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Displaying 1 - 25 of 1717

Time-gated Raman spectroscopy of recovered plastics

July 1, 2022
Anthony Kotula, Sara Orski, Kayla Brignac, Jennifer Lynch, Bryan Heilala
Raman spectroscopy is a powerful non-destructive technique for the identification and characterization of plastics. The technique often has limited use due to fluorescence emission, which often occurs in polymer samples containing colorants or that have

Thermal Shrinkage Reveals the Feasibility of Pulse-delay Photocuring Technique

April 13, 2022
Sri Vikram Palagummi, Taeseung Hong, Li Jiang, Martin Chiang
Objectives: To resolve applicability of the pulse-delay photocuring technique to restorative dental composites as a clinical strategy for the reduction in the detrimental polymerization stress. Methods: Model dental composites with high and low-filler

Coherent anti-Stokes Raman scattering (CARS) microscopy for polymers

April 1, 2022
Shuyu Xu, Charles Camp, Young Jong Lee
Coherent anti-Stokes Raman scattering (CARS) microscopy is a label-free chemical imaging modality capable of interrogating local molecular composition, concentration, and even orientation. In comparison to traditional Raman spectroscopy/imaging, CARS

Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers

March 24, 2022
Zois Tsinas, Sara Orski, Viviana Bentley, Lorelis Gonzalez-Lopez, Mohamad Al-Sheikhly, Amanda L. Forster
Ultra-high molar mass polyethylene (UHMMPE) is commonly used for ballistic-resistant body armor applications due to the superior strength of the fibers fabricated from this material combined with its low density. However, polymeric materials are

Imaging 3D molecular orientation by orthogonal-pair polarization IR microscopy

February 28, 2022
Shuyu Xu, Chad R. Snyder, Jeremy Rowlette, Young Jong Lee
Anisotropic molecular alignment occurs ubiquitously and often heterogeneously in three dimensions (3D). However, conventional imaging approaches based on polarization can map only molecular orientation projected onto the 2D polarization plane. Here, an

Orientation of Thin Polyamide Layer-by-Layer Films on Non-Porous Substrates

December 16, 2021
Tawanda J. Zimudzi, Sarah E. Sheffield, Kathleen E. Feldman, Peter Beaucage, Dean DeLongchamp, Douglas I. Kushner, Christopher Stafford, Michael A. Hickner
The orientation of polyamide thin films on non-porous substrates was investigated using Fourier transform infrared (FTIR) spectroscopy and corroborated by near edge X-ray absorption fine structure (NEXAFS) measurements. Polyamide films comprised of m

Activation of Mechanophores in a Thermoset Matrix by Instrumented Scratch

November 17, 2021
Chelsea S. Davis, Jeremiah Woodcock, Ryan Beams, Mitchell Rencheck, Muzhou Wang, Stephan J. Stranick, Aaron M. Forster, Jeffrey Gilman
Scratches in polymer coatings and barrier layers negatively impact optical properties (haze, light transmission, etc.), initiate routes of degradation or corrosion (moisture permeability), and nucleate delamination of the coating. Detecting scratches in

Solvent-cast 3D Printing of Biodegradable Polymer Scaffolds

October 22, 2021
John Tolbert, Diana Hammerstone, Nathaniel Yuchimiuk, Jonathan Seppala, Lesley Chow
Three-dimensional (3D) printing is a popular technique to fabricate scaffolds for tissue engineering because of its ability to produce complex tissue-like architectures. Scaffolds are often 3D printed using biodegradable polymers like poly(caprolactone)

Imperfect Surface Order and Functionalization in Vertical Carbon Nanotube Arrays Probed by Near Edge X-ray Absorption Fine Structure Spectroscoy (NEXAFS)

October 12, 2021
T Hemraj-Benny, S Banerjee, S Sambasivan, Daniel A. Fischer, G Eres, Alexander Puretzky, David B. Geohegan, D H. Lowndes, J A. Misewich, S S. Wong
Probing surface order in nanotube systems is of fundamental importance for incorporation of these materials into practical electronic devices. The current study pertains to analysis of the surface orientation of vertically aligned single-walled and multi

Measuring Tie Chains and Trapped Entanglements in Semicrystalline Polymers

September 21, 2021
Amanda G. McDermott, Paul DesLauriers, Jeff Fodor, Ronald L. Jones, Chad R. Snyder
A label-free method for quantifying stress-transmitter (or elastically effective molecule) content (p) in semicrystalline polymers, including both tie molecules and bridging entanglements, is developed and demonstrated based on swelling with deuterated

Temperature-insensitive silicone composites as ballistic witness materials: the impact of water content on the thermophysical properties

July 28, 2021
Ran Tao, Fan Zhang, Huong Giang Nguyen, Philip Bernstein, Amanda L. Forster, Randy Mrozek, Aaron M. Forster
In this work, different formulations of a room-temperature silicone composite backing material (SCBM) composed of polydimethylsiloxane (PDMS), fumed silica and corn starch were investigated using different characterization techniques, i.e., differential

Simulated filament shapes in embedded 3D printing

July 22, 2021
Leanne Friedrich, Jonathan Seppala
Embedded 3D printing, wherein fluid inks are extruded into a bath, has enabled the manufacture of complex, custom structures ranging from cell-laden tissue analogues to soft robotics. This method encompasses two techniques: embedded ink writing (EIW)

Molecular Mass Dependence of Interfacial Tension in Complex Coacervation

June 11, 2021
Debra Audus, Samim Ali, Artem Rumyantsev, Yuanchi Ma, Juan J. de Pablo, Vivek Prabhu
The interfacial tension of coacervates, the liquidlike phase composed of oppositely charged polymers that coexists at equilibrium with a supernatant, forms the basis for multiple technologies. Here we present a comprehensive set of experiments and

Buried Structure in Block Copolymer Films Revealed by Soft X-ray Reflectivity

May 20, 2021
Daniel Sunday, Jacob L. Thelen, R Joseph Kline, Chun Zhou, Jiaxing Ren, Paul Nealey
Interactions between polymers and surfaces can be used to influence properties including mechanical performance in nanocomposites, the glass transition temperature, and the orientation of thin film block copolymers (BCPs). In this work we investigate how

Fabrication of 3D Printed Hydroxyapatite Composite Scaffolds for Bone Regeneration

May 19, 2021
Yoontae Kim, Eun-Jin Lee, Albert Davydov, Stanislav Frakhtbeyen, Jonathan Seppala, Laurence Chow, Tagaki Shozo, Stella Alimperti
Additive biomanufacturing has been adapted in a wide variety of biomedical and tissue engineering applications, including orthopedics. The ability to print biocompatible, patient-specific geometries with controlled porosity, mechanical strength has made
Displaying 1 - 25 of 1717