Polymer Science Commons^™

Light Responsive With Metallo-, And Hydrogen Bonded Benzoxazine Dimer-Based Supramolecular Structure, Sorapat Niyomsin

Chulalongkorn University Theses and Dissertations (Chula ETD)

The present work focuses on multi-responsive molecule based on supramolecular chemistry of benzoxazine dimer as a benzoxazine supramolecular crosslinker, fluorescent labelling benzoxazine conjugated with rotaxane system and benzoxazine pendant group block copolymer. The use of azobenzene derivatives in benzoxazine synthesis provides light responsive behaviour. The remained hydroxyl group from aminoalcohol allows benzoxazine to conjugate with desired functional group. The dihydroxyl benzoxazine acts as molecular crosslinker for poly(acrylic acid) by conjugation. The ring-opening reaction brings benzoxazine dimeric unit on the crosslinker which also showed metal ion complexation. The complexation strengthens the cross-linked polymer network. The complex can reversely form by treating …

Catalytic Applications Of Cuo Loaded Mesoporous Ceo₂ And Cuo Loaded Mesoporous Ceo₂-Zro₂ Catalyst, Sureerat Jampa

Chulalongkorn University Theses and Dissertations (Chula ETD)

Copper oxide (CuO) loaded mesoporous ceria (CeO₂) and Copper oxide (CuO) loaded mesoporous ceria-zirconia (CeO₂-ZrO₂) catalysts are successfully synthesized for preferential oxidation of CO (CO-PROX) and autothermal steam reforming of methanol (ASRM). Mesoporous CeO₂ and mesoporous CeO₂-ZrO₂ as catalyst supports with high specific surface area and ordered structure are prepared via a nanocasting process by using MCM-48 as template. Deposition-precipitation technique is chosen to load various Cu contents (1 to 9 wt.%) on the synthesized mesoporous supports. The synthesized CuO loaded mesoporous CeO₂ (Cu-C) and CuO loaded mesoporous CeO₂-ZrO₂ (Cu-CZ) catalysts are characterized by N₂ adsorption-desorption, X-ray diffraction, transmission electron …

Thermomechanical Behavior And Chemical Sensing Cationic Poly(Diallyldimethylammonium Chloride) And Anionic Poly(Sodium 4-Styrene Sulfonate) Assembled Into Composite Polyelectrolyte Multilayer Thin Films And Complex Membranes, Rateeya Saikaew

Chulalongkorn University Theses and Dissertations (Chula ETD)

Polyelectrolyte composite membranes of cationic PDADMAC and anionic PSS assembled into polyelectrolyte multilayer (PEM) thin film and polyelectrolyte complex (PEC) membranes were used as matrix embedded with several additive molecules. Nano-scale PEM films fabricated using the layer-by-layer deposition method and the loading and release of a hydrophobic model drug curcumin (Cur) was studied for drug delivery and sensing applications. Interestingly, it was found that the loading and release of Cur could be triggered by solvent composition and temperature. In a parallel study, the alternative to the nanoscale PEM was studied in the form of PEC, which were used as stand-alone …

The Role Of Microenvironment Reagent Solubility On Reaction Kinetics Of 4-Nitrophenol Reduction, Michael P. Zeevi, Andrew Harrison, Christina Tang

Undergraduate Research Posters

The Role of Microenvironment Reagent Solubility on Reaction Kinetics of 4-Nitrophenol Reduction

Michael Zeevi¹ with Andrew Harrison¹ and Christina Tang, PhD¹

¹Department of Chemical and Life Science Engineering, VCU School of Engineering

Introduction: Nanoparticles are of increasing interest due to their high surface area to volume ratio, as well as that they enable fine-tuning of the reaction microenvironment. Through flash nanoprecipitation, core-shell polymer nanoreactors were formed by directed self-assembly. Using the reduction of 4-nitrophenol as a model reduction reaction, we investigated the effect of reagent solubility in the nanoreactor microenvironment’s on nanoreactor kinetics.

