Spherulitic morphology

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WebFree and constrained amorphous phases in polyethylene: Interpretation of 1H NMR and SAXS data over a broad range of crystallinity WebThe different types of morphology that can be developed in a large number of low-density (branched) polyethylene whole polymers, as well as in a series of fractions, have been studied for two different extreme crystallization modes. ... After isothermal crystallization at elevated temperatures, spherulitic structures are found in all the whole ...

On the Growth and Form of Spherulites NIST

WebNov 1, 2024 · The present work introduces a novel method to estimate the morphology of semicrystalline polymers, namely the average spherulite size, size distribution, and … WebThe spherulitic morphologies of the two pure polymers were examined. Figure 1 shows optical micrographs with crossed polarizers and corresponding Hvscattering patterns for pure PET samples crystallized at various temperatures. At temperatures lower than 200oC, the spherulites display the “Maltese Cross” extinction pattern. sporcle find capital cities of the world

Crystal Morphology - an overview ScienceDirect Topics

WebThe influence of blend morphology (co-continuous or sub-micrometer droplets dispersions) on the nucleation and crystallization kinetics of double crystalline polyethylene/polyamide blends prepared by reactive extrusion [J]. Córdova M.E., Lorenzo A.T., Müller A.J., Macromolecular chemistry and physics . 2011,第13期 WebMay 1, 2016 · Spherulite blend morphology is linked to the competition between radial growth rate G and diffusivity D of the diluent, expressed as the diffusion length δ. Polymer … WebThe initial crystalline morphology has been found to exert influence on the structural evolution of the samples, including cavitation, orientation behavior of molecular chains in crystalline and amorphous phases, the occurrence of mesophase, and reduction in crystallinity, etc. Compared with the iPPBu with spherulitic morphology, no obvious ... shells for sale in bulk

Direct structure determination of vemurafenib …

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WebIt is proposed that spherulitic growth depends on the initial morphology of the crystallite, wherein the gelatin concentration, temperature, and initial supersaturation play a vital role. Gelatin can significantly inhibit NQ nucleation, promote branching, and modify the morphology of NQ subunits. WebMar 31, 2024 · In this article, we will review the recent research progresses on the crystalline and spherulitic morphology of polymers crystallized in the nanoscale confined … sporcle find north american capitalsWebJun 7, 2024 · Crystallization behavior and morphology of two crystal forms growing from thermoplastic polyurethane (TPU) melt in films have been studied by polarized lig … shells for pickup trucks

"WebJul 1, 2005 · This highly non-equilibrium process leads to an extraordinary variety of polycrystalline growth patterns that are broadly termed 'spherulites' because of their large-scale spherical shape. Despite the prevalence and practical importance of spherulite formation, only rather qualitative models of this phenomenon exist. " - Spherulitic morphology

Spherulitic morphology

Microstructural evidence of the toughening mechanisms …

WebMay 19, 2024 · In this article, we will review the recent research progresses on the crystalline and spherulitic morphology of polymers crystallized in the nanoscale confined … WebOct 11, 2024 · The morphological results showed reduced spherulitic crystal nucleus size and increased distribution in blends with increasing LMPP. The blends showed subtle linear viscoelastic responses with strong nonlinear mechanical responses to variant strain and stress compared to pure iPP. ... The crystalline morphology of iPP/LMPP blends can be …

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WebJan 1, 2007 · The structure is modified by the addition of specific nucleating agent, special processing conditions or blending with polyethylene. The addition of β-nucleating agent … WebMay 6, 2024 · Spherulitic morphology and growth rates are examined over a wide range of crystallization temperatures (90–120 °C). With incorporation of CSN, the isothermal crystallization kinetics of PLA/CSN increases, however, the crystallization mechanism remains unaltered. The apparent activation energy and surface energy barrier for …

WebBased upon quantitative analysis of the crystal-nucleation behavior at low temperatures near the glass transition, using Tammann’s two-stage nuclei development method, a nucleation pathway for an acceleration of the crystallization process and for tailoring the semicrystalline morphology is provided. WebOct 1, 1998 · Spherulitic morphology and the melting behavior of the blends were strongly dependent upon the crystallization kinetics and some unique phenomena were found out: (i) in contrast to the other ...

In polymer physics, spherulites (from Greek sphaira = ball and lithos = stone) are spherical semicrystalline regions inside non-branched linear polymers. Their formation is associated with crystallization of polymers from the melt and is controlled by several parameters such as the number of nucleation sites, structure of the polymer molecules, cooling rate, etc. Depending on those parameters, spherulite diameter may vary in a wide range from a few micrometers to milli… WebJun 24, 2015 · The indistinct spherulitic morphology of PBS in the PES-rich phase in Figure 1d suggests that PES and PBS have different lamellar growth directions. This result implies that PES crystallized ...

WebJun 23, 2024 · Here, the microstructural fracture mechanism of the neat PU and HNT-PU nanocomposite are explained through: (i) morphological analysis of the spherulite structure via Field Emission Scanning...

WebMay 1, 2016 · Spherulite blend morphology is linked to the competition between radial growth rate G and diffusivity D of the diluent, expressed as the diffusion length δ. Polymer crystals in which chain helices all have the same sense show banded spherulites, as do crystals in which the chain axes are not perpendicular to the basal surfaces. sporcle find european countriesWebJan 23, 2024 · The spherulitic morphology is considered to be the most common morphology of crystalline materials and is particularly apparent in melt-crystallized products. Yet, historically, the polycrystalline nature of spherulites has hindered successful crystal structure determination. Here, we report the direct structure determination of a … sporcle find european flagsWebNov 4, 2024 · Spherulites are the most common crystalline morphology and thus the visual expression of crystal structures for polymers. The diversified patterns have provided intuitive morphology probes for various crystallization behaviors, while the correlations … We would like to show you a description here but the site won’t allow us. sporcle find counties of englandWebJul 2, 2024 · The spherulitic and lamellar morphology of melt-crystallized isotactic polypropylene. Polymer (Guildf). 26 , 704–716 (1985). CAS Article Google Scholar sporcle find the african countriesWebMay 20, 2024 · This value replaces in the Hoffman–Lauritzen expression (equation (6)) T m,0 allowing to determine the effect of flow on the spherulitic growth rate. In its turn, the excess of growth rate allows to evaluate the nucleation density increase according to Fig. 7 b; thus, the evolution of the spherulitic morphology under flow is completely described. sporcle find the countries of africaWebJan 23, 2024 · The spherulitic morphology is considered to be the most common morphology of crystalline materials and is particularly apparent in melt-crystallized … sporcle find the countries of oceaniaWebApr 15, 2024 · First, the PLLA morphology and microstructure are observed before PEG crystal formation. Figure 3a–e shows the spherulitic morphologies of different compositions of PEG(1OH-1CH 3)/PLLA blends isothermally crystallized at 120 °C using POM, where only PLLA crystallizes from the blends under the experimental condition. PEG … shells for serving seafood