Thermoset-Cross-Linked Lignocellulose: A Moldable Plant Biomass

Abstract

The present work demonstrates a high biomass content (i.e., up to 90% by weight) and moldable material by controlled covalent cross-linking of lignocellulosic particles by a thermoset through epoxide-hydroxyl reactions. As an example for lignocellulosic biomass, Eastern redcedar was employed. Using scanning fluorescence microscopy and vibrational spectroscopy, macroscopic to molecular scale interactions of the thermoset with the lignocellulose have been revealed. Impregnation of the polymer resin into the biomass cellular network by capillary action as well as applied pressure results in a self-organizing structure in the form of thermoset microrods in a matrix of lignocellulose. We also infer permeation of the thermoset into the cell walls from the reaction of epoxides with the hydroxyls of the lignin. Compression tests reveal, at 30% thermoset content, thermoset-cross-linked lignocellulose has superior mechanical properties over a commercial wood plastic composite while comparable stiffness and strength to bulk epoxy and wood, respectively. The failure mechanism is understood to be crack propagation along the particle-thermoset interface and/or interparticle thermoset network.

Highly Toughened and Transparent Biobased Epoxy Composites Reinforced with Cellulose Nanofibrils

“…Figure 5 shows the infrared spectra of pure CNF film, cured neat epoxy, and composite with 23 wt % CNF. CNF film showed major absorption peaks at 3330 cm −1 (O-H stretching), 1161 cm −1 (C-O-C asymmetric stretching), 990 cm −1 and 1056 cm −1 (C-O stretching), 1369 cm −1 (symmetric C-H deformation), 1425 cm −1 (asymmetric C-H deformation) associated with various polysaccharides (cellulose and hemicellulose) [35,36]. The cured neat epoxy showed major peaks at 3370 cm −1 (O-H stretching), 1607 cm −1 (C=C stretching in phenyl groups), 1036 cm −1 (C-O symmetric stretching in ether groups), 1334 cm −1 (C-H deformation in epoxide groups), 1295 cm −1 (C-H vibration in epoxide groups), and 915 cm −1 (in-plane asymmetric deformation of epoxide ring) [35,37,38].…”

Photoprintable nanowire–polymer blends synthesized by dynamic emulsion polycondensation

“…Additionally, the IR spectra of the AgNW–N66 blends in Figure (c), reveal a continuous shift of the N─H stretching band with increasing concentration of AgNWs. This higher wave‐number shift is due to the stiffening of the N─H bonds, as the H‐bonding crosslinks in nylon (e.g., between N─H and C═O groups) are cleaved with the increasing population of AgNWs . Concomitantly, the C═O stretching at 1710 cm −1 , associated with free end groups in N66, intensifies.…”

Enhanced oil resistance and mechanical properties of nitrile butadiene rubber/lignin composites modified by epoxy resin

“…The authors believe that the OH groups (or COOH groups) of lignin could react with the epoxy groups of F51 by the ring‐opening reaction . Since F51 and lignin are both the multifunctional polymers, F51 and lignin would link into an insoluble, rigid, 3‐D structure networks.…”

“…interaction between Lignin and F51 in the NBR Matrix The authors believe that the OH groups (or COOH groups) of lignin could react with the epoxy groups of F51 by the ringopening reaction. 23,27 Since F51 and lignin are both the multifunctional polymers, F51 and lignin would link into an ARTICLE WILEYONLINELIBRARY.COM/APP insoluble, rigid, 3-D structure networks. N-NBR/50lignin/F51 compounds are subjected to torque analysis by the vulcameter.…”