Methods: The standard …

Surface Engineering And Monomer Design For Light-Mediated Ring Opening Metathesis Polymerization, Ishan A. Fursule

Theses and Dissertations--Chemical and Materials Engineering

Stimuli-responsive materials are changing the landscape of actuated materials, optoelectronics, molecular machines, solar cells, temporary memory storage, and biomedical materials. Specifically, photo-responsive polymers have gained acceleration in research and application since the last two decades in the form of a surface coating and micro-patterns. Light as a stimulus can be coherent, mono or polychromatic, tunable for power (intensity) and energy (wavelength), and has precise spatiotemporal control. Conventional surface coating techniques such as spin coating are unable to impart properties to the coatings in terms of sturdiness, homogeneity, uniformity over the complex surface, post deposition modification, and process efficiency. Also, in …

Design And Analysis Of Curcumin Conjugated Poly(Beta-Amino Ester) Networks For Controlled Release In Oxidative Stress Environments, Carolyn T. Jordan

Theses and Dissertations--Chemical and Materials Engineering

Oxidative stress, the imbalance of free radical generation with antioxidant defenses, leads to cellular inflammation, apoptosis and cell death. This compromised environment results in debilitating diseases, such as oral mucositis (OM), atherosclerosis, and ischemia/reperfusion injury. Antioxidant therapeutics has been a proposed strategy to ameliorate these imbalances and maintain homeostatic environments. However, the success of these approaches, specifically curcumin, has been limited due to characteristics such as hydrophobicity and high reactivity when released as bolus doses to contest to oxidative stress induced diseases. The development of a controlled release system to aid in protection of the antioxidant capacity of curcumin, as …

Surface Functionalization Via Photoinitiated Radical Polymerization For Rare Cell Isolation And Mechanical Protection, Calvin Frank Cahall

Theses and Dissertations--Chemical and Materials Engineering

Surface functionalization of living cells for cell therapeutics has gained substantial momentum in the last two decades. From encapsulating islets of Langerhans, to cell laden gels for tissue scaffolds, to individual cell encapsulation in thin hydrogels, to surface adhesives and inert surface camouflage, modification of living cell surfaces has a wide array of important applications. Here we use hydrogel encapsulation of individual cells as a mode of protection from mechanical forces for high throughput cell printing, and chemical stimuli for the isolation of rare cells in blood.

In the first study, we review methods of surface functionalization and establish a …

Comparison Study Between Post-Fermentation Stillage And Pre-Fermentation Mash Utilizing Acidification And Steam Explosion Techniques For Cellulose Saccharification, Daniel Mckee

Master's Theses

Pre-fermentation mash fiber and post-distillation stillage fiber were examined and compared using a variety of preparatory techniques to determine the better source for cellulose fiber saccharification. Once screened, dried, and diluted to a 10% solution, mash fiber and stillage fiber were exposed to increasing temperatures for steam explosion techniques as well as increasing acidification techniques. Both underwent enzymatic saccharification to convert the exposed cellulose to glucose and other sugars. Once the optimum steam explosion technique parameters and acidification parameters were determined to be 2.5% sulfuric acid at 127.8°C for 1 hour, a comparison of the saccharification of pre-fermentation mash fiber …

Responsive Nanogel Probe For Ratiometric Fluorescent Sensing Of Ph And Strain In Hydrogels, Mingning Zhu, Dongdong Lu, Shanglin Wu, Qing Lian, Wenkai Wang, Amir H. Milani, Zhengxing Cui, Nam T. Nguyen, Mu Chen, L. Andrew Lyon, Daman J. Adlam, Anthony J. Freemont, Judith A. Hoyland, Brian R. Saunders

