Isocyanate-Free Polyurethane Coatings and Adhesives from Mono- and Di-Saccharides
Abstract
Mostly biosourced non-isocyanate polyurethanes (NIPU) were prepared from mono- and
disaccharides, namely glucose and sucrose, reacted with dimethyl carbonate and hexamethylene
diamine. The main aim of this research was to show that NIPU can be prepared from mono- and
disaccharides, this just being an initial exploratory work and its sole main aim. The oligomers obtained
were detected by MALDI-ToF, CP-MAS 13C NMR, and FTIR spectrometries. The glucose-derived
NIPU were shown to harden at a markedly lower temperature than the sucrose-derived ones and to
be easier to handle and spread. The NIPU obtained were applied as wood and steel surface coatings
and tested by the sessile drop test (on wood) and cross-cut test (on steel) with encouraging results.
The glucose NIPU gave good surface coating results already at 103 ◦C, while the sucrose NIPU
yielded good results only at a markedly higher temperature of hardening. The NIPU saccharide
resins were also tested as thermosetting wood joint adhesives with the glucose NIPU yielding very
encouraging results.