Thermal and Mechanical Properties of Polyurethanes Derived from Mono- and Disaccharides

✍ Scribed by Zetterlund, Per; Hirose, Shigeo; Hatakeyama, Tatsuko; Hatakeyama, Hyoe; Albertsson, Ann-Christine

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 334 KB
• Volume: 42
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199701)42:1<1::aid-pi636>3.0.co;2-l

✦ Synopsis

Thermal and mechanical properties of polyurethane (PU) sheets prepared from the glucose/fructose/sucroseÈpolyethylene glycol (PEG)È diphenylmethane diisocyanate (MDI) system were examined by di †erential scanning calorimetry, thermogravimetry, dynamic mechanical analysis and tensile tests. The saccharide content was varied at a constant NCO : OH ratio of 1É0. The glass transition temperature increased with increasing saccharide (T g ) content. The incorporation of saccharides into the PU structure results in a higher crosslinking density and a higher content of hard segments. The thermal decomposition was dependent on the saccharide content, an increase leading to a lower thermal decomposition temperature

The dissociation of saccharide (T d

). OH groups and NCO groups is a major part of the thermal decomposition of these PUs. Dynamic mechanical analysis revealed two kinds of relaxation : the high temperature relaxation corresponds to main chain motion and the other is a local mode relaxation due to non-reacted isocyanate groups. The tensile stress and YoungÏs modulus increased with the saccharide content.