Synthesis and properties of transparent thermoplastic segmented polyurethanes

✍ Scribed by Po Hung Chen; Yu Fen Yang; Da-Kong Lee; Ya-Fen Lin; Hsine-Hsyan Wang; Hong-Bing Tsai; Ruey-Shi Tsai

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 185 KB
• Volume: 26
• Category: Article
• ISSN: 0730-6679
• DOI: 10.1002/adv.20086

✦ Synopsis

Abstract

Various segmented polyurethanes with a hard segment content of about 50 wt% were prepared from 4,4′‐diphenylmethane diisocyanate (MDI), a poly(tetramethylene adipate) glycol with an M~n~ of 2000, and various combinations of aliphatic diols as chain extenders by a one‐shot, hand‐cast bulk polymerization method. The segmented polyurethanes were characterized by gel permeation chromatography (GPC), ultraviolet‐visible spectrometry, differential scanning calorimetry (DSC), and X‐ray diffraction, and their tensile properties and Shore A hardness were determined. The DSC data indicate rather good miscibility between the soft segments and the hard segments that accounts for the good transparency. The incorporation of a small amount of a second chain extender into MDI and 1‐4‐butanediol‐based segmented polyurethanes decreases the crystallinity of the hard segment, thus enhancing the transparency. A segmented polyurethane derived from MDI and 1,6‐hexanediol exhibits better transparency due to its relatively lower crystallinity of the hard segment. © 2007 Wiley Periodicals, Inc. Adv Polym Techn 26:33–40, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20086