scholarly journals Rotational Rheology of Wood Flour Composites Based on Recycled Polyethylene

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2226
Author(s):  
Antonella Patti ◽  
Gianluca Cicala ◽  
Stefano Acierno
Keyword(s):  
Wood Flour ◽  
Viscoelastic Behavior ◽  
Melt Mixing ◽  
Processing Technologies ◽  
Viscoelastic Moduli ◽  
Torque Measurements ◽  
Recycled Polyethylene ◽  
Potential Applications ◽  
Two Phases ◽  
Crosslinking Reactions

In this paper, we study the effect of the addition of wood flour as a filler in a recycled polyethylene (r-PE) in view of its potential applications in 3D printing. The composites, prepared by melt mixing, are characterized with torque measurements performed during the compounding, dynamic rotational rheology, and infrared spectroscopy. Data show that the introduction of wood results in increased viscosity and in sensible viscous heating during the compounding. The r-PE appear to be stable at temperatures up to 180 °C while at higher temperatures the material shows a rheological response characterized by time-increasing viscoelastic moduli that suggests a thermal degradation governed by crosslinking reactions. The compounds (with wood loading up to 50% in wt.) also shows thermal stability at temperatures up to 180 °C. The viscoelastic behavior and the infrared spectra of the r-PE matrix suggests the presence of branches in the macromolecular structure due to the process. Although the addition of wood particles determines increased viscoelastic moduli, a solid-like viscoelastic response is not shown even for the highest wood concentrations. This behavior, due to a poor compatibility and weak interfacial adhesion between the two phases, is however promising in view of common processing technologies as extrusion or injection molding.

Is Domain Highlighting Actually Helpful in Identifying Phishing Web Pages?

2017 ◽  
Vol 59 (4) ◽  
pp. 640-660 ◽  
Author(s):  
Aiping Xiong ◽  
Robert W. Proctor ◽  
Weining Yang ◽  
Ninghui Li
Keyword(s):  
Eye Gaze ◽  
Phase 1 ◽  
Web Pages ◽  
Web Page ◽  
Domain Name ◽  
Heat Map ◽  
Potential Applications ◽  
Two Phases ◽  
Phishing Detection ◽  
Better Than

Objective: To evaluate the effectiveness of domain highlighting in helping users identify whether Web pages are legitimate or spurious. Background: As a component of the URL, a domain name can be overlooked. Consequently, browsers highlight the domain name to help users identify which Web site they are visiting. Nevertheless, few studies have assessed the effectiveness of domain highlighting, and the only formal study confounded highlighting with instructions to look at the address bar. Method: We conducted two phishing detection experiments. Experiment 1 was run online: Participants judged the legitimacy of Web pages in two phases. In Phase 1, participants were to judge the legitimacy based on any information on the Web page, whereas in Phase 2, they were to focus on the address bar. Whether the domain was highlighted was also varied. Experiment 2 was conducted similarly but with participants in a laboratory setting, which allowed tracking of fixations. Results: Participants differentiated the legitimate and fraudulent Web pages better than chance. There was some benefit of attending to the address bar, but domain highlighting did not provide effective protection against phishing attacks. Analysis of eye-gaze fixation measures was in agreement with the task performance, but heat-map results revealed that participants’ visual attention was attracted by the highlighted domains. Conclusion: Failure to detect many fraudulent Web pages even when the domain was highlighted implies that users lacked knowledge of Web page security cues or how to use those cues. Application: Potential applications include development of phishing prevention training incorporating domain highlighting with other methods to help users identify phishing Web pages.

Natural durability of organomodified layered silicate filled wood flour reinforced polypropylene nanocomposites

2013 ◽  
Vol 20 (3) ◽  
pp. 227-232 ◽  
Author(s):  
Behzad Kord
Keyword(s):  
Weight Loss ◽  
Flexural Strength ◽  
Water Absorption ◽  
Wood Flour ◽  
Flexural Modulus ◽  
Layered Silicate ◽  
Natural Durability ◽  
Thickness Swelling ◽  
Melt Mixing ◽  
The Impact

AbstractThe effect of organomodified montmorillonite (OMMT) loading on the natural durability properties of polypropylene/wood flour composites exposed to brown-rot fungi (Coniophora puteana) was studied. To meet this objective, the blend composites were prepared through the melt mixing of polypropylene/wood flour at 50% weight ratios, with various amounts of OMMT (0, 3 and 6 per hundred compounds [phc]) in a hake internal mixer. The samples were then made by injection molding. The amount of coupling agent was fixed at 2 phc for all formulations. After specimen and culture medium preparation, the specimens were exposed to the purified fungus at 25°C and 75% relative humidity for 14 weeks. Identical specimens of the same composite, without being exposed to the fungus, were provided as the control specimens. After the discussed periods; weight loss, flexural strength, flexural modulus, hardness, water absorption, and thickness swelling of specimens were measured. Results indicated that OMMT had significant effects on the natural durability of the studied composite formulations. All mechanical properties were affected by the fungus, to a greater extent in the case of specimens without OMMT than the specimens with OMMT. Furthermore, the flexural strength and modulus increased with an increase of OMMT up to 3 phc and then decreased. However, the impact strength, water absorption and thickness swelling was decreased with increase of OMMT loading. Also, the lowest weight loss and the highest hardness were observed in the composite containing 6 phc organoclay. The morphology of the nanocomposites was examined by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Morphological findings revealed that intercalation came from the sample with 3 phc concentration of OMMT, which implies the formation of intercalation morphology and better dispersion than 6 phc.

