LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 3 of total 3

Search options

  1. Article ; Online: Influence of Oxygen Uptake on Pitch Carbon Fiber.

    Harrell, Timothy M / Scherschel, Alexander / Love-Baker, Cole / Tucker, Amy / Moskowitz, Jeremy D / Li, Xiaodong

    Small (Weinheim an der Bergstrasse, Germany)

    2023  Volume 19, Issue 45, Page(s) e2303527

    Abstract: Carbon fiber precursor materials, such as polyacrylonitrile, pitch, and cellulose/rayon, require thermal stabilization to maintain structural integrity during conversion into carbon fiber. Thermal stabilization mitigates undesirable decomposition and ... ...

    Abstract Carbon fiber precursor materials, such as polyacrylonitrile, pitch, and cellulose/rayon, require thermal stabilization to maintain structural integrity during conversion into carbon fiber. Thermal stabilization mitigates undesirable decomposition and liquification of the fibers during the carbonization process. Generally, the thermal stabilization of mesophase pitch consists of the attachment of oxygen-containing functional groups onto the polymeric structure. In this study, the oxidation of mesophase pitch precursor fibers at various weight percentage increases (1, 3.5, 5, 7.5 wt%) and temperatures (260, 280, 290 °C) using in situ differential scanning calorimetry and thermogravimetric analysis is investigated. The results are analyzed to determine the effect of temperature and weight percentage increase on the stabilization process of the fibers, and the fibers are subsequently carbonized and tested for tensile mechanical performance. The findings provide insight into the relationship between stabilization conditions, fiber microstructure, and mechanical properties of the resulting carbon fibers.
    Language English
    Publishing date 2023-07-07
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2168935-0
    ISSN 1613-6829 ; 1613-6810
    ISSN (online) 1613-6829
    ISSN 1613-6810
    DOI 10.1002/smll.202303527
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Article: Thermo-oxidative stabilization of polyacrylonitrile and its copolymers: Effect of molecular weight, dispersity, and polymerization pathway

    Moskowitz, Jeremy D / Jeffrey S. Wiggins

    Polymer Degradation and Stability. 2016 Mar., v. 125

    2016  

    Abstract: Careful control of polyacrylonitrile (PAN) precursor properties and, in particular, the polymerization method and ensuing molecular weight and molecular weight distribution are important considerations for mitigating defects and enhancing processability ... ...

    Abstract Careful control of polyacrylonitrile (PAN) precursor properties and, in particular, the polymerization method and ensuing molecular weight and molecular weight distribution are important considerations for mitigating defects and enhancing processability of carbon fibers. Herein, a comprehensive study was performed to understand the influence of molecular weight, molecular weight distribution, and polymerization method between reversible addition-fragmentation chain transfer (RAFT) and conventional free radical (FR) solution polymerization on the cyclization behavior and structural evolution of stabilized PAN. The kinetic parameters of activation energy (Ea) and pre-exponential factor (A) were determined along with the cyclization index (CI) by differential scanning calorimetry (DSC) and the extent of stabilization (Es) was measured via fourier transform infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA) was used to determine the degradation differences in the polymers. Structural characterization was performed by wide-angle X-ray scattering (WAXS). DSC and FTIR analysis indicate that cyclization initiates at lower temperature for FR polymers. Significantly, PAN-based RAFT copolymers show greater mass retention post thermo-oxidative degradation as compared to analogous FR copolymers.
    Keywords activation energy ; carbon fibers ; composite polymers ; differential scanning calorimetry ; Fourier transform infrared spectroscopy ; molecular weight ; polyacrylonitrile ; polymerization ; temperature ; thermogravimetry ; X-radiation
    Language English
    Dates of publication 2016-03
    Size p. 76-86.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 1502217-1
    ISSN 0141-3910
    ISSN 0141-3910
    DOI 10.1016/j.polymdegradstab.2015.12.025
    Database NAL-Catalogue (AGRICOLA)

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  3. Article: High molecular weight and low dispersity polyacrylonitrile by low temperature RAFT polymerization

    Moskowitz, Jeremy D. / Abel, Brooks A. / McCormick, Charles L. / Wiggins, Jeffrey S.

    Journal of polymer science

    Volume v. 54,, Issue no. 4

    Abstract: High molecular weight polyacrylonitrile (PAN) with low dispersity has been successfully synthesized utilizing reversible addition‐fragmentation chain transfer (RAFT) polymerization. A comprehensive study was performed to understand the influence of ... ...

    Abstract High molecular weight polyacrylonitrile (PAN) with low dispersity has been successfully synthesized utilizing reversible addition‐fragmentation chain transfer (RAFT) polymerization. A comprehensive study was performed to understand the influence of reaction temperature, RAFT agent structure, and [M]₀:[CTA]₀[I]₀ on the polymerization kinetics, molecular weight, and dispersity. Enhanced control is attributed to reduction of side reactions by conducting the polymerization at lower temperature, and optimizing the radical exchange between active and dormant states via appropriate selection of RAFT agent and initiator. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 553–562
    Keywords molecular weight ; polymerization ; polyacrylonitrile ; temperature
    Language English
    Document type Article
    ISSN 0887-624X
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

To top