Solid"green" polyurethanes based on rapeseed oil polyol and modified withglycerol and microcellulose

Abstract

Solid bio-based polyurethanes (PUs) were prepared from a rapeseed oil-based polyol (ROPO) synthesized by epoxidation reaction followed by oxirane ring-opening with diethylene glycol. The reference material was modified by replacement of the ROPO with glycerol in different proportions and also by addition of a commercial microcellulose (MC). The curing process of the reactive mixtures was monitored by rheological measurements and the analysis showed that both, MC and glycerol increase the time of crossover between storage and loss modulus (liquid to solid transition in the response at 1 Hz) in the samples. The completely cured polyurethanes were characterized by physical, morphological and mechanical analysis. The results proved that the addition of glycerol and MC increases the modulus and ultimate stress. Despite the higher modulus of the composites, the ultimate deformation also increases with the incorporation of 3 and 5 wt.% of MC, which was associated to the good interaction cellulose-polymeric matrix.