Comparative Fatigue Analysis Of Cf-Pla Metamaterial Bone Plates For Orthopaedic Fixation, Ani Daniel, Hamed Bakhtiari, Barun K. Das, Muhammad Aamir, Majid Tolouei-Rad

Research outputs 2022 to 2026

Bone plates are widely used in orthopaedic surgery to stabilise fractured bones and support healing following traumatic injuries or osteotomies. However, conventional metallic bone plates suffer from stress shielding and stiffness mismatch with bone, which can hinder optimal healing. Additive manufacturing enables the incorporation of novel metamaterial architectures into polymer-based implants to enhance mechanical properties. The fatigue behaviour of these implants during the healing period is critical to ensuring their structural integrity and long-term performance. In this study, the compressive fatigue performance of fused deposition modelling (FDM)-printed carbon fibre-reinforced polylactic acid (CF-PLA) bone plates were investigated. Four metamaterial structures—tetrachiral, re-entrant, …

Electrochemical And Mechanical Evaluation Of Cellulose Acetate Electrolyte Films As A Function Of Polyetherimide And Polyethylene Glycol Additives For Supercapacitor Applications, Chase E. Golden

Chemical Engineering Undergraduate Honors Theses

Polymer electrolytes for supercapacitor applications require a balance between mechanical robustness and electrochemical performance. In this study, cellulose acetate (CA) films were modified with additives such as polyetherimide (PEI) and polyethylene glycol (PEG) to test how compositional changes influence mechanical performance, ionic conductivity, and electrochemical charge storage. Films were cast using phase inversion, soaked in a 1 M NaCl aqueous solution, and characterized using Fourier-transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and tensile testing. Films were also evaluated based on fluid uptake for insight into electrolyte retention.

Characterizations show that the addition of PEI increased ionic …

Molecular Origins Of Non-Frozen Water In Polyelectrolyte Brushes, Ali Dhinojwala, Saveen Jayaweera, Md Golam Kibria, George Mallinos

University Research

Polyelectrolyte brushes (PEBs) are promising coatings for reducing ice adhesion and regulating water freezing at interfaces, yet direct measurements of nonfrozen water retention at subzero temperatures remain scarce. Here, we investigate the freezing behavior of water confined in poly([2-(methacryloyloxy)ethyl]trimethylammonium) (PMETA) brushes with chloride, iodide, and sulfate counterions using a custom-built low-temperature attenuated total reflectance infrared spectroscopy system. Furthermore, we quantify the fraction of water that was present within the brush that does not freeze as well as the changes in polymer volume fraction within the brush as a function of temperature. Spectroscopic analysis of water vibrational modes reveals that PMETA …

Energy Efficient Windows Using Pvme, James S. Bronstrup

Williams Honors College, Honors Research Projects

This Honors Project aims to improve window energy efficiency using the thermoplastic polymer PVME (polyvinyl methyl ether), which displays temperature-dependent transparency that can be adjusted by mixing it with water and salt to reduce heat transfer through a window. The objective is to determine the optimal PVME water-salt ratios for placement inside a windowpane, evaluate energy savings compared to a traditional argon-filled window, and compare estimated costs. A small-scale model will test different concentrations for various climates, with heat transfer measured by temperature indicators via a LabQuest. Building on research by Yang Zhou at Nanyang Technological University, who used a …

Chemical Recycling Of Pet Plastic Waste, Charlie Parker, Benjamin Puga, Jake Verschoor

Materials Engineering

The growing accumulation of plastic waste, specifically polyethylene terephthalate (PET), has driven the need for more efficient and scalable chemical recycling methods. This study investigated the methanolysis of PET using zinc oxide (ZnO) nanoparticles as a catalyst and tetrabutylammonium chloride (NBu₄Cl) as an ionic liquid, aiming to reduce methanol consumption while achieving high PET conversion efficiency. ZnO nanoparticles were synthesized via wet chemistry and characterized using Dynamic Light Scattering (DLS), which showed an average particle size of 13.5 nm with a polydispersity index of 0.1556, indicating a moderately-high monodisperse distribution of particles sufficient for reactions. The main conversion product, dimethyl …

