Polymer Science Commons^™

Adaption Of Catechol And Reversible Addition-Fragmentation Chain-Transfer (Raft) Chemistries For Water-Based Applications, Olabode Oyeneye

Electronic Thesis and Dissertation Repository

Incorporating the binding chemistry of catechol functionality with RAFT chemistry offers a facile and simplified approach for developing a suite of new 2D and 3D hybrid materials with tailored morphologies. Leveraging both chemistries by synthesizing catechol-end functionalized RAFT agents and catechol-containing monomeric species for RAFT (co)polymerization, this dissertation examined a new series of advanced materials that were designed for water-based applications including model flocculants, thermoresponsive hydrogels, adsorbents and underwater adhesives.

To prepare the RAFT agents, novel trithiocarbonates with several catechol end R groups (as postpolymerization anchors) were synthesized that differ in their carbonyl α-substituents (Dopa-CTAs). These materials were evaluated for …

Spray-Dried Cellulose Nanofibril-Reinforced Polypropylene Composites For Extrusion-Based Additive Manufacturing, Lu Wang

Electronic Theses and Dissertations

Compared to conventional manufacturing process, additive manufacturing (AM) offers free-form design, lighter and more ergonomic products, short lead time and less waste. Extrusion-based AM can be used to print thermoplastics. However, extrusion-based AM has processing challenges in printing semi-crystalline thermoplastics, for instance, polypropylene (PP). Cellulose nanofibrils (CNF) are one type of cellulose nanofibers that are produced from pulp fibers. CNF has extraordinary properties which make it an ideal candidate to reinforce polymers. Spray-dried CNF (SDCNF) is able to be incorporated into thermoplastic matrices without modifying conventional processing procedures.

The mechanical properties of 3D printed plastic parts have been considered significantly …

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 …

The Role Of Chain Configuration In Governing The Rational Design Of Polymers For Adhesion, Onyenkachi Wamuo

Doctoral Dissertations

ABSTRACT THE ROLE OF CHAIN CONFIGURATION IN GOVERNING THE RATIONAL DESIGN OF POLYMERS FOR ADHESION SEPTEMBER 2017 ONYENKACHI C. WAMUO, B.Eng., FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI (FUTO), NIGERIA M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Shaw Ling Hsu The chain configurational control of polymers used in adhesion can be utilized as a means of tuning the cohesive properties of hot melt adhesives (HMAs). The cohesive properties control the solidification, strength, setting speed. Propylene-Ethylene copolymers (PP-co-PE) and thermoplastic polyurethanes (TPUs) were studied. In the first project, the effects of sequence distribution of the two types …

Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel

Doctoral Dissertations

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic …

Nanocomposite Polymer Networks For Reconfigurable Materials, Adam W. Hauser

Doctoral Dissertations

This thesis broadly aims to design reconfigurable materials through complementary combinations of nanoparticles and polymers. Understanding nanoparticle dispersion pathways and mechanisms is a critical first step in any polymer nanocomposite work as it continues to be a non-trivial subject. To this end, Chapter 2 describes a simple method to control nanoparticle dispersion within polymer melts by photografting random copolymers to selectively reactive nanoparticle ligands. The chapters following focus on harnessing the functionality of well dispersed nanocomposite networks to elicit macro-scale responses. Chapter 3 exploits the unique optical properties of gold nanoparticles in combination with thermally responsive hydrogels and liquid crystalline …

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 …

Hybrid Polymer Electrolyte For Lithium-Oxygen Battery Application, Amir Chamaani

FIU Electronic Theses and Dissertations

The transition from fossil fuels to renewable resources has created more demand for energy storage devices. Lithium-oxygen (Li-O₂) batteries have attracted much attention due to their high theoretical energy densities. They, however, are still in their infancy and several fundamental challenges remain to be addressed. Advanced analytical techniques have revealed that all components of a Li-O₂ battery undergo undesirable degradation during discharge/charge cycling, contributing to reduced cyclability. Despite many attempts to minimize the anode and cathode degradation, the electrolyte remains as the leading cause for rapid capacity fading and poor cyclability in Li-O₂ batteries. In this …

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 …

So2-Alcohol-Water Fractionation Of Sugarcane Straw, Asif Sharazi

Electronic Theses and Dissertations

Climate change resulting from fossil fuels combustion is motivating researchers to explore feasible routes to convert renewable biomass into biofuels and biochemicals for a sustainable society. Typically, biofuel is produced from corn or sugarcane but both feedstocks compete with human food supply. Thus, lignocellulosics as renewable feedstock represent a more ethical and ecofriendly approach. Sugarcane straw (SCS) is a cheap and abundantly available feedstock which potentially can be used for biofuels/biochemicals production. It can also help to mitigate environmental and health problems resulting from conventional practice of SCS burning in the fields.

