New polyols with isocyanuric structure by thiol-ene “click” chemistry reactions

Abstract

New polyols with isocyanuric structure were synthesized by thiol-ene “click” chemistry of triallyl isocyanurate with 1-thioglycerol and 2-mercaptoethanol. The synthesized polyols, prepared with high reaction rates and in very high yields, were chemically and structurally characterized. These polyols were used for the preparation of rigid polyurethane foams with excellent physical–mechanical properties and inherent flame retardancy. By alkoxylation of isocyanuric polyols with propylene oxide and/or ethylene oxide in a self-catalytic process, odorless polyols with lower hydroxyl numbers and lower viscosities were obtained, leading to PU foams with good properties, but without inherent flame retardancy. The synthesized polyols with isocyanuric structure are suitable for the preparation of all types of rigid polyurethane foams, including thermoinsulation of freezers, buildings, storage tanks and pipes for the food and chemical industry, for packaging, and as wood substitutes.

Expendable Graphite as an Efficient Flame-Retardant for Novel Partial Bio-Based Rigid Polyurethane Foams

“…Wavenumber (cm -1 ) A compression test was performed to analyze the effect of an increasing amount of EG on the mechanical properties of PU foams (Figure 9). EG is being reported as a cost-effective FR with the drawbacks of harder processing and a decrease of mechanical strength [24,34]. The ultimate compressive strength value was found to be 210 kPa and 209 kPa for neat PU foam prepared using synthesized biopolyol and Jeffol 522, respectively.…”

“…The 10 EG-PU foam showed a yield at the break of 175 kPa. Although EG acts as an effective FR when used in the form of flakes, its higher concentration in PU foams may cause defects into segments of the foam, hence it deteriorates some of its mechanical properties, causing the compressive strength to vary [21,24,[35][36][37][38]. Even though there was a decrease in mechanical properties with increasing concentration of PU foams, all the EG-PU foams showed higher compression strength than foams originated from castor, cardanol, and corn oils that were 150, 130, and 75 kPa, respectively [5,39].…”

“…The EG pyrolysis comprises of SO 2 , CO 2 , and water that gets entrapped while escaping near the edges of the graphitic structure, leading to the irreversible expansion of the graphene structure [21]. The expansion then creates a graphitic char layer on the surface of the foam that prevents the heat transfer through the solid phase and stops the fire [21,24,35]. This type of phenomenon is observed by the expansion of foam surface during the burning test, which may sometimes form blisters of charred graphene.…”

“…Its flame retardancy occurs due to the formation of a protective char layer on the surface, inhibiting fire growth. It is also used as a filler within the foams to reduce the overall cost of the foams [18,24]. However, extensive quantities can result in a systematic decrease in mechanical properties of the foams.…”

Elaboration and Characterization of Advanced Biobased Polyurethane Foams Presenting Anisotropic Behavior

“…Several researchers have studied the elaboration and the physical characterization of biobased polymer foams by using different approaches . However, the mechanical and thermal properties of these materials have been less investigated.…”