Biobased Acrylate Composites With Enhanced Strength For Additive Manufacturing, Nicole Wagner, Joseph Mcwherter

Engineering Faculty Articles and Research

With the expanding use of polymers in additive manufacturing, sustainable resins for use in vat photopolymerization are required to reduce their environmental impact. One promising approach to achieve this is to incorporate biobased fillers that replace the acrylates in photopolymer resins as ‘green’ alternatives. In this study, photopolymer composites consisting of a methacrylate resin with varying calcium carbonate powder content between 0 and 50 wt.% were investigated. A digital light processing technique was used to fabricate tensile test specimens for mechanical testing. Good printability, dimensional accuracy, and good interlayer adhesion were observed for composite resin formulations that incorporated calcium carbonate …

A Comprehensive Review Of Piezoelectric Pvdf Polymer Fabrications And Characteristics, Nadia Ahbab, Sidra Naz, Tian-Bing Xu, Shihai Zhang

Mechanical & Aerospace Engineering Faculty Publications

Polyvinylidene fluoride (PVDF) polymer films, renowned for their exceptional piezoelectric, pyroelectric, and ferroelectric properties, offer a versatile platform for the development of cutting-edge micro-scale functional devices, enabling innovative applications ranging from energy harvesting and sensing to medical diagnostics and actuation. This paper presents an in-depth review of the material properties, fabrication methodologies, and characterization of PVDF films. Initially, a comprehensive description of the physical, mechanical, chemical, thermal, electrical, and electromechanical properties is provided. The unique combination of piezoelectric, pyroelectric, and ferroelectric properties, coupled with its excellent chemical resistance and mechanical strength, makes PVDF a highly valuable material for a wide …

Fatigue Properties Of 3d-Printed Polymeric Metamaterials: A Review, Ani Daniel, Hamed Bakhtiari, Alireza Nouri, Barun K. Das, Muhammad Aamir, Majid Tolouei-Rad

Research outputs 2022 to 2026

The present article provides an in-depth review of the fatigue properties of polymeric metamaterials, with particular emphasis on those manufactured using 3D printing techniques. Despite the significant potential of 3D-printed metamaterial polymers in the biomedical field, there has been limited studies dedicated to their fatigue behaviour. The article highlights the significance of fatigue behaviour in determining the reliability and longevity of polymeric materials under cyclic loading, which is crucial for biomedical applications. The effects of different 3D printing parameters, metamaterial designs, and polymer properties on fatigue life are explored. The fatigue response of metamaterials depends on material properties, geometric factors, …

Effects Of Polyolefin Types On Catalytic Hydrocracking, Kenneth Jackson Seeber

Williams Honors College, Honors Research Projects

Plastic waste recycling has become an important conversation in the last couple of decades with pollution on the rise. One of the few ways to recycle plastics is by breaking these long-chained polymers down via catalytic processes. Due to many plastic products being a blend, it is imperative that any chosen catalyst that could be used for recycling should be able to handle different types of polymers. This paper discusses how tungsten carbide over silica (W_xC/SiO₂) catalyzes the degradation of a few selected polymers and polymer blends. From this research it was determined that W_{x …}

Precision Bottlebrush Polymers: Synthesis, Characterization, And Structure-Property Relationship, Nduka D. Ogbonna

LSU Doctoral Dissertations

Bottlebrush polymers, a type of non-linear polymer characterized by densely grafted side chains on a linear backbone, offer a versatile platform for material design due to their unique thermomechanical and rheological behavior. Addressing the grand challenge of achieving structural precision for bottlebrush polymers remains crucial because traditional disperse mixtures are plagued with batch variability, limiting our ability to control their functions, and correlate theoretical predictions with experiments. To date, narrow-dispersity bottlebrush polymers remain highly heterogeneous, as they are typically synthesized from disperse linear building blocks.

