Preparation and properties of segmented thermoplastic polyurethane elastomers with two different soft segments

✍ Scribed by Han-Do Kim; Tae-Jung Lee; Jae-Ho Huh; Dong-Jin Lee

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 214 KB
• Volume: 73
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19990718)73:3<345::aid-app5>3.0.co;2-t

✦ Synopsis

Thermoplastic polyurethane elastomers were prepared from 4,4-diphenylmethane diisocyanate (MDI)/1,4-butanediol (BD)/poly(propylene glycol) (PPG) and MDI/BD/poly(oxytetramethylene glycol) (PTMG). The MDI/BD-based hard-segment content of polyurethane prepared in this study was of 39 -65 wt %. These polyurethane elastomers had a constant soft-segment molecular weight (M n , 2000), but a variable hard-segment block length (n, 3.0 -10.1; M n , 1020 -3434). The effects of the hardsegment content on the thermal properties and elastic behavior were investigated. These properties of the PPG-based MPP samples and the PTMG-based MPT samples were compared. The polyurethane prepared in this study had a hard-segment crystalline melting temperature in the range of 185.5-236.5°C. With increasing hard-segment content, the dynamic storage modulus and glass transition temperature increased in both the MPP and MPT samples. The permanent set (%) increased with increasing hard-segment content and successive maximum elongation. The permanent set (%) of the MPP samples was higher than that of MPT samples at the same hard-segment content. The value of K (area of the hydrogen-bonded carbonyl group/area of the free carbonyl group) increased with increasing hard-segment content in both the MPP and MPT samples, and the K value of the MPT samples was higher than that of the MPP samples at the same hard-segment content.