Characterization and acid-catalysed depolymerization of condensed tannins derived from larch bark

Zhang, Aibin; Li, Jiongjiong; Zhang, Shifeng; Mu, Youbing; Zhang, Wei

doi:10.1039/c7ra03410e

Cited by 41 publications

(31 citation statements)

References 54 publications

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“…Several depolymerization techniques have been utilized to convert tannin to oligomers and monomers in order to decrease steric hindrance and enhance chemical reactivity. Zhang et al depolymerized larch tannin into condensed tannin by sulfonation pretreatment, and used it for PF resin preparation [ 95 ]. Recently, Li et al depolymerized acacia mangium tannin under acidic conditions in the presence of the nucleophilic reagent, 2-methylfuran.…”

Section: Phenol Substitutes For Pf Resinmentioning

confidence: 99%

Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Sarika

Nancarrow

Khansaheb³

et al. 2020

Polymers

146

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Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.

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Section: Phenol Substitutes For Pf Resinmentioning

confidence: 99%

Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Sarika

Nancarrow

Khansaheb³

et al. 2020

Polymers

146

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“…Thus, in this temperature range, 44.1% of weight loss for T-Fs-2, 41.2% of weight loss for T-Fs-7, 43.7% of weight loss for T-Fs-11, and 42.9% of weight loss for T-Fs-13 take place. This step may be caused by breaking C-C bonds and the decomposition of pyrolysis residual products from the first two stages [55,67]. These results show that the tannin-based NIPU foams present similar pyrolysis temperature weight losses (within 8 • C).…”

Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 63%

“…The second weight loss range is between 150 • C and 250 • C, showing 18.3% of weight loss for T-Fs-2, 19.2% of weight loss for T-Fs-7, 19.3% of weight loss for T-Fs-11, and 18.1% of weight loss for T-Fs-13. The weight loss in this range is related to decomposition reactions by bond cleavage of urethane and tannin intermolecular bonds (onset temperature of mimosa tannin was 146 • C) [55,67]. The third weight loss occurs in the 350 • C and 550 • C range.…”

Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 95%

Preparation and Characterization of Condensed Tannin Non-Isocyanate Polyurethane (NIPU) Rigid Foams by Ambient Temperature Blowing

Chen

Pizzi

et al. 2020

Polymers

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Ambient temperature self-blowing mimosa tannin-based non-isocyanate polyurethane (NIPU) rigid foam was produced, based on a formulation of tannin-based non-isocyanate polyurethane (NIPU) resin. A citric acid and glutaraldehyde mixture served as a blowing agent used to provide foaming energy and cross-link the tannin-derived products to synthesize the NIPU foams. Series of tannin-based NIPU foams containing a different amount of citric acid and glutaraldehyde were prepared. The reaction mechanism of tannin-based NIPU foams were investigated by Fourier Trasform InfraRed (FT-IR), Matrix Assisted Laser Desorption Ionization (MALDI-TOF) mass spectrometry, and 13C Nuclear Magnetic Resonance (13C NMR). The results indicated that urethane linkages were formed. The Tannin-based NIPU foams morphology including physical and mechanical properties were characterized by mechanical compression, by scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). All the foams prepared showed a similar open-cell morphology. Nevertheless, the number of cell-wall pores decreased with increasing additions of glutaraldehyde, while bigger foam cells were obtained with increasing additions of citric acid. The compressive mechanical properties improved with the higher level of crosslinking at the higher amount of glutaraldehyde. Moreover, the TGA results showed that the tannin-based NIPU foams prepared had similar thermal stability, although one of them (T-Fs-7) presented the highest char production and residual matter, approaching 18.7% at 790 °C.

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“…The FTIR spectra of the PPCs and OPCs are very similar and show feature characteristic of condensed tannins, in agreement with theoretical predictions. 9,43,44 The similarity of the FTIR spectra further demonstrates that the depolymerization reaction breaks the linkages between monomers but does not affect the basic structural units of the proanthocyanidins.…”

Section: Resultsmentioning

confidence: 85%

Low-Cost Ru/C-Catalyzed Depolymerization of the Polymeric Proanthocyanidin-Rich Fraction from Bark To Produce Oligomeric Proanthocyanidins with Antioxidant Activity

Zhu

Ren

et al. 2019

ACS Omega

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A new method has been developed for the high-value utilization of larch bark, which is regarded as a low-value byproduct of the logging industry. Polymeric proanthocyanidins (PPCs) were extracted from the Larix gmelinii bark and depolymerized by catalytic hydrogenolysis, using ruthenium/carbon (Ru/C) as the catalyst. The method has been found that although the molecular weight of the depolymerized product was significantly lower, the basic structural units were not destroyed, and the product retained a condensed flavanol polyphenol structure; the depolymerized product contains very little Ru metal and thus complies with food safety standards; the antioxidant properties of both the depolymerized products and PPCs were better than those of the commonly used antioxidant 2,6-di-tert-butyl-4-methylphenol. The relative molecular weight and steric hindrance of the depolymerized products were lower than those of the PPCs, leading to better antioxidant performance. A new technical route for the depolymerization of PPCs from the L. gmelinii bark is provided. The route offers practical and commercial advantages, and the product could have many applications as an antioxidant.

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Characterization and acid-catalysed depolymerization of condensed tannins derived from larch bark

Abstract: Condensed tannins from larch bark extracts are a natural renewable and eco-friendly material and are potential substitutes for phenolic petrochemicals.

Cited by 41 publications

References 54 publications

Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Preparation and Characterization of Condensed Tannin Non-Isocyanate Polyurethane (NIPU) Rigid Foams by Ambient Temperature Blowing

Low-Cost Ru/C-Catalyzed Depolymerization of the Polymeric Proanthocyanidin-Rich Fraction from Bark To Produce Oligomeric Proanthocyanidins with Antioxidant Activity

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