Engineering Faculty Articles and Research

In this study a new pH-responsive nanogel probe containing a complementary nonradiative resonance energy transfer (NRET) fluorophore pair is investigated and its ability to act as a versatile probe of network-related changes in three hydrogels demonstrated. Fluorescent sensing using NRET is a powerful method for studying relationships between Angstrom length-scale structure and macroscopic properties of soft matter. Unfortunately, inclusion of NRET fluorophores into such materials requires material-specific chemistry. Here, low concentrations of preformed nanogel probes were included into hydrogel hosts. Ratiometric photoluminescence (PL) data for the gels labeled with the nanogel probes enabled pH-triggered swelling and deswelling to be studied …

Development Of Starch-Polyvinyl Alcohol (Pva) Biodegradable Film: Effect Of Cross-Linking Agent And Antimicrobials On Film Characteristics, Aniket Satish More, Chandani Sen, Madhusweta Das

Journal of Applied Packaging Research

To satisfy the need of developing eco-friendly flexible antimicrobial packaging film with minimum use of synthetic chemical ingredients, the present study examined the efficacy of citric acid (CA) as cross-linking agent and essential oils (EOs), viz., cinnamon essential oil (CEO) and oregano essential oil (OEO) as natural antimicrobials in corn starch-polyvinyl alcohol (CS-PVA) film. Compared to film prepared from filmogenic solution (FS) containing 75 kg CS+8.75 kg PVA+24.6 kg glycerol per m³ FS, film additionally containing CA at 0.07 kg/kg CS indicated 95% higher ultimate tensile strength (UTS) and 27% lower water vapor permeability (WVP). Film developed with incorporation …

Cellulose Reinforced Thermoplastic Composites By In-Situ Ring-Opening Polymerization, Shahab Kashani Rahimi

Dissertations

Over the past two decades, the increasing concern about the negative environmental impacts of synthetic materials has led to rising interests in utilizing renewable natural resources to develop polymer materials with comparable properties and performance to their synthetic counterparts. One of the major fields of interest is polymer composites where the replacement of synthetic fibers with bio renewable natural fibers is of great potential. However, the processing difficulties, in terms of fiber dispersion and thermal stability have limited the application of cellulosic fibers to polymers with low processing temperatures which are mostly hydrophobic polymers. As a result, the true reinforcing …

Drawing And Twisting Of Graphene Fibers, Gregory T. Lane, Robert J. Sekerak, Isaias Diaz

Mechanical Engineering

The aim of this project was to develop a more automated process for drawing and twisting of graphene fibers than was currently in place. This was implemented by having two chemical baths with variable speed rollers at either end, and intermediate roller to spool fiber between stages, and a twisting cylinder with integral spool to twist the fiber as it is collected. The goal was to have this first iteration deliver a working prototype, however due to manufacturing delays and timing constraints, that will be missed. A second follow-on project would be able to continue the work presented here and …

A Comparison Study Of Two Synthesis Methods For Polymer Of Intrinsic Microporosity 1 (Pim-1), Conor S. Perry

Materials Engineering

Polymers of Intrinsic Microporosity (PIMs) are an emerging polymeric material class for molecular sieving applications. This study focuses on PIM-1, an alternating copolymer of 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethyl-1,1’-spirobisindane and tetrafluoroterephthalonitrile synthesized via nucleophilic aromatic substitution. PIM-1 been widely studied as a gas separating material and filtering membrane, but in this case, it is studied as a battery separator material. PIM-1’s microporous (pore diameters less than 2 nm) structure allows smaller favorable ions to transport while preventing larger ions and compounds from transporting. Two synthesis methods, round bottom flask synthesis and ball mill synthesis, of PIM-1 are compared to see any improved characteristics. The …

Synthesis And Characterization Of Molybdenum Sulfide And For Hydrogen Evolution Reaction And Supercapacitor Applications, Zhuo Wang

Electronic Theses & Dissertations

To meet the constantly rising requirement of energy other than traditional fossil fuel and environment protection, it is a perfect time to development low cost, and efficient materials for clean energy production. Hydrogen generation by water splitting is one of the cleanest ways to produce cheaper energy. Hydrogen evolution reaction (HER) is one of the key steps in water splitting process. Ideally, the thermodynamic potential for HER should be at 0 V (vs. SHE). However, without an efficient catalyst, this reaction occurred at higher potential, called overpotential. A good HER catalyst is needed to lower the overpotential and hence to …

