Materials Engineering

UV Polymerization of a Zwitterionic Antifouling Membrane Coating

Membrane filtration is used in a wide array of industries to separate components in a mixture. Filtration membranes suffer from the external deposition of pollutants and microorganisms, a phenomenon known as fouling. Fouling reduces the lifetime of a membrane and therefore increases production costs. The goal of this project was to modify the surface of a hydrophobic commercial membrane with a charged coating to induce antifouling and hydrophilic properties. A zwitterionic monomer, sulfobetaine methacrylate (SBMA), was used for its steric hindrance and hydration shell formation mechanisms, which result in superior non-specific antifouling performance. When polymerizing the coating onto the surface of the commercial hydrophobic membrane, incremental amounts of SBMA monomer, SpeedCure 4265 initiator, and ethylene glycol dimethacrylate crosslinker (EGMA) were added to a 1:2 solution composed of water and isopropyl alcohol (IPA). The coated membranes were polymerized for 30 seconds using a COBRA Cure™ FX2 UV LED Curing System with a wavelength of 365 nm. An existing commercial antifouling membrane and the 9.50% SBMA, 0.50% EGMA, and 1.50% SpeedCure 4265 modified membrane exhibited superior antifouling performance compared to the other membranes. Additionally, contact angle measurements confirmed that the modification process successfully changed the surface of all membrane combinations except the 23.75% SBMA, 1.25% EGMA, and 1.50% SpeedCure 4265 membrane from hydrophobic to hydrophilic.

Void and Density Analysis of Cyanate Ester Composites

In large scale composite manufacturing, voids and their frequency within prepreg materials play an important role in predicting the mechanical properties of a final composite laminate. The industry standard process for determining voids in composite materials is through resin digestion and resin ignition via ASTM D3171. One limitation to this standard is its ability to frequently produce negative void volume values in quality control testing, due to the
calculation sensitivity of input resin and fiber densities. For this reason, Toray Advanced Composites wanted to investigate the process steps of ASTM D3171 to determine if discrepancies in resin density data may be leading to negative void volumes in their EX-1515 cyanate ester resin system. In order to analyze the matrix density, three groups of materials were investigated including: neat EX-1515 resin, EX-1515/CN-60 composite, and EX-1515/Astroquartz composite. All three materials underwent dimensional and specific gravity density measurements, in addition to optical microscopy. In combination with data from resin ignition and digestion, the density data revealed that original assumed density for EX-1515 was lower than the actual density of the resin system, which led to the prevalence of negative void volume calculations. Furthermore, the results of the project revealed the importance of there being a range of density values for composite resin systems due to the high sensitivity of the process steps and calculations found within ASTM D3171.

Computational BCC Refractory High-Entropy Alloys

This project simulated the formational energy and equilibrium phases of body-centered cubic (BCC) refractory high-entropy alloys (HEAs). Perfect crystal supercells were generated in a random and special quasirandom (SQS) atomic placement. Generated perfect crystals were modified to have either a vacancy or an interstitial carbon atom. Total energy for each structure was then calculated. After, phase diagrams were calculated for the equi-atomic HEAs. The software used for simulating included nanoHUB, BURAI, and Thermo-Calc.

Life Cycle Assessment of an iFixit Pro Tech Toolkit

iFixit provided two of their Pro Tech Toolkits to be used in a Life cycle assessment. Data obtained in this project will provide quantitative information for the sustainability of the product and of the environmental impact of repairing a device versus replacing it.

Solvent Analysis of Phenolic Resin Glass Fiber Reinforced Prepreg

An investigation into whether high temperature or time has a stronger effect on the loss of volatiles present in phenolic resin glass fiber reinforced prepreg from B-stage till application manufacturing. The loss of volatiles resulted in a loss of tackiness which often rendered the prepreg unfit for application manufacturing.

Effect of Distal Core Flattening on 304 Stainless Steel Guide Wires

Abbott cardiovascular produces a variety of medical guide wires to accommodate a wide array of minimally invasive medical procedures. These wires can have their properties tuned by altering one of their many components. One such method we explore is the effect of flattening on the core material of the wires.

Effects of UV Exposure on the Thermo-Mechanical Properties of a Cactus Based Biopolymer

Biopolymers comprised of nopal cactus juice, animal protein, natural wax, and glycerin in differing percentages were studied to obtain thermo-mechanical data in relation to UV exposure. To quantify degradation, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy, goniometry and gravimetric measurements were performed.