scholarly journals Rheological Behaviour of Highly Filled Materials for Injection Moulding and Additive Manufacturing: Effect of Particle Material and Loading

2020 ◽  
Vol 10 (22) ◽  
pp. 7993
Author(s):  
Marko Bek ◽  
Joamin Gonzalez-Gutierrez ◽  
Christian Kukla ◽  
Klementina Pušnik Črešnar ◽  
Boris Maroh ◽  
...  
Keyword(s):  
Matrix Material ◽  
Rheological Behaviour ◽  
Thermoplastic Polymer ◽  
Molten State ◽  
Binder System ◽  
Inorganic Fillers ◽  
High Concentrations ◽  
Shape And Size ◽  
Alloy Titanium ◽  
Number Of Particles

Within this paper, we are dealing with a mixture of thermoplastic polymer that is filled with inorganic fillers at high concentrations up to 60 vol.%. A high number of particles in the compound can substantially change the rheological behaviour of the composite and can lead to problems during processing in the molten state. The rheological behaviour of highly filled materials is complex and influenced by many interrelated factors. In the present investigation, we considered four different spherical materials: steel, aluminium alloy, titanium alloy and glass. Particles with similar particle size distribution were mixed with a binder system at different filling grades (30–60 vol.%). We showed that the rheological behaviour of highly filled materials is significantly dependent on the chemical interactions between the filler and matrix material. Moreover, it was shown that the changes of the particle shape and size during processing lead to unexpected rheological behaviour of composite materials as it was observed in the composites filled with glass beads that broke at high contents during processing.

scholarly journals Subcellular compartmentalization of maize storage proteins in Xenopus oocytes injected with zein messenger RNAs.

1981 ◽  
Vol 89 (2) ◽  
pp. 292-299 ◽  
Author(s):  
W J Hurkman ◽  
L D Smith ◽  
J Richter ◽  
B A Larkins
Keyword(s):  
Storage Proteins ◽  
Matrix Material ◽  
Membrane Vesicles ◽  
Subcellular Fractionation ◽  
Dense Matrix ◽  
Messenger Rnas ◽  
Material Density ◽  
Optimal Separation ◽  
High Concentrations ◽  
Subcellular Compartmentalization

Maize storage proteins synthesized in oocytes were compartmentalized in membrane vesicles because they were resistant to hydrolysis by protease, unless detergent was present. The site of storage protein deposition within the oocyte was determined by subcellular fractionation. Optimal separation of oocyte membranes and organelles was obtained when EDTA and high concentrations of NaCl were included in the homogenization and gradient buffers. Under these conditions, fractions in sucrose gradients containing a heterogeneous mixture of smooth membranes (presumably endoplasmic reticulum, Golgi apparatus, and plasma membrane, density = 1.10-1.12 g/cm3), mitochondria (densities = 1.14 and 1.16 g/cm3), yolk platelets (density = 1.21 g/cm3), and a dense matrix material (density = 1.22 g/cm3) could be separated. Some zein proteins were recovered in the mixed membrane fraction, but the majority occurred in vesicles sedimenting with yolk platelets and granular material at a density of approximately 1.22 g/cm3. When metrizamide was included in the gradient to increase the density, little of the dense matrix material was isolated, and vesicles containing zein proteins were separated from other oocyte components. These vesicles were similar to protein bodies in maize endosperm because they were of identical density and contained the same group of polypeptides.

scholarly journals Simulation of Processes Occurring in the Extrusion Head Used in Additive Manufacturing Technology

2017 ◽  
Vol 11 (4) ◽  
pp. 317-321 ◽  
Author(s):  
Artur Prusinowski ◽  
Roman Kaczyński
Keyword(s):  
Additive Manufacturing ◽  
Matrix Material ◽  
Flow Simulation ◽  
Thermoplastic Polymer ◽  
Fused Deposition ◽  
Extrusion Head ◽  
Element Simulation ◽  
Proper Design ◽  
Nozzle Temperature ◽  
Manufacturing Technologies

