resumo
In this study, modification of LignoBoost (TM) softwood kraft lignin with epichlorhydrin in water-organic solvents media was realized. Lignin-based epoxy resins were obtained by two ways: acetone extraction of glycidylated lignin or glycidylation of the acetone soluble lignin fraction. The effect of glycidylation regimes on the yields of acetone soluble fractions, their functional composition and physical-chemical characteristics was investigated using wet chemistry methods, FTIR spectroscopy, size exclusion chromatography (SEC) and differential scanning calorimetry (DSC). The positive effect of the biphasic phase transfer catalytic system - KOH/quaternary ammonium salt on glycidylation of both phenolic and aliphatic hydroxyl groups was testified, exemplified using a lignin-like model compound 4-hydroxy-3-methoxylbenzyl alcohol (vanillyl alcohol). The partial substitution (up to 10%) of commercial epoxy resin on the basis of bisphenol A (Araldite. LY1564) by lignin-based epoxy resin significantly increased the viscosity of resin. Therefore, the possible practical application of lignin-containing epoxies as adhesive, mastic or crack filler instead of binder for fiber reinforced composites was considered. A tendency towards increasing Young's modulus of cured lignin-containing epoxies, compared with the case of the reference composition, was observed. The lignin chemically incorporated into the matrix of cured commercial epoxy resin acts as a charcoal formation promoter in high temperature treatment.
palavras-chave
ORGANOSOLV LIGNIN; FRACTIONATION; PROTECTION; COMPOSITE; TANNINS
categoria
Agriculture
autores
Jablonskis, A; Arshanitsa, A; Arnautov, A; Telysheva, G; Evtuguin, D
nossos autores
Dmitry Evtyugin
Professor Associado com Agregaçãoagradecimentos
The financial support from the Collaborative European project US4GREENCHEM, Grant Agreement Number 669055 is gratefully acknowledged.