scholarly journals Mechanism of Post-Radiation-Chemical Graft Polymerization of Styrene in Polyethylene

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2512
Author(s):  
Anatoly E. Chalykh ◽  
Vladimir A. Tverskoy ◽  
Ali D. Aliev ◽  
Vladimir K. Gerasimov ◽  
Uliana V. Nikulova ◽  
...  
Keyword(s):  
Cross Section ◽  
Graft Polymerization ◽  
Sample Volume ◽  
Degree Of Crystallinity ◽  
Graft Polymer ◽  
Radiation Chemical ◽  
Sulphate Content ◽  
The Matrix ◽  
Polymer Distribution ◽  
Post Radiation

Structural and morphological features of graft polystyrene (PS) and polyethylene (PE) copolymers produced by post-radiation chemical polymerization have been investigated by methods of X-ray microanalysis, electron microscopy, DSC and wetting angles measurement. The studied samples differed in the degree of graft, iron(II) sulphate content, sizes of PE films and distribution of graft polymer over the polyolefin cross section. It is shown that in all cases sample surfaces are enriched with PS. As the content of graft PS increases, its concentration increases both in the volume and on the surface of the samples. The distinctive feature of the post-radiation graft polymerization is the stepped curves of graft polymer distribution along the matrix cross section. A probable reason for such evolution of the distribution profiles is related to both the distribution of peroxide groups throughout the sample thickness and to the change in the monomer and iron(II) salt diffusion coefficients in the graft polyolefin layer. According to the results of electron microscope investigations and copolymer wettability during graft polymerization, a heterogeneous system is formed both in the sample volume and in the surface layer. It is shown that the melting point, glass transition temperature and degree of crystallinity of the copolymer decreases with the increasing proportion of graft PS. It is suggested that during graft polymerization a process of PE crystallite decomposition (melting) and enrichment of the amorphous phase of graft polymer by fragments of PE macromolecules occurs spontaneously. The driving force of this process is the osmotic pressure exerted by the phase network of crystallites on the growing phase of the graft PS.

Regularities of changes in microhardness in the volume of EDT-69N binder cured at different temperatures

2020 ◽  
Vol 4 ◽  
pp. 65-71
Author(s):  
E.A. Veshkin ◽  
◽  
V.I. Postnov ◽  
V.V. Semenychev ◽  
E.V. Krasheninnikova ◽  
...  
Keyword(s):  
Cross Section ◽  
High Sensitivity ◽  
Sample Volume ◽  
Curing Temperature ◽  
Molding Temperature ◽  
Parabolic Law ◽  
Dimensionless Coefficient ◽  
Straight Line ◽  
Different Temperatures ◽  
The Difference

The change in the microhardness over the thickness of samples made of EDT-69N binder cured in vacuum and at atmospheric pressure at temperatures from 130 to 170°C was investigated. It was found that the change in microhardness along the thickness of the samples occurs according to the parabolic law, with the maximum values being achieved in the middle of the sample cross-section along the thickness. With an increase in the molding temperature, the microhardness in the middle section of the sample increases from 222 MPa at a molding temperature of 130°C to 410 MPa during molding at 170°C. At the critical molding temperature (170°C), the microhardness in all zones of the specimen cross section (subsurface, semi-average, and core) levels off, while the parabolic dependence degenerates into a straight line. It is shown that the method of scratching (sclerometry) demonstrated a sufficiently high sensitivity to the state of samples cured at different temperatures. With an increase in the molding temperature, the width of the sclerometric grooves decreases. At a critical molding temperature of 170°C, the groove width is stabilized and becomes constant throughout the sample thickness. To characterize the difference in the values of the microhardness of the cured binder in the sample volume, it is proposed to use a dimensionless “coefficient of volume anisotropy,” which can take a positive, negative or zero value. With an increase in the curing temperature of the binder and, accordingly, with an increase in the microhardness of the sample, the coefficient of volume anisotropy decreases, and when the samples are molded at the critical temperature, it turns to zero, which indicates the absence of anisotropy.

