Article
Chemistry, Multidisciplinary
Diana Kim, Addie Bahi, Li-Yang Liu, Thomas Bement, Steven Rogak, Scott Renneckar, Frank Ko, Parisa Mehrkhodavandi
Summary: In this study, lignin-grafted-PLLA and lignin-grafted-PDLA nanofibers were produced using electrospinning. The nanofibers showed potential as lignin-based aerosol filters, but the stereocomplexation resulted in some drawbacks.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Giulia Scoponi, Nora Francini, Athanassia Athanassiou
Summary: In this study, bio-based products composed of blends of star-shaped PDLLA and linear PLLA were produced through large-scale manufacturing techniques, with thermomechanical degradation induced by different processes evaluated. The incorporation of star-PDLLA was found to promote the formation of a more flexible and tougher material with reduced crystallization capability, while also decreasing melt viscosity and increasing shear-thinning behavior for improved manufacturing flow. Tuning of final material performances was achieved by varying the star-PDLLA content.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2021)
Review
Polymer Science
Przemyslaw Kubisa, Grzegorz Lapienis, Tadeusz Biela
Summary: Star-shaped PLA-b-PEG polymers have a more compact structure with more end-groups than linear counterparts, and introducing PEG segments can improve hydrophilicity and change the properties of PLA polymers, expanding their applications in biomedical field. Research on the architecture, number of arms, and content of hydrophilic and hydrophobic blocks of synthesized polymers for potential biomedical applications is emphasized.
POLYMERS FOR ADVANCED TECHNOLOGIES
(2021)
Article
Polymer Science
Cuiping Hou, Chulu Zhou, Jianhua Cheng
Summary: A series of star gradient copolymers with variable grafting densities and backbone lengths were synthesized by one-shot ROMP, showing that the structure and properties can be controlled by the feed ratio between PS and PFP. These copolymers were further modified with activated ester chemistry to afford novel functional materials.
Article
Polymer Science
Hedayatollah Sadegh Ghari, Hossein Nazockdast
Summary: The toughening efficiency of differently plasticized thermoplastic starches in PLA/TPS blend was studied. The addition of citric acid as a co-agent significantly reduced the viscosity and melt elasticity of TPS, leading to smaller particle size and enhanced toughness. The addition of dynamically cross-linked EVA in PLA/TPS ternary blends resulted in a special matrix-disperse morphology, enabling the blends to exhibit remarkably higher toughness.
Article
Polymer Science
Fatimah Algarni, Valentina Elena Musteata, Gheorghe Falca, Stefan Chisca, Nikos Hadjichristidis, Suzana P. Nunes
Summary: This study reported the synthesis and fabrication of thermo-responsive membranes using PNIPAM-b-PVDF copolymers with linear and star structures. The membranes exhibited reversible thermo-responsive behavior with water permeability and rejection alternately varying with the operating temperature. Nanoporous membranes with zig-zag morphology were successfully fabricated by non-solvent-induced phase-separation method.
Article
Polymer Science
Henry Foster, Martina H. Stenzel, Robert Chapman
Summary: Compared to conventional techniques, photoinitiated electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) allows for better control over the polymerization of multiblock star copolymers, avoiding the generation of termination products. This technique is also tolerant to oxygen, enabling the automated synthesis of multiblock star copolymers at short block lengths, providing a useful approach for screening the effect of polymer composition on solution structure.
Article
Chemistry, Multidisciplinary
Qian Zhu, Jianlong Wen, Mingyang Ma, Yijing Nie
Summary: By controlling the simulation time during the diffusion step, polymer blend systems with different initial mixing parameters can be obtained. The formation of stereocomplex crystals (SCs) in these systems with different segmental miscibility was investigated. It was found that systems with higher initial mixing parameters have stronger stereocomplexation ability. The study also demonstrated that local segment diffusion can affect the SC formation.
