Flexible polyurethane foams modified with biobased polyols: Synthesis and physical‐chemical characterization

Abstract

A series of flexible polyurethane foams with different polyol compositions were synthesized through the replacement of a portion of the petroleum‐based polyether polyol with biobased polyols, namely, glycerol (GLY) and hydroxylated methyl esters (HMETO). HMETO was synthesized by the alkaline transesterification of tung oil (TO; obtaining GLY as a byproduct) and the subsequent hydroxylation of the obtained methyl esters with performic acid generated in situ. FTIR spectroscopy, 1H‐NMR, and different analytical procedures indicated that the hydroxyl content increased significantly and the molecular weight decreased with respect to those of the TO after the two reaction steps. The characterization of the obtained foams, achieved through the measurement of the characteristic reaction times, thermal and dynamic mechanical analysis, scanning electronic microscopy, and density measurements, is reported and discussed. The most important changes in the modified foams were found with the addition of GLY to the formulation; this led to an increased foam density and storage rubbery modulus, which were associated with a higher crosslinking density because of the decrease in the chain length between crosslinking points. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43831.

Hidroxilação dos óleos de girassol, milho e crambe e caracterização química dos polióis vegetais obtidos

“…Muitos esforços vêm sendo realizados com o intuito de substituir os polióis petroquímicos por polióis obtidos a partir da modificação química de óleos vegetais, obtendo-se polímeros "ecologicamente corretos". Nesse sentido, os polióis oleoquímicos se destacam como matérias-primas alternativas para a síntese de produtos uretânicos, cujas propriedades competem com a de PUs produzidas a partir de polióis petroquímicos [14,15].…”

Open-Cell Rigid Polyurethane Foams from Peanut Shell-Derived Polyols Prepared under Different Post-Processing Conditions

“…Generally, vegetable oils [4,8,12,13,14,15,16,17,18,19,20,21,22] and plant fibers [23,24,25,26,27,28,29] contain abundant hydroxyl groups or double bonds, which require chemical modification or liquefaction to generate bio-based polyols (BBPs) with proper hydroxyl numbers [10,11]. BBPs with hydroxyl numbers in the range of 200–550 mg KOH·g −1 would be suitable alternatives to replace the petroleum-based polyols for RPUFs synthesis [30].…”

Bio‐based flexible polyurethane foams derived from succinic polyol: Mechanical and acoustic performances

“…Smaller cavities and pores with a narrow distribution of sizes were achieved with the polyol mixture SP + BP. This result may be attributed to the reactivity of polyols SP and BP that built viscosity faster and gel earlier . In contrast, in presence of CB the addition of higher amount of flame retardant TEP which plasticizes the foam system (see the lower viscosity of PUC system reported in Table ), lead to irregular coalescence between close cavities, and it thus results to large cavity and pore sizes with high size uncertainties .…”