Abstract
Polyurethane (PU) foams physically modified by two additive phosphorous flame retardants (FR)—phenol isobutylenated phosphate or phenol isopropylated phosphate, and chemically reinforced by functionalized 1,2-propanediolizobutyl POSS (PHI-POSS) have been synthesized and investigated towards thermal and mechanical properties, as well as flammability behaviour. The foamed PU hybrid materials were prepared in a two-step process using a polyether polyol and polymeric 4,4′-diphenylmethane diisocyanate. On the basis of the obtained results of mechanical properties, thermal insulation, thermal stability and flammability investigations, the influence of the applied additives—including POSS nanoparticles, on the rigid polyurethane foams was determined. The analysis of thermogravimetric and microcalorimetry data revealed an improved resistance to burning of the PU foams containing hybrid reactive (POSS)/additive (phosphate) FR systems, as evidenced by reduced rate of heat release. Importantly, mechanical properties tests showed that incorporation of bulky silsesquioxane nanoparticles to polyurethane structure via covalent bonds strengthens the foam integrity.
Highlights
Polyurethanes (PU) are widely used materials, obtained in the reaction of isocyanates with compounds containing active hydrogen, most often polyols
We present results of investigations on the application of 1,2-propanediolizobutyl polyhedral oligomeric silsesquioxanes (POSS) (PHI-POSS) as a reactive co-flame retardant for rigid polyurethane foams, which were modified by two additive phosphorous
The best thermal insulation properties of systems containing PIBP as flame retardant had a system consisting of PHI-POSS and 0.25 mass% phosphorus content, which may be caused by the smallest apparent density of the obtained material (Fig. 1a)
Summary
Polyurethanes (PU) are widely used materials, obtained in the reaction of isocyanates with compounds containing active hydrogen, most often polyols. PU are produced as foams, elastomers, as well as coatings and adhesives. Among the porous polyurethane materials, one can distinguish flexible and rigid polyurethane foams. Flexible polyurethane foams are used, among others, in the automotive and furniture industry, as fillings for mattresses and car seats, whereby rigid polyurethane foams find broad application as thermal insulation materials in, e.g. automotive and building sector [1–7]. One of the most important problems that is still not resolved is the polyurethane foams flammability—despite the very good thermal insulation properties, these materials do not often show the required values in the latest fire This problem has been partially solved by modifying foams chemically through the formation of isocyanurate rings, which in turn improves the properties determined in the fire tests [17, 18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
