Effect of structure on properties of polyols and polyurethanes based on different vegetable oils

Abstract

We synthesized six polyurethane networks from 4,4Ј-diphenylmethane diisocyanate and polyols based on midoleic sunflower, canola, soybean, sunflower, corn, and linseed oils. The differences in network structures reflected differences in the composition of fatty acids and number of functional groups in vegetable oils and resulting polyols. The number average molecular weights of polyols were between 1120 and 1300 and the functionality varied from 3.0 for the midoleic sunflower polyol to 5.2 for the linseed polyol. The functionality of the other four polyols was around 3.5. Canola, corn, soybean, and sunflower oils gave polyurethane resins of similar crosslinking density and similar glass transitions and mechanical properties despite somewhat different distribution of fatty acids. Linseed oil-based polyurethane had higher crosslinking density and higher mechanical properties, whereas midoleic sunflower oil gave softer polyurethanes characterized by lower T g and lower strength but higher elongation at break. It appears that the differences in properties of polyurethane networks resulted primarily from different crosslinking densities and less from the position of reactive sites in the fatty acids.

Polymer precursors from catalytic reactions of natural oils

“…50 The precursors lead to various materials with different properties which are more a consequence of the crosslinking densities and less from the position of the cross-link in the chain. 51 The isocyanate needed for a polyurethane synthesis can be prepared from oleic acid, via the ozonolysis of the C=C bond followed by an oxidation yielding to 1,9-nonanedioic acid, which is converted to 1,7-heptamethylene diisocyanate (Curtius rearrangement, Figure 1.6). 52 The diisocyanide can be reacted with 1,9-nonanediol prepared from oleic acid, yielding a polyuethane.…”

Rigid and semi rigid polyurethane resins: A structural investigation using DMA, SAXS and Le Bail method

“…Castor oil, obtained from the castor seed of Ricinus communis [11], is one of the most important renewable resources for the production of many industrial polymers. Their unusual composition and chemistry promotes valuable applications, including preparation of polyurethanes [12,13]. The high concentration of triglycerides in castor oil makes it almost a pure chemical, allowing to be treated as a natural polyol [5].…”

Microwave-Assisted Synthesis of Polyols from Rapeseed Oil and Properties of Flexible Polyurethane Foams

“…The usage of vegetable oil-based polyols with different functionalities determines the PUR chemical structure [10].…”