Isocyanate-Free Polyurethane Coatings and Adhesives from Mono- and Di-Saccharides.

Xuedong Xi,Luc Delmotte,Antonio Pizzi

doi:10.3390/polym10040402

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.

Highlights

Polyurethanes can and have already been prepared for a number of possible applications by using biosourced polyols from renewable materials [1,2,3,4,5,6,7,8]
There are examples of glucose molecules just reacted with the dimethyl carbonate such as the species at 263.8 Da
Mono- and disaccharides appeared to yield workable non-isocyanate polyurethanes having a definite potential for application as both wood and steel surface thermosetting coatings and for thermosetting wood adhesives

Summary

Introduction

Polyurethanes can and have already been prepared for a number of possible applications by using biosourced polyols from renewable materials [1,2,3,4,5,6,7,8]. Polymeric isocyanates need always to be used in industry to prepare polyurethanes even if in conjunction with biosourced polyols. Oligomers terminated with five-membered cyclic carbonate groups [9] are reacted with diamines to form polyhydroxyurethanes [10]. Several studies on this type of approach do exist in the literature [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]. Polyamines could be produced from fatty diacids [27]

Objectives

Methods

Results

Conclusion