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A Machine Learning Approach To Robotic Additive Manufacturing Of Uv-Curable Polymers Using Direct Ink Writing, Luis A. Velazquez 2022 Louisiana State University and Agricultural and Mechanical College

A Machine Learning Approach To Robotic Additive Manufacturing Of Uv-Curable Polymers Using Direct Ink Writing, Luis A. Velazquez

LSU Master's Theses

This thesis presents the design and implementation of a robotic additive manufacturing system that uses ultraviolet (UV)-curable thermoset polymers. Its design considers future applications involving free-standing 3D printing by means of partial UV curing and the fabrication of samples that are reinforced with fillers or fibers to manufacture complex-shape objects.

The proposed setup integrates a custom-built extruder with a UR5e collaborative manipulator. The capabilities of the system were demonstrated using Anycubic resin formulations containing fumed silica (FS) at varying weight fractions from 2.8 to 8 wt%. To fully cure the specimens after fabrication, a UV chamber was used. Then, measurements …


Fabrication Of Thin-Film Composite, Reverse-Osmosis Membranes With Polyethylenimine Modifications For Enhancing Membrane Fouling Resistance, Stephanie N. Hamilton 2022 California Polytechnic State University, San Luis Obispo

Fabrication Of Thin-Film Composite, Reverse-Osmosis Membranes With Polyethylenimine Modifications For Enhancing Membrane Fouling Resistance, Stephanie N. Hamilton

Master's Theses

Increasing water reuse opportunities for communities has become increasingly important as access to clean water is becoming more scarce. Reverse Osmosis (RO) is an advanced treatment technology used in water recycling wastewater for potable reuse applications. RO is a promising technology; however, the membranes have limitations including their high energy demand and their susceptibility to membrane fouling. The main objective of this study was to develop a reproducible method for the fabrication of RO membranes with enhanced flux and reduced susceptibility to fouling. Literature contains numerous publications on fabrication of thin film composite (TFC) RO membranes with high performance. However, …


Synthesis And Assembly Of Polymer Materials At Interfaces, Xiaoshuang Wei 2022 University of Massachusetts Amherst

Synthesis And Assembly Of Polymer Materials At Interfaces, Xiaoshuang Wei

Doctoral Dissertations

The overarching goal of the thesis is to understand growth and assembly of polymer materials at interfaces. Chapter 2 and Chapter 3 study simultaneous polymer growth and assembly at fluid interfaces, where in-situ photopolymerization and vapor phase deposition were utilized to grow polymers, respectively. Chapter 4 leverages capillary condensation to pattern polymer growth at solid substrates. Chapter 1 provides background information on polymer materials at interfaces, and vapor phase deposition method (initiated chemical vapor deposition, iCVD) to grow polymers. This chapter also reviews polymer thin film wetting, and colloidal assemblies at interfaces. In Chapter 2, we demonstrate the preparation …


Frontiers In The Self-Assembly Of Charged Macromolecules, Khatcher O. Margossian 2022 University of Massachusetts Amherst

Frontiers In The Self-Assembly Of Charged Macromolecules, Khatcher O. Margossian

Doctoral Dissertations

The self-assembly of charged macromolecules forms the basis of all life on earth. From the synthesis and replication of nucleic acids, to the association of DNA to chromatin, to the targeting of RNA to various cellular compartments, to the astonishingly consistent folding of proteins, all life depends on the physics of the organization and dynamics of charged polymers. In this dissertation, I address several of the newest challenges in the assembly of these types of materials. First, I describe the exciting new physics of the complexation between polyzwitterions and polyelectrolytes. These materials open new questions and possibilities within the context …


Quantifying Elasto-Adhesion And Fluid-Elastic Dynamics For Ultra-Soft Hydrogel Interfaces, Hongbo Fu 2022 University of Massachusetts Amherst

Quantifying Elasto-Adhesion And Fluid-Elastic Dynamics For Ultra-Soft Hydrogel Interfaces, Hongbo Fu

Doctoral Dissertations

Hydrogels are constructed with polymer networks swollen with water, which are soft and with much smaller shear moduli than bulk moduli. Due to the similar moduli to biological tissues, synthetic hydrogels have been used for biological applications. While interfacial properties are important for many of the applications of soft materials, quantifying these properties is challenging for ultra-soft materials. Ultra-softness causes difficulties in measuring interfacial properties with conventional force-based methods. For example, soft specimens deform largely under gravity and external forces, and thus the assumptions of the established methods are invalid. Additionally, many of the applications for hydrogels require them to …


