Article
Chemistry, Physical
Fabian Coupette, Long Zhang, Bjoern Kuttich, Andrei Chumakov, Stephan V. Roth, Lola Gonzalez-Garcia, Tobias Kraus, Tanja Schilling
Summary: We investigate network formation and percolation of carbon black using Monte Carlo simulations and experiments. The percolation threshold shows a quasi-universal relation with the weighted average radius of gyration of the aggregate ensemble. The concentration of large carbon black aggregates has a stronger influence on the percolation threshold than the concentration of small aggregates, while higher order moments of the size distribution do not affect the percolation threshold.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Polymer Science
Vanessa Garcia-Martinez, Maria R. Gude, Silvia Calvo, Alejandro Urena
Summary: By introducing two different contents of graphene nanoplatelets into benzoxazine resin, a polymeric nanocomposite with multifunctional properties including high electrical and thermal conductivity was obtained. The nanocomposites showed improved mechanical and thermo-mechanical properties, as well as increased electrical and thermal conductivities. Additionally, the barrier properties of the resin were enhanced by the addition of graphene nanoplatelets.
Article
Chemistry, Physical
Hani Manssor Albetran
Summary: The sol-gel electrospinning process was used to prepare electrospun carbon nanofibers (ECNFs) from polyacrylonitrile and graphite nanoplatelets. The synthesized ECNFs were characterized by scanning electron microscopy, transmission electron microscopy with energy-dispersive X-ray spectroscopy, and X-ray diffractometry (XRD). The smooth ECNFs with conical platelets and crystallites mainly parallel to the long fiber axis were obtained.
Article
Materials Science, Multidisciplinary
A. Ballesteros, E. Laguna-Gutierrez, M. L. Puertas, A. Esteban-Cubillo, J. Santaren, M. A. Rodriguez-Perez
Summary: The study found that the extensional rheological behavior controls the foam degeneration mechanisms in foamed polystyrene based nanocomposites, while the dispersion degree of particles in the matrix determines the nucleation mechanisms. Improving the dispersion degree is crucial in reducing cell size significantly.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Mohammad Shafiei, Ismaeil Ghasemi, Sepideh Gomari, Ali Abedini, Roghayeh Jamjah
Summary: Hybrid nanocomposites of high-density polyethylene were prepared using the melt-mixing method with different amounts of graphene nanoplatelets (GNPs) and conductive carbon black (CB). The effect of crystallinity on electrical conductivity was studied, showing an increase in electrical conductivity with the addition of CB and GNP. The highest electrical conductivity was achieved in the sample containing 18% CB and 1% GNP.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
Marshall C. Tekell, Georgia Nikolakakou, Emmanouil Glynos, Sanat K. Kumar
Summary: Nanoparticles are commonly added to polymer electrolytes to enhance their mechanical and ion transport properties. This work carefully controls the dispersion state of silica nanoparticles in a model polymer electrolyte system and finds that controlling the dispersion leads to improved mechanical properties while reducing the ionic conductivity. These results suggest that achieving increases in bulk, ionic conductivity requires percolating aggregates of ceramic surfaces.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Ceramics
Francesca R. Lamastra, Mehdi Chougan, Emanuele Marotta, Samuele Ciattini, Seyed Hamidreza Ghaffar, Stefano Caporali, Francesco Vivio, Giampiero Montesperelli, Ugo Ianniruberto, Mazen J. Al-Kheetan, Alessandra Bianco
Summary: The addition of graphite nanoplatelets (GNPs) improved the density, compressive, and flexural strength of mortar, with high aspect ratio GNPs showing the best mechanical properties. However, the use of low aspect ratio GNPs resulted in decreased electrical resistivity and increased thermal conductivity in cementitious nanocomposites.
CERAMICS INTERNATIONAL
(2021)
Article
Polymer Science
Ivonne Otero Navas, Milad Kamkar, Mohammad Arjmand, Uttandaraman Sundararaj
Summary: This study found that the addition of styrene-butadiene block copolymers to PP:PS/MWCNT blends can reduce droplet size, improve electrical conductivity, and impact viscoelastic behavior. The copolymers interact favorably with MWCNTs, changing their localization and enhancing electrical conduction while also affecting linear and nonlinear viscoelastic properties.
