Polymer Science Commons^™

Effects Of Crosslinking Conditions On Biofouling Of Polymer Substrates With A Hydrogel Layer, Laura Davila

Williams Honors College, Honors Research Projects

The introduction of a hydrogel coating to a surface has been looked at for different benefits. Certain hydrogels offer antifouling properties that are beneficial to different applications like medical components. Previous attempts (2) (3)have been done to introduce a hydrogel surface to plastic substrates. One of them is to use grafting brushes which works properly but it is not sufficient since the layer is too thin and therefore can be damaged. The second method have a bulkier coating without crosslinking. Opposite to grafting brushes this method has too thick of a layer. Additionally, there is no crosslink therefore the coating …

Methods For Film Coating Electrospun Fibers, Kristopher Dejean

Williams Honors College, Honors Research Projects

Electrospinning uses high voltages to form polymer nanofiber membranes. These membranes have potential for use in filtration, tissue engineering, drug delivery, and catalysis. The nonwoven fiber mat is malleable but has a low tensile strength compared to a solid film of the same polymer. Joining the fibers with a thin film is desired to balance the strength and flexibility. Three methods of producing a film on fiber membrane were tested. The techniques are spraying then melting, spin coating, and dip coating. Electrospinning setup conditions, solvent ratios, damage to fibers, and spin coating speeds were determined. Research was abruptly stopped and …

Formulation And Validation Of Nanoparticle Controlled Delivery For Chemotherapeutic Drug Products, Shani L. Levit

Theses and Dissertations

Taxol, a formulation of paclitaxel (PTX), is one of the most widely used anticancer drugs, particularly for treating recurring ovarian carcinomas following surgery. Clinically, PTX is used in combination with other drugs such as lapatinib (LAP) to increase treatment efficacy. Delivering drug combinations with nanoparticles has the potential to improve chemotherapy outcomes. In this study, we use Flash NanoPrecipitation, a rapid, scalable process to encapsulate weakly hydrophobic drugs (logP in vitro. Encapsulating either PTX or LAP into nanoparticles increases drug potency. When PTX and LAP are co-loaded in the same nanoparticle, they have a synergistic effect that is greater than …

Dendrimer-Based Therapeutic Delivery Vehicle For The Treatment Of Ocular Diseases, Remy C. Cooper

Theses and Dissertations

The treatment of ocular diseases poses a significant challenge to drug delivery design, due to the eye’s complex anatomy, with a semi-permeable blood-ocular barrier and associated immune privilege. To address some of the delivery challenges, polycationic dendrimers are explored as vehicle for the treatment of posterior chamber disease. Dendrimers are a class of polymeric nanoparticles that are highly branched, multivalent and monodisperse, whose three-dimensional globular architecture has given them the nickname of “synthetic proteins”. Dendrimers are synthesized by reacting monomers in a step-wise fashion to produce generationally and radially increasing structures, with core, interior and surface chains that are highly …

Enhanced Methane Hydrate Formation Using Promoters For Natural Gas Storage And Transportation Application, Katipot Inkong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Solidified natural gas (SNG) is an alternative technology for natural gas storage and transportation in the clathrate hydrate formed. It has higher volumetric energy storage with the ease to handle not to mention its safety. Effects of different hydrate promoters, including methyl ester sulfonate (MES), tetrahydrofuran (THF), hollow silica (HS), and sodium dodecyl sulfate (SDS), on the methane hydrate formation was investigated. All experiments were performed in an unstirred tank reactor at desired experimental conditions. The results indicated that all promoters significant enhanced the hydrate formation both kinetics and methane uptake compared with pure water. The increase in the MES …

Bimetallic Nanoparticles Integrated Membranes For Groundwater Remediation: Synthesis, Characterization And Applications, Hongyi Wan

Theses and Dissertations--Chemical and Materials Engineering

The detoxification of chlorinated organics from groundwater, such as trichloroethylene (TCE), tetrachloroethylene (PCE), polychlorinated biphenyl (PCB) and carbon tetrachloride (CTC), is a challenging area. Reductive dechlorination has been investigated using iron and iron-based nanoparticles, such as bare Fe, sulfidized Fe (S-Fe) and palladized Fe (Pd-Fe). However, issues including particle agglomeration, difficulties in recycling and particle leaching have been reported to hinder the application and wide usage of these techniques. The integration of nanoparticles and membranes can address these issues because of the large surface area, stability, and the potential for versatile functionalities. In this study, commercial polyvinylidene difluoride (PVDF) microfiltration …

A Thermodynamic And Feasibility Study Of Green Solvents For The Fabrication Of Water Treatment Membranes, Xiaobo Dong