An Industrial Process For The Production Of Nylon 6 6 Through The Step-Growth Reaction Of Adipic Acid And Hexamethylenediamine, David Wallace Jacobson

Chemical Engineering Undergraduate Honors Theses

A continuous, two stage, four reactor system process is presented here for the proposed purpose of nylon 6 6 manufacture at the rate of 85 million lbs per year. Report components include: process descriptions, simulation methods and results, economic analysis, EH&S considerations, process control descriptions, and a general recommendation for how to proceed with plans enclosed. The general design of the plant is a two stage system composed of one PFR used for the formation of nylon salt and low molecular weight nylon chains, followed by three CSTR’s used for increasing nylon molecular weight. The overall process has been found …

Polyisobutylene Telechelic Prepolymers By In Situ End-Quenching And Post-Polymerization Modifications, Bin Yang

Dissertations

This volume focuses on the development of telechelic polyisobutylene (PIB) prepolymers by combining end-capping of living carbocationic polymerization of isobutylene (IB) with suitable reactants and post-polymerization modifications. Alkylation kinetics of PIB tert-chloride with alkoxybenzenes using either TiCl₄ or AlCl₃ were investigated. Quantitative para-position end-capped products were only achieved if the alkoxybenzene/AlCl₃ molar ratio was greater than unity; while no such molar ratio is required for TiCl₄, but the alkylation rate was slower than AlCl₃ under the same conditions. Photopolymerization kinetics analysis of PIB triphenol tri(meth)acrylates with low and high M_ns, …

Evaluating The Bond Behavior Between Frp And Grooved Concrete Specimens Using Single Shear Pull Out Test, John Omboko

Master's Theses (2009 -)

Surface preparation affects the bond behavior between Fiber Reinforcing Polymer (FRP) composite material and concrete. In this research, a special type of surface preparation known as grooving, which involves cutting transverse grooves, is conducted on concrete blocks (specimens) that are categorized as either Unfilled (U) or Filled (F). This idea is to ascertain how the grooves affect the strength of FRP-bonded-concrete specimen. These two categories are then benchmarked to control (C) specimens which do not have grooves on them. Category U specimens only have the epoxy applied on the concrete surface while category F specimens have epoxy applied on both …

High-Density Non-Fouling Bioactive Coatings: Development And Characterization, Bonan Yu, Ramya Raman, Karl Schlike

Biomedical Engineering Western Regional Conference

No abstract provided.

Producing Food Packaging Printing Ink Via Green Emulsion Aggregation Method, Maryam Ataeefard, Shohre Rouhani

Journal of Applied Packaging Research

Digital printing will become more and more important in the packaging industry. Digital printing technology is growing because it allows the print suppliers to improve the level of service they offering to their customers, as well as, it opens new opportunities and helps them to make more money. Additives, dyestuffs, resin and other chemicals in packaging printing ink may influence safety of the food. Therefore, choosing suitable materials are very important in food packing ink. Over the last years, many printing ink manufacturers moved toward more sustainable inks. Drivers for this development, besides the resource scarcity and a higher legislative …

Engineering Icephobic Coatings: Surface Characterization Of Pt Cured Silicones, Sithara Shylaja Nair

Theses and Dissertations

Ice buildup on structures leads to problems that include reduced performance, structural damage and power outages. It is therefore important to limit the energy required for removal of ice from substrates to minimize buildup. Understanding the mechanism of ice adhesion and its dependence on variables like coating thickness, stiffness, surface free energy and morphology is critical for minimizing adhesion. Despite several developments in “icephobic” coatings, which are those that have low ice adhesion, it is important to understand adhesion on the fundamental level to make way for advanced coatings. To do so, a study has been carried out that explores …