Bio-Based Food Packaging Material For Intelligent Food Packaging Applications For Chicken Fillets, Kalpani Y. Perera, Amit K. Jaiswal, Swarma Jaiswal, Shubham Sharma 2022 Technological University Dublin

Bio-Based Food Packaging Material For Intelligent Food Packaging Applications For Chicken Fillets, Kalpani Y. Perera, Amit K. Jaiswal, Swarma Jaiswal, Shubham Sharma

Articles

Bionanocomposite packaging is made up of bio- based materials that have high performance activity and are ecologically sustainable alternatives to packaging made of synthetic polymers. Intelligent packaging retains track of the state of the food and the environment in which it is stored, and communicates relevant changes to the consumer through visualization or other methods. The aim of this study was to develop a bionanocomposite intelligent packaging material by utilising sodium alginate, gelatin, nanoclay and curcumin. Sodium alginate, gelatin film incorporated with Curcumin (Cur), and Nanoclay (NC) in various concentrations (0% W/V, 0.5% W/V, 1% W/V and 1. 5% W/V) …


Enabling Nanoimprint Lithography Techniques Across Multiple Manufacturing Processes, Vincent Einck 2022 University of Massachusetts Amherst

Enabling Nanoimprint Lithography Techniques Across Multiple Manufacturing Processes, Vincent Einck

Doctoral Dissertations

Advanced nanooptics in the areas of flat lenses, diffractive elements, and tunable emissivity require a route to high throughput manufacturing. Nanooptics are often demanding of high refractive index materials, nanometer precision and ease of fabrication. Nanoimprint lithography (NIL) is a low-cost, high throughput manufacturing technique beginning to be realized in commercial industry.1,2 The NIL process is an ideal manufacturing candidate due to its ability to have a fast process time, efficient use of materials, repeatability and high precision while also having wide diversity of potential structures and material choices. Appling NIL techniques to other facets of manufacturing enable the …


Biobased Packaging Materials From Cellulose Nanofibrils Produced From Virgin Wood Pulp Or Recycled Cardboard Pulp, Md Ikramul Hasan 2022 University of Maine

Biobased Packaging Materials From Cellulose Nanofibrils Produced From Virgin Wood Pulp Or Recycled Cardboard Pulp, Md Ikramul Hasan

Electronic Theses and Dissertations

Self-standing cellulose nanofibril (CNF) films are regarded as one of the promising alternatives to current petroleum-based packaging materials. The mechanical and barrier properties of CNF films are not yet up to the mark for certain applications, especially at high relative humidity. Those properties of CNF films can be tuned by the drying methods of films, degree of fibrillation, cross-linking, and controlled shrinkage. A comprehensive understanding of these processes and their influence on the structure and properties of CNF films have been presented in this thesis.

First, we prepared CNF films from CNF suspensions with two different degrees of fibrillation- standard …


Contact Dewatering Of Cellulose Nanofibers For Biopolymer Composite Applications, Alexander Collins 2022 University of Maine

Contact Dewatering Of Cellulose Nanofibers For Biopolymer Composite Applications, Alexander Collins

Electronic Theses and Dissertations

Cellulose Nanofibrils (CNFs) are promising materials for reinforcement of polymer matrices attributable to their impressive physical and mechanical properties, as well as their biodegradability. However, the utilization of these materials in composites is made challenging by the water content of CNF slurries, the tendency of CNFs to agglomerate as they dry, and incompatibility between hydrophilic CNFs and hydrophobic polymer matrices. The most commercially viable drying methods to produce small-scale dry CNFs, such as spray drying, are very energy intensive, can only dry the materials down to micron-scale agglomerates, and do not preserve fibrillar aspect ratios. “Contact dewatering,” or the removal …


Numerical Modeling Of Localized Heating In Continuous Fiber Reinforced Thermoplastic Laminates, James T. Gayton 2022 University of Maine

Numerical Modeling Of Localized Heating In Continuous Fiber Reinforced Thermoplastic Laminates, James T. Gayton

Electronic Theses and Dissertations

The manufacturing of continuous fiber-reinforced thermoplastic (CFRTP) laminates requires the application of heat and pressure. Standard CFRTP manufacturing methods like thermoforming take a global approach to manufacturing, where the whole part is heated and undergoes a forming process. There is an opportunity to develop advanced manufacturing methods based on localized heating and deformations of consolidated stock. This thesis provides a localized heating method via networks of resistive heating elements embedded within the laminate and a means to evaluate that method.

