Lignin-based Foams: Production Process and Characterization

Tondi, Gianluca; Link, Martin; Kolbitsch, Christian; Gavino, Johannes; Luckeneder, Paul; Petutschnigg, Alexander; Herchl, Richard; Doorslaer, Charlie Van

doi:10.15376/biores.11.2.2972-2986

Cited by 33 publications

(21 citation statements)

References 21 publications

(25 reference statements)

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“…This leads to a more violently exothermal furfuryl alcohol self-condensation reaction. The higher intensity of F1 leads to a similar cell morphology as reported for furanic-lignin foams [33]. Second, the cell shape of foams F2 and F3 seems to be more spherical, and there is a large number of pores in the cell walls.…”

Section: Sem Analysissupporting

confidence: 64%

Characterization and Preparation of Furanic-Glyoxal Foams

Pizzi

Lei

et al. 2020

Polymers

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Synthetic foams have become an essential industrial product for a great variety of applications. Furfuryl alcohol, as a biomass chemical, was reacted with glyoxal at room temperature to prepare furanic-glyoxal rigid foams, and p-toluenesulfonic acid was used as a catalyst to initiate the reaction. Foams with different molar ratios (furfuryl alcohol/glyoxal) were prepared in this work, and uniform cells foams have been obtained. Their compression resistance, 24-h water absorption, density, and other basic properties were tested. Scanning electron microscopy (SEM) was used to observe the cellular morphology of the foams prepared, thermogravimetric analysis (TGA) helped to understand their thermal and combustion properties, and FTIR and Matrix Assisted Laser Desorption Ionisation Time of Flight (MALDI ToF) mass spectroscopy to explain the structure of the resulting foams to clarify the reactions occurring during foaming. The results show that the compression resistance of furanic-glyoxal foams declined as the furfuryl alcohol/glyoxal ratio decreases also. SEM observations revealed that foams with open-cell were obtained when furfuryl alcohol was added in greater amounts, and more closed cell structures were formed as the proportion of glyoxal increased. TGA results showed that the initial ignition temperature of furanic-glyoxal foams is ~200 °C higher than that of wood, and the smaller comprehensive combustion index S (about 0.15 × 10−7 (%2 K−3 min−2)) indicates that the foam burns slowly and has poor flammability, that is, it is not easy to burn.

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Section: Sem Analysissupporting

confidence: 64%

Characterization and Preparation of Furanic-Glyoxal Foams

Pizzi

Lei

et al. 2020

Polymers

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“…Nevertheless, the tannin foams have been constantly monitored for a decade now, for their structure and morphology [6][7][8], and their chemical and physical properties [9][10][11]. Tannin foams have shown remarkable properties: they are based on natural resources [12,13]; they are very light, and can be produced with different heating systems [14,15]; they are fire and water resistant [16]; they can be modified and functionalized [17][18][19]; they can be easily combined with different top layers [20]; and they can even be reused at the end of their working life [21].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of High-Performing Sulfur-Free Tannin Foams

et al. 2020

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Tannin foams are green lightweight materials that have attracted industrial interest for the manufacturing of sandwich panels for insulation purposes. However, the dimensions of the cells and the presence of sulfur in the formulation developed until now have discouraged their upscaling. In this work, we present the synthesis and the characterization of the more promising small cell and sulfur-free materials. It was observed that, with respect to standard ones, foams catalyzed with nitric acid present similar physical properties and more phenolic character, which favors the absorption of ionic pollutants. Conversely, the foams blown with aliphatic solvents and surfactants present smaller pores, and higher mechanical and insulating properties, without affecting the chemical properties or the heating value. The combined foam produced with nitric acid as a catalyst and petroleum ether as a blowing agent result in sulfur-free and small cell material with overall improved features. These foams have been produced at 30 × 30 × 3 cm3, with high homogeneity and, to date, they represent the most suitable formulation for industrial upscaling.

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“…Many applications could be developed using lignin as the main ingredient and also as a secondary ingredient such as dispersants, binders, emulsifiers, epoxy resins, or even foams (El Mansouri et al 2011;Arkell et al 2014;Tondi et al 2016). In addition, lignin can be used in the synthesis of new, more environmentally compatible polymeric materials, such as hydrogels, which are more suitable for various applications that range from biomedical to automotive (El-Zawawy and Ibrahim 2012;Thakur and Thakur 2015).…”

Section: Introductionmentioning

confidence: 99%