Polymer and Organic Materials Commons^™

The Effect Of Process Parameters And Surface Condition On Bond Strength Between Additively Manufactured Components And Polymer Substrates, Bharat Bhushan Chivukula

Graduate Theses and Dissertations

Additive patching is a process in which printers with multiple axes deposit molten material onto a pre-defined surface to form a bond. Studying the effect of surface roughness and process parameters selected for printing auxiliary part on the bond helps in improving the strength of the final component. Particularly, the influence of surface roughness, as established by adhesion theory, has not been evaluated in the framework of additive manufacturing (AM). A full factorial design of experiments with five replications was conducted on two levels and three factors, viz., layer thickness, surface roughness, and raster angle to examine the underlying effects …

Spray Printing Of Organic Semiconducting Single Crystals, Grigorios-Panagiotis Rigas, Marcia M. Payne, John E. Anthony, Peter N. Horton, Fernando A. Castro, Maxim Shkunov

Chemistry Faculty Publications

Single-crystal semiconductors have been at the forefront of scientific interest for more than 70 years, serving as the backbone of electronic devices. Inorganic single crystals are typically grown from a melt using time-consuming and energy-intensive processes. Organic semiconductor single crystals, however, can be grown using solution-based methods at room temperature in air, opening up the possibility of large-scale production of inexpensive electronics targeting applications ranging from field-effect transistors and light-emitting diodes to medical X-ray detectors. Here we demonstrate a low-cost, scalable spray-printing process to fabricate high-quality organic single crystals, based on various semiconducting small molecules on virtually any substrate by …

Molecular Tetrapods For Optoelectronic Applications, Jianzhong Yang

Chemistry and Chemical Biology ETDs

Most conjugated molecules including polymers and small molecules applied in organic solar cells (OSCs) have linear structures containing multiple aromatic groups connected in series. However, unfavorable film forming ability and grain boundaries both originated from high crystallinity of linear small molecules are detrimental to device performances. Thus, among multi-dimensional structures, tetrapodal molecules are especially interesting owing to their unique ability to mutually interlock, which prevents dislodging and provides high structural stabilities. Such molecular design can also increase absorption cross-sections and provide more extensively percolating pathways for charge transport, making such molecular tetrapods promising in OSCs applications. In my dissertation, I …

Study On Mechanical Properties Of Silicone Rubber Materials Used As Gaskets In Pem Fuel Cell Environment, Guo Li

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Analysis Of Optimal Process Conditions And Mechanical Properties On Nanocomposites According To Structural Changes Of Halloysite Nanotubes, Yun-Hae Kim, Soo-Jeong Park, Antonio Norio Nakagaito

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Plasticized Polymer Coatings For Sh-Saw Sensors For High Sensitivity And Long-Term Monitoring Of Btex Analytes In Liquid Phase, Pintu Adhikari

Master's Theses (2009 -)

BTEX compounds (benzene, toluene, ethylbenzene, and xylene) are constituents of crude oil and hazardous to human health. Among them, benzene has the lowest maximum contaminant level for drinking water because of its carcinogenicity. Spills or leakage from underground storage tanks or hazardous waste sites can contaminate nearby groundwater with these volatile organic compounds. Therefore, it is very important to detect the presence of BTEX contamination as early as possible in order to start the remediation process and maintain a healthy environment. To develop an in-situ continuous monitoring sensor system, shear horizontal surface acoustic wave (SH-SAW) sensor devices are being investigated …

Degradation Of Carbon Fiber Reinforced Polymer And Graphite By Laser Heating, Nicholas C. Herr

Theses and Dissertations

The availability of high power, diode pumped solid state and fiber lasers at powers 10 kW and shorter wavelengths (1.07 micrometer) has invigorated the development of tactical laser weapons. This shift to tactical missions greatly increases the variety of potential targets including carbon fiber reinforced polymers and related materials. The complexity of laser-material interactions has driven a historical reliance on live-fire testing and empirical models, but this becomes more difficult as the number of target materials grow. This dissertation combines thermal imagery and existing thermal models of the fire response of composite materials to develop a hybrid modeling approach of …

Silk As A Biomaterial Paste For Biomimetic Composite, Sang Hyun Park

McKelvey School of Engineering Graduate Student Theses & Dissertations

Silk is a highly promising biomaterial with unique bio-physicochemical properties, such as excellent mechanical and optical properties, biocompatibility and programmable biodegradability. Among many different types, silk from domesticated silkworm, bombyx mori has received wide attention owing to its availability in virtually unlimited quantities and ease of extraction. In this study, we investigated silkworm silk as a protein glue to realize nacre-like composites. We have employed spin assisted layer-by-layer technique to fabricate ultrathin free-standing biocomposite films. Two different composites have been studied: (i) graphene oxide (GO)/silk and (ii) chitin/silk. From our prior work, it is known that the adsorption of amphiphilic …