To address this longstanding challenge of structural heterogeneity in brush polymers, the primary objective of …

Ir Spectral Analysis Of Broussonetia Papyrefera Plant, Umid Hamroyevich Alamov, Zaytuna Ali Qizi Qurbonaliyeva, Dostonbek Qurbonsho Ugli Shomurodov, Elmurod Abduqodirovich Egamberdiev

Technical science and innovation

in this study, a method for determining the concentration of lignin, cellulose and hemicellulose in plant materials using Fourier-transform IR spectroscopy of Broussonetia papyrefera was developed and tested. The procedure is based on the use of calibration functions that reflect the dependence of the intensity of analytical absorption lines on the concentration of lignin (1512 cm-1) and cellulose (1450 cm-1) in standard samples; indirect correlation was used for hemicellulose. The model samples were ternary mixtures composed of lignin, bacterial cellulose and hemicellulose in different proportions. The proposed method was tested on a wide range of plant biomass samples.

Effect Of Local Chain Stiffness On Oligomer Crystallization From A Melt, Pierre Kawak, Christopher Akiki, Douglas R. Tree

Faculty Publications

While the process by which a polymer crystal nucleates from the melt has been extensively studied via molecular simulation, differences in polymer models and simulated crystallization conditions have led to seemingly contradictory results. We make steps to resolve this controversy by computing low-temperature phase diagrams of oligomer melts using Wang-Landau Monte Carlo simulations. Two qualitatively different crystallization mechanisms are possible depending on the local bending stiffness potential. Polymers with a discrete bending potential crystallize via a single-step mechanism, whereas polymers with a continuous bending potential can crystallize via a two-step mechanism that includes an intermediate nematic phase. Other model differences …

Mechanical Property Simulations Of Ploybenzimidazole Membranes., Blake Alexander Clark

Electronic Theses and Dissertations

This work explores mechanical properties of membranes made of polybenzimidazole utilizing molecular simulations. These simulations researchers to narrow down polybenzimidazole membrane compositions to viable candidates. These simulations are quicker than current purely experimental methods. The increase in throughput would be achieved by eliminating compositions that have unfavorable mechanical properties through preliminary simulation work before moving onto experimental methods. Determining polybenzimidazole membranes’ mechanical properties experimentally would, therefore, allow for researchers to speed up research in areas such as fuel cells and electrolyzers that make use of polybenzimidazole membranes. This study uses Materials Studio and the COMPASS III forcefield to perform these …

Development Of Synthetically Accessible Glycolated Polythiophenes For High-Performance Organic Electrochemical Transistors, Bowen Ding, Vianna N. Le, Hang Yu, Guanchen Wu, Adam V. Marsh, Edgar Gutiérrez-Fernández, Nicolás Ramos, Martina Rimmele, Jaime Martín, Jenny Nelson, Alexandra F. Paterson, Martin Heeney

Chemical and Materials Engineering Faculty Publications

Four glycolated polythiophene-based organic mixed ionic-electronic conductors (OMIECs), PE2gTT, PE2gT, PT2gTT, and PT2gT are prepared by atom-efficient direct arylation polymerization, avoiding the need for toxic organometallic pre- cursors. PE2gT, PT2gTT, and PT2gT are operable in p-type accumulation mode organic electrochemical transistors (OECTs), with PT2gT displaying the best device performance with a μC* product figure-of-merit of 290 F cm−1 V−1 s−1 . A record volumetric capacitance among p-type glycolated polythiophene OMIECs of 313 F cm−3 is observed for PE2gT, ascribed to the high proportion- ality of polar components in its materials design. The good OECT performance of PE2gT with μC* = …

Experimental Evaluation Of Mesh Size In Physically Crosslinked Polymer Gels Using Dynamic Light Scattering, Duncan M. Hill