Article
Polymer Science
G. M. Janeesh, V. Meera, A. M. Shalom, D. Rajan Babu, N. Arunai Nambi Raj, M. S. Sreekanth, V. Samba Siva, T. P. Sumangala
Summary: Polymer based nanocomposites, specifically PVA-GnP composite films, show a significant enhancement in electrical conductivity but a decrease in crystallinity and tensile strength. The maximum tensile strength obtained was 15 MPa, making it suitable for electronic applications.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Shuangqiao Yang, Zhibo Jin, Chunyang Song, Zhicen Pu, Bianying Wen
Summary: The reasonable structure design of graphite nanoplatelets (GNP) is crucial for achieving high electrical and thermal conductivity in polymer/GNP composites. In this study, high-performance polyethylene composites based on GNP cluster and flake were fabricated, and the composites with GNP cluster exhibited superior performance in functional applications.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Polymer Science
Jun-Ven Lim, Soo-Tueen Bee, Lee Tin Sin, Chantara Thevy Ratnam, Zuratul Ain Abdul Hamid
Summary: The study showed that enhancing the surface activity of graphite nanosheets through high temperature water treatment promoted the formation of oxygen-containing functional groups. Incorporating the treated nanosheets in nylon 610 nanocomposites improved their conductivity.
Article
Chemistry, Applied
Gabriela Noel Barrera, Roxana Veronica Piloni, Paula Moldenaers, Laura Beatriz Iturriaga, Pablo Daniel Ribotta
Summary: This study investigated the influence of hydrochloric acid, sodium hydroxide, and sodium chloride on the rheological behavior of the galactomannan fraction from Gleditsia triacanthos seeds in aqueous solution. The results showed that these chemicals affected the microstructure and electrical conductivity of the macromolecular systems, contributing to improved resistance to shear deformation.
FOOD HYDROCOLLOIDS
(2022)
Article
Multidisciplinary Sciences
Alexandre Poulin, Xavier Aeby, Gilberto Siqueira, Gustav Nystroem
Summary: Emerging technologies, like smart packaging, have shifted the requirements on electronic components, leading to the development of a conductive ink to meet these new demands. The ink, made of carbon particles dispersed in shellac solution, shows high conductivity, stability towards moisture, and compatibility with various patterning methods.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Applied
Chaiwut Gamonpilas, Akapong Kongjaroen, Pawadee Methacanon
Summary: Food texture manipulation and modification is an effective approach to reduce the risk of aspiration in dysphagia management. By adding thickening agents, the transit time of the bolus can be increased, promoting safer swallowing. The rheological and tribological properties of the bolus, including viscosity, hardness, cohesiveness, and adhesiveness, play crucial roles in determining safe swallowing.
FOOD HYDROCOLLOIDS
(2023)
Article
Materials Science, Characterization & Testing
Sameh Dabees, Abou Bakr Elshalakany, Vineet Tirth, Bahaa M. Kamel
Summary: The study found that the 3 wt.% MWCNTs/HDPE nanocomposites exhibited the best tribological performance, and adding 1.2 wt% Al2O3 further improved performance; the reinforcement of MWCNTs and Al2O3 changed the wettability and surface energy of the nanocomposites, with the percolation threshold of MWCNTs appearing between 2 and 3 wt%.
Article
Mechanics
Simon Ingelsten, Andreas Mark, Roland Kadar, Fredrik Edelvik
Summary: The study uses a backwards-tracking method to simulate planar viscoelastic squeeze flow, validating numerical methods and investigating grid resolution dependence of important flow quantities. By exploring different models, the research reveals the significance of these findings in industrial applications.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2022)
Article
Nanoscience & Nanotechnology
Chiara Magnani, Mina Fazilati, Roland Kadar, Alexander Idstrom, Lars Evenas, Jean -Marie Raquez, Giada Lo Re
Summary: In this study, chitin nanocrystals (ChNCs) were extracted using a waterborne topochemical one-pot acid hydrolysis/Fischer esterification method, and their surfaces were simultaneously decorated with lactate or butyrate moieties. The modified ChNC colloids showed a gel-like phase, disrupting the formation of liquid crystalline clusters. Pickering emulsions prepared from lyophilized nanocrystals demonstrated that the individualization of the modified ChNCs can be regenerated from the dry state.