Theses and Dissertations--Chemical and Materials Engineering

Nonsolvent induced phase separation (NIPS) has been widely used to fabricate polymeric membranes. In NIPS, a polymer is dissolved in a solvent to form a dope solution, which is then cast on a substrate and immersed in a nonsolvent bath, where phase inversion occurs. Petroleum-derived organic solvents, such as N-Methyl-2-Pyrrolidone (NMP) and Dimethylacetamide (DMAc), have been traditionally used to fabricate polymeric membranes via NIPS. However, these solvents may have negative impacts on environmental and human health; therefore, using greener and less toxic solvents, preferably derived from biomass, is of great interest to make membrane fabrication sustainable. In this dissertation, two …

Polymeric Nanocomposite Membranes With Phosphorene Based Pore Fillers For Fouling Control, Joyner Eke

Theses and Dissertations--Chemical and Materials Engineering

Phosphorene is a two-dimensional material exfoliated from bulk phosphorus. Specifically, relevant to the field of membrane science, the band gap of phosphorene provides it with potential photocatalytic properties, which could be explored in making reactive membranes able to control the accumulation of compounds on the surface during filtration, or fouling. Another reason phosphorene is a promising candidate as a membrane material additive is due to its catalytic properties which can potentially destroy foulants on the membrane surface.

The first goal of this study was to develop an innovative and robust membrane able to control and reverse fouling with minimal changes …

Self-Assembled Metal Nanoparticle/Polymer Nanocomposites As Nanoreactors For One-Pot Reactions, Andrew Harrison

Theses and Dissertations

Polymer nanoreactors incorporating gold nanoparticle catalysts were self-assembled via Flash Nanoprecipitation. The incorporated gold nanoparticles maintained catalytic activity, which was evaluated using reduction of 4-nitrophenol with sodium borohydride as a model reaction. The diffusion coefficient for 4-nitrophenol was determined by NMR and used to calculate the second Damköhler number, which indicated that the systems were not diffusion limited. Despite similar diffusion coefficients, catalytic performance was strongly affected by the co-precipitant. For example, the apparent reaction rate per surface area using castor oil was over 8-fold greater than polystyrene. Thus, we measured the partition coefficient of 4-nitrophenol between water and castor …

Time-Dependent Reliability Framework For Durability Design Of Frp Composites, Rajneesh Kumar Bharil

Graduate Theses, Dissertations, and Problem Reports (ETD)

The life-cycle performance, durability, and aging characteristics of Fiber Reinforced Polymer (FRP or Structural Composites) have been of keen interest to the engineers engaged in the FRP design, construction, and manufacturing. Unlike conventional construction materials such as steel and concrete, the design guidelines to account for the aging of FRP are somewhat scattered or not available in an approved or consistent format. Loss of strength over time or aging of any structural material should be of concern to engineers as the in-service lifespan of many engineering structures is expected to exceed 100 years. Use of durability strength-reduction factors or factors …

Innovative Sustainable Wood Preservatives From Pulp And Paper Industry Byproduct, Raisa Carmen Andeme Ela

Dissertations, Master's Theses and Master's Reports

In the modern forest industry, the need for bio-based, renewable, and environmentally-benign wood preservatives is increasing. Preservatives are used to prevent or limit decay and there has been an increasing interest in developing wood preservatives from renewable materials. To support the need for bio-based, environmentally-friendly preservatives, this work employed kraft lignin as a raw material to produce a novel bio-based wood preservative.

For the first project, a statistical design of experiments approach in Minitab® was used to study how fractionation process variables during acid precipitation of lignin influence the lignin mass yield and characteristics. After precipitating lignin from black liquor, …

Ph-Sensitive Oxygen Release Microspheres To Enhance Cell Survival In Ischemic Condition, Zhongting Liu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Ischemic diseases such as myocardial infarction, stroke and limb ischemia are severe cardiovascular diseases with high rate of death and millions of people suffered from these diseases. Under ischemic environment, cells die due to deficient supply of nutrient and oxygen. To regenerate ischemic tissues, stem cell therapy is a promising approach because stem cells can differentiate into cells necessary for the regeneration. However, stem cell therapy has limitations. For example, few cells can survive under harsh ischemic environment. To enhance stem cells survival, implantation of oxygen release microspheres to sustained supply cells with oxygen represents an effective strategy. Previously, our …

Formulation Optimization Effects On Mechanical And Rheological Properties Of Filled Polysiloxanes, Kevin Mcnay

Electronic Theses & Dissertations

Polysiloxanes are a class of high-performance polymeric materials that are used in a wide variety of applications, including O-rings, gaskets, sealants, coatings, and adhesives. These materials have high temperature resistances as well as flexibility at low temperatures. This is due to the bond between the oxygen and silicon atom, a bond that requires a high dissociation energy to break. However, their elastomers, which can be obtained by crosslinking linear precursors using various crosslinkers, generally exhibit low strength and have poor mechanical properties unless reinforced. Therefore, fillers, additives, UV-stabilizers, and anti-oxidants are often incorporated in order to improve the resulting properties. …

The Effect Of Precursor Design And Processing On The Semi-Crystalline Morphologies Of Polyacrylonitrile-Based Carbon Fiber, Katelyn Cordell