Honors Theses

Block copolymer gels are under consideration as drug delivery patches. Controlling and modeling the transport inside the gel is an important contribution to the successful delivery of pharmaceuticals. The diffusive transport of a solute – such as a therapeutic compound – within the gel can be described by the mesh size of the gel, which is defined as the distance between polymer chains. Existing experimental evaluations of mesh size do not work for block copolymer gels due to differences in the fundamental gel structure. As such, an experimental method of measuring mesh size of block copolymer gels using dynamic light …

Synthetic Approaches Of Carbohydrate Based Self-Assembling Systems, Guijun Wang, Anji Chen, Pramod Aryal, Jonathan Bietsch

Chemistry & Biochemistry Faculty Publications

Carbohydrate-based self-assembling systems are essential for the formation of advanced biocompatible materials via a bottom-up approach. The self-assembling of sugar-based small molecules has applications encompassing many research fields and has been studied extensively. In this focused review, we will discuss the synthetic approaches for carbohydrate-based self-assembling (SA) systems, the mechanisms of the assembly, as well as the main properties and applications. This review will mainly cover recent publications in the last four years from January 2020 to December 2023. We will essentially focus on small molecule self-assembly, excluding polymer-based systems, which include various derivatives of monosaccharides, disaccharides, and oligosaccharides. Glycolipids, …

Optimized Pi Compound Mixing Strategy, Cecilia Mainzer

Williams Honors College, Honors Research Projects

The project focuses on developing an optimal mixing strategy for a polyisoprene (PI) compound at the Goodyear Tire & Rubber Company. The aim is to optimize performance objectives of the compound. The project involved research, design iterations, mixing analyses, and performance evaluations, while adhering to engineering codes and standards.

The design process includes analyzing differences between two mixing technologies, intermesh and tangential rotors; altering mixing conditions; and exploring additional polymer systems and coupling technology of the compound.

Validation data confirms that the mixing technology and compound recipe meets all success metrics, including stiffness, hysteresis, adhesion, cure rate, and tear performance …

Removal Of Residual Stress In 3d Printed Polymers, Christian Jenkins

Williams Honors College, Honors Research Projects

This project aims to investigate the relationship between stress relaxation and the reduction of dimensional shrinkage and warping in 3D printed polymers produced through fused filament fabrication. The hypothesis suggests that residual stress in 3D printed structures results from factors such as temperature differences, molecular-level contributions, and rapid cooling, causing post-printing warpage and damage. To mitigate these issues, the project proposes annealing 3D printed polymers in a hot sandbath to allow stress relaxation without warping. The study will employ a Dynamic Mechanical Analysis (DMA) machine to assess mechanical properties of relaxed and unrelaxed samples, comparing their effectiveness. The project's timeline …

Nonsolvent-Induced Phase Separation Inside Liquid Droplets, Rami Alhasan, Tanner A. Wilcoxson, Dakota S. Banks, Sion Jung, Douglas R. Tree

Faculty Publications

Nonsolvent-induced phase separation (NIPS) is a popular method for creating polymeric particles with internal microstructure, but many fundamental questions remain surrounding the kinetics of the complex coupled mass transfer and phase separation processes. In this work, we use simulations of a phase-field model to examine how (i) finite domain boundaries of a polymer droplet and (ii) solvent/nonsolvent miscibility affect the NIPS process. To isolate the effects of phase separation kinetics and solvent/nonsolvent mass transfer on the NIPS process, we study two different cases. First, we investigate droplet concentrations that originate inside the two-phase region, where phase separation kinetics alone governs …

Elucidating The Mechanical And Transport Properties Of Lignin-Based Hydrogel Composites, Nicholas Gregorich

All Dissertations

The use of lignin in the fabrication of soft composites has become an emerging area of research in polymer science and polymer chemistry. These lignin-based materials present numerous benefits, notably, a reduction in the use of petroleum-based precursor, improved structural benefits to otherwise soft host polymers, as well as the inherent antimicrobial and antioxidant properties of lignin, making it suitable for biomaterials. Herein, we present two chemical reaction pathways of incorporating lignin that was fractionated and cleaned using the Aqueous Lignin Purification with Hot Agents (ALPHA) process into poly(vinyl alcohol) (PVA) hydrogel composites for aqueous-based separations. By leveraging the ALPHA …