The synthesis of organically modified layered double hydroxide and its effect on the structure and physical properties of low-density polyethylene/ethylene–vinyl acetate blends

2019 ◽  
Vol 27 (5) ◽  
pp. 287-298
Author(s):  
Xincheng Guo ◽  
Mengqi Tang ◽  
Na Wang ◽  
Lingtong Li ◽  
Yifan Wu ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Layered Double Hydroxide ◽  
Organic Anion ◽  
Ethylene Vinyl Acetate ◽  
Degree Of Crystallinity ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Organically Modified ◽  
The Matrix ◽  
Double Hydroxide

Organically modified layered double hydroxide (OM-LDH) was synthesized via anion exchange reaction and potassium monolauryl phosphate (MAPK) was used as an intercalator. The OM-LDH nanofillers were embedded into low-density polyethylene/ethylene–vinyl acetate (LDPE/EVA) via melt blending process which provided LDPE/EVA/OM-LDH nanocomposites. The structure and properties of the fabricated samples were characterized through Fourier transform infrared spectroscopy, X-ray diffraction techniques, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and tensile testing. The results showed that the organic anion was intercalated into the interlayer region of LDH and enlarged the interlayer distance. The TGA results of the nanocomposites showed significantly improved thermal stability at a higher temperature when containing 6 wt% OM-LDH due to the good dispersion of OM-LDH in the matrix. The DSC data indicated that the degree of crystallinity was increased obviously due to the incorporation of OM-LDH in the matrix. The formation of organic side chains on the OM-LDH surface also contributed to an improvement in the interfacial adhesion, resulting in enhanced tensile strength and elongation at break compared with LDH.

Influence of collagen hydrolysate components on fabrication of collagen/PVA composite fiber

2019 ◽  
Vol 90 (9-10) ◽  
pp. 1141-1148 ◽  
Author(s):  
Luming Yang ◽  
Jinwei Zhang ◽  
Jiacheng Wu ◽  
Wu-yong Chen
Keyword(s):  
Molecular Weight ◽  
Cross Section ◽  
Composite Fiber ◽  
Ash Content ◽  
Retention Rates ◽  
Degree Of Crystallinity ◽  
Composite Fibers ◽  
Collagen Hydrolysate ◽  
Initial Modulus ◽  
The Cross

In order to prepare a collagen/PVA composite fiber with collagen hydrolysate, the influence of the molecular weight and ash content of the collagen hydrolysate on the spinning properties and fabrication of the composite fiber should be studied. In this work, collagen with various molecular weights and different ash contents was first blended with PVA for fabrication of different collagen/PVA composite fibers. Next, protein retention rates, titer, tensile strength, elongation at break, and initial modulus of the composite fibers were characterized. Meanwhile, the degree of crystallinity of the composite fiber was measured by X-ray diffraction and the cross-section morphology was observed by a scanning electron microscope. The results show that the cross section of the collagen/PVA composite fiber has a skin-core structure and the collagen hydrolysate mainly distributes on the surface of the composite fiber. A molecular weight of collagen hydrolysate range from 10,000 Da to 100,000 Da is suitable for fabrication; however, if the collagen hydrolysate molecular weight is lower than 10,000 Da, there is obvious protein loss during spinning. In addition, the inorganic salt and ash content in the spinning collagen hydrolysate should be controlled below 1.5%, otherwise there are some holes on the cross section of the collagen/PVA composite fiber and the mechanical properties and crystallinity of the composite fiber are poor. The results of this research would provide a potential choice for applying collagen hydrolysate in textiles and could be a reference for selecting the proper collagen hydrolysate to obtain collagen/PVA composite fiber materials with better performances.

scholarly journals The Validation of the Sample6 DETECTTM HT/L for AOAC Research Institute

2018 ◽  
Vol 101 (5) ◽  
pp. 1584-1592
Author(s):  
Kakolie Banerjee ◽  
Brittney Pierson ◽  
Chuxuan Hu ◽  
Elijah Carrier ◽  
Lauren Malsick ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Incubation Temperature ◽  
Detection System ◽  
Reference Method ◽  
Culture Method ◽  
The Elderly ◽  
Sample Volume ◽  
Test Portion ◽  
Environmental Surfaces ◽  
The Matrix

