Lignin containing nanocellulose fibrils are an emerging highly attractive type of nanocellulose that holds excellent promises for improving performance of a wide range of polymer systems. With the presence of a large amount of lignin on their surfaces, LCNF exhibits some distinctive characteristics compared to nanocellulose fibrils without lignin. Our group has developed a novel processing method for producing LCNFs using bark residues that is simple and requires low energy input. We have shown the strong potential of applying bark derived LCNF for enhancing performance of the resulting composite products in thermoplastics, thermosets, and polyurethane adhesive systems. Polyolefin engineering plastics as well as fully biodegradable biopolymers were investigated. Melt blending of spray dried LNCF with polypropylene showed the resulting composites having significantly improved water-repellence, thermal stability, and tensile properties compared to composites made with nanocellulose fibrils without lignin. With LCNF additions to the PLA matrix, higher mechanical, thermal, and water vapour barrier properties was observed for the fully biodegradable biocomposites due to effective interfacial coupling. Meanwhile, the addition of 20–36 wt% of LCNFs to neat epoxy had almost doubled the tensile modulus and strength of the resulting thermoset composites. These novel composites showed much better mechanical properties than those reported in the literature with a similar loading amount