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Displaying 376 - 400 of 3711

Design and Characterization of an Architecturally Perfect Family of Linear Low-Density Polyethylenes (LLDPEs) by Multi-Detector Size Exclusion Chromatography

March 27, 2020
Author(s)
Sara V. Orski, Luke Kassekert, Wesley Farrell, Grace A. Kenlaw, Marc Hillmyer, Kathryn L. Beers
Separations of commercial polyethylenes, which often involve mixtures and copolymers of linear, short-chain, and long-chain branched chains, can be very challenging to optimize as species with similar hydrodynamic sizes or solubility often co-elute in

Effect of Elevated Temperature and Humidity on Fibers Based on 5-amino-2-(p-aminophenyl) benzimidazole (PBIA)

March 19, 2020
Author(s)
Amy E. Engelbrecht-Wiggans, Ajay Krishnamurthy, Lucas H. Kaplan, Amanda L. Forster, Thanh N. Hoang, Viviana Bentley
Traditionally, soft body armor has been made from materials such as poly(p-phenylene terephthalamide) (PPTA) and ultra-high molar mass polyethylene (UHMMPE). However, to diversify the fiber choices in the United States body armor market, copolymer fibers

Dispersing nanosized portlandite particulates via electrosteric exclusion at short screening lengths

March 16, 2020
Author(s)
Jason Timmons, Iman Mehdipour, Shang Gao, Hakan Atahan, Narayanan Neithalath, Mathieu Bauchy, Edward Garboczi, Samanvaya Srivastava, Gaurav Sant
In spite of their high surface charge (ζ = + 34 mV), aqueous suspensions of portlandite (calcium hydroxide: Ca(OH)2) exhibit a strong tendency to aggregate, and thereby present unstable suspensions. While a variety of commercial dispersants seek to modify

Nanoscale Pattern Decay Monitored via in-situ Heated Atomic Force Microscopy

March 12, 2020
Author(s)
Sonal Bhadauriya, Jianan Zhang, Jaejun Lee, Michael R. Bockstaller, Alamgir Karim, Richard J. Sheridan, Christopher Stafford
We combine in-situ heated atomic force microscopy (AFM) with automated line-by-line spectral analysis to quantify the relaxation or decay of nanopatterned polymer films at temperatures above the glass transition. This approach enables assessment of pattern

Macroscopic degradation behaviors of polyethylene under the influence of UV radiation and temperature

February 17, 2020
Author(s)
Hsiang C. Hsueh, Jae H. Kim, Sara Orski, Andrew Fairbrother, Deborah Jacobs, Donald L. Hunston, Christopher C. White, Li Piin Sung, Lakesha Perry
Accelerated weathering tests were performed to investigate the effects of multiple ultraviolet (UV) light intensities and temperatures on the tensile behavior of high-density polyethylene (HDPE). In the macroscopic degradation behavior of HDPE, tensile

Compressive deformation analysis of large area pellet-fed material extrusion 3D printed parts in relation to in situ thermal imaging*

February 8, 2020
Author(s)
Eduardo M. Trejo, Xavier Jimenez, Kazi M. Billah, Jonathan Seppala, Ryan Wicker, David Esplain
In large area pellet extrusion additive manufacturing, the temperature of the substrate just before the deposition of a new subsequent layer affects the overall structure of the part. Warping and cracking occur if the substrate temperature is below a

Insights into the Water Transport Mechanism in Polymeric Membranes from Neutron Scattering

February 5, 2020
Author(s)
Edwin P. Chan, Bradley R. Frieberg, Jacob Daniel Tarver, Madhusudan Tyagi, WenXu Zhnag, Bryan Coughlin, Christopher M. Stafford, Abhishek Roy, Steve Rosenberg, Christopher L. Soles
Polymeric membranes are ubiquitous in a number of transport ap- plications including gas separation, water desalination, solid state batteries and fuel cells. The permeability and selectivity of these membranes are intimately linked to the structure and
Displaying 376 - 400 of 3711