There are different biomass conversion technologies for production …

Creating Renewable Tunable Polymers From Hydroxymethylfurfural, Meredith C. Allen

Electronic Theses and Dissertations

The research here deals with the conversion of 5-hydroxymethylfurfural (HMF) into a tunable polymer. HMF is a known derivative that can be acquired from biomass via hydrolysis of cellulose followed by isomerization and finally selective dehydration. The process considered here is being developed to create tunable polymers from HMF and involves several different steps, three of which are covered here. The first step, an etherification, is the reaction of HMF with an alcohol. This step is significant because in this step the R-group from the alcohol is added to HMF and the branching portion formed is carried over to the …

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 …

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 …

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 …

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 …

All Acrylic Based Thermoplastic Elastomers: Design And Synthesis For Improved Mechanical Performance, Wei Lu

Doctoral Dissertations

Thermoplastic elastomers (TPEs) have been widely studied because of their recyclability, good processability, low production cost and distinct performance. Compared to the widely-used styrenic TPEs, acrylate based TPEs have potential advantages including exceptional chemical, heat, oxygen and UV resistance, optical transparence, and oil resistance. However, their high entanglement molecular weight lead to “disappointing” mechanical performance as compared to styrenic TPEs. The work described in this dissertation is aimed at employing various approaches to develop the all acrylic based thermoplastic elastomers with improved mechanical performance.

The first part of this work focuses on the introduction of acrylic polymers with high glass …

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, …

Photoactive Properties Of Nanostructured Titania Modified Polyurethanes, Chao Chen

Electronic Thesis and Dissertation Repository

In order to enhance both the photoactivity and physical/mechanical properties of titania/polyurethane (PU) nanocomposites, in-situ polymerization and film casting were investigated. Both self-degrading PU foams and self-cleaning PU coatings were prepared. Functional monomers were prepared usingDMPA (2,2-dimethylolpropionic acid) functionalized anatse TiO₂ and P25 for integration into polyurethane foam with a "grafting-from" synthetic method. This technique was found to successfully reduce the agglomeration effect of titania nanoparticles inside the foams. In addition, the photodegradation rate was enhanced by > 120% over unmodified foam at an optimized loading of 3wt% DMPA functionalized anatase TiO₂. The presence of DMPA functionalized P25 …

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 …

The Self-Assembly Of Lamellae-Forming Block Copolymer For High Resolution Nanolithography, Zhiwei Sun

Doctoral Dissertations

This thesis will be focused on the thin film self-assembly and high resolution nanolithography of lamellae-forming PS-b-P2VP block copolymer. Some of the scientific and engineering problems of block copolymer self-assembly will be studied using the state-of-the-art characterization facilities including AFM, SEM and synchrotron radiation X-ray scattering, pushing forward the application of block copolymer in high resolution nanolithography, storage media, and separation membranes, etc. The first challenge is the design of BCP with small domain spacing, which defines the resolution of BCP nanolithography. Small domain spacing can be achieved by reducing the degree of polymerization, but order-to-disorder transition happens …

Deformation And Adhesion Of Soft Composite Systems For Bio-Inspired Adhesives And Wrinkled Surface Fabrication, Michael Imburgia

Doctoral Dissertations

The study of soft material deformation and adhesion has broad applicability to industries ranging from automobile tires to medical prosthetics and implants. When a mechanical load is imposed on a soft material system, a variety of issues can arise, including non-linear deformations at interfaces between soft and rigid components. The work presented in this dissertation embraces the occurrence of these non-linear deformations, leading to the design of functional systems that incorporate a soft elastomer layer with application to bio-inspired adhesives and wrinkled surface fabrication. Understanding the deformation of a soft elastomer layer and how the system loading and geometry influence …

