Toughening mechanism of long chain branched polyamide 6

Ternary composites of Polyamide 6 (PA6), the mixture of Maleated and Unmaleated Ethylene Propylene Diene terpolymer rubber (named EPDM-M), and nanoCalcium Carbonate (nanoCaCO3) were prepared by one-step and two-step compounding routes. The toughness of the composites was tested by impact test. The microstructure morphology of impact surface and etched impact surface was investigated through scanning electron microscope (SEM). The result shows that toughness of the ternary composites with sandbag microstructure was 270 % higher than neat PA6. The SEM morphology shows that strongly elongated microfibrils and deformation are formed in ternary composite with sandbag microstructure, which cause larger shear yielding and crazes in the surrounding matrix to dissipate more impact energy. Additionally, strong ligaments are observed at the crack tip, which could promote plastic deformation and consumption of fracture energy.

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Phase morphology and toughening mechanism of polyamide 6/EPDM-g-MA blends obtained via dynamic packing injection molding

Polymer ◽

10.1016/j.polymer.2006.03.012 ◽

2006 ◽

Vol 47 (9) ◽

pp. 3197-3206 ◽

Cited By ~ 66

Author(s):

Cong Wang ◽

Juan Xia Su ◽

Jiang Li ◽

Hong Yang ◽

Qin Zhang ◽

...

Keyword(s):

Injection Molding ◽

Polyamide 6 ◽

Phase Morphology ◽

Toughening Mechanism

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Formation of Short and Long Chain Branches during the Free Radical Functionalization of Polyamide 6 in the Melt

Macromolecules ◽

10.1021/ma051893o ◽

2006 ◽

Vol 39 (6) ◽

pp. 2153-2161 ◽

Cited By ~ 15

Author(s):

Maria-Beatrice Coltelli ◽

Marco Angiuli ◽

Elisa Passaglia ◽

Valter Castelvetro ◽

Francesco Ciardelli

Keyword(s):

Free Radical ◽

Polyamide 6 ◽

Long Chain ◽

Radical Functionalization

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Polymer Morphology Revealed by Staining Techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098204 ◽

1981 ◽

Vol 39 ◽

pp. 340-341

Author(s):

A. C. Reimschuessel ◽

V. Kramer

Keyword(s):

Polymer Melt ◽

Nylon 6 ◽

Morphological Features ◽

Negative Staining ◽

Polymer Morphology ◽

Crystallizable Polymer ◽

Staining Techniques ◽

Long Chain

Staining techniques can be used for either the identification of different polymers or for the differentiation of specific morphological domains within a given polymer. To reveal morphological features in nylon 6, we choose a technique based upon diffusion of the staining agent into accessible regions of the polymer.When a crystallizable polymer - such as nylon 6 - is cooled from the melt, lamellae form by chainfolding of the crystallizing long chain macromolecules. The regions between adjacent lamellae represent the less ordered amorphous domains into which stain can diffuse. In this process the lamellae will be “outlined” by the dense stain, giving rise to contrast comparable to that obtained by “negative” staining techniques.If the cooling of the polymer melt proceeds relatively slowly - as in molding operations - the lamellae are usually arranged in a radial manner. This morphology is referred to as spherulitic.

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A theory of contamination in electron microscopes by surface diffusion

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107721 ◽

1978 ◽

Vol 36 (1) ◽

pp. 116-117

Author(s):

J.T. Fourie

Keyword(s):

Electron Beam ◽

Surface Diffusion ◽

High Vacuum ◽

Ultra High Vacuum ◽

Physical Parameters ◽

Carbon Compounds ◽

Hydrocarbon Molecules ◽

Electron Microscopes ◽

Primary Electrons ◽

Long Chain

Contamination in electron microscopes can be a serious problem in STEM or in situations where a number of high resolution micrographs are required of the same area in TEM. In modern instruments the environment around the specimen can be made free of the hydrocarbon molecules, which are responsible for contamination, by means of either ultra-high vacuum or cryo-pumping techniques. However, these techniques are not effective against hydrocarbon molecules adsorbed on the specimen surface before or during its introduction into the microscope. The present paper is concerned with a theory of how certain physical parameters can influence the surface diffusion of these adsorbed molecules into the electron beam where they are deposited in the form of long chain carbon compounds by interaction with the primary electrons.

