Crystallization and multiple melting behavior of oriented …
Here, well-oriented thick lamellae (22–37 nm) have been produced in isotactic polypropylene (iPP) by crystallization under the combined effects of flow (30 s −1) and pressure (50, 75, 100, 125 MPa). The melting of these oriented thick lamellae is followed by real-time wide- and small-angle X-ray scattering measurements. The results show ...
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PARTICLE CRUSHING AND DEFORMATION BEHAVIOUR
In our study, an existing constitutive model, the Severn-Trent sand model, in which the critical state line plays a central role as the locus of asymptotic states, has been extended to include …
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3.5: Isostasy
Isostasy is the state in which the force of gravity pulling the plate toward Earth's centre is balanced by the resistance of the mantle to letting the plate sink.
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Cold Isostatic Pressing
Hot isostatic pressing is a manufacturing process which utilizes elevated temperature and isostatic gas pressure to eliminate porosity and increase density in metals, ceramics, …
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9.4: Isostasy
The literal meaning of the word isostasy is "equal standstill," but the importance behind it is the principle that Earth's crust is floating on the mantle, like a raft floating in the water, rather than resting on the mantle like a raft sitting on the ground.
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9.4 Isostasy – Physical Geology – 2nd Edition
The literal meaning of the word isostasy is "equal standstill," but the importance behind it is the principle that Earth's crust is floating on the mantle, like a raft floating in the water, rather than …
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9.4 Isostasy – Physical Geology
The literal meaning of the word isostasy is "equal standstill," but the importance behind it is the principle that Earth's crust is floating on the mantle, like a raft floating in the water, rather than resting on the mantle like a raft sitting on the ground. The relationship between the crust and the mantle is illustrated in Figure 9.16.
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Mechanistic Study of Isotactic Poly(propylene oxide) …
Initial catalyst dormancy has been mitigated for the enantioselective polymerization of propylene oxide using a tethered bimetallic chromium(III) salen complex. A detailed mechanistic study provided insight into the species responsible for this induction ...
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Preparation and characterization of isotactic polypropylene …
Isotactic polypropylene (iPP), as one of the most successful commercial polymers, has a wide range of applications in construction, automobile, medical, electrical, and electronic fields, because of its outstanding properties, such as excellent strength, high thermal stability, superior chemical resistance, and cost-effectiveness [[1], [2], [3 ...
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Photooxidative degradation and fragmentation …
The photooxidative degradation and fragmentation behaviors of isotactic polypropylene (itPP) were simulated in laboratory after various postconditions, such as quenching, gradual cooling and...
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Isostasy | Plate Tectonics, Earth's Crust & Gravity | Britannica
isostasy, ideal theoretical balance of all large portions of Earth's lithosphere as though they were floating on the denser underlying layer, the asthenosphere, a section of the upper mantle composed of weak, plastic rock that is about 110 km (70 miles) below the surface.
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Competition between α and γ phases in isotactic …
Isotactic polypropylene (iPP) is on the one hand an 'ordinary' commodity polymer with a very simple chemical structure. On the other hand despite its chemical simplicity it shows a remarkable complexity of crystal structures, and self-assembly behavior [1], [2].Control of the growth of the different polymorphs as a function of material grade and crystallization conditions …
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Crystal Ordering of Isotactic Polypropylene and Carbon
Isotactic polypropylene forms three different crystalline phases, α, β, γ. Of the three forms, α is the most common and forms under normal crystallization conditions (Varga 1989). Each of the three crystalline phases can be identified by their distinctive wide angle X …
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Photooxidative degradation and fragmentation …
The photooxidative degradation and fragmentation behaviors of isotactic polypropylene (itPP) were simulated in laboratory after various postconditions, such as quenching, gradual cooling …
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Morphological study of isotactic polypropylene thin films on …
Isotactic polypropylene (iPP) is one of the most commonly used polymers, having a wide range of applications ranging from automobile parts and packaging to necessities, owing to its excellent mechanical properties and well-balanced physical properties such as low density and heat resistance. To achieve these excellent properties, many ...
