Segmented Polyurethanes and Thermoplastic Elastomers from Elemental Sulfur with Enhanced Thermomechanical Properties and Flame Retardancy

Kyung Seok Kang, Anthony Phan, Chisom Olikagu, Taeheon Lee, Douglas A. Loy, Minho Kwon, Hyun jong Paik, Seung Jae Hong, Joona Bang, Wallace O. Parker, Monia Sciarra, Alberto R. de Angelis, Jeffrey Pyun

    Research output: Contribution to journalArticlepeer-review

    65 Citations (Scopus)

    Abstract

    The production of elemental sulfur from petroleum refining has created a technological opportunity to increase the valorization of elemental sulfur by the creation of high-performance sulfur based plastics with improved thermomechanical properties, elasticity and flame retardancy. We report on a synthetic polymerization methodology to prepare the first example of sulfur based segmented multi-block polyurethanes (SPUs) and thermoplastic elastomers that incorporate an appreciable amount of sulfur into the final target material. This approach applied both the inverse vulcanization of S8 with olefinic alcohols and dynamic covalent polymerizations with dienes to prepare sulfur polyols and terpolyols that were used in polymerizations with aromatic diisocyanates and short chain diols. Using these methods, a new class of high molecular weight, soluble block copolymer polyurethanes were prepared as confirmed by Size Exclusion Chromatography, NMR spectroscopy, thermal analysis, and microscopic imaging. These sulfur-based polyurethanes were readily solution processed into large area free standing films where both the tensile strength and elasticity of these materials were controlled by variation of the sulfur polyol composition. SPUs with both high tensile strength (13–24 MPa) and ductility (348 % strain at break) were prepared, along with SPU thermoplastic elastomers (578 % strain at break) which are comparable values to classical thermoplastic polyurethanes (TPUs). The incorporation of sulfur into these polyurethanes enhanced flame retardancy in comparison to classical TPUs, which points to the opportunity to impart new properties to polymeric materials as a consequence of using elemental sulfur.

    Original languageEnglish
    Pages (from-to)22900-22907
    Number of pages8
    JournalAngewandte Chemie - International Edition
    Volume60
    Issue number42
    DOIs
    Publication statusPublished - 2021 Oct 11

    Bibliographical note

    Publisher Copyright:
    © 2021 Wiley-VCH GmbH

    Keywords

    • flame retardants
    • segmented polyurethanes
    • sulfur utilization
    • thermoplastic elastomers

    ASJC Scopus subject areas

    • Catalysis
    • General Chemistry

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