Hydroxymethylation of technical lignins obtained from different pretreatments for preparation of high-performance rigid polyurethane foam

Lee, Yerin; Tran, My Ha; Lee, Eun Yeol

doi:10.1007/s00107-022-01845-z

Cited by 9 publications

(4 citation statements)

References 40 publications

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“…Lignin-based foams even outperformed oxypropylated lignin as a 100% polyol replacement in low-density rigid PUR foam (90 kPa) . A similar result was found with the compression strength of hydroxymethylated lignin used as 2–30% polyol replacement in low-density rigid PUR foam (∼40 kPa) …”

Section: Resultssupporting

confidence: 76%

“…33 A similar result was found with the compression strength of hydroxymethylated lignin used as 2−30% polyol replacement in low-density rigid PUR foam (∼40 kPa). 69 The horizontal burn flammability test was used to determine the foams' flammability rating (HF1 and HF2). 44 This test can ensure the safety of products by elucidating the relative burn rate, time, and extent of the burn.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Lignin-Based Low-Density Rigid Polyurethane/Polyisocyanurate Foams

Henry

Nejad

2023

Ind. Eng. Chem. Res.

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In this study, unmodified kraft softwood lignin was utilized to fully replace the petroleum-based polyol for the first time in low-density rigid polyurethane/polyisocyanurate (PUR/PIR) foam. The effects of different lignin incorporation levels (0, 25, 50, 75, and 100%) on foam properties were investigated by measuring foam's reactivity, polyol viscosity (using a rheometer), apparent density, compression strength, closed cell content (using a gas pycnometer), thermal conductivity, fire resistance, and morphology (observed through SEM). All formulated lignin-based foams met the ASTM minimum requirements for type 1 rigid insulation foams. Remarkably, the foam made by replacing 100% of the petrochemical polyol with the commercially available kraft lignin demonstrated outstanding fire resistance performance, reducing the burn length by 127%.

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Section: Resultssupporting

confidence: 76%

Section: ■ Results and Discussionmentioning

confidence: 99%

Lignin-Based Low-Density Rigid Polyurethane/Polyisocyanurate Foams

Henry

Nejad

2023

Ind. Eng. Chem. Res.

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“…117,118 Lignin reactivity in hydroxymethylation is affected by its source (softwood, hardwood, or grass), pulping factors ( pulping chemicals, pH value, temperature, pressure), and reaction circumstances. [119][120][121] Benar et al used Acetosolv (EAc) lignin and Formacell (EFo) lignin from Eucalyptus as phenol substitutes to synthesize LPR using a hydroxymethylation modification method. 93 The hydroxymethylation was performed using a lignin : formaldehyde : NaOH mixture of 1 : 2.4 : 1 molar ratio with a solid content of 15%.…”

Section: Synthesis Of Lpr From Modified Ligninmentioning

confidence: 99%

Lignin as a green and multifunctional alternative to phenol for resin synthesis

Sun

Wang

et al. 2023

Green Chem.

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“…130,131 The hydroxymethylation reaction is affected by the type of lignin, lignin/formaldehyde ratio, and temperature. 130,132 High temperature, long reaction time, and strong alkaline will cause the condensation of hydroxymethylated lignin. Mild reaction conditions will result in a low degree of hydroxymethylation.…”

Section: Functionalization Strategies For Ligninmentioning

confidence: 99%