Typical heating methods for CFRTP laminates include infrared and convective ovens or surface contact heaters. They have the same drawbacks …


Investigating Features And Output Correlation Coefficient Of Natural Fiber-Reinforced Poly(Lactic Acid) Biocomposites, Andreas Federico, Siti Norasmah Surip, Wan Nor Raihan Wan Jaafar, Jaka Fajar Fatriansyah, Agrin Febrian Pradana 2022 Universitas Indonesia

Investigating Features And Output Correlation Coefficient Of Natural Fiber-Reinforced Poly(Lactic Acid) Biocomposites, Andreas Federico, Siti Norasmah Surip, Wan Nor Raihan Wan Jaafar, Jaka Fajar Fatriansyah, Agrin Febrian Pradana

Journal of Materials Exploration and Findings

Polylactic acid (PLA) material has the potential to be applied in various industrial fields, but this material has shortcomings in terms of mechanical properties, especially mechanical strength, due to brittleness nature of PLA. The manufacture of PLA composite material with the addition of natural fibers as a reinforcing phase is one of the methods to increase the impact strength and maintain the biodegradable properties of the material. However, in theory, there are many factors that affect the mechanical properties of composite materials, thus making the mechanical properties of composites more complex than monolithic materials. The mechanical properties of these composite …


Functional Bottlebrush Polymer Additives For Thin Films And Coatings, Travis S. Laws 2022 University of Tennessee, Knoxville

Functional Bottlebrush Polymer Additives For Thin Films And Coatings, Travis S. Laws

Doctoral Dissertations

Bottlebrush polymers are a class of highly branched polymers consisting of polymeric side chains that are densely grafted to a linear backbone. Their highly branched architecture results in surface enrichment across a broad range of materials. The goal of my research has been centered around the design of functional bottlebrush polymers and their use as surface active additives in blend films and coatings.

In the first chapter, we examine the segregation behavior of polystyrene bottlebrushes that are blended with linear polystyrene. We systematically vary the lengths of the bottlebrush backbone (Nb), side-chain (Nsc), and the linear matrix (Nm) in order …


How Dynamic Bond Results In The Unique Viscoelastic Behavior Of The Associating Polymers, Sirui Ge 2022 University of Tennessee, Knoxville

How Dynamic Bond Results In The Unique Viscoelastic Behavior Of The Associating Polymers, Sirui Ge

Doctoral Dissertations

Associating polymer is a special kind of polymer possessing transient reversible bonds in addition to the conventional covalent bonds. The reversible bonds provide unique dynamics and fascinating viscoelastic properties, resulting in attractive applications for these polymers, such as self-healing and shape memory materials. Despite many years of studies, the understanding of dynamics of polymers with reversible bonds, especially on molecular level, is still in the rudimentary stage, preventing the rational design of the potential novel functional materials based on associating polymers. In this dissertation, we provide a detailed and quantitative understanding of the dynamics and viscoelastic properties of associating polymers. …


Modeling Phase Behavior And Agglomeration In Polymer Systems Incorporating Complex Architectures: From Bottlebrush To Lysozyme, Sidong Tu 2022 Clemson University

Modeling Phase Behavior And Agglomeration In Polymer Systems Incorporating Complex Architectures: From Bottlebrush To Lysozyme, Sidong Tu

All Dissertations

Using computational modeling, we focus on the phase behavior of multicomponent systems incorporating enzyme and bottlebrush polymers where the agglomeration of multiple components occurs. We start with all-atom molecular dynamics (MD) simulations of lysozyme and polyethylene glycol (PEG) based polymer mixture to understand the mechanisms of preservation of lysozyme bioactivity at high temperatures with addition of PEG-derived bottlebrushes. We show that the PEG part of bottlebrushes phase separates at high temperature and shells the access of water to lysozyme, resulting in the preservation of lysozyme secondary structures. We then developed a coarse-grained model using a Dissipative Particle Dynamics approach to …


Brain Inspired Organic Electronic Devices And Systems For Adaptive Signal Processing, Memory, And Learning., Subhadeep Koner 2022 University of Tennessee, Knoxville

Brain Inspired Organic Electronic Devices And Systems For Adaptive Signal Processing, Memory, And Learning., Subhadeep Koner

