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open access

Anomalous thermo-osmotic conversion performance of ionic covalent-organic-framework membranes in response to charge variations

Description: Authors of the article systematically investigated how the membrane charge populations affect permselectivity by decoupling their effects from the impact of the pore structure using a multivariate strategy for constructing covalent-organic-framework membranes. The complex interplay between pore-pore interactions in response to charge variations for ion transport across the upscaled nanoporous membranes helps explain the obtained results. This study has far-reaching implications for the rational… more
Date: June 13, 2022
Creator: Xian, Weipeng; Zuo, Xiuhui; Zhu, Changjia; Guo, Qing; Meng, Qing-Wei; Zhu, Xincheng et al.
Partner: UNT College of Science
open access

Self-reporting molecularly imprinted polymer with the covalently immobilized ferrocene redox probe for selective electrochemical sensing of p-synephrine

Description: Article simultaneously imprinting the p-synephrine 1 template and covalently immobilizing a a ferrocene redox probe in a (bis-bithiophene)-based polymer. The resulting molecularly imprinted polymer (MIP) was deposited on the Pt electrode as a thin film to form a redox self-reporting MIP film-based chemosensor.
Date: June 10, 2021
Creator: Lach, Patrycja; Cieplak, Maciej; Noworyta, Krzysztof R.; Pieta, Piotr; Lisowski, Wojciech; Kalecki, Jakub et al.
Partner: UNT College of Science
open access

Self-reporting molecularly imprinted polymer with the covalently immobilized ferrocene redox probe for selective electrochemical sensing of p-synephrine

Description: This article uses a molecularly imprinted polymer (MIP) to form a redox self-reporting MIP film-based chemosensor applied for p-synephrine determination.
Date: June 10, 2021
Creator: Lach, Patrycja; Cieplak, Maciej; Noworyta, K.; Pieta, Piotr; Lisowski, Wojciech; Kalecki, Jakub et al.
Partner: UNT College of Science
open access

Adhesive Joint and Composites Modeling in SIERRA

Description: Polymers and fiber-reinforced polymer matrix composites play an important role in many Defense Program applications. Recently an advanced nonlinear viscoelastic model for polymers has been developed and incorporated into ADAGIO, Sandia's SIERRA-based quasi-static analysis code. Standard linear elastic shell and continuum models for fiber-reinforced polymer-matrix composites have also been added to ADAGIO. This report details the use of these models for advanced adhesive joint and composites sim… more
Date: November 1, 2005
Creator: Ohashi, Yuki; Brown, Arthur A.; Hammerand, Daniel Carl; Adolf, Douglas Brian; Chambers, Robert S. & Foulk, James W., III
Partner: UNT Libraries Government Documents Department
open access

Development of a Simplified Fracture Toughness Tool for Polymers

Description: This thesis presents research toward the development of a simple inexpensive fracture toughness tool for polymeric materials. Experiments were conducted to test the specimen configuration and the fracture toughness tool against an established ASTM standard for polymer fracture toughness, D5045, and a commonly used four-point bend method. The materials used in this study were polycarbonate and high density polyethylene. Reductions in both the production time and the variability resulting from th… more
Date: August 1997
Creator: Marnock, Patrick J. (Patrick Joseph)
Partner: UNT Libraries
open access

Pyrene Bearing Azo-Functionalized Porous Nanofibers for CO₂ Separation and Toxic Metal Cation Sensing

Description: This article describes the construction of a novel luminescent azo-linked polymer from 1,3,6,8-tetra(4--aminophenyl)pyrene using a copper(I)-catalyzed oxidative homocoupling reaction.
Date: November 14, 2018
Creator: El-Kadri, Oussama M.; Tessema, Tsemre-Dingel; Almotawa, Ruaa M.; Arvapally, Ravi K.; Al-Sayah, Mohammad H.; Omary, Mohammad A. et al.
Partner: UNT College of Science
open access

Rational design of bifunctional conjugated microporous polymers

Description: This article is a review discussing the rational design and synthesis of bifunctional conjugated microporous polymers (CMPs), summarizes their advanced applications, and concludes with the authors' perspectives on the research prospects of these materials.
Date: July 22, 2021
Creator: Song, Yanpei; Lan, Pui Ching; Martin, Kyle & Ma, Shengqian
Partner: UNT College of Science
open access

DYTHERM: a new temperature-resistant removable foam encapsulant

Description: A new commercially available copolymer produced by ARCO/Polymers, Inc., under the tradename of DYTHERM X214 has been evaluated for use as a removable foam encapsulant. DYTHERM X214 is a styrene-maleic anhydride copolymer that increases the upper use temperature of previously employed polystyrene bead foam from 80/sup 0/C to about 115/sup 0/C. The processing of DYTHERM X214 is similar to polystyrene foam beads except that higher fusion temperatures (approx. 125/sup 0/C) are necessary and polar s… more
Date: August 1, 1981
Creator: Wischmann, K.B.
Partner: UNT Libraries Government Documents Department
open access

Definition of Brittleness: Connections Between Mechanical and Tribological Properties of Polymers.

Description: The increasing use of polymer-based materials (PBMs) across all types of industry has not been matched by sufficient improvements in understanding of polymer tribology: friction, wear, and lubrication. Further, viscoelasticity of PBMs complicates characterization of their behavior. Using data from micro-scratch testing, it was determined that viscoelastic recovery (healing) in sliding wear is independent of the indenter force within a defined range of load values. Strain hardening in sliding we… more
Date: August 2008
Creator: Hagg Lobland, Haley E.
Partner: UNT Libraries
open access

Determination of Wear in Polymers Using Multiple Scratch Test.

