Synthesis of biopolyols by mild oxypropylation of liquefied starch and its application to polyurethane rigid foams

Abstract

The liquefaction of starch in the presence of commercial polyol resulted in liquefaction products (LPs) with much lower hydroxyl values compared to those resulting from glycerol liquefaction. With the use of the obtained LPs (as initiators) and a catalytic amount of potassium hydroxide, oxypropylation was conducted under mild conditions (at 120 C, inner pressure generation of <0.2 MPa). Urethane resin foams were prepared from the obtained biopolyols. The reactivities of the biopolyols toward isocyanates were almost the same as those of commercial polyols. The physical properties of the obtained foams were as good or better than the ones obtained with the commercial polyols, including the sucrose/glycerol polyol GR-84T. The biomass content values of the foams prepared with the biopolyols ranked among the highest in the world.

Characterization of Rigid Polyurethane Foam Prepared from Recycling of PET Waste

“…On the other hand, it was observed that the glycolysis products synthesized using PG in the molar ratio of 2.52 in about 4 hours had the same weight and numberaverage molecular weights, Table 5 and Fig. 2, compared to the reported glycolysis products in the same conditions synthesized in about 5 hours and in the atmospheric pressure [24]. It can be seen, in Table 5, with increasing of proportion Glycol/PET, both numerical average molecular weight (M n ), and average molecular weight (M w ) of glycolyzed product have decreased.…”

Recent Developments in Polyurethane Foams Containing Low-Cost and Pro-Ecological Modifiers

“…Such low molecular weight fragments are characterized by low stability and high reactivity, which allows their re-polymerization and preparation of oil compounds with vast range of molecular weight. Materials prepared by this way can be applied in production of PU, epoxy resins, phenolic resins, polyesters and others [34][35][36][37]. In lignocellulose biomass one can find many compounds containing hydroxyl groups, which can be used, among others, in reactions with isocyanates.…”

Synthesis and characterization of bio-polyols through the oxypropylation of bark and alkaline extracts of bark

“…This is an appealing process since it can be done under mild alkaline conditions that will result in less degradation of sugars compared to the strongly acidic and oxidizing conditions experienced during liquefaction (Yamada and Ono, 2001); the high pressure and temperature produce high yields (Aniceto et al, 2012); and most importantly, the alkoxylation of sugar, glycerol, and short glycols is already a common practice in industry to produce polyols (Oertel, 1993). The reported procedures for alkoxylation are quite varied, such as room temperature reactions in solvent (García et al, 2013), pressure controlled reactions through gradual addition of PO monomer into the reactor (Yoshioka et al, 2013), and higher pressure/higher exothermic reaction conditions that utilized PO as a solvent. Alkoxylation has already been performed on a variety of biomass resources such as chitin/chitosan, (Fernandes et al, 2008) cork (Evtiouguina et al, 2001), date seeds (Briones et al, 2011), lignin (Cateto et al, 2010;Nadji et al, 2005;Wu and Glasser, 1984), inulin, (Rogge et al, 2005) starch, (Yoshioka et al, 2013) sugar beet (Pavier and Gandini, 2000a,b), tannin (Arbenz and Avérous, 2014;García et al, 2013) and terpenes (De Meireles et al, 2014).…”