Polymer Science Commons^™

Phosphine Oxide Containing Poly(Pyridinium Salt)S As Fire Retardant Materials, Maksudul M. Alam, Bidyut Biswas, Alexi K. Nedeltchev, Haesook Han, Asanga D. Ranasinghe, Pradip K. Bhowmik, Kisholoy Goswami

Chemistry and Biochemistry Faculty Research

Six new rugged, high-temperature tolerant phosphine oxide-containing poly(4,4′-(p-phenylene)-bis(2,6-diphenylpyridinium)) polymers P-1, P-2, P-3, P-4, P-5, and P-6 are synthesized, characterized, and evaluated. Synthesis results in high yield and purity, as confirmed by elemental, proton (1H), and carbon 13 (13C) nuclear magnetic resonance (NMR) spectra analyses ... See full text for complete abstract.

Non-Einstein Viscosity Phenomenon Of Acrylonitrile–Butadiene–Styrene Composites Containing Lignin–Polycaprolactone Particulates Highly Dispersed By High-Shear Stress, Sing-Hoon Kim, Kisuk Choi, Kyouk Ryeol Choi, Taesung Kim, Jonghwan Suhr, Kwang Jin Kim, Hyoung Jin Choi, Jae-Do Nam

Mechanical Engineering Faculty Research

Lignin powder was modified via ring-opening polymerization of caprolactone to form a lignin–polycaprolactone (LPCL) particulate. The LPCL particulates were mixed with an acrylonitrile–butadiene–styrene (ABS) matrix at an extremely high rotational speed of up to 3000 rpm, which was achieved by a closed-loop screw mixer and in-line melt extruder. Using this high-shear extruding mixer, the LPCL particulate size was controlled in the range of 3395 nm (conventional twin-screw extrusion) down to 638 nm (high-shear mixer of 3000 rpm) by altering the mixing speed and time. The resulting LPCL/ABS composites clearly showed non-Einstein viscosity phenomena, exhibiting reduced viscosity (2130 Pa·s) compared to …

Nano-Enhanced Composite Membranes For Water Desalination, Benjamin Fredrik Victor Sundling Von Fürstenrecht

Materials Engineering

In theory single walled carbon nanotubes (SWCNT) will aid in ion rejection due hydrophobicity and smoothness of the SWCNT. An efficient means of water desalination utilizing SWCNT in a membrane seems plausible. A lyotropic liquid crystal (LLC) solution was made with a synthesized polymerizable surfactant methacryloxy ethyl hexadecyl dimethyl ammonium bromide (C16MA) to help with vertical alignment of SWCNT. Due to SWCNT lack of solubility and tendency to agglomerate in water, a dispersion performed using an inert surfactant centrimonium bromide (CTAB) to make sure that the SWCNT were homogeneously dispersed in the solution without altering the hexagonal packing factor of …

Production Optimization Of Ring-Banded Spherulitic Crystals Of Poly (3-Butylthiophene-2,5-Diyl) Using Controlled Solution Evaporation, Frederick Paul Henderson Iii

Materials Engineering

Conductive polymers can carry a charge due to the presence of excess electrons along the carbon backbone. By growing these polymers into crystals, the usual insulative isotropic matrix that polymers form will be replaced with anisotropic regions where conduction is possible parallel to the crystal lattice growth direction. In previous research, while growing sphere shaped crystals it was observed that a few would exhibit rings that formed parallel to the circumference of the sphere. In this project, the conditions to produce this ring structure were examined by looking at two polymer solutions (with carbon disulfide or dichlorobenzene as solvent) and …

Designing A Simulator For An Electrically-Pumped Organic Laser Diode, Robert Hulbert

