Unwinding of spherulites in polymers

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August undefined, 2024

WebWhen crystallization behaviour semi-crystalline polymers are referred, the term spherulite always comes into the picture. Spherulites is the crystalline entity that is responsible giving different characteristics such as melting and crystallization temperatures to semi-crystalline polymers in contrast to amorphous polymers [3]. WebThe extinction patterns between crossed nicols shown by two types of arrays of uniaxial crystals have been investigated. The arrays were (a) a disk whose radii were twisted …

Spherulite Morphology in Thin Films of Natural Rubber - JSTOR

Webclassical semicrystalline polymers such as PP during processing can, for instance, be controlled with nucleating agents. While spherulites are aimed to be very small in this … WebAn investigation on polymer spherulites is being described in three parts. Part I (the present paper) describes the various effects observed under the polarizing microscope. These are interpreted in terms of the concepts of crystal optics; the problem of the position of the molecules and that of the microscopic fine structures will form Parts II and III. chris pentz phone number

APS -APS March Meeting 2024 - Event - Spherulites, Cylindirtes …

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. The present work … WebJul 31, 2024 · As shown in Figure 4f, the Raman peak for an excitation perpendicular to the orientation direction is shifted about 3 cm −1 toward higher energies with respect to parallel excitation, indicating that a higher ratio of amorphous polymer chains lies in perpendicular direction. 27 In regions where the formation of spherulites has been suppressed by an … WebCrystallinity refers to the degree of structural order of a solid. In a crystal, the arrangement of atoms or molecules is consistent and repetitive. Many materials such as glass ceramics and some polymers can be prepared in such a way as to produce a mixture of crystalline and amorphous regions. Crystallisabilty • Crystallisabilty is the ... geographical stress

Controlled Pinning of Conjugated Polymer Spherulites and Its ...

On extinction patterns of polymer spherulites - Price - 1959

WebThe extinction behavior of spherulites in many polymers and nonpolymers is shown to result from a characteristic twisting of crystal orientation acquired during growth. Extinction … Webfor a special polyethylene studied, that the spherulites deform affinely at least up to 60-% elongation. It was also indicated that the spherulite deformation model of the multiple con geographical strategyWebSep 1, 1999 · The morphology of spherulites shows that they form because of a short-range force operative at the branch points of dominant lamellae causing them to diverge at non … geographical status of haryana

"WebJan 16, 2001 · The dynamic growth processes of lamellae and spherulites of a polymer (BA-C8) synthesized by condensation polymerization of bisphenol A and 1,8-dibromooctane were directly observed using an atomic force microscope at 25 ± 1 °C. The phase shift measured at the tip of growing lamellae is lower than the phase shifts of the other regions of the … " - Unwinding of spherulites in polymers

Unwinding of spherulites in polymers

WebSep 2, 2016 · 1. Introduction. Using gallstone spherulite crystals as models for covering all spherulites of organic compounds or polymers, Burns [] illustrated relationships between stresses and cracks.Spherulites in general have spherical symmetry, but crystal properties are anisotropic in the radial and tangential directions. WebDec 5, 2024 · Dendritic spherulites are one type of diversified ways of crystal aggregations into micrometer-size consortia by kinetics-driven assembly from nanometer-size crystal …

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WebNov 4, 2024 · In this work, the complicated spherulitic morphology of poly (propylene fumarate) (PPF), which is sensitive to crystallization temperature, is investigated. PPF … WebJul 15, 2024 · Affiliations 1 Graduate Institute of Biomedical Engineering, Chang Gung University, Taoyuan 33302, Taiwan, ROC.; 2 Graduate Institute of Biomedical Engineering, Chang Gung University, Taoyuan 33302, Taiwan, ROC; Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, Taoyuan 33305, Taiwan, ROC; Department of Materials …

WebMay 1, 2016 · Spherulites appear in a wide range of material systems. They can be found in nearly all crystallizable organic polymers (see Geil [3] for an early collection of examples), as well as in polymeric selenium [4], [5].Spherulites are also formed by small organic … WebMagnetically Aligned DNA Liquid Crystals 22 Transition region between cholesteric and high density liquid crystalline DNA. Orientation of the transition region with a 5 Tesla magnetic field increases the helical pitch of the unwinding cholesteric mesophase, which is spontaneously forming batonnets during the phase transition as is evident in the image …

Webgated polymers or small molecules on crystalline 1,3,5-trichlo- robenzene (TCB) from the melt, [15] or directly from solution, [16] resulting in larger macroscopic spherulitic …

WebAug 20, 2024 · Polymer Morphology in 3D. Common plastics like polyethylene, polypropylene and Nylon crystallize during melt-processing. Their thin lamellar crystals …

WebPolymer Journal, Vol. 40, No. 10, pp. 1005–1009, 2008 #2008 The Society of Polymer Science, Japan 1007 large retardation in the PTT spherulite which was much larger than … geographical structure businessWebFeb 21, 2008 · Spherulite ring-band patterns and growth regimes in neat poly(ɛ-caprolactone) (PCL) and its miscible blends were analyzed using polarized-light optical microscopy and differential scanning calorimetry (DSC). Spherulite growth in thin-film forms and transformation of spherulite patterns in different regimes were investigated by … geographical structure advantagesWebAn investigation on polymer spherulites is being described in three parts. Part I (the present paper) describes the various effects observed under the polarizing microscope. These are … chris peoplesWebMar 21, 2024 · Morphology of semicrystalline polymers on the super-µm scale, spherulites, shish-kebabs, and cylindrites, strongly affects the mechanical and other material properties. Current imaging techniques give only a 2D picture of these objects, whose features in the 3rd dimension have been assumed rather than observed. chris peoples farmersWebApr 19, 2024 · Various spherulites or spherulitic crystals are widely encountered in polymeric materials when crystallized from viscous melts or concentrated solutions. … chris pepe mylifeWebAug 19, 2006 · Morphology of polyethylene spherulites has been investigated by the low-dose technique using transmission electron microscopy (TEM) in a scanning mode for … chris peotWebApr 29, 2015 · Polymer Journal - The melt memory of isotactic polystyrene spherulites from the melt is investigated using optical microscopy. When the melting–recrystallization … geographical structure is also called