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9.4 Isostasy – Physical Geology
The literal meaning of the word isostasy is "equal standstill," but the importance behind it is the principle that Earth's crust is floating on the mantle, like a raft floating in the …
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29.5: Correlation of Polymer Properties with Structure
Isotactic polypropene is a hard, clear, strong crystalline polymer that melts at 175o 175 o. It is practically insoluble in all organic solvents at room temperature, but will dissolve to the extent …
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PARTICLE CRUSHING AND DEFORMATION BEHAVIOUR
In our study, an existing constitutive model, the Severn-Trent sand model, in which the critical state line plays a central role as the locus of asymptotic states, has been extended to include the eŠects of particle breakage.
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Advantage of Preserving Bi-orientation Structure of Isotactic
The isotactic polypropylene (iPP) usually shows a unique parent-daughter lamellae structure in which the parent and daughter lamellae are against each other with a near perpendicular angle (80° or 100°). Inducing a high fraction of oriented cross-hatched structure in iPP during processing is desirable for designing the bi-oriented iPP products. We processed a …
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The three basic structures for polypropylene (a) isotactic, …
Most (90-95%) of commercial PP are isotactic PP produced by Ziegler-Natta catalyst with head-to-tail incorporation of propylene monomer. Isotactic configuration is the most stable structure since ...
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In-situ synchrotron X-ray investigating crystallization of isotactic …
Isotactic polypropylene (iPP) is a widely used semi-crystalline polymorphic polymer and one of the most commonly used raw materials for injection molded products. It has three common crystalline phases, i.e., monoclinic α-crystal, trigonal β-crystal and orthorhombic γ-crystal [[5], [6], [7], [8]].
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Enhanced Mechanical Toughness of Isotactic Polypropylene …
Herein, we report the use of bulk molybdenum disulfide (MoS 2) as the reinforcing agent to enhance the toughness of isotactic polypropylene (iPP).The iPP-MoS 2 nanocomposites with varying amounts of MoS 2 (0.1 to 5 wt %) were prepared by a one-step melt extrusion method, and the effects of MoS 2 on the morphology, thermal, and mechanical properties …
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Effects of crystal structure on the ing of isotactic …
This paper aims to study, for the first time, the effect of crystal structure on the cell formation in an isotactic polypropylene (iPP) during a solid-state ing process using supercritical carbon dioxide (scCO 2) as a ing agent.Results show that the spherulite structure exerted a significant impact on the cell morphology of ed iPP.
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Experimental Study of the Crushing Characteristics of Single …
The crushing process of material particles in a vertical shaft impact (VSI) crusher is highly complex. It is hard to quantify and characterize the crushing behavior of particles. In this work, an experimental setup for active impact crushing is designed and constructed to investigate the crushing behavior of particles in a VSI crusher. Impact crushing experiments are carried …
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Isostasy | Plate Tectonics, Earth's Crust & Gravity
isostasy, ideal theoretical balance of all large portions of Earth's lithosphere as though they were floating on the denser underlying layer, the asthenosphere, …
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29.5: Correlation of Polymer Properties with Structure
Isotactic polypropene is a hard, clear, strong crystalline polymer that melts at 175o 175 o. It is practically insoluble in all organic solvents at room temperature, but will dissolve to the extent of a few percent in hot 1,1,2,2-tetrachloroethane.
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Cold Isostatic Pressing
Hot isostatic pressing is a manufacturing process which utilizes elevated temperature and isostatic gas pressure to eliminate porosity and increase density in metals, ceramics, polymers, and composite materials. This improves the material's mechanical properties and …
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9.4: Isostasy
The literal meaning of the word isostasy is "equal standstill," but the importance behind it is the principle that Earth's crust is floating on the mantle, like a raft floating in the …
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Unusual Tuning of Mechanical Properties of Isotactic …
Preparation, Structure, and Properties of an Isotactic Polypropylene Film with Ultrahigh Content, Ordered, and Continuous β-Transcrystallinity. Macromolecules 2019, 52 (18), 6963-6975.
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Probing the difference of crystalline modifications and …
Isotactic polypropylene (iPP) crystallized in different crystalline modifications has been investigated by high-resolution FTIR spectroscopy. We focus on the spectral behavior of a band at ~841 cm −1 that is generally employed as a probe to monitor the crystallization process of iPP. The peak position of the ~841 cm −1 band (P 841) in the IR spectrum of α-form iPP is …
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