Synthesis Of Biopolymer Materials Tailored For Biological Applications, Nathan P. Birch

Doctoral Dissertations

Biopolymers are able to address a wide variety of medical concerns from chronic wounds to stem cell cultivation to antibacterial and antifouling applications. They are non-toxic, biodegradable, and biocompatible, making them ideal candidates for creating green materials for biological applications. In this thesis, we cover the synthesis of two novel materials from the biopolymers, chitosan and pectin. Chitosan is a biocompatible antibacterial polycation and pectin is an anti-inflammatory polyanion with a strong propensity for hydrogen-bonding. The two chitosan:pectin materials, particles and hydrogels, explore some of the structures that can be created by tuning the electrostatic interactions between chitosan and pectin. …

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

Biomedical Engineering Western Regional Conference

No abstract provided.

Modifications To Acm Classifier And Fine Powder Coating For Plastic Components, Xinping Zhu

Electronic Thesis and Dissertation Repository

Powder coating is a dry coating technology, which has several advantages over conventional liquid coatings. However, wider applications were limited by its inferior surface finish and increased film thickness. Making powder finer (fine powder technology) can provide much better surface appearance and smaller film thickness comparable to liquid coating, but it’s much more difficult to produce fine powder products with narrow particle size distributions than coarse powder. Another issue that restricts the applications is its electrostatic spraying method, which limits the applications mainly to be with conductive substrates, like metals.

In this study, to ensure a narrow particle size distribution …

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 …

Uses For Graphene, Marcus R. Schmidt

Natural Sciences Student Research Presentations

This slide presentation for the Natural Sciences Poster Session at Parkland College discusses graphene, which is a chemically or mechanically produced single layer of pure carbon atoms. The thinnest compound known to man is also one of the strongest, with uses in technology and the health industry from faster charging batteries to motorcycle helmets. The remaining slides summarize a process by which free radicals are reduced in graphene by being treated with butyl acrylate polymerization.

Green Thermosetting Factory: Novel Star-Shaped Bio-Based Systems And Their Thermosetting Resins; Synthesis And Characterization, Arash Jahandideh

Electronic Theses and Dissertations

Increasing attentions toward sustainable development, economic and environmental issues have led to many attempts at replacing the petroleum-based materials with renewables. Substitution of petroleum-based platforms with green alternative technologies is beneficiary in different ways. Using bio-renewables reduces the dependency of the national plastic industry to the petroleum resources and substantially promotes the environmental profile and sustainability of the product. It is expected that the emergence of the corn-based thermosetting industry generates substantial profits for the corn production sector. Developments in the emerging biobased thermosets are spectacular from a technological point of view. However, there are still several disadvantages associated with …

A Quartz Crystal Microbalance Study Of Thiol:Ene Poly(Ionic Liquid) Polymerization And Gas Absorption, Yueming Wu

Murray State Theses and Dissertations

ABSTRACT

The polymerization process of, and gas absorption by, imidazolium-containing thiol:ene poly (ionic liquid)s (PILs), prepared from bisallylimidazolium bis(trifluoromethyl sulfonyl)imide [NTf₂^-] and pentaerythritoltetrakis(3 mercaptopropionate), was studied. The thiol:ene PILs examined were recently reported by groups at Murray State University. The advantage of thiol:ene PILs over other reported PILs is that thiol:ene polymers are made rapidly by UV exposure and exhibit high mechanical and thermal stability due to high cross-linking. The properties of interest for the thiol:ene PILs were studied using a quartz crystal microbalance (QCM). QCM techniques are based on the piezoelectric effect, where certain crystals (e.g., …

Assisted Methane Hydrate Formation With The Addition Of Promoters, Chutikan Jaikwang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Natural gas hydrates play an important role in the largest reservoir of hydrocarbons on earth. The gas hydrates have received increasing attention in an excellent way of new technology for gas in large quantity storage and transportation. However, the main challenge to use methane hy¬drates has faced many challenges such as the slow formation rate, low growth rate during hydrate formation, and low conversion ratio of gas to solid hydrates leading to poor storage capacity. In this work, methane hydrate formation and dissociation in the presence of different Cyclopentane (CP), Tetra-n-butyl phosphonium bromide (TBPB) and Tetra-n-butyl ammonium bromide (TBAB) concentrations …