Article
Polymer Science
Jeremy L. Swartz, Benjamin R. Elling, Ioannina Castano, Matthew P. Thompson, Daylan T. Sheppard, Nathan C. Gianneschi, William R. Dichtel
Summary: This study introduces a method to enhance the mechanical properties of a miscible blend of thermoplastic polyurethane and polycaprolactone by introducing a copolymer of the two corresponding monomers. The copolymers were generated through a solvent-free, ester/urethane bond-exchange process conducted during the coextrusion of the two polymers. The extrusion conditions affected the extent of bond exchange and the resulting properties of the blend.
Article
Engineering, Chemical
Satpal Singh, Anup K. Ghosh, Saurindra N. Maiti, Rahul K. Gupta, Satinath Bhattacharya
Summary: The study investigated the rheological properties of blown films of PLA/LLDPE blends. It was found that an increase in LLDPE and compatibilizer content led to higher storage and loss moduli, indicating pronounced viscoelastic behavior of PLA with the addition of LLDPE and compatibilizer. Blends with higher LLDPE content exhibited much more prominent strain hardening characteristics compared to those with lower LLDPE content.
POLYMER ENGINEERING AND SCIENCE
(2021)
Article
Polymer Science
Marica Bianchi, Andrea Dorigato, Marco Morreale, Alessandro Pegoretti
Summary: This research investigates the microstructural, thermomechanical, and shape memory properties of PLA/PBAT blends prepared by melt compounding. The PLA and PBAT phases were found to be immiscible with low interfacial adhesion. The addition of PBAT slightly improved the thermal stability of PLA. However, it decreased the stiffness and strength of the blends and impaired the shape memory performance of PLA. By adding suitable compatibilizers, the physical properties of these innovative biodegradable polymer blends could be further enhanced.
Article
Biochemistry & Molecular Biology
Nour Jaouadi, Mohamed Jaziri, Abderrahim Maazouz, Khalid Lamnawar
Summary: The objective of this study was to investigate multiphase systems based on blends of polylactic acid (PLA) and polyamide 11 (PA11), ranging from blends to multilayers. By using reactive extrusion, PLA/PA11 blends compatibilized with a multifunctionalized epoxide, Joncryl, were obtained. The thermal, morphological, rheological, and mechanical behaviors of these materials were studied. The results revealed that the addition of Joncryl as a compatibilizer significantly reduced particle size and interfacial tension, resulting in ductile behavior in the tensile properties. Furthermore, the effects of interdiffusion and diffuse interphase formation on structure, rheology, and mechanics of compatible multilayered systems fabricated with forced-assembly multilayer coextrusion were investigated based on these findings. This study contributes to a deeper understanding of the interfacial properties, such as rheological, mechanical, and morphological behaviors, and their control in multilayer polymers produced by coextrusion, enabling their use in advanced applications.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Polymer Science
Saefur Rohman, Kaewta Kaewtatip, Duangporn Kantachote, Manee Tantirungkij
Summary: Blending alginate with starch to prepare hydrogels creates a more suitable matrix for cell entrapment, with starch helping beads retain their spherical shape and increasing cell encapsulation efficiency.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Saeid Nikafshar, Jiarun Wang, Kevin Dunne, Prakit Sangthonganotai, Mojgan Nejad
Summary: Thirteen unmodified lignin samples from various biomass sources were used to replace bisphenol A (BPA) in epoxy resin formulations using a novel method. It was found that lignins with higher phenolic hydroxy content and lower molecular weights were more suitable for this purpose, and a regression model was developed to establish correlations between lignin properties and epoxy contents. Additionally, epoxidized lignin samples with high epoxy contents showed comparable performance to a petroleum-based epoxy system when cured with a bio-based hardener.