Study Of Oxidative-Crosslink Reaction In Polyphenyl Sulfide (Pps) / Carbon Fiber And Its Influence In Additive Manufacturing, Dong Hee Kim, Eduardo Barocio, Bastian Brenken, Anthony Favaloro, Byron Pipes

The Summer Undergraduate Research Fellowship (SURF) Symposium

Ever since its development in 1980s, Fused Filament Fabrication (FFF) has been an attractive additive manufacturing technology due to its flexibility to create intricate shapes at lower costs and faster manufacturing process than subtractive techniques. These advantages make FFF suitable for printing molds for use in traditional composites manufacturing processes. Combining FFF with high-temperature thermoplastic composites enables producing molds that not only sustain autoclave conditions but also have low coefficient of thermal expansion (CTE). A semi-crystalline polymer, Poly-phenylene Sulfide (PPS), with 50% by weight of carbon fiber is used as feedstock material for FFF. Nonetheless, PPS is sensitive to undergo …

Characterization Of Suspension Polymerized Polyacrylamide And Poly(Sodium Acrylate-Acrylamide) Copolymer And Their Size Influence On The Properties Of Concrete, Cole R. Davis, Kendra A. Erk, Stacey L. Kelly

The Summer Undergraduate Research Fellowship (SURF) Symposium

Shrinkage leading to cracking and mechanical instability is a major problem for concrete due to the loss of water during the curing process. However, through the addition of Superabsorbent Polymer (SAP) hydrogels, shrinkage can be prevented, increasing the strength of concrete. Characterization of suspension polymerized polyacrylamide (PAM) poly(sodium acrylate-polyacrylamide) (PANa-PAM) copolymer microsphere sizes, morphology and swelling behavior was conducted before adding them to concrete. Size was determined using microscopy paired with ImageJ analysis. Coulter Counter size characterization was also used to determine the particle size distribution. Swelling behavior was determined using the tea bag method as well as size analysis …

Characterization Of Superabsorbent Polymers In Aluminum Solutions, Nicholas D. Macke, Matthew J. Krafcik, Kendra A. Erk

The Summer Undergraduate Research Fellowship (SURF) Symposium

Over the past few decades, super absorbent polymers (SAPs) have been the topic of research projects all around the world due to their incredible ability to absorb water. They have applications in everything from disposable diapers to high performance concrete. In concrete, aqueous cations permeate the polymer network, reducing swelling and altering properties. One of these ions, aluminum, alters SAP properties by creating a stiff outer shell and greatly reducing absorbency, but these effects have not been well characterized. One method of characterizing the effects of aluminum on SAP hydrogels was performing gravimetric swelling tests to determine equilibrium water capacity …

Correlation Of Polymer Performance And Hansen Solubility Parameters, Daniel Jobse Mania

Master's Theses

Ready-to-use (RTU) grout is becoming more important to the finish and remodeling construction industry. Market research shows it is a fast-growing product that not only is creating its own space, but is beginning to supplant existing technology.

The original intent of this research was to investigate formulation parameters and how they affect grout performance. It was learned that particle size and oil absorption (OA) value are important filler properties that affect performance as much as adequate packing density and optimal pigment volume concentration (PVC) without going beyond critical PVC (CPVC).

Polymer architecture was also determined to be extremely important, but …

Material Selection And Testing For A Radiation Therapy Catheter, Philip James Wadlow

Master's Theses

Three different polymers (a high-density polymer and two other polymers) were tested for use as an x-ray catheter in a radiation therapy application. This report describes the testing of these three materials to determine which material is the best option for a long use catheter. Tests included tensile, simulated clinical life, and other tests. Some testing was performed using nitrogen and an industrial coolant. Testing revealed significant non-circularities for some catheters. With increasing pressure, the circularity of these catheters increased. The tensile tests were performed on samples with varying doses of radiation. Tensile testing showed significant decreases in ultimate tensile …

Film Performance Of Poly(Lactic Acid) Blends For Packaging Applications, Carlos A. Diaz, Hsunpao Y. Pao, Sungyoung Kim

Journal of Applied Packaging Research

Poly(lactic acid) (PLA), a biodegradable thermoplastic derived from renewable resources, stands out as a substitute to petroleum-based plastics. PLA based films for food packaging has been an area of both commercial and research interest within the context of sustainability. In spite of its high strength, packaging applications have been limited because PLA is more brittle than traditional oil-based plastics. Because of this, films display low tear and impact resistance and produce a loud crackling sound when manipulated. Although many studies address the toughening of PLA in the bulk, little attention has been placed on the film performance. The present study …