Abstract Background: Listeria spp. are an important foodborne human pathogen because of their ability to cause disease and high mortality in individuals, particularly pregnant women, neonates, the elderly, immunocompromised individuals, and children. The Sample6 DETECTTM HT/L Kit is a semi-automated qualitative pathogen detection system designed to detect Listeria spp. (L. monocytogenes, L. innocua, L. ivanovii, L. seeligeri, L. welshimeri, and L. marthii) in environmental samples using the Sample6 BioIlluminationTM technology. Objective: The study was done to evaluate the Sample6 DETECT HT/L Kit. The assay was evaluated for inclusivity, exclusivity, robustness, product consistency, and stability, and a matrix study of one environmental surface. Methods: The performance of the Sample6 DETECT HT/L was compared with U.S. Food and Drug Administration reference culture method for Listeria using an unpaired study design. Results: The Sample6 DETECT HT/L assay correctly identified all 50 inclusivity isolates and correctly excluded all 30 nontarget strains evaluated. The assay was not affected by minor variations in incubation temperature and time, or sample volume. Results across three production lots spanning the shelf life of the assay were consistent. In the matrix study, the Sample6 DETECT HT/L for Listeria correctly identified each test portion for the presence or absence of Listeria, and there were no statistically significant differences between candidate and reference method results. Conclusions: The data collected in this study demonstrate that the Sample6 DETECT HT/L assay is a reliable method for the detection of Listeria spp. on stainless-steel environmental surfaces after 22 h of enrichment.

scholarly journals Graft polymerization of MMA onto the styrene elastomers and mechanical properties of graft polymer and blend polymer.

1993 ◽  
Vol 66 (8) ◽  
pp. 585-590
Author(s):  
Tomohiro KURAMOCHI ◽  
Masanori HIRAMOTO ◽  
Takehiko KIKUCHI ◽  
Masaru IBONAI
Keyword(s):  
Mechanical Properties ◽  
Graft Polymerization ◽  
Graft Polymer ◽  
Blend Polymer

scholarly journals Freeze-Etching Studies of Human Platelets

Blood ◽  
1972 ◽  
Vol 40 (4) ◽  
pp. 514-522 ◽  
Author(s):  
John C. Hoak
Keyword(s):  
Cross Section ◽  
Direct Contact ◽  
Membrane Surface ◽  
Human Platelets ◽  
Etching Technique ◽  
Plasma Surface ◽  
Fixation Methods ◽  
The Matrix ◽  
Freeze Etching ◽  
Normal Human

Abstract The freeze-etching technique was used to study morphologic features of normal human platelets. A well-developed canalicular system was demonstrated within the platelet, with communication to the plasma surface of the platelets and with direct contact of the canaliculi with organelles. Cross-section fractures of granules revealed compartmentalization in some while others appeared homogeneous. Several types of filamentous structures were observed within the matrix of the platelet. Microtubular subfilaments were approximately 80 Å in diameter. Microfilaments were observed in other areas of platelets and had a diameter of 50-70 Å, a size consistent with that described for actinoid filaments. The interior of the platelet membrane contained 85-Å particles, while the membrane surface had a more granular appearance. Earlier morphologic descriptions of platelets prepared by fixation methods have been confirmed and expanded with this technique.

scholarly journals TM Electromagnetic Scattering from PEC Polygonal Cross-Section Cylinders: A New Analytical Approach for the Efficient Evaluation of Improper Integrals Involving Oscillating and Slowly Decaying Functions

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Mario Lucido ◽  
Chiara Santomassimo ◽  
Fulvio Schettino ◽  
Marco Donald Migliore ◽  
Daniele Pinchera ◽  
...  
Keyword(s):  
Cross Section ◽  
Electromagnetic Scattering ◽  
Computation Time ◽  
Electric Field Integral Equation ◽  
Analytical Technique ◽  
Electrically Conducting ◽  
Acceleration Technique ◽  
Integral Equation Formulation ◽  
The Matrix ◽  
Improper Integrals

The analysis of the TM electromagnetic scattering from perfectly electrically conducting polygonal cross-section cylinders is successfully carried out by means of an electric field integral equation formulation in the spectral domain and the method of analytical preconditioning which leads to a matrix equation at which Fredholm’s theory can be applied. Hence, the convergence of the discretization scheme is guaranteed. Unfortunately, the matrix coefficients are improper integrals involving oscillating and, in the worst cases, slowly decaying functions. Moreover, the classical analytical asymptotic acceleration technique leads to faster decaying integrands without overcoming the most important problem of their oscillating nature. Thus, the computation time rapidly increases as higher is the accuracy required for the solution. The aim of this paper is to show a new analytical technique for the efficient evaluation of such kind of integrals even when high accuracy is required for the solution.

scholarly journals Effect of CNT Contents on the Microstructure and Properties of CNT/TiMg Composites

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1620
Author(s):  
Xiaomin Yuan ◽  
Haonan Zhu ◽  
Huiling Ji ◽  
Yiwei Zhang
Keyword(s):  
Cross Section ◽  
Optical Microscope ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure Observation ◽  
The Matrix ◽  
Scanning Electron

Carbon nanotubes (CNTs), dispersed in absolute ethanol, were evenly mixed into Ti/MgH2 powders by wet milling. Then, we applied the vacuum hot-pressed sinteringmethod to the CNTs/TiMg composite materials. An optical microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and a field emission scanning electron microscope (FESEM) were used for the microstructure observation and phase analysis of samples. The mechanical properties were measured via the micro-vickers hardness. The results show that the main phases in the composites were Ti, Mg and C. Meanwhile, a small amount of Ti-Mg solid solution phase was also found. The cross-section morphology of the composites shows that the melted magnesium fills the grain interface during extrusion and that the composites have a better compactness.The microstructures of the composites have been greatly refined as the CNT contents increased. The structure of the composites was further refined when 0.5 wt.% CNTs were added. The fracture surface is obviously a ductile fracture. The microhardness increases obviously with the CNT content increasing. When the content of the CNTs is 1.0 wt.%, the microhardness of the composites reaches 232 HV, which is 24% higher than that of the matrix.

scholarly journals STUDIES ON CILIA

1965 ◽  
Vol 26 (3) ◽  
pp. 805-834 ◽  
Author(s):  
Peter Satir
Keyword(s):  
Cross Section ◽  
Length Change ◽  
The Body ◽  
Cell Of Origin ◽  
Ciliary Movement ◽  
The Matrix ◽  
Morphological Specialization ◽  
Dense Band ◽  
The Cross ◽  
Different Order

Termination of peripheral filaments of the axoneme of gill cilia of fresh-water mussels (Elliptio or Anodonta) occurs in characteristic fashion: (a) subfiber b of certain doublets ends leaving a single simplified tubular unit; (b) the wall of the unit becomes thick and may even obliterate the interior; and (c) the filament drops out of the 9 + 2 pattern. The order in which doublets begin simplifying is also characteristic. This may be determined by numbering the filaments, those with the bridge being 5–6, with the direction of numbering determined by the apparent enantiomorphic configuration (I to IV) of the cross-section. Shorter filaments can be identified in simplifying tips with mixed double and single peripheral units. In this material, laterofrontal cirri show a morphological specialization in the region where individual cilia simplify. The cilia studied run frontally from the body of the cirrus and point in the direction of effective stroke. The longest filaments (Nos. 3, 4, 5, 6, 7) appear as the doublets at the bottom of the cross-section, nearest the surface of the cell of origin. Above them, and above the central pair, a dark band (a section of a dense rod) runs through the matrix. The remaining filaments are the single units. Effective-pointing frontal and lateral ciliary tips end in a fashion similar to laterofrontal tips, although no dense band is present. For all effective-pointing tips studied, the order in which the peripheral filaments end appears to be Nos. (9, 1), 8, 2, 7, 6, 3, 4, 5. However, recovery-pointing lateral tips show a different order: Nos. 7, 6, 8, 5, 9, 4, 1 (3, 2), although the longer filaments are still at the bottom of the cross-section. In simple models of ciliary movement involving contraction of the peripheral filaments, filaments at the top of the cross-section should be longer, if any are. Such models are not supported by the evidence here. These results can be interpreted as supporting sliding-filament models of movement where no length change of peripheral filaments occurs.

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