Spherulitic crystallization

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August undefined, 2024

WebFeb 27, 2003 · Spherulitic textures formed during crystallization of partially melted arkose, Rum, Scotland - Volume 139 Issue 6 ... Crystallization (to form granophyre) of these highly melted rocks was generally static in the vicinity of minor intrusions, although disruption of bedding is apparent in the aureole of the main mafic pluton. A distinctive ... WebLow-temperature annealing close to the glass transition temperature (Tg) leads to the formation of crystal nuclei, which grow to crystals at higher temperatures, and yield a much finer spherulitic superstructure, as obtained after direct melt-crystallization.

Effects of crystallization temperature and spherulite size

WebNone of the bundlelike models will lead to a typical lamellar spherulite, though a spherical microcrystalline object might be formed. It is concluded that lamellar spherulites consist largely of chain folded structures. The factors that could cause chain folded crystals to appear in profusion in bulk polymers are discussed. WebJan 1, 2014 · The most common higher order structure of crystalline polymers is called spherulite. A spherulite is a polycrystalline aggregate densely filled with thin lamellar crystals and formed by consecutive lamellar branching and reorientation of those crystals in non-crystallographic directions. alegoria malbec

Nucleation in medium density polyethylenes: comparisons …

WebSubsequent DSC scans of isothermally crystallized PBS and PBSR exhibited two melting endotherms, respectively, which was due to the melt-recrystallization process occurring … WebJan 1, 2004 · The spherulitic aggregate is too fine grained to be determined directly of what minerals it is composed. Bigger spherulites have a much more complicated inner structure. The alkali feldspar is... WebJun 4, 2024 · The theory of spherulitic crystallization is here applied to sedimentary deposits for the first time. The intimate association of calcite and quartzine in the concretions requires a chemical change from alkaline to acidic conditions, which occurs below the carbonate-reduction zone owing to the dissolution of sponge spicules or … alegoria marina mazatlan

Spherulitic Crystallization in Polypropylene: Journal of Applied ...

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WebApr 19, 2024 · Various spherulites or spherulitic crystals are widely encountered in polymeric materials when crystallized from viscous melts or concentrated solutions. However, the microstructures and growth processes are quite complicated and remain unclear and, thus, the formation mechanisms are rather elusive. Here, diverse kinds of … WebOct 11, 2024 · Spherulitic growth rate is related to the crystallization temperature and is nonlinear in non-isothermal conditions of the polymeric blends. The POM shown in Figure 1 , the spherulitic growth rate of the blends presents regular growth with the addition of LMPP contents, affecting the size and shape of the spherulites. alegoria metaforaWebMar 18, 2016 · A method of gradient cooling-down isothermal crystallization was used to prepare layered spherulites. The polyester was dissolved in chloroform to obtain a uniform solution (3 wt% for PLLA and 2 wt% for PHB). A drop of the solution was cast and uniformly spread on a clean glass slide. alegoria na arte

"WebFeb 1, 2011 · Spherulitic crystallization of β‐In2Te3 by physical vapour deposition. Different morphologies of indium telluride (In2Te3) including novel spherulites were crystallized … " - Spherulitic crystallization

Spherulitic crystallization

Polymers Free Full-Text Viscoelastic Rheological Behaviors of ...

WebJan 1, 2001 · This study aims to make a spherical spherulite of NTO by cooling crystallization using co-solvent. N -methyl-2-pyrrolidone (NMP) and water were … WebSpherulite formation is an example of self-assembly, where building blocks spontaneously arrange themselves into larger, more complex structures. These structures determine the material's functionality in both foods and biological systems. Understanding of spherulite formation is limited.

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WebJan 28, 1999 · Chitosan crystallization, performed by simple drying of an oligomer or polymer solution on a glass or mica surface, was studied at room temperature. Polarizing … WebNov 1, 2024 · The method presented here can be a useful technique to construct the spherulitic morphology based on crystallization conversion curves and predict properties dependent on the spherulite size, size ...

WebPP developed spherulites, whose growth was unaffected by blending, while its overall isothermal crystallization kinetics was strongly influenced by nucleation effects caused by blending. Addition of nanosilica resulted in an enhancement of the strain at break of PP-PC blends whereas it was observed to weaken PP-PA blends. WebJun 16, 2004 · ABSTRACT. A survey has been made of spherulites formed by the isothermal crystallization of polypropylene from the melt in the temperature range 110°–148°C. Four types of spherulite have been distinguished and their structural morphology, optical properties, melting behavior, and growth rates have been examined.

WebThese results provide quantitative support for the mechanism of spherulitic growth proposed by Keith and Padden. AB - I show that diffusion-controlled growth can account … WebSep 1, 2010 · Spherulitic crystal growth has been extensively studied in systems of polymeric blends of large molecules and in cooling of high temperature melts. High viscosity or presence of impurities is often regarded as an …

Webkeith, h.d., spherulitic crystallization from melt .i. fractionation + impurity segregation + their influence on crystalline morphology, journal of applied physics 35: 1270 (1964). Google Scholar KELLER, A, THE SPHERULITIC STRUCTURE OF CRYSTALLINE POLYMERS .2.

WebLow-temperature annealing close to the glass transition temperature (Tg) leads to the formation of crystal nuclei, which grow to crystals at higher temperatures, and yield a … alegoria medicalWebWhile Avrami exponents fluctuated between lamellar and spherulitic growth, rate constants increased and crystallization half-times decreased with decreasing crystallization temperature. The chromium catalysed polyethylene was found to crystallize faster and have higher crystallinity. This effect of enhanced nucleation was not seen in the other ... alegoria oratoriaWebThe growth of spherulitic crystal patterns in a Belousov–Zhabotinski (BZ) type reaction system by using acetyl acetone (AA)– succinic acid (SA) as dual organic substrates has … alegoria pediatrico plmWebMar 23, 2014 · The crystal growth proceeds as the stacks of lamellar crystals and amorphous layers in between. (c, e, f) When polymers are crystallized from the melt, … alegoria party rentalWebThe present work was undertaken to establish rates of primary nucleation for isotactic polypropylene and to put forth a modified classical model for the secondary nucleation process in isotactic polypropylene systems. alegoria pdfWebJul 5, 2024 · Spherulitic devitrification is a post-eruptive process affecting many rhyolitic lavas of the Taupo region. The spherulites consist of cryptocrystalline intergrowths of α … alegoria mito da cavernaWebSpherulite is a spheriform aggregate of chain-folded fibrillar or lamellar primary crystallites. According to a simplified model, crystallites start from a central, pin-point type nucleus … alegoria origin