Occurrence Of Reverse Side Effects In Corona Treatment Of Dispersion-Coated Paperboard And Its Influence On Grease Barrier Properties, Sami-Seppo Ovaska, Ringaudas Rinkunas, Tadeusz Lozovksi, Robertas Maldzius, Jonas Sidaravicius, Leena-Sisko Johansson, Monika Österberg, Kaj Backfolk

Journal of Applied Packaging Research

The uncoated side of dispersion-barrier-coated paperboards was exposed to positive and negative direct current corona treatments in order to confirm the occurrence of backside treatment and clarify its effects on the usability of the paperboard. The main component of the coating dispersions was hydroxypropylated potato starch and the effects of talc and styrene-butadiene latex additions on backside treatment were evaluated. Coatings with a high talc proportion showed excellent initial grease resistance, but corona-induced strikethroughs caused a drastic decrease in grease penetration time. The root-mean-square roughness measurements revealed moderate surface roughening at the backside, indicating thus backside treatment. The alterations in …

Wide Bandgap Organo‐Lead Trihalide Perovskites For Solar Cells, Miao Hu

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Methylammonium lead trihalide perovskite (MAPbX3, where MA is methylammonium, and X is a halide)-based solar cells have been extensively investigated recently, with a demonstrated and certified solar power conversion efficiency (PCE) exceeding 20%. To further boost the PCE beyond the Schockley–Queisser limit, tandem structured solar cells have been investigated based on integrating MAPbX3 and the lower bandgap solar cells. Although the best reported efficiency for this type of tandem cells is not close to the theoretically achievable value, mixed-halide perovskite MAPbBrxI3–x is still one of the most promising candidates as the wide-bandgap light absorber for the tandem application to match …

Technical Developments In Fish Exclusion, Guidance, And Collection Materials, A. L. Peters

International Symposium on Hydraulic Structures

Construction of mills, dams and other structures in rivers and streams, and the withdrawal of water for irrigation or cooling industrial facilities vital to social and economic progress, have impacted the survival of marine life. Barriers and guidance or collection nets can protect fish and aquatic species while allowing water to flow unimpeded for commercial and industrial use. However, nets can attract aquatic growth, fill with debris, degrade with environmental stress, and be expensive to operate and maintain.

A closer look at the technical developments of materials and net designs in diverse settings can offer guidance that will be of …

Improving The Mechanical Performance Of 3d Printed Parts Using Fused Filament Fabrication, Inderpreet Binning

Industrial and Manufacturing Engineering

The 3D printing industry has seen rapid growth in the last 10 years and has been called the next industrial revolution. There are several different processes used in 3D printing, but the most popular process is called Fused Filament Fabrication (FFF) or Fused Deposition Modeling (FDM). This is the process where (most commonly) plastic filament enters a nozzle, is heated to a semi-liquid state, and then deposited into a pattern to create a print. One major drawback to this process is that the prints are anisotropic. This means that the strength of the print varies with the orientation that it …

Solution Casting And Mechanical Testing Of Arabinan-Cellulose Nanocomposites, Kevin Su, Alina Lusebrink

Materials Engineering

The purpose of this work was to investigate methods to produce consistent, reliable, and testable thin films of arabinan-cellulose nanocomposites. Mechanical properties and composition of the Opuntia ficus-indica cactus spines served as motivation for this research. The high specific strength and stiffness, biodegradability, and sustainability of these spines inspired the creation of composites fabricated from the same materials found in cactus spines: arabinan and nanocrystalline cellulose (NCC). Arabinan serves as the matrix material and NCC as the reinforcement. To explore the feasibility of using a non-toxic solvent, different solution casting techniques with water as a solvent were investigated. Ultrasonication was …

Effect Of Metal Organic Framework Concentration On The Crystallization Of Pla-Al-Mof Composites, Eric Futak, Jeffrey Norton, Jessie O'Connell, Nestor Vazquez

Materials Engineering

Poly(lactic acid) (PLA), a well-known biopolymer, is lacking in barrier properties and toughness. The research goal of this project is to look at the crystallinity of PLA when combined with metal organic framework (MOF). It is speculated that MOF has an effect on PLA chain mobility, and therefore crystallinity. In this study, aluminum MOF was added to PLA in varying concentrations (0, 0.5, 1, 2, 5, 10, and 20 wt%) to observe the crystallinity of the composite. The resulting PLA-Al-MOF composite films were characterized using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron …