title: Epoxy resin synthesis using low molecular weight lignin separated from various lignocellulosic materials.
abstract: A low molecular weight lignin from various lignocellulosic materials was used for the synthesis of bio-based epoxy resins. The lignin extracted with methanol from steam-exploded samples (steaming time of 5 min at steam pressure of 3.5 MPa) from different biomasses (i.e., cedar, eucalyptus, and bamboo) were functionalized by the reaction with epichlorohydrin, catalyzed by a water-soluble phase transfer catalyst tetramethylammonium chloride, which was further reacted with 30 wt% aqueous NaOH for ring closure using methyl ethyl ketone as a solvent. The glycidylated products of the lignin with good yields were cured to epoxy polymer networks with bio-based curing agents i.e., lignin itself and a commercial curing agent TD2131. Relatively good thermal properties of the bio-based epoxy network was obtained and thermal decomposition temperature at 5% weight loss (Td5) of cedar-derived epoxy resin was higher than that derived from eucalyptus and bamboo. The bio-based resin satisfies the stability requirement of epoxy resin applicable for electric circuit boards. The methanol-insoluble residues were enzymatically hydrolyzed to produce glucose. This study indicated that the biomass-derived methanol-soluble lignin may be a promising candidate to be used as a substitute for petroleum-based epoxy resin derived from bisphenol A, while insoluble residues may be processed to give a bioethanol precursor i.e., glucose.
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Asada
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan.
authors.forename: Sunita
authors.initials: S
authors.lastname: Basnet
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Otsuka
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan.
authors.forename: Chizuru
authors.initials: C
authors.lastname: Sasaki
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan. Electronic address: ynakamu@bio.tokushima-u.ac.jp.
authors.forename: Yoshitoshi
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D018533:Biomass; D004853:Epoxy Resins / Q000138:chemical synthesis / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry*; D000432:Methanol; D008970:Molecular Weight; D019906:Nuclear Magnetic Resonance, Biomolecular; D010944:Plants / Q000737:chemistry; D012995:Solubility; D012997:Solvents; D013816:Thermodynamics
chemical_list: D004853:Epoxy Resins; D012997:Solvents; C036909:lignocellulose; D008031:Lignin; D000432:Methanol
keywords: Lignin epoxy resin; Lignocellulosic material; Low molecular weight lignin