Dissertations

Basic research to control the morphology of polyacrylonitrile (PAN)-based carbon fiber is crucial for next generation composites as it determines their mechanical properties and final use. Poor molecular design of PAN-based precursors and fiber processing causes morphological defects and mechanical limitations.^1,2 This research focused on utilizing the controlled polymerization technique, reversible addition-fragmentation chain transfer (RAFT), of novel acrylamide comonomers to afford well-defined precursors with precisely controlled molecular design. This controlled RAFT technique improved the overall precursor graphitic structure as evident by the increased extent of stabilization and reduced activation energy as compared to precursors prepared by traditional free radical …

Development Of Forward Osmosis Based Separations: A Novel Approach In Membrane Technology, Yu-Hsuan Chiao

Graduate Theses and Dissertations

Tackling the worldwide severe water shortage, the membrane technology is considered to be the most efficient approach and hence, used widely as a cost-effective sustainable solution. “Forward osmosis (FO)” has been the major attention in recent time. FO uses osmotic pressure as the driving force to draw the water passing the membrane and achieve the desired separation performance. In general, it is considered to be a process with tremendous potential to resolve the present-day water shortage with extremely low energy consumption. However, the challenges of membrane and draw solution regeneration associated with FO processes must be conquered prior to their …

Decorative Articles Based On Polymeric Materials, Yaser M. Asal Mr., M. A. Radwan, Hany A. Elazab Dr, Bassant Hussein, Mohamed A. Sadek

Chemical Engineering

The aim of the research is to create decorative articles based on polymeric materials, study the effects of fillers and the type of moulds that it can cope with the exothermic reaction nature of resin to create a scientific background on the usage of the resins in daily life products. The polymeric materials that will be concentrated on are the unsaturated polyester resins and epoxy resins. The unsaturated polyester is of many types and chemical constituents, the used experimentally is a general-purpose type and the epoxy also have different types and the used is a commercially 3D floor coating type. …

Primary Homogeneous Pathways Of Lignin Depolymerization In Gas Phase, Mohamad Barekati-Goudarzi

LSU Doctoral Dissertations

The unique decomposition pathways of hydrolytic lignin (HL) dissolved in acetone/water mixture and dispersed into gas phase has been investigated using two unique reactors. The first one is a non-isothermal continuous wave-IR CO₂ Laser Powered Homogeneous Pyrolysis (LPHP) and the second one is an isothermal Continuous Droplet Evaporation (CDE) reactor. Both of these reactors operated using atmospheric N₂ carrier gas. A temperature region of 400 – 550°C, and various residence time of 0.12-2 sec were chosen for CDE reactor. The temperature distribution in the LPHP reactor was evaluated via thermocouple measurements and validated by the method of “chemical …

Evaluation Of Biodegradability Characteristics Of Cellulose-Based Film As Per Is/Iso 14855-1, Narayan C. Saha Dr, Gaurav Madhu Dr, Diksha B. Kadu Ms

Journal of Applied Packaging Research

Biodegradable polymers (especially those derived from plant sources) begin their lifecycle as renewable resources, usually in the form of starch or cellulose. In this paper, the evaluation of biodegradability of cellulose-based polymer film under controlled composting conditions as per the guidelines of IS/ISO 14855 (Part-1) standard has been described. Microcrystalline cellulose (MCC) powder was taken as positive-control polymer. The apparatus used to analyse the degree and rate of biodegradation was developed indigenously. The validation of the biodegradability testing apparatus was also performed as per the prescribed test method given in IS/ISO 14855-1.

Fabrication Of Polyvinylidene Fluoride Hollow Fiber Membranes For Membrane Distillation, Abdullah Al Balushi

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Desalination technologies can help humanity tap into the most abundant source of water on earth, seawater; however, desalination is an energy-demanding process. Most of the desalination plants worldwide use conventional energy resources; therefore, desalination leaves a large carbon footprint. Solar energy is an available source of energy that can be harvested and integrated into desalination systems.

Membrane distillation (MD) is an emerging purification technology that many offers many advantages over traditional desalination systems. For starters, it can utilize low-grade thermal energy to drive the separation, therefore, it can be suitably integrated into the solar-thermal energy scheme. Additionally, MD can be …

Engineered Carbon-Nanocatalyst Composites And Carbon Mixed ‎Matrix Membranes ‎For Water And Wastewater Treatment ‎, Mojtaba Abolhassani

Graduate Theses and Dissertations

Carbonaceous materials such as graphene oxide, and activated ‎carbon have a wide range of ‎applications in water and wastewater treatment due to the high surface ‎area, unique structure, ‎and chemical and thermal stability. Carbon-based materials can be used as a ‎membrane, an ‎adsorbent, a support for nanomaterials, or ‎as a filler within membranes to remove contaminants ‎from water. In this research, the specific carbon materials and how their properties influence their ‎use and performance in ‎specific engineering applications is explored. ‎

Here, membrane filtration and adsorption/degradation of the water and wastewater using carbon-‎based material are investigated. The research firstly focuses …