Rigid polyurethane foams from unrefined crude glycerol and technical lignins

The need for green materials has driven interest in the preparation of rigid polyurethane foam (PUF) from various biomass types. The present study aims at increasing bio-based content by utilizing by-products from both the pulp and paper and biodiesel industries. Bio-based polyols from respective liquefaction of kraft lignin, organosolv lignin and lignosulphonate in crude glycerol were employed to prepare rigid PUFs. The highest foam compressive strength was 345 kPa with density 79 kg m−3; thermal conductivity was 0.039 W m−1 K−1 and the corresponding material had 44 wt% renewable content. Thermal characteristics and biodegradability were also evaluated. Technical lignin type was found to determine product properties to a large extent. Based on the use of existing industrial scale by-products in this study, the findings can be beneficial for present and future biorefineries in the valorization of lower value by-product streams.

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Polyurethane Synthesis from Sugarcane Bagasse Organosolv and Kraft Lignin

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.659.527 ◽

2015 ◽

Vol 659 ◽

pp. 527-532 ◽

Cited By ~ 1

Author(s):

Chularat Sakdaronnarong ◽

Nattawee Srimarut ◽

Navadol Laosiripojana

Keyword(s):

Sodium Hydroxide ◽

Sugarcane Bagasse ◽

Paper Industry ◽

Pulp And Paper Industry ◽

Kraft Lignin ◽

Single Step ◽

Pulp And Paper ◽

Hydrolysis Reaction ◽

Hydroxyl Groups ◽

Organosolv Lignin

Sugarcane bagasse (SCB) was subjected to a single-step fractionation and hydrolysis reaction in the presence of various organic solvents. The reaction was performed at 170 °C for 3 h when sodium hydroxide was used as catalyst. The results showed that suitable solvents significantly enhanced the yield of lignin fractionation and simultaneous hydrolysis reaction took place indicated by an increase of hydroxyl groups in lignin molecules. Lignin-based polyurethane (LPU) from SCB organosolv lignin polyols had relatively better mechanical and thermal resistant properties compared to LPU from liquefied Kraft lignin from pulp and paper industry.

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Functionalising lignin in crude glycerol to prepare polyols and polyurethane

Polymers from Renewable Resources ◽

10.1177/2041247919830833 ◽

2019 ◽

Vol 10 (1-3) ◽

pp. 3-18

Author(s):

Louis Christiaan Muller ◽

Sanette Marx ◽

Hermanus CM Vosloo ◽

Idan Chiyanzu

Keyword(s):

Crude Glycerol ◽

Solid Phase ◽

Paper Industry ◽

Fatty Acid Esters ◽

Size Exclusion ◽

Hydroxyl Group ◽

Organosolv Lignin ◽

Exclusion Chromatography ◽

By Products ◽

Acid Esters

In this work, crude glycerol liquefaction of lignins produced in the pulp and paper industry, as well as an organosolv lignin (sugarcane bagasse), was studied with the ultimate aim of preparing bio-based polyols for polyurethane (PU) preparation. This is a proposed strategy to valorise the by-products of biodiesel and lignocellulose biorefineries. Size-exclusion chromatography revealed that the lignins behave differently during liquefaction based on a ranging product molecular weight (MW). The MW of the liquefaction products was concluded to be related to the phenolic and aliphatic hydroxyl group content of the respective lignins, as well as the removal of glycerol and monoacylglycerol during liquefaction. Lignin was modified to yield mostly a solid-phase product. Fourier transform infrared spectroscopy suggests that crude glycerol constituents like glycerol and fatty acid esters are bound to lignin during liquefaction through formation of ether and ester bonds. Liquefaction yield further also varied with lignin type. The liquefaction products were effectively employed as bio-based polyols to prepare PU.

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Comparison of four technical lignins as a resource for electrically conductive carbon particles

BioResources ◽

10.15376/biores.14.1.1091-1109 ◽

2018 ◽

Vol 14 (1) ◽

pp. 1091-1109 ◽

Cited By ~ 2

Author(s):

Janea Köhnke ◽

Notburga Gierlinger ◽

Batirtze Prats-Mateu ◽

Christoph Unterweger ◽

Pia Solt ◽

...

