Oxypropylation of Lignins and Preparation of Rigid Polyurethane Foams from the Ensuing Polyols

Nadji, Hamid; Bruzzese, Cécile; Belgacem, Mohamed Naceur; Benaboura, Ahmed; Gandini, Alessandro

doi:10.1002/mame.200500200

Cited by 178 publications

(174 citation statements)

References 15 publications

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“…Several studies have suggested that the solubility and uniformity of the lignin are the key parameters that affect its reactivity as a substitute for polyol in PU fabrication (Hsu and Glasser 1976;Saraf et al 1985;Rials and Glasser 1986;Mörck et al 1988;Ciobanu et al 2004;Hatakeyama et al 2008). Lignin substitution in PU could be achieved directly by the combination with polyol (Yoshida et al 1990;Evtuguin et al 1998;Vanderlaan and Thring 1998;Cateto et al 2008) or through chemical modifications (Glasser 1989;Gandini et al 2002;Nadji et al 2005;Ahvazi et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Formation of Ligno-Polyols: Fact or Fiction

Ahvazi

Wojciechowicz

et al. 2017

BioResources

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The physical and chemical characteristics of several lignin-polyol blends were investigated by qualitative and quantitative methods from the view of biobased polyurethane applications. Four differently isolated biomass lignins from forestry and agricultural residues were blended with polyester polyol, and one was blended with polyethylene glycol. The isolated products were examined thoroughly to elucidate the subsequent lignin and polyol interactions during the premixing stage of biobased polyurethane formulation. Polyol was detected in lignin even after vigorous washings with several organic solvents and Soxhlet extraction. The experimental data coupled with two-dimensional heteronuclear multiple quantum coherence (HMQC) and nuclear magnetic resonance (NMR) spectroscopy confirmed the formation of ligno-polyols via strong intermolecular attractions, as well as some linkages between several lignin hydroxyl and polyol functional groups.

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Section: Introductionmentioning

confidence: 99%

Formation of Ligno-Polyols: Fact or Fiction

Ahvazi

Wojciechowicz

et al. 2017

BioResources

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“…Lignin substitution in polyurethane could be achieved either by direct substitution, in combination with polyols, 10,11,15 or through chemical modification. 8,16,17 The objective of lignin modification is to increase the reactivity of specific functional groups in lignin and enhance the polycondensation process during the production of biobased polyurethanes. 16,17 For example, free phenolic ÀOH groups are found to be more reactive 18 than benzylic ÀOH except toward diisocyanates.…”

Section: ' Introductionmentioning

confidence: 99%

Preparation of Lignopolyols from Wheat Straw Soda Lignin

Ahvazi

Wojciechowicz

Ton-That

et al. 2011

J. Agric. Food Chem.

112

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Wheat straw soda lignin was modified and characterized by several qualitative and quantitative methods such as 31 P NMR spectroscopy to evaluate its potential as a substitute for polyols in view of polyurethane applications. Chemical modification of the lignin was achieved with propylene oxide to form lignopolyol derivatives. This was performed by a two-step reaction of lignin with maleic anhydride followed by propylene oxide and by direct oxyalkylation under acidic and alkaline conditions. The physical and chemical properties of lignopolyols from each method and the subsequent chain-extended hydroxyl groups were evaluated. Direct oxyalkylation of lignin under alkaline conditions was found to be more efficient than acidic conditions and more effective than the two-step process for preparing lignopolyol with higher aliphatic hydroxyl contents.

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“…The high functionality associated to these polyols makes them ideal for the synthesis of RPU foams. Several studies revealed that RPU foams obtained from lignin based polyols present insulating properties, dimensional stability and accelerated ageing behaviour very similar to those prepared with commercial polyols [2][3]. Moreover, the intrinsic properties of lignin will also contribute to an improvement of moisture and flame resistance [4].…”

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confidence: 99%

Rigid Polyurethane Foams From Lignin Based-Polyols

Cateto¹,

Barreiro²,

Rodrigues³

et al. 2008

AIP Conference Proceedings

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Rigid polyuretliane (RPU) foams were syntliesized using lignin-based polyols obtained by an oxypropylation process. Alcell, Indulin AT, Curan 27-11P and Sarkanda lignins have been oxypropylated using formulations deduced from an optimization study with Alcell. L/PO/C (ratio between lignin, PO and catalyst content) of 30/70/2 and 20/80/5 were used to obtain the desired polyols. The resulting RPU foams were characterized in terms of density, mechanical properties, conductivity and morphology. All Sarkanda lignin based polyols and the 30/70/2 Curan 27-11P polyol were found inadequate for RPU formulations. Alcell and Indulin AT based polyols and the 20/80/5 Curan 27-1 IP polyol resulted in RPU foams with properties very similar to those obtained from conventional commercial polyols. RPU foams produced with the 30/70/2 Alcell and the 30/70/2 Indulin AT polyols exhibited improved properties compared with those from 20/80/5 based formulations. INTRODUCTIONPolyurethanes are considered as one of the most versatile polymeric materials offering a wide range of products with applications in diverse sectors. Rigid polyurethane (RPU) foams belong to this class of products. Due their excellent insulation and mechanical properties they are widely used in construction, automotive, freeze industry and nautical applications. Nowadays, due to economical and environmental concerns, the utilization and development of low-cost polyols from abundant and renewable biomass resources has gained an increasing attention in polyurethane industry. Lignin is among these biomass resources, and its application as a macromonomer in polyurethane synthesis, has been the subject of study of several research groups [1-2]. Oxypropylation has been recognized as a viable and promising approach to overcome the technical limitations and constrains imposed by the polymeric nature of lignin when directly used as a macromonomer for synthesis purposes. By means of oxypropylation, the hydroxyl groups, in particular the phenolic ones hardly accessible because entrapped inside the molecule are liberated from steric and/or electronic constrains. Moreover, such chain extension reaction leads to the formation of lignin-based liquid polyol, thanks to the introduction of multiple ether moieties. The high functionality associated to these polyols makes them ideal for the synthesis of RPU foams. Several studies revealed that RPU foams obtained from lignin based polyols present insulating properties, dimensional stability and accelerated ageing behaviour very similar to those prepared with commercial polyols [2][3]. Moreover, the intrinsic properties of lignin will also contribute to an improvement of moisture and flame resistance [4]. These results were quite motivating, giving emphasis to the need of further research in this domain allowing lignin valorisation through its incorporation in a polymeric material. This work aims to evaluate the suitability of two lignin-based formulations (20/80/5 and 30/70/2) to produce RPU foams. Density, mechanical properties, ...

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Oxypropylation of Lignins and Preparation of Rigid Polyurethane Foams from the Ensuing Polyols

Cited by 178 publications

References 15 publications

Formation of Ligno-Polyols: Fact or Fiction

Formation of Ligno-Polyols: Fact or Fiction

Preparation of Lignopolyols from Wheat Straw Soda Lignin

Rigid Polyurethane Foams From Lignin Based-Polyols

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