact that nucleation might be accompanied by large scale density fluctuations has been investigated for the flow‐induced crystallization of iPB. SALS was applied to measure density and orientation fluctuations, whereas complementary results were obtained from optical microscopy. The observations from both crystallization and melting experiments seem to indicate that the detected density fluctuations result from the presence of weakly anisotropic structures, rather than being an indication of densification before the onset of crystallization.magnified image

SAXS study on the crystallization of PET under physical confinement in PET/PC multilayered films

“…A commonly accepted view to describe the initial stages of crystallization in polymers is still missing. Different approaches including the classical nucleation and growth theory, the stepwise formation of lamellae by merging of mesomorphic domains or the spinodal decomposition type microphase separation have been proposed [29]. The induction period is the time prior to the formation of stable crystal nuclei.…”

On clarification of haze in polypropylene

“…An important experimental tool to study the interaction of light with matter is small-angle light scattering (SALS), which has often been used to explore and model polymer morphology, especially in early stages of crystallization. [19][20][21][22][23][24][25][26] As optical transparency and perceived clarity of semi-crystalline polymers are determined by the angular dependence of the scattered light, SALS seems also an ideal technique to study clarification of polymers. This notwithstanding, SALS has only been used sparsely in connection with clarifying agents.…”

The First 10 Years …

“…Peter Van Puyvelde et al [18] Characterization of Solution-Processed Double-Walled Carbon Nanotube/Poly(vinylidene fluoride) Nanocomposites…”