Polyurethanes and polyesters from lignin

Abstract

Lignin, obtained through steam explosion\ud from straw, was completely characterized via elemental\ud analysis, gel permeation chromatography, ultraviolet and\ud infrared spectroscopy, and 13C and 1H nuclear magnetic\ud resonance spectrometry. Polyurethanes were obtained by\ud treating steam-exploded lignin from straw with 4,4-methylenebis(\ud phenylisocyanate), 4,4-methylenebis(phenylisocyanate)\ud –ethandiol, and poly(1,4-butandiol)tolylene-2,4-diisocyanate\ud terminated. The obtained materials were characterized\ud by using gel permeation chromatography, infrared\ud spectroscopy, and scanning electron microscopy. Differential\ud scanning calorimetry analysis showed a Tg at 6°C,\ud assigned to the glass transition of the poly(1,4-butandiol) chains. The presence of ethylene glycol reduced the yields of\ud the polyurethanes. The use of the prepolymer gave the best\ud results in polyurethane formation. Steam-exploded lignin\ud was used as the starting material in the synthesis of polyesters.\ud Lignin was treated with dodecanoyl dichloride. The\ud products were characterized by using gel permeation chromatography,\ud infrared spectroscopy, 13C and 1H nuclear\ud magnetic resonance spectrometry, and scanning electron microscopy

Microstructure-Property Relationship in Self-Crosslinked Non-Derivative Acetic Acid Lignin-Containing Polyurethane Membranes

“…LPU1-THF particles had the biggest dimension with about 10 µm in diameter; LPU1-dioxane had globular particles about 5 µm in diameter, and the LPU1-DMAc had smallest diameter of about 2 µm in grain shape. It was reported that PU from lignin and MDI in THF appeared as grain with dimension higher than 200 µm [41]. In contrast, our research showed that LPU particles had much smaller particle size.…”

“…Increasing the TMP content from 0% to 2%, the LPUT2 membrane became more homogeneous. The results can be explained by the hypothesis that the PU domains and lignin domains are interpenetrated into each other, due to the increased physical and chemical interlocks when two molecules are simultaneously crosslinked in the close vicinity of the other component [41]. This interlocks will minimize phase separation and improve the compatibility.…”

Chemistry of lignin-based materials

“…Diacyl chloride can be reacted with hydroxyl groups of lignin to form ester linkages under basic conditions. 114,172 Here, the diacyl chloride ratio to hydroxyl groups at lignin is important because the ratio determines the density of the fi nal lignin-based polyester by the degree of cross-linking. Lignin-based polyesters were synthesized by polycondensation of lignin and dicarboxylic acid, adipic acid and/or phthalic anhydride.…”

“…Lignin-based polyesters were synthesized by polycondensation of lignin and dicarboxylic acid, adipic acid and/or phthalic anhydride. 114,172 Hydrothermally treated sulfuric acid lignin 191 was reacted with caprolactone to produce polyesters. Ring opening polymerization of caprolactone occurred with the participation of hydroxyl groups and carboxylic groups at lignin and a highly cross-linked lignin-based polyester was obtained as a result.…”

Preparation of Lignin-Based Quaternary Amine Anion Exchangers in NaOH Solutions and their Characteristics

“…Lignin can be used to prepare polymeric materials, such as polyurethanes (Bonini et al 2005;Liu et al 2009), phenolic resins (Cavdar et al 2008;Wang et al 2009), and epoxy resins (Nieh and Glasser 1989;Zhao et al 2000). Researchers have developed several methods to synthesize lignin-based epoxy resins.…”