ACS APPLIED NANO MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Christos K. Georgantopoulos, Masood K. Esfahani, Michael A. Pollard, Ingo F. C. Naue, Andrea Causa, Roland Kadar, Manfred Wilhelm
Summary: The study investigates the extrusion flow instabilities of commercial polybutadiene (PBD) by using different extrusion die geometries. Qualitative models are used to fit the experimental data and predict the spatial characteristic wavelength (lambda) for extrudates obtained by complex cross-section profile slit die geometries. The correlation between the ratio of extensional and shear stress at the die exit area and the characteristic dimension of the dies is presented. A geometry-dependent model is also used to predict the spatial characteristic wavelength of the extrusion flow instabilities.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2022)
Article
Polymer Science
Christos K. Georgantopoulos, Masood K. Esfahani, Ingo F. C. Naue, Manfred Wilhelm, Roland Kadar
Summary: The extrusion flow instabilities of two commercial polyethylenes (PE), both with similar weight average molecular weight, were characterized using capillary rheology, optical analysis, and modeling. The characteristic time periodicity τ* and spatial characteristic wavelength λ were obtained and compared using three different methods. It was found that both the characteristic time periodicity τ* and the spatial characteristic wavelength λ exhibit Arrhenius temperature-dependent behavior.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Polymer Science
Lorenz Faust, Marie-Christin Roepert, Masood K. Esfahani, Mahdi Abbasi, Valerian Hirschberg, Manfred Wilhelm
Summary: The influence of topology on strain hardening in uniaxial elongation was studied using synthesized model polystyrenes. The results showed that topology significantly affects the strain hardening factor and strain rate of the materials.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Patrick Petschacher, Reza Ghanbari, Carina Sampl, Helmar Wiltsche, Roland Kadar, Stefan Spirk, Tiina Nypelo
Summary: Sulfate groups on cellulose nanocrystals (CNCs) provide colloidal stability, and the introduction of sodium counter cations enables drying of the CNC suspensions without irreversible aggregation. Ion exchange is an efficient method to exchange sulfate half esters with alkali metal cations. K-CNC exhibits different rheological and birefringence properties compared to other alkali metal modifications.
Article
Chemistry, Applied
Sylwia Wojno, Astrid Ahlinder, Annika Altskar, Mats Stading, Tiffany Abitbol, Roland Kadar
Summary: The influence of surface charge on the percolation, gel-point, and phase behavior of CNC suspensions was examined in relation to their nonlinear rheological material response. Desulfation decreased the CNC surface charge density which resulted in an increase in attractive forces between CNCs. The study found that nonlinear behavior marked the presence of a weakly percolated network at lower concentrations, regardless of whether the gel-point occurred at the biphasic -liquid crystalline transition or at the isotropic -quasi-biphasic transition.
CARBOHYDRATE POLYMERS
(2023)
Article
Engineering, Multidisciplinary
Enrico Carmeli, Federico di Sacco, Giuseppe Portale, Dario Cavallo, Roland Kadar, Antonis Gitsas, Thomas Gkourmpis, Davide Tranchida
Summary: Understanding the solidification behavior of iPP composites with reduced graphene oxide nanoplatelets is crucial for their widespread use. This study investigated the crystallization behavior of these composites and found that the nucleation efficiency of the graphene filler is high even at low concentrations, with a significant impact on the crystallization transition.
COMPOSITES PART B-ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Sylwia Wojno, Amit Kumar Sonker, Jelka Feldhusen, Gunnar Westman, Roland Kadar
Summary: Nonlinear material parameters are more sensitive than linear viscoelastic parameters to the onset of weakly interconnected networks in cellulose nanocrystal(CNC) isotropic suspensions. All surface-modified CNC suspensions resulted in isotropic gels. The length of the grafted chains and the degree of branching were the primary factors influencing the nonlinear material response.