Master's Theses

Organic semiconductors provide an alternative set of basis materials to fabricate electronic devices like PN Junctions, LEDs, and FETs. These materials have several benefits over traditional inorganic semiconductors including their mechanical flexibility, reliance on renewable resources, and inexpensive large-scale manufacturability. Despite the contemporary device implementations with organic semiconductors, a solid-state electrically-pumped organic laser diode does not exist. However, organically-based lasers do exist by utilizing the organic material strictly for optical gain. The challenge occurs when charge carriers appear in the organic material. The charge carriers must reach a concentration such that population inversion occurs producing optical gain. However, between the …

Glass Transition Temperature Of Particles For Drug Delivery, Yiqing Yang

Theses

Drug delivery plays an important role in targeted therapies and nanoparticles which can be used as drug carriers and it’s a frequently researched topic. Poly(lactic-co-glycolic acid) (PLGA), a highly biocompatible polymer, has been used as a drug delivery vehicle in many studies. One of the challenges facing drug delivery particles is the problem of burst release which is when a large amount of the drug is suddenly released from the particle once it is placed in the body. This is generally undesirable as usually a slow and controlled release is preferred. The glass transition temperature has an effect on drug …

A Model-Based Framework For The Smart Manufacturing Of Polymers, Santiago D. Salas Ortiz

LSU Doctoral Dissertations

It is hard to point a daily activity in which polymeric materials or plastics are not involved. The synthesis of polymers occurs by reacting small molecules together to form, under certain conditions, long molecules. In polymer synthesis, it is mandatory to assure uniformity between batches, high-quality of end-products, efficiency, minimum environmental impact, and safety. It remains as a major challenge the establishment of operational conditions capable of achieving all objectives together. In this dissertation, different model-centric strategies are combined, assessed, and tested for two polymerization systems.

The first system is the synthesis of polyacrylamide in aqueous solution using potassium persulfate …

“Polysoaps” Via Raft Copolymerization To Form Well-Defined Micelles For Water Remediation And Targeted Drug Delivery Applications, Phillip Pickett

Dissertations

Amphiphilic copolymers have become increasingly important for environmental and biological applications due to their behavioral characteristics in aqueous solution. For example, structurally-tailored statistical amphiphilic copolymers or “polysoaps” can self-assemble into micelles or other architectures in water at various concentrations. Polysoaps may be differentiated from small molecule surfactant micelles in their capability to self-assemble into unimolecular associates (unimolecular micelles) with no dependence on concentration. Such micelles offer enormous potential for dispersion of hydrophobic species in water at high dilution. Importantly, each polymer chain forms its own micelle and upon dilution, these micelles remain intact and capable of dispersing hydrocarbon material in …

Chemical And Physical Modification Of Thiol-Ene And Epoxy-Amine Networks For Advanced Control Of Gas Transport And Flame Retardant Behavior, Vivek Vasagar

Dissertations

Crosslinked polymers are widely used due to its several advantages not limited to high mechanical strength combined with the easy processability. Despite of its popular usage, the fundamental understanding of polymer structure affecting the desired properties is still lacking. This PhD thesis is in two parts, the first part is devoted to the design and developing a basic understanding of structure and chemical composition dependencies of gas transport, whereas in the second part a fundamental relationship between structure to the fire-retardant properties is established.

Membrane based gas separation technique has attracted interest of selective removal of carbon dioxide gas from …

Bioinspired Glycopolymers: Models To Investigate The Effect Of Saccharide Structure And Concentration On Amyloid Beta Aggregation, Pradipta Kumar Das

Dissertations

Aggregation and subsequent deposition of amyloid-β (Aβ) peptide on neuronal cell membranes have been implicated as a cause of Alzheimer’s disease. Gangliosides in their clustered form seed and promote the Aβ aggregation process. However, the effects of the structure and the concentration of ganglioside saccharides on Aβ aggregation are not well understood. We investigated how the specific structure of saccharides (β-D-galactose and β-D-glucose) affect the aggregation pathways, kinetics, and the aggregated structures of Aβ via in vitro experiments. The effects of the local concentration of saccharides on the Aβ aggregation were also investigated.