AbstractThe purpose of this research is unsatisfactory state of knowledge of the abrasive wear of composites with thermoplastic polymer as matrix material and reinforcing material in the form of short and focused carbon fibers that can be used in additive manufacturing technologies. The paper presents a conceptual design of an extrusion head used in Fused Deposition Technology, which allows for the implementation of appropriately stacked fibers at the level of detail production. Finite element simulation was performed to simulate the thermal effect of the system to demonstrate the effect of head cooling on the system. The assumed extrusion temperature of the material was obtained at a uniform nozzle temperature and stable temperature of the entire system. Flow simulation of thermoplastic polymer was carried out in the designed extrusion nozzle. By supplying 0.5 mm wire of 1.75 mm diameter thermoplastic material to the nozzle, the extrusion rate was 0.192 m/s. The proper design of the extrusion head for the intended applications has been demonstrated and the purpose of further research in this field has been confirmed.

scholarly journals Synergy of Inorganic Fillers in Composite Thermoplastic Polymer/Ionic Liquid/LiTFSI Electrolytes

2020 ◽  
Vol 167 (7) ◽  
pp. 070519 ◽  
Author(s):  
F. González ◽  
O. Garcia-Calvo ◽  
P. Tiemblo ◽  
N. García ◽  
E. Fedeli ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Thermoplastic Polymer ◽  
Inorganic Fillers

scholarly journals Characterization of cytoplasmic and nuclear genomes in the colorless alga Polytoma. I. Ultrastructural analysis of organelles.

1976 ◽  
Vol 69 (2) ◽  
pp. 352-370 ◽  
Author(s):  
C Siu ◽  
H Swift ◽  
K Chiang
Keyword(s):  
Protein Synthesis ◽  
Structural Organization ◽  
Matrix Material ◽  
Limited Ability ◽  
Main Emphasis ◽  
The Matrix ◽  
Photosynthetic Mutants ◽  
Nuclear Genomes ◽  
Shape And Size

Electron microscope studies have been made on the fine structure of the colorless biflagellate, Polytoma obtusum, with main emphasis on the structural organization of the mitochondria and the leucoplast. Both organelles have been demonstrated to contain DNA aggregates as well as ribosomal particles within their matrix material. Reconstructions from serial showed that (a) the mitochondria were highly convoluted and irregular in shape and size, and (b) the leucoplast was a single cup-shaped entity, with large starch grains, localized at the posterior end, and multiple sites of DNA aggregates. The starch-containing compartments appeared to be interconnected by narrow tubular or sheetlike bridges. Cytoplasmic invaginations into the plastid, often containing mitochondria, were of frequent occurrence, and membranes of mitochondria and the leucoplast appeared to be closely apposed. Membranes elements, both sheetlike and vesicular, were also present in the matrix. The Polytoma leucoplast was, in certain respects, morphologically similar to the plastids of various photosynthetic mutants of Chlamydomonas, most of which show Menedelian segregation. It is suggested that Polytoma arose from a Chlamydomonas-like ancestor, possibly through combined mutational processess of both chloroplast and nuclear genomes. Since Polytoma leucoplasts contain both DNA and ribosomal particles, it is probable that these organelles still possess semiautonomy and limited ability for protein synthesis.

Study of mechanical and physical properties of LLDPE-G-MA injection grade reinforced with coffee husk post-industrial waste

2016 ◽  
Vol 51 (3) ◽  
pp. 419-429 ◽  
Author(s):  
William Urrego Yepes ◽  
Juan Carlos Posada ◽  
Leyla Yamile Jaramillo ◽  
Juan Diego Sierra
Keyword(s):  
Calcium Carbonate ◽  
Rheological Behaviour ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Melt Mixing ◽  
Crystallinity Degree ◽  
Coffee Husk ◽  
Inorganic Fillers ◽  
Post Industrial

In this work, the evaluation of a post-industrial residue of coffee industry (coffee husk) as organic filler in functionalised linear low-density polyethylene matrix was investigated. The properties of these composites were compared with more widely used inorganic fillers, such as calcium carbonate and SiO2. All the composites were prepared by grafting of linear low-density polyethylene maleic anhydride and then by melt mixing of fillers. The rheological behaviour of the compounds during processing was established to evaluate the effects of a nanosized (SiO2), micron sized calcium carbonate and coffee husk fillers. Additionally, thermal, morphological and mechanical properties of the polymer composites were evaluated. The results indicated an increase in tensile modulus and tensile strength resulting from incorporation of fillers in the polymer matrix. Some relevant modifications of melting temperature and crystallinity degree for coffee husk composites were observed, but not observed for inorganic fillers composites. The properties of the composites prepared with coffee husk were comparable to those obtained with inorganic fillers, demonstrating that this coffee residue can be used as filler for obtaining composites for many possible applications.