Poly(Ether Imide)S: Synthesis And Properties, Rachel Price

Honors College Theses

The synthesis of strong polymers is crucial to the creation of heat-resistant, durable, and mechanically useful plastics that we use every day. Poly(ether imide)s are used in applications such as food service, aerospace, automotive, and many more. This thesis will discuss the synthesis and properties of these plastics to help express a larger understanding of these polymers.

Application Of A Novel Green Nano Polymer For Chemical Eor Purposes In Sandstone Reservoirs: Synergetic Effects Of Different Fluid/Fluid And Rock/Fluid Interacting Mechanisms, Abbas K. Manshad, Alireza Kabipour, Erfan Mohammadian, Lei Yan, Jagar A. A., Stefan Iglauer, Alireza Keshavarz, Milad Norouzpour, Amin Azdarpour, S. Mohammad Sajadi, Siyamak Moradi

Research outputs 2022 to 2026

In this research, a novel natural-based polymer, the Aloe Vera biopolymer, is used to improve the mobility of the injected water. Unlike most synthetic chemical polymers used for chemical-enhanced oil recovery, the Aloe Vera biopolymer is environmentally friendly, thermally stable in reservoir conditions, and compatible with reservoir rock and fluids. In addition, the efficiency of the Aloe Vera biopolymer was investigated in the presence of a new synthetic nanocomposite composed of KCl-SiO2-xanthan. This chemically enhanced oil recovery method was applied on a sandstone reservoir in Southwest Iran with crude oil with an API gravity of 22°. The Aloe Vera biopolymer’s …

Programming The Properties Of Branched Polymers Through Precision Architectures, Michael R. Dearman

LSU Master's Theses

The glass transition of branched polymers is determined by multiple structural parameters that dictate their inter- and intramolecular interactions, and ultimately, their molecular packing in the amorphous phase. Here we examined the impact of side chain length, backbone length, molecular weight composition, and topology on the glass transition behavior of bottlebrush polymers. Through examining precision bottlebrush polymer libraries (PBP, ĐSC = 1.0), we find the infinite molecular weight Tg is reached at a specific brush length after which the effect of the side-chain length dominates. Being a factor more dominant than the backbone, side-chain length affects the Tg of bottlebrush …

Comprehensive Review Of Polymer And Polymer Gel Treatments For Natural Gas-Related Conformance Control, Ali Al Brahim, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Conformance problems often exist in natural gas-related activities, resulting in excessive water production from natural gas production wells and/or excessive natural gas production from oil production wells. Several mechanical and chemical solutions were reported in the literature to mitigate the conformance problems. Among the chemical solutions, two classes of materials, namely polymer gels and water-soluble polymers, have been mostly reported. These systems have been mainly reviewed in several studies for their applications as water shutoff treatments for oil production wells. Natural gas production wells exhibit different characteristics and have different properties which could impact the performance of the chemical solutions. …

Comprehensive Review Of Polymer And Polymer Gel Treatments For Natural Gas-Related Conformance Control, Ali Al Brahim, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Conformance problems often exist in natural gas-related activities, resulting in excessive water production from natural gas production wells and/or excessive natural gas production from oil production wells. Several mechanical and chemical solutions were reported in the literature to mitigate the conformance problems. Among the chemical solutions, two classes of materials, namely polymer gels and water-soluble polymers, have been mostly reported. These systems have been mainly reviewed in several studies for their applications as water shutoff treatments for oil production wells. Natural gas production wells exhibit different characteristics and have different properties which could impact the performance of the chemical solutions. …

Thermosensitive Polymers And Thermo-Responsive Liposomal Drug Delivery Systems, Waad H. Abuwatfa, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini

Faculty Publications

Temperature excursions within a biological milieu can be effectively used to induce drug release from thermosensitive drug-encapsulating nanoparticles. Oncological hyperthermia is of particular interest, as it is proven to synergistically act to arrest tumor growth when combined with optimally-designed smart drug delivery systems (DDSs). Thermoresponsive DDSs aid in making the drugs more bioavailable, enhance the therapeutic index and pharmacokinetic trends, and provide the spatial placement and temporal delivery of the drug into localized anatomical sites. This paper reviews the fundamentals of thermosensitive polymers, with a particular focus on thermoresponsive liposomal-based drug delivery systems.

Therapeutic Injectable Iron-Chelating Hydrogels, Debbie Campbell-Rance

Theses and Dissertations

ABSTRACT

Therapeutic Injectable Iron-Chelating Hydrogels for Improved Central Nervous System Regeneration

By

Debbie S. Campbell-Rance

A dissertation submitted in partial fulfillment of the requirements of the degree of Doctor of Philosophy at Virginia Commonwealth University 2021.

Director: Xuejun Wen, M.D., Ph.D., AIMBE Fellow, Alice T. and William H. Goodwin Jr. Endowed Chair Professor in Regenerative Medicine, Institute for Engineering and Medicine, Department of Chemical and Life Science Engineering

Severe traumatic brain and spinal cord injuries are major global public health and socioeconomic problems in terms of mortality and morbidity. Currently there are two main lines of treatment under development for …

Application Of Sla 3d Printing For Polymers, Taylor Wilson

Williams Honors College, Honors Research Projects

Stereolithography is a type of 3D printing that allows liquid photopolymer resin to be cured into layers that make up a 3D object. Creation of such resins for these purposes can require a significant amount of time to test and develop, and commercial resins also require some amount of testing for printer settings before use. This paper reviews how stereolithography works, the materials used, and experimentation done to compare the resin properties to the determined curing times. Using several commercially available resins, varying base exposure and layer exposure times were used to determine the lowest possible curing time that gave …

Itraconazole Nanocomposites Prepared Via Rotary Evaporator Drying Of Nanomilled Suspensions, Alexander Santos Coelho

Theses

The aim of this study is to explore the feasibility of rotary evaporation for drying wetmilled drug suspensions as a novel approach to produce drug nanocomposites that exhibit fast redispersion and immediate drug release. To this end, the physical stability of the nanomilled itraconazole (drug) suspensions, a.k.a., nanosuspensions, during the milling and storage; the drying of the itraconazole nanosuspensions via the rotary evaporator; and the type/loading of various polymers/surfactants (dispersants) on aqueous redispersion and drug release from the nanocomposites were examined. Our results suggest that smaller drug particle size, owing to nanomilling, and smaller nanocomposite particle size, owing to optimized …

Investigation Of Human Adipose-Derived Stem-Cell Behavior Using A Cell-Instructive Polydopamine-Coated Gelatin-Alginate Hydrogel., Settimio Pacelli, Aparna R Chakravarti, Saman Modaresi, Siddharth Subham, Kyley Burkey, Cecilia Kurlbaum, Madeline Fang, Christopher A Neal, Adam J Mellott, Aishik Chakraborty, Arghya Paul

Chemical and Biochemical Engineering Publications

Hydrogels can be fabricated and designed to exert direct control over stem cells' adhesion and differentiation. In this study, we have investigated the use of polydopamine (pDA)-treatment as a binding platform for bioactive compounds to create a versatile gelatin-alginate (Gel-Alg) hydrogel for tissue engineering applications. Precisely, pDA was used to modify the surface properties of the hydrogel and better control the adhesion and osteogenic differentiation of human adipose-derived stem cells (hASCs). pDA enabled the adsorption of different types of bioactive molecules, including a model osteoinductive drug (dexamethasone) as well as a model pro-angiogenic peptide (QK). The pDA treatment efficiently retained …