To mimic the multivalent effect of the …

Using Green Emitting Ph-Responsive Nanogels To Report Environmental Changes Within Hydrogels: A Nanoprobe For Versatile Sensing, Mingning Zhu, Dongdong Lu, Shanglin Wu, Qing Lian, Wenkai Wang, L. Andrew Lyon, Weiguang Wang, Paulo Bártolo, Brian R. Saunders

Engineering Faculty Articles and Research

Remotely reporting the local environment within hydrogels using inexpensive laboratory techniques has excellent potential to improve our understanding of the nanometer-scale changes that cause macroscopic swelling or deswelling. Whilst photoluminescence (PL) spectroscopy is a popular method for such studies this approach commonly requires bespoke and time-consuming synthesis to attach fluorophores which may leave toxic residues. A promising and more versatile alternative is to use a pre-formed nanogel probe that contains a donor/acceptor pair and then “dope” that into the gel during gel assembly. Here, we introduce green-emitting methacrylic acid-based nanogel probe particles and use them to report the local environment …

Self-Assembled Nanoantenna Enhance Optical Activity And Transport In Scalable Thin Films And Interfaces, Keith Richard Berry Jr.

Graduate Theses and Dissertations

Continued population growth and the decrease of existing energy platforms demands long-term solutions for development and implementation of scalable plasmonic metamaterials for energy and agricultural applications. Self-assembled nanoantenna into random and ordered arrangements are advanced herein for optical and thermal enhancements in scalable thin film. An analytical approach to estimating the thermal dynamics of random arrangements of nanoantenna resulted in estimates within 30% across a range of geometric parameters, nanoantenna-containing media, and thermal parameters. Multimodal thermal dynamics of polymer thin films containing gold nanoparticles (AuNPs) were observed through the natural log of the dimensionless temperature driving force plotted versus time …

Nanogels And Microgels: From Model Colloids To Applications, Recent Developments, And Future Trends, Mattias Karg, Andrij Pich, Thomas Hellweg, Todd Hoare, L. Andrew Lyon, J. J. Crassous, Daisuke Suzuki, Rustam A. Gumerov, Stefanie Schneider, Igor I. Potemkin, Walter Richtering

Engineering Faculty Articles and Research

Nanogels and microgels are soft, deformable, and penetrable objects with an internal gel-like structure that is swollen by the dispersing solvent. Their softness and the potential to respond to external stimuli like temperature, pressure, pH, ionic strength, and different analytes make them interesting as soft model systems in fundamental research as well as for a broad range of applications, in particular in the field of biological applications. Recent tremendous developments in their synthesis open access to systems with complex architectures and compositions allowing for tailoring microgels with specific properties. At the same time state-of-the-art theoretical and simulation approaches offer deeper …

Biodegradable Polymeric Film For Food Packaging, Neelam Yadav, Raminder Kaur

Journal of Applied Packaging Research

Food packaging films that show post-consumer biodegradability are rarely explored by researchers. The present study was carried out to investigate the physicomechanical characteristics of ethyl cellulose (EC) based films to be used in food packaging. Ethyl cellulose was plasticized with different percentage of polyethylene glycol (PEG). The samples of standard dimensions were subjected to different testing such as soluble matter content, moisture content, oil permeability, surface morphology, mechanical testing etc. The data obtained was analysed to decide the moderate percentage of plasticizer that can be used to provide a rational explanation of a perfect quality specimen. It has been revealed …

Silver Nano Polymer Composite Membrane For Hydrogen Sulfide Sensing, Muhammad Bagus Arif

Chulalongkorn University Theses and Dissertations (Chula ETD)

Optical and electrochemical sensor for H2S sensing were developed using silver nanoparticles (AgNPs) immobilized onto polyelectrolyte membranes (PEMs) as substrate. Two approach for the deposition of the silver nanoparticles namely in-situ and ex-situ were compared for their sensing efficiency. The Poly(diallyldimethylchloride) (PDADMAC) and Poly(sodium styrenesulfonate) (PSS) were used to build PEMs via layer-by-layer assembly mechanism as polycation and polyanion respectively. In situ synthesis of silver nanoparticles was achieved by dipping the PEM coated substrate in silver nitrate (AgNO₃) solution followed by sodium borohydride (NaBH₄) as reducing agent. For ex situ technique, a monolayer of pre-synthesized silver nanoparticles was deposited as …