Article
Polymer Science
Polyxeni P. Angelopoulou, Maria-Malvina Stathouraki, Jong K. Keum, Kunlun Hong, Apostolos Avgeropoulos, Georgios Sakellariou
Summary: This study describes the synthesis, molecular characterization, and morphological evaluation of ABn, (n = 2,3) miktoarm star block copolymers consisting of poly(glycerol mono-methacrylate) (PGMA) and polystyrene (PS) with varying molecular weights and compositions. Well-ordered nanostructures of various morphologies were formed, with domain spacing as low as 7.2 nm. The study highlights the potential of incorporating macromolecular architecture in the self-assembly of block copolymers to achieve ultra-small nanofeatures with desired morphologies.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Mechanics
Marziyeh Danesh, Damien Mauran, Richard Berry, Marek Pawlik, Savvas G. Hatzikiriakos
Summary: The effects of CNC and NaCl concentrations on the stability and properties of water-based zirconia suspensions were studied. It was found that the adsorption capacity of CNC on the surface of zirconia particles increases as salt concentration increases, leading to an increase in the viscoelastic properties of the suspension and the formation of a denser structure on the surface.
Article
Mechanics
Jourdain Piette, Aref Abbasi Moud, Jade Poisson, Babak Derakhshandeh, Zachary M. Hudson, Savvas G. Hatzikiriakos
Summary: The rheological characteristics of mature fine tailings (MFTs) were examined in both the linear and non-linear viscoelastic regimes. It was found that MFT samples exhibited thixotropic behavior and apparent slip, which could be suppressed by using sandpaper. The presence of bitumen in MFTs and temperature were also found to have significant effects on the rheology.
Article
Materials Science, Ceramics
Marziyeh Danesh, Damien Mauran, Richard Berry, Marek Pawlik, Savvas G. Hatzikiriakos
Summary: In this study, cellulose nano crystals (CNC) were used as a dispersant in water-based suspensions of zirconia to investigate their stabilization in ceramic processing. The optimal pH value and minimum CNC concentration for producing stable highly concentrated suspensions were determined. The adsorption of CNC nanofibers around the zirconia particles was observed by scanning electron microscopy (SEM), which contributed to the achieved stability. The suspensions with the lowest viscosity and highest stability were obtained with 30 wt% zirconia particles at pH 4 and 1 wt% CNC.
CERAMICS INTERNATIONAL
(2022)
Article
Mechanics
Ruiying Xiong, Jourdain H. Piette, Ziyue Zhang, Jixiang Guo, Savvas G. Hatzikiriakos
Summary: This paper investigates the rheological behavior of bitumen as a function of asphaltene concentration. Bitumen samples with different amounts of asphaltene were prepared and characterized using differential scanning calorimetry and rheological measurements. The results showed that the glass transition temperature of bitumen increases with increased asphaltene concentration. A constitutive model was proposed, which can predict the asphaltene concentration.
Article
Mechanics
Jourdain H. Piette, Marziyeh Danesh, Savvas G. Hatzikiriakos
Summary: This paper investigates the behavior of Kaolinite suspensions in the presence of two ionic surfactants, CTAB and SDS, and explores their steady-shear behavior. The study finds that the yield stress increases monotonically with CTAB concentration, while initially decreasing with an increase in SDS concentration and slightly increasing at higher concentrations. Both Kaolinite and Kaolinite-CTAB systems exhibit thixotropic and anti-thixotropic behavior at short and long timescales, respectively.
Article
Mechanics
B. M. Yavitt, T. Tomkovic, D. J. Gilmour, Z. Zhang, N. Kuanr, E. van Ruymbeke, L. L. Schafer, S. G. Hatzikiriakos
Summary: The rheological and self-healing behavior of a class of catalytically synthesized amine-functionalized polyolefins are investigated. It is demonstrated that these materials possess tunable rheological properties according to the molecular weight and also exhibit autonomous self-healing ability. The combination of experiments, modeling, and theory provides insights into the design of new materials with programmable rheological properties and superior self-healing ability.