Keyword(s):

Composite Films ◽

Particle Morphology ◽

Major Effect ◽

Kraft Lignin ◽

High Mass ◽

Carbon Particles ◽

Organosolv Lignin ◽

High Mass Loss ◽

Soda Lignin ◽

Technical Lignins

Carbon microparticles were produced from different technical lignins, i.e., kraft lignin, soda lignin, lignosulfonate, and organosolv lignin, at different carbonisation temperatures (800 °C, 1200 °C, 1600 °C, and 2000 °C). Before carbonisation, oxidative thermostabilization was performed. The combination of thermostabilization and carbonisation led to a high mass loss and shrinkage, but no major effect on the particle morphology was apparent. The carbon particles obtained from all four lignin variants developed disordered graphitic structures at high carbonisation temperatures, and good electrical conductivities in the carbon powders were observed for all lignin variants, with the exception of lignosulfonate. The polycaprolactone composite films filled with 30% lignin-derived carbon exhibited various conductivities, with the best results achieved using the kraft lignin-derived carbon.

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Valorization of Lignin Side-Streams into Polyols and Rigid Polyurethane Foams—A Contribution to the Pulp and Paper Industry Biorefinery

Energies ◽

10.3390/en14133825 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3825

Author(s):

João A. Pinto ◽

Isabel P. Fernandes ◽

Virginia D. Pinto ◽

Elson Gomes ◽

Cátia F. Oliveira ◽

...

Keyword(s):

Thermal Conductivity ◽

Paper Industry ◽

Black Liquor ◽

Pulp And Paper Industry ◽

Polyurethane Foams ◽

Pulp And Paper ◽

Chemical Production ◽

Material Synthesis ◽

Kraft Black Liquor ◽

By Products

Valorization of industrial low-value side-streams are of great interest, contributing to boosts in the circular economy. In this context, lignin side-streams of the pulp and paper industry were oxypropylated to produce biobased polyols and tested in the synthesis of rigid polyurethane (RPU) foams. E. globulus lignins, namely a lignin isolated from an industrial Kraft black liquor and depolymerized lignins obtained as by-products of an oxidation process, were used. RPU foams, synthesized with 100% lignin-based polyols and using a 1.1 NCO/OH ratio, were characterized concerning apparent density, morphology, thermal conductivity, thermal stability, and heat release rate (HRR). Foams containing the lignin-based polyols presented densities varying from 44.7 to 112.2 kg/m3 and thermal conductivity in the range of 37.2–49.0 mW/mK. For the reference foam (sample produced with 100% wt. Daltofoam TP 32015 polyol), values of 70.9 kg/m3 and 41.1 mW/mK were obtained, respectively. The achieved results point out the viability of using the generated lignin-based polyols at 100% content in RPU foams, mainly when depolymerized lignins are used. Moreover, fire retardancy was favored when the lignin-based polyols were introduced. The proposed strategies can contribute to establishing the integrated pulp and paper biorefinery concept where material synthesis (polyols and RPU foams) can be combined with chemical production (vanillin and syringaldehyde).

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Structural Analysis of Residual and Technical Lignins by 1H-13C Correlation 2D NMR-Spectroscopy

Holzforschung ◽

10.1515/hf.2001.050 ◽

2001 ◽

Vol 55 (3) ◽

pp. 302-308 ◽

Cited By ~ 43

Author(s):

Ewellyn A. Capanema ◽

Mikhail Yu Balakshin ◽

Chen-Loung Chen ◽

Josef S. Gratzl ◽

Hanna Gracz

Keyword(s):

Structural Analysis ◽

Eucalyptus Globulus ◽

2D Nmr ◽

Kraft Lignin ◽

Coniferyl Alcohol ◽

Spectroscopic Techniques ◽

Carbonyl Groups ◽

2D Nmr Spectroscopy ◽

Organosolv Lignin ◽

Technical Lignins

Summary Structural analysis was conducted on residual lignin from pine Kraft AQ pulp, Eucalyptus Kraft lignin from Eucalyptus globulus and Repap Organosolv lignin by 2D 13C-1H correlation NMR spectroscopic techniques such as HMQC sequence. These lignins contain a rather wide variety of saturated aliphatic groups. The HMQC NMR spectra of the lignins do not verify the presence of diarylmethane moieties in any lignin investigated. The type and amount of other condensed structures depend on the nature of lignin preparation. All the lignins investigated still contained β-O-4′, pino- and syringayresinol (β-β′) and phenylcoumarane (β-5′) structures. Stilbene structures were also identified. Vinyl ether structures were present only in Eucalyptus Kraft lignin. All the lignins contain α-carbonyl groups conjugated to aromatic moieties as terminal side chains rather than involving β-O-4′ structures. No coniferyl alcohol and coniferyl aldehyde type structures are detected in the lignins after pulping. The spectra of kraft lignins show some new signals, the origin of which is discussed.

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