scholarly journals Morphology, Rheological and Mechanical Properties of Isotropic and Anisotropic PP/rPET/GnP Nanocomposite Samples

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3058
Author(s):  
Francesco Paolo La Mantia ◽  
Vincenzo Titone ◽  
Alessandro Milazzo ◽  
Manuela Ceraulo ◽  
Luigi Botta
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Morphological Analysis ◽  
Capillary Viscometer ◽  
Melt Mixing ◽  
Elongation At Break ◽  
Recycled Polyethylene ◽  
Fibrillar Morphology ◽  
High Deformability ◽  
Poor Adhesion

The effect of graphene nanoplatelets (GnPs) on the morphology, rheological, and mechanical properties of isotropic and anisotropic polypropylene (PP)/recycled polyethylene terephthalate (rPET)-based nanocomposite are reported. All the samples were prepared by melt mixing. PP/rPET and PP/rPET/GnP isotropic sheets were prepared by compression molding, whereas the anisotropic fibers were spun using a drawing module of a capillary viscometer. The results obtained showed that the viscosity of the blend is reduced by the presence of GnP due to the lubricating effect of the graphene platelets. However, the Cox–Merz rule is not respected. Compared to the PP/rPET blend, the GnP led to a slight increase in the elastic modulus. However, it causes a slight decrease in elongation at break. Morphological analysis revealed a poor adhesion between the PP and PET phases. Moreover, GnPs distribute around the droplets of the PET phase with a honey-like appearance. Finally, the effect of the orientation on both systems gives rise not only to fibers with higher modulus values, but also with high deformability and a fibrillar morphology of the dispersed PET phase. A fragile-ductile transition driven by the orientation was observed in both systems.

scholarly journals Nanographene’s influence on a recycled high-density polyethylene/poplar wood flour nanocomposite

BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1233-1251
Author(s):  
Jafar Ghaje Beigloo ◽  
Habibollah Khademi Eslam ◽  
Amir Hooman Hemmasi ◽  
Behzad Bazyar ◽  
Ismaeil Ghasemi
Keyword(s):  
High Density Polyethylene ◽  
Wood Flour ◽  
Tensile Modulus ◽  
High Density ◽  
Poplar Wood ◽  
Thickness Swelling ◽  
Plastic Composites ◽  
Microscope Images ◽  
Recycled Polyethylene ◽  
Scanning Electron

The effect of nanographene amount was evaluated relative to the physical, mechanical, thermal, and morphological features of wood-plastic composites. Composites were prepared using recycled polyethylene (high-density polyethylene), nanographene, and wood-flour. The amount of 80% of polymer matrix and 20% of wood flour, and nanographene at four weight levels of 0.5%, 1.5%, and 2.5%, were used. An internal mixture was utilized for making the samples. The results showed that with the 0.5 wt% increase of the amount of nanographene, the tensile and flexural strengths, the flexural and tensile modulus and the notched impact strength composite increased. With the addition of 2.5 wt% nanographene, these properties decreased. With the increase of the level of nanographene by 2.5 wt%, water absorption and the thickness swelling of the composite decreased. With the increase of the level of nanographene, the level of residue ash and thermal stability also increased. Scanning electron microscope images showed that the samples with 0.5 wt% nanographene had less holes and a smoother surface compared to the other samples.

Modeling Microbubble Microvessel Interaction for Sonoporation Application

2020 ◽  
Author(s):  
Aswin Gnanaskandan ◽  
Xiaolong Deng ◽  
Chao-Tsung Hsiao ◽  
Georges Chahine
Keyword(s):  
Acoustic Waves ◽  
Ultrasound Contrast Agents ◽  
Material Interfaces ◽  
Mapping Procedure ◽  
Flow Solver ◽  
Maximum Deformation ◽  
Drug Molecules ◽  
Lagrangian Solution ◽  
Potential Applications ◽  
Two Phases