JOURNAL OF RHEOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Samuel J. Kaser, Ty Christoff-Tempesta, Linnaea D. Uliassi, Yukio Cho, Julia H. Ortony
Summary: This study investigates the thermal phase behavior within nanomaterials using Xband EPR spectroscopy. The results show distinct dynamics between different domains within the nanomaterial, and first- and second-order phase transitions are observed.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Mechanics
Savvas G. Hatzikiriakos
Summary: Professor Evan Mitsoulis has made numerous contributions to rheology and computational non-Newtonian fluid mechanics. His research has had a lasting impact and he has worked at multiple universities, including McMaster University, the University of Ottawa, and the National Technical University of Athens. His work has focused on areas such as polymer melts, viscoelastic flows, capillary rheometry, and the development of advanced numerical algorithms for complex materials. Additionally, he has mentored graduate students and postdoctoral fellows, served professional societies, and made significant contributions to the scientific community.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2023)
Article
Materials Science, Composites
Alen Oseli, Tanja Tomkovic, Savvas G. Hatzikiriakos, Alenka Vesel, Matija Arzensek, Tadej Rojac, Mohor Mihelcic, Lidija Slemenik Perse
Summary: The research shows that the formation and morphology of carbon nanotube networks play a significant role in the mechanical and conductive performance of polymer-based nanocomposites. The networks are mainly constructed from nanotube bundles and their configuration affects the electrical percolation threshold and conductivity of the materials. The study enables the production of highly reinforced and conductive nanocomposites with minimal addition of carbon nanotubes.
COMPOSITES SCIENCE AND TECHNOLOGY
(2023)
Article
Mechanics
Marziyeh Danesh, Parya Keyvani, Ruiying Xiong, Babak Derakhshandeh, Jixiang Guo, Savvas G. Hatzikiriakos
Summary: This research acknowledges the financial support from The National Science and Technology Council, Taiwan, the provision of fine sediments by Dr. Ching-Hsien Wu, and the assistance of Mr. Le Trang Nguyen. It also recognizes the support from the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Institute for Oil Sands Innovation at the University of Alberta (IOSI), and Canada's Oil Sands Innovation Alliance (COSIA).
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2023)
Article
Mechanics
Amir Malmir, Jourdain H. Piette, Babak Derakhshandeh, Danuta Sztukowski, Savvas G. Hatzikiriakos
Summary: The rheological behavior of mature fine tailings (MFTs) was examined using transient and steady shear flow fields. The structure breakdown of intact MFT samples was investigated through a startup flow experiment. The yield stress of MFTs was estimated by the steady shear stress values at low shear rates. Thixotropy and a positive hysteresis loop were observed in MFT samples during short shearing time intervals, but disappeared as the system reached its equilibrium steady-state structure.
Article
Chemistry, Multidisciplinary
Yukio Cho, Yu-Jin Choi, Samuel J. Kaser, Rebecca Meacham, Ty Christoff-Tempesta, Siyu Wu, Xiaobing Zuo, Julia H. Ortony
Summary: This study introduces diacetylene moiety into aramid amphiphiles, which allows for the self-assembly of various nanoribbon geometries with maintained structural and thermodynamic stability by incorporating rotational freedom into the molecular design.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Mechanics
Evan Mitsoulis, Savvas G. Hatzikiriakos
Summary: This paper reviews the connections of the K-BKZ rheological constitutive model and its variants with polymer melt flow and presents a recap of research and major findings. It discusses the historical perspective of the model's development, mathematical modeling of polymer flows, numerical techniques for viscoelastic stresses evaluation, and successful application examples.
Editorial Material
Mechanics
B. C. Khoo, A. J. Giacomin, S. G. Hatzikiriakos, K. A. Feigl, N. Phan-Thien
Article
Engineering, Chemical
I Ochoci, S. G. Hatzikiriakos, E. Mitsoulis
Summary: Blends of different PTFE fine powder resins were prepared and extruded to improve the PTFE paste extrusion process and the mechanical properties of the extrudates. Additives such as boron nitride and montmorillonite clays were tested to enhance processing aids. Fibrillation and mechanical properties of the extrudates can be controlled by adjusting the degree of fibrillation and temperature.
INTERNATIONAL POLYMER PROCESSING
(2022)