Description: Wear is an important phenomenon that occurs in all the polymer applications in one form or the other. However, important links between materials properties and wear remain illusive. Thus optimization of material properties requires proper understanding of polymer properties. Studies to date have typically lacked systematic approach to all polymers and wear test developed are specific to some polymer classes. In this thesis, different classes of polymers are selected and an attempt is made to us… more
Date: August 2004
Creator: Damarla, Gowrisankar
Partner: UNT Libraries
open access

Electrochemical sensor for selective tyramine determination, amplified by a molecularly imprinted polymer film

Description: This article devised, fabricated, and tested a molecularly imprinted polymer (MIP) film based electrochemical sensor for selective determination of tyramine.
Date: November 17, 2020
Creator: Ayerdurai, Viknasvarri; Cieplak, Maciej; Noworyta, Krzysztof R.; Gajda, Marianna; Ziminska, Agnieszka; Sosnowska, Marta et al.
Partner: UNT College of Science
open access

Fabrications of PVDF gratings :final report for LDRD project 79884.

Description: The purpose of this project was to do some preliminary studies and process development on electroactive polymers to be used for tunable optical elements and MEMS actuators. Working in collaboration between Sandia National Labs and The University of Illinois Urbana-Champaign, we have successfully developed a process for applying thin films of poly (vinylidene fluoride) (PVDF) onto glass substrates and patterning these using a novel stamping technique. We observed actuation in these structures in… more
Date: December 1, 2005
Creator: Rogers, J. A. (University of Illinois, Urbana-Champaign); Carr, Dustin Wade & Bogart, Gregory R.
Partner: UNT Libraries Government Documents Department
open access

Evaluation of improved polyamides

Description: Three polyamides, nylon 11, nylon 12, and a transparent nylon, were evaluated by physical testing, characterization and analytical methods, and injection molding. None of the materials proved to be clearly superior to the others. Results of the evaluation will be used to determine applications for the materials in future production programs.
Date: June 1, 1980
Creator: Hishaw, R.J.
Partner: UNT Libraries Government Documents Department
open access

Preparation and Characterization of a Treated Montmorillonite Clay and Epoxy Nanocomposite

Description: Montmorillonite reinforced polymers are a new development in the area of nanocomposite materials. Since reinforcement of epoxy is important to the development of high strength adhesives and composite matrices, the introduction of montmorillonite to epoxy is of interest. Compositional effects on epoxy reactivity, on molecular relaxation, and on mechanical properties were investigated. Change in reactivity was determined by Differential Scanning Calorimetry. Tensile properties at room temperature… more
Date: December 2000
Creator: Butzloff, Peter Robert
Partner: UNT Libraries
open access

Ring Walking/Oxidative Addition Reactions for the Controlled Synthesis of Conjugated Polymers

Description: Power conversion efficiencies of plastic solar cells depend strongly on the molecular weight characteristics of the semiconducting polymers used for their fabrication. The synthesis of these materials typically relies on transition metal mediated catalytic reactions. In many instances, the ideal structures cannot be attained because of deficiencies in these reactions, particularly when it comes to being able to achieve high number average molecular weights and narrow molecular weight distributi… more
Date: April 3, 2012
Creator: Bazan, Guillermo C
Partner: UNT Libraries Government Documents Department
open access

Thermo/hydration responsive shape memory polymers with enhanced hydrophilicity for biomedical applications

Description: Article states that thiol-ene/acrylate shape memory polymers (SMPs) have sufficient stiffness for facile insertion and precision placement and soften after exposure to physiological conditions to reduce the mechanical mismatch with body tissue; as a result, they have demonstrated excellent potential as substrates for various flexible bioelectronic devices, such as cochlear implants, nerve cuffs, cortical probes, plexus blankets, and spinal cord stimulators. Here, the authors report a new strate… more
Date: December 5, 2022
Creator: Suzuki, Yuta; Hu, Qichan; Batchelor, Benjamin; Voit, Walter & Ecker, Melanie
Partner: UNT College of Engineering
open access

Plastic neutron detectors.

Description: This work demonstrated the feasibility and limitations of semiconducting {pi}-conjugated organic polymers for fast neutron detection via n-p elastic scattering. Charge collection in conjugated polymers in the family of substituted poly(p-phenylene vinylene)s (PPV) was evaluated using band-edge laser and proton beam ionization. These semiconducting materials can have high H/C ratio, wide bandgap, high resistivity and high dielectric strength, allowing high field operation with low leakage curren… more
Date: December 2008
Creator: Doty, F. Patrick; Wilson, Tiffany M. S. & King, Michael J.
Partner: UNT Libraries Government Documents Department
open access

Investigation of methylpentene polymer (TPX) molding resin. Final report

Description: A polymethylpentene polymer (TPX) produced by Mitsui Petrochemical Industries, Ltd., Japan, was evaluated and compared to a TPX previously obtained from Imperial Chemical Industries, Ltd., England, who no longer produce TPX and have sold their manufacturing process for this polymer to Mitsui. The rheological, chemical, and physical properties of the materials were compared and the two materials were found to be essentially identical.
Date: March 1, 1978
Creator: Walter, C.L.
Partner: UNT Libraries Government Documents Department
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