Abstract Modeling the dynamics of microbubbles inside confined spaces has many potential applications in biomedicine, sonoporation being one classic example. Sonoporation is the permeabilization of a blood vessel’s endothelial cell membrane by acoustic waves in order to non-invasively deliver large-sized drug molecules into cells for therapeutic applications. By controlled activation of ultrasound contrast agents (UCA) in a microvessel, one can achieve better permeabilization without causing permanent damage associated with high intensity ultrasound. This paper considers numerically, the fluid-structure interactions (FSI) of UCA microbubbles with a microvessel accounting for large deformations. The modeling approach is based on a multi-material compressible flow solver that uses a Lagrangian treatment for numerical discretization of cells containing an interface between two phases and an Eulerian treatment for cells away from material interfaces. A re-mapping procedure is employed to map the Lagrangian solution back to the Eulerian grid. The model is first validated by simulating a microbubble oscillating due to an imposed ultrasound inside a microvessel and good agreement with experiments is obtained for both the bubble and vessel dynamics. The effect of vessel elasticity is then studied and it is shown that increasing the vessel elasticity damps the bubble oscillations. Then the effect of placing the bubble away from the axis of vessel is studied and it is shown that bubbles closer the vessel wall are capable of creating maximum deformation on the wall compared to those away from the wall.

scholarly journals Influence of Water on Tribological Properties of Wood-Polymer Composites

2017 ◽  
Vol 37 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Olga Mysiukiewicz ◽  
Tomasz Sterzyński
Keyword(s):  
Polymer Composites ◽  
Coefficient Of Friction ◽  
Wood Flour ◽  
Poly Lactic Acid ◽  
Processing Technologies ◽  
Wood Polymer ◽  
Starting Point ◽  
Influence Of Water ◽  
Good Starting Point ◽  
Wood Polymer Composites

AbstractUtilization of ecological materials for appliances and products is one of the ways to achieve the goal of sustainability.Wood-polymer composites as a cheap, lightweight, durable and esthetic material has gained attention of scientists, engineers and consumers alike. Different kinds of polymeric matrices, plants used as the fillers, chemical of physical modifiers and processing technologies have already been widely studied. Nonetheless, surprisingly few information on Wood-Polymer Composites’ tribology can be found. This paper is an attempt to fill this gap. Polypropylene-and poly(lactic acid)-based composites with varying wood flour content have been analyzed. The Brinell’s hardness and coefficient of friction of the samples have been determined. In order to evaluate the influence of the moisture content on the tribological and mechanical properties of the composites, the samples have also been aged in water. The investigation revealed that polymeric composites filled with wood flour can present favorable coefficient of friction, compared to the neat resins. The results of our study can establish a good starting point for further investigation.

Mapping the Viscoelastic Behavior of Soft Solids From Time Harmonic Motion

2018 ◽  
Vol 85 (4) ◽  
Author(s):  
Yue Mei ◽  
Sevan Goenezen
Keyword(s):  
Inverse Method ◽  
Loss Modulus ◽  
Viscoelastic Behavior ◽  
Adjoint Equations ◽  
Optimization Strategy ◽  
Low Frequencies ◽  
Harmonic Motion ◽  
Soft Solids ◽  
Viscoelastic Moduli ◽  
Time Harmonic

We present a nondestructive approach to map the heterogeneous viscoelastic moduli from time harmonic motion via a constrained optimization strategy under the framework of finite element techniques. The adjoint equations are carefully derived to determine the gradient of the objective function with respect to the viscoelastic moduli. The feasibility of this inverse scheme is tested with simulated experiments under various driving frequencies. We observe that the overall strategy results in well-reconstructed moduli. For low frequencies, however, the mapped loss modulus is of inferior quality. To explain this observation, we analyze two simple one-dimensional (1D) models theoretically. The analysis reveals that the known displacement amplitude is less sensitive to the loss modulus value at low frequencies. Thus, we conclude that the inverse method is incapable of finding a well-reconstructed loss modulus distribution for low driving frequencies in the presence of noisy data. Overall, the inverse algorithms presented in this work are highly robust to map the storage and loss modulus with high accuracy given that a proper range of frequencies are utilized.

scholarly journals Effect of interfacial modifiers and wood flour treatment on the rheological properties of recycled polyethylene/wood flour composites

2019 ◽  
Vol 36 (1) ◽  
pp. 31-46 ◽  
Author(s):  
Haoqun Hong ◽  
Quannan Guo ◽  
Haiyan Zhang ◽  
Hui He
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Graft Copolymer ◽  
High Performance ◽  
Wood Flour ◽  
Interfacial Interactions ◽  
Wood Plastic Composites ◽  
Plastic Composites ◽  
Recycled Polyethylene ◽  
Processing Properties

The article presents the preparation of a high-performance wood–plastic composites with improved interfacial interactions by adding ternary-monomer graft copolymers as the interfacial modifiers and by braising wood flour (WF) and investigates their effects on the rheological properties of recycled polyethylene (rPE)/WF composites. The processing properties, capillary rheological properties, dynamical rheological properties, and mechanical properties were investigated. Results show that graft copolymer of polyethylene is effective in improving the interfacial interactions of rPE/WF composites, dramatically changing the rheological and mechanical properties. The braising of WF enlarges the gaps of cells and promotes the infiltration of rPE into the gaps, as promoting the increasing in mechanical properties of rPE/WF composites and significantly changing the rheological properties of the composites.

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