Effects Of Micro-Features On Cell Detachment From Poly(N-Isopropylacrylamide) Coated Polydimethylsiloxane Membranes, Luke Webel

Williams Honors College, Honors Research Projects

The tested hypothesis was that features on polydimethylsiloxane (PDMS) surfaces coated with a poly(N-isopropylacrylamide)/aminopropyltriethoxysilane or pNIPAAM/APTES thin film would accelerate cell detachment than the film coated on a unfeatured surface. This project tested samples with features generated by molds, wrinkling, and sandpaper roughened substrates. Surface feature generation methods were limited to mechanical means, and characterized by microscopy and strain rates. 50/50 mixtures of 1.5 wt.% pNIPAAM/ APTES were used to coat thin films (30-40 nm) on PDMS membranes by spin-coating, and the coated membranes were thermally annealed to chemically graft pNIPAAm/APTES on the membrane and their thermo-responsive property was assessed …

Synthesis Of Polyurethane From Sustainable Sources, Jovan Jevric

Williams Honors College, Honors Research Projects

The most common method of polyurethanes involves a reaction between various petroleum-based isocyanates and a polyol along with a catalyst; all of which have a negative impact on environmental and human health. The objective of this research project is to eliminate or mitigate the risks and hazards associated with the production and degradation of polyurethane. Hexamethylene diisocyanate isocyanurates (3HDI) are one of the most common isocyanates used in the polyurethane processing industry. 3HDI contains numerous toxins, and it has a negative impact on the environment and human health¹. It has been found that there are other compounds that …

Developing A Portable Prototype To Utilize An Electrospun Colorimetric Sensor For The Detection Of Trihalomethanes In Water, Amanda Svensson

Williams Honors College, Honors Research Projects

Trihalomethane (THM) detection in water is important due to the potential health effects caused by their presence, including increased cancer risk. A cheap, quick, and portable method of identifying THM concentration at the Environmental Protection Agency limit of 80 parts per billion (ppb) will improve detection and water treatment. Electrospinning was used to make nanofiber membranes using a 2.6 wt% polypropylene solution. These membranes were utilized in the Fujiwara reaction, which creates a color change in the presence of THMs, to detect the THM bromoform in water. The color intensity of the reaction was quantified for 250 and 80 ppb …

Requalification Of Coated Fabrics Using Chemlok 2332 In Place Of Chemlok 233, Daniel Madler

Williams Honors College, Honors Research Projects

Rubber coated fabrics are an essential component in the deicing systems of the aerospace industry. Adhesives cements are applied to a fabric prior to being pressed into a rubber compound that will adhere to the fabric. The resulting fabric maintains the strength of the fabric with the added benefits of elasticity and compatibility from the rubber compound. UTC Aerospace Systems relies on these coated fabrics to create safe deicers for the aerospace industry. Chemlok 233, a now obsolete primer cement, was used extensively in the coated fabrics used by UTC. Materials testing and performance evaluation allowed for a replacement cement, …

Compression Set Improvement Of Thermoplastic Vulcanizates For High Temperature Tubing, Mitchell Valaitis

Williams Honors College, Honors Research Projects

It was hypothesized that increasing the curative level of the fluorocarbon rubber (FKM) used in manufacturing of thermoplastic vulcanizate (TPV) materials would decrease the compression set values of the TPV enough for it to be suitable as a flexible, lightweight alternative to high operating temperature thermoset rubber tubing currently being used for power steering hose. First, promising TPV formulations were identified by varying the polyamide (PA) and FKM used in a Brabender mixer. Four different types of polyamide and four different types of FKM were investigated, with two of the FKM types and one polyamide type identified as being promising. …