Rheological Properties Analysis of WC-Co Injection Feedstock

2013 ◽  
Vol 773-774 ◽  
pp. 880-886 ◽  
Author(s):  
Sri Yulis M. Amin ◽  
Norhamidi Muhamad ◽  
Khairur Rijal Jamaludin
Keyword(s):  
Rheological Properties ◽  
Rheological Behaviour ◽  
Critical Factor ◽  
Palm Stearin ◽  
Solid Loading ◽  
Binder System ◽  
Capillary Rheometry ◽  
High Solid Loading ◽  
Flow Behaviour Index ◽  
Behaviour Index

In order to produce a defect-free component, the feedstock composition plays as a critical factor. The feedstock needs to meet the following criteria; high solid loading with excellent flowability. The flowability of the feedstock is greatly determined by the rheological response. Therefore, the aim of this paper is to investigate the rheological behaviour of MIM feedstock comprising of WC-Co powder, with a binder system of Palm Stearin (PS) and Polyethylene (PE), by means of a capillary rheometry. The viscosity and shear rate of various feedstocks at powder loading ranging from 59, 61 and 63% were measured at L/D = 10 die. The rheological properties such as flow behaviour index, activation energy and moldability parameter of each feedstock were calculated and from the analysis, it was concluded that they show a good pseudo-plastic behaviour within acceptable ranges in MIM.

scholarly journals Rheological characteristics of platy kaolin

TAPPI Journal ◽  
2019 ◽  
Vol 18 (9) ◽  
pp. 535-544
Author(s):  
Anthony Lyons
Keyword(s):  
Water Retention ◽  
Barrier Properties ◽  
Rheological Characteristics ◽  
Binder System ◽  
Indirect Measure ◽  
Extensive Analysis ◽  
Tan Δ ◽  
The University ◽  
Coating Formulation ◽  
Shape And Size

Platy kaolin can provide significant value in the coating of paper and paperboard. It can be used in multiple applications and can provide benefits such as titanium dioxide (TiO2) extension, smoothness improvement, improved print gloss or ink set rates, calendering intensity reduction, and improved barrier properties. It is not a pigment that can be simply substituted for traditional hydrous kaolin without some adjustment to the coating formulation. These adjustments can be as simple as reducing solids, but may require binder changes as well. The coater setup may need to be adjusted because of the unique rheological behaviors these pigments exhibit. The unique rheological characteristics of platy kaolin are explored here. Measurements of the water retention of platy kaolin containing coatings confirm that water retention is not reduced in comparison to more blocky kaolin pigments, despite the lower coating solids at which they need to be run. This means that the rheological characteristics are the most important in understanding the runnability. An extensive analysis reveals some unique behaviors that need to be understood when utilizing these materials. Viscoelastic measurements indicate that, for this binder system, Tan δ is mainly a function of solids. This may explain how weeping is initiated on a blade coater. The degree of shear thinning behaviors is investigated using the Ostwald de-Waele power law. The immobilization point was determined using the Dougherty-Krieger equation and related to the work of Weeks at the University of Maine on blade coater runnability. An indirect measure of particle shape and size synergy is also demonstrated using the Dougherty- Krieger equation parameters.

Freeze-fracture, freeze-etch complementary pairs of virus-infected cells reveal value of etching even when relatively high concentrations of cryoprotectants are used

1978 ◽  
Vol 36 (2) ◽  
pp. 136-137
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Plant Tissue ◽  
Phosphate Buffer ◽  
Infected Plant ◽  
Freeze Fracture ◽  
Distilled Water ◽  
Virus Infected Plant ◽  
Infected Cells ◽  
High Concentrations

It has been assumed by many involved in freeze-etch or freeze-fracture studies that it would be useless to etch specimens which were cryoprotected by more than 15% glycerol. We presumed that the amount of cryoprotective material exposed at the surface would serve as a contaminating layer and prevent the visualization of fine details. Recent unexpected freeze-etch results indicated that it would be useful to compare complementary replicas in which one-half of the frozen-fractured specimen would be shadowed and replicated immediately after fracturing whereas the complement would be etched at -98°C for 1 to 10 minutes before being shadowed and replicated.Standard complementary replica holders (Steere, 1973) with hinges removed were used for this study. Specimens consisting of unfixed virus-infected plant tissue infiltrated with 0.05 M phosphate buffer or distilled water were used without cryoprotectant. Some were permitted to settle through gradients to the desired concentrations of different cryoprotectants.

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