Affiliation:
1. College of Materials Science and Engineering , Nanjing Forestry University , Nanjing 210037 , China
Abstract
Abstract
In recent years, tannin degradation has been used to obtain tannin materials with an optimal molecular weight distribution (MWD) for synthesizing tannin-formaldehyde (TF) resin with high performance, but the optimal MWD of tannins is still unknown. The excellent formaldehyde reactivity of tannins is the basis for the synthesis of high-performance TF resin. Based on the formaldehyde reactivity of tannins, bayberry tannins and larch tannins were used to explore the optimal MWD of tannins for TF resin synthesis. Progressive solvent precipitation (PSP) was used to obtain tannin fractions with different MWDs. The formaldehyde reactivity of tannins was determined using the modified Stiansy method combined with the standard curve method (GB/T 17657-2013). The bayberry tannin fraction [weight-average molecular weight (Mw) of acetylated tannin: 4115, mean degree of polymerization (mDP): 6.64] and the larch tannin fraction (Mw of acetylated tannin: 3906, mDP: 5.84) had the best formaldehyde reactivity. Furthermore, significant differences in the formaldehyde reactivity of condensed tannins (CTs) with different MWDs were observed. The obtained results can be used to purposefully degrade tannins to achieve an optimal MWD, which is beneficial for the production of TF adhesives with high performance.
Reference39 articles.
1. Arbenz, A., Averous, L. (2015) Chemical modification of tannins to elaborate aromatic biobased macromolecular architectures. Green Chem. 17:2626–2646.
2. Barbosa, A.P., Mano, E.B., Andrade, C.T. (2000) Tannin-based resins modified to reduce wood adhesive brittleness. Forest Prod. J. 50:89–92.
3. Cadahía, E., Conde, E., García-Vallejo, M.C., Simón, B.F.D. (1996) Gel permeation chromatographic study of the molecular weight distribution of tannins in the wood, bark and leaves of Eucalyptus spp. Chromatographia 42:95–100.
4. Can, M., Bulut, E., Ozacar, M. (2012) Synthesis and characterization of gallic acid resin and its interaction with palladium(II), rhodium(III) chloro complexes. Ind. Eng. Chem. Res. 51: 6052–6063.
5. Chai, W.M., Huang, Q., Lin, M.Z., Ou-Yang, C., Huang, W.Y., Wang, Y.X., Xu, K.L., Feng, H.L. (2018) Condensed tannins from longan bark as inhibitor of tyrosinase: structure, activity, and mechanism. J. Agr. Food Chem. 66:908–917.
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