Article
Materials Science, Multidisciplinary
Sajjad Pashazadeh, Alexandra Aulova, Christos K. Georgantopoulos, Marko Bek, Iakovos Vittorias, Ingo F. C. Naue, Manfred Wilhelm, Roland Kadar
Summary: This study investigates the influence of molecular weight and long-chain branching on the types of melt flow extrusion instabilities (MFEI). Four linear low-density polyethylenes (LDPEs) are extruded using a single-screw extruder coupled with an inline optical imaging system. Through the analysis of space-time diagrams constructed with an inline imaging system, three main MFEI types are identified, distinct from those observed in linear and short-chain branched polymers. Higher long-chain branching appears to have a stabilizing effect on the transition sequences.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Shadi Rahimi, Teo Lovmar, Alexandra Aulova, Santosh Pandit, Martin Lovmar, Sven Forsberg, Magnus Svensson, Roland Kadar, Ivan Mijakovic
Summary: To combat bacterial infections in the post-antibiotic era, efforts are being made to engineer new materials with antibacterial properties. A new automated pipeline based on scanning electron microscopy images has been developed to predict the antibacterial potential of these materials. The density of sharp exposed edges of graphite-oriented nanoplatelets (GNPs) is a key factor in killing bacteria on contact.
Review
Engineering, Biomedical
Hengzhi Ruan, Alexandra Aulova, Viney Ghai, Santosh Pandit, Martin Lovmar, Ivan Mijakovic, Roland Kadar
Summary: To address the global threat of antimicrobial resistance, which is a common cause of healthcare-associated infections and imposes significant costs on healthcare systems, extensive research has been dedicated to developing polysaccharide-based strategies that prevent bacterial attachment and biofilm formation on surfaces. Polysaccharides, as essential building blocks for life and abundant renewable resources, have attracted attention for their intrinsic antibacterial activities. If efficiently transformed into antibacterial coatings for a wide range of surfaces and applications, polysaccharide-based coatings could have a substantial global impact. However, their ultimate success will depend on their potential for scalable, versatile, and affordable manufacturing processes.
ACTA BIOMATERIALIA
(2023)
Article
Materials Science, Composites
Sajjad Pashazadeh, Reza Ghanbari, Marko Bek, Alexandra Aulova, Tobias Moberg, Anders Brolin, Roland Kadar
Summary: For the first time, surface defects in highly-filled wood polymer composites (WPCs) are mapped using inline optical spectral analysis during single-screw extrusion. The effects of wood fiber content and drying on surface defects dynamics are resolved through space-time inline optical imaging. The study reveals that surface tearing appears at low shear rates and gradually decreases in spectral intensity with increasing shear rates/slip velocities. Increasing shear rates, wood fiber content, and drying have mitigating effects on surface tearing, but it still persists in undried samples even at high shear rates and high wall slip velocities. A regime dominated by bubbles on the extrudate surface is identified at high shear rates and low wood fiber contents in undried WPCs.
COMPOSITES SCIENCE AND TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Hengzhi Ruan, Marko Bek, Santosh Pandit, Alexandra Aulova, Jian Zhang, Philip Bjellheim, Martin Lovmar, Ivan Mijakovic, Roland Kadar
Summary: This study presents a facile approach of incorporating dopamine and [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide via in situ synthesis into gelatin hydrogels. The resulting hydrogels show exceptional antibacterial efficiency and multifunctional performance, making them highly promising for various biomedical applications.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Polymer Science
Shirin Naserifar, Petrus F. Kuijpers, Sylwia Wojno, Roland Kadar, Diana Bernin, Merima Hasani
Summary: This study investigates the effect of different bases on the solubility, reaction process, and product properties of cellulose etherification. The results show that using quaternary ammonium hydroxides as solvents can improve the solubility and reaction stability of cellulose, as well as reduce the degree of substitution. Sodium hydroxide, on the other hand, exhibits lower temperature stability and product solubility.