Doctoral Dissertations

A new class of electronic device has emerged which bear the potential for low powered brain like adaptive signal processing, memory, and learning. It is a non-linear resistor with memory coined as memristor. A memristor is a two-terminal electrical device which simultaneously changes its resistance (processing information) and store the resistance state pertaining to the applied power (memory). Therefore, it can collocate memory and processing much like our brain synapse which can save time and energy for information processing. Leveraging stored memory, it can thereby help future engineered systems to learn autonomously from past experiences. There has been a growing …


Polynorbornenes For Advanced Applications And Processes, Xinyi Wang 2022 University of Tennessee, Knoxville

Polynorbornenes For Advanced Applications And Processes, Xinyi Wang

Doctoral Dissertations

Polynorbornenes have dramatically different properties and various applications depending on their chemical structures. The modular nature of norbornene-based systems provides a facile route toward synthesizing diverse polymeric materials, thus making them ideal materials for systematic structure-property investigations. Herein, their application as gas separation membranes and the correlation between their gas-transport properties and polymer structures will be investigated. Though many valuable correlations between gas-permeability and polynorbornene structure have been studied previously, many of these efforts have focused heavily on designing materials with various chemical structures to achieve high permeabilities. In contrast, the influence of molecular structure on: a) polynorbornene chain packing …


Fabrication And Non-Covalent Functionalization And Characterization Of Graphene-Based Devices On Novel Substrate Cadmium Trithiophosphate (Iv) — Cdps, Abayomi Omotola Omolewu 2022 University of Arkansas, Fayetteville

Fabrication And Non-Covalent Functionalization And Characterization Of Graphene-Based Devices On Novel Substrate Cadmium Trithiophosphate (Iv) — Cdps, Abayomi Omotola Omolewu

Graduate Theses and Dissertations

With graphene at the center of several application areas such as sensing, circuits, high-frequency devices for communication systems, etc., it is crucial to understand how the intrinsic properties of devices made from graphene and other materials like platinum and palladium nanoparticles affect the performance of such devices for the specific application area. Many graphene-based devices for different application areas have focused mainly on the material composition of the graphene-based devices and how it affects performance parameters for the specific application. However, it would be insightful to understand how the intrinsic electrical properties of the graphene devices for different applications affect …


Characterization Of Thermal Gelation Properties In Bioresorbable Thermally Activated Hydrogel Polymers For Hernia Surgery Applications, Alexander Mayfield 2022 Clemson University

Characterization Of Thermal Gelation Properties In Bioresorbable Thermally Activated Hydrogel Polymers For Hernia Surgery Applications, Alexander Mayfield

All Theses

Hydrogel adhesives are a new class of materials with excellent biocompatibility, which makes them very attractive for biomaterial applications. It has been previously shown that Tetronic T1107, a four-arm poly (propylene oxide)-poly (ethylene oxide) (PPO-PEO) block copolymer, is useful as a chemical crosslinking thermo-responsive hydrogel for bioadhesive applications. The end groups of this polymer are modified with acrylate and N-hydroxysuccinimide (NHS) functional groups. The acrylate end group gives the polymer cohesive properties with long-range chemical crosslinking using dithiothreitol (DTT), while the NHS end group gives the polymer adhesive properties through bonding with amines found in organic tissue. It was found …


3d Printed Multicomponent Polymer Based Materials Via Hybrid Filaments: Fabrication And Characterization, Erik Antonio 2022 Clemson University

3d Printed Multicomponent Polymer Based Materials Via Hybrid Filaments: Fabrication And Characterization, Erik Antonio

All Dissertations

Additive manufacturing, also known as 3D printing, promises a manufacturing revolution for both industry and academic circles. One of the most widely used method of 3D printing is Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF), which requires a thermoplastic filament to be directed towards a heating block and then deposited via extrusion layer by layer to produce a finished part. However, there are significant issues with this technology, mainly a limitation on the materials available for use and mechanical property deficiencies when compared to traditional manufacturing. These issues are brought about by the temperature limited nature of the …


Modeling Pattern Formation And Morphology Development In Polymer Networks, Yao Xiong 2022 Clemson University

Modeling Pattern Formation And Morphology Development In Polymer Networks, Yao Xiong

All Dissertations

Topography and morphology have considerable impacts on the functionalities of soft materials in an entire range of applications from smart optics to tissue engineering. Adapting theoretical and computational approaches, we focus on the dynamics of pattern formation and morphology development in polymer networks. This dissertation starts with studying the dynamical control of pattern formation in confined thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm) gel films. The patterns are formed due to mechanical instabilities. We perform a linear stability analysis and identify the limits of this analysis in predicting pattern formation in gels. We then study the restructuring between patterns and hysteresis phenomena …


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