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Phase separation in sol gel-derived ceramic films of silica-zirconia, alumina-zirconia, and titania-zirconia system

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170967 ◽

1994 ◽

Vol 52 ◽

pp. 646-647

Author(s):

J. Tong ◽

L. Eyring

Keyword(s):

Fracture Toughness ◽

Phase Separation ◽

Sol Gel ◽

Great Influence ◽

High Strength ◽

Chemical Durability ◽

Separation Method ◽

Toughening Mechanism ◽

Ceramic Films ◽

Zirconia Toughened Alumina

There is increasing interest in composites containing zirconia because of their high strength, fracture toughness, and its great influence on the chemical durability in glass. For the zirconia-silica system, monolithic glasses, fibers and coatings have been obtained. There is currently a great interest in designing zirconia-toughened alumina including exploration of the processing methods and the toughening mechanism.The possibility of forming nanocrystal composites by a phase separation method has been investigated in three systems: zirconia-alumina, zirconia-silica and zirconia-titania using HREM. The morphological observations initially suggest that the formation of nanocrystal composites by a phase separation method is possible in the zirconia-alumina and zirconia-silica systems, but impossible in the zirconia-titania system. The separation-produced grain size in silica-zirconia system is around 5 nm and is more uniform than that in the alumina-zirconia system in which the sizes of the small polyhedron grains are around 10 nm. In the titania-zirconia system, there is no obvious separation as was observed in die alumina-zirconia and silica-zirconia system.

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The effects of low-ratio n-6/n-3 PUFA on biomarkers of inflammation: a systematic review and meta-analysis

Food & Function ◽

10.1039/d0fo01976c ◽

2021 ◽

Author(s):

Yali Wei ◽

Yan Meng ◽

Na Li ◽

Qian Wang ◽

Liyong Chen

Keyword(s):

Systematic Review ◽

Fatty Acid ◽

Polyunsaturated Fatty Acid ◽

Meta Analysis ◽

Chain Polyunsaturated Fatty Acid ◽

Inflammation Markers ◽

Pufa Supplementation ◽

Long Chain

The purpose of the systematic review and meta-analysis was to determine if low-ratio n-6/n-3 long-chain polyunsaturated fatty acid (PUFA) supplementation affects serum inflammation markers based on current studies.

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Biophysics (and sociology) of ceramides.

Biochemical Society Symposium ◽

10.1042/bss0720177 ◽

2005 ◽

Vol 72 ◽

pp. 177-188 ◽

Cited By ~ 28

Author(s):

Félix M. Goñi ◽

F-Xabier Contreras ◽

L-Ruth Montes ◽

Jesús Sot ◽

Alicia Alonso

Keyword(s):

Cell Biology ◽

Positive Curvature ◽

Acyl Chain ◽

Cell Signalling ◽

Hexagonal Structure ◽

Lipid Monolayer ◽

Flip Flop ◽

Long Chain ◽

Bilayer Permeability

In the past decade, the long-neglected ceramides (N-acylsphingosines) have become one of the most attractive lipid molecules in molecular cell biology, because of their involvement in essential structures (stratum corneum) and processes (cell signalling). Most natural ceramides have a long (16-24 C atoms) N-acyl chain, but short N-acyl chain ceramides (two to six C atoms) also exist in Nature, apart from being extensively used in experimentation, because they can be dispersed easily in water. Long-chain ceramides are among the most hydrophobic molecules in Nature, they are totally insoluble in water and they hardly mix with phospholipids in membranes, giving rise to ceramide-enriched domains. In situ enzymic generation, or external addition, of long-chain ceramides in membranes has at least three important effects: (i) the lipid monolayer tendency to adopt a negative curvature, e.g. through a transition to an inverted hexagonal structure, is increased, (ii) bilayer permeability to aqueous solutes is notoriously enhanced, and (iii) transbilayer (flip-flop) lipid motion is promoted. Short-chain ceramides mix much better with phospholipids, promote a positive curvature in lipid monolayers, and their capacities to increase bilayer permeability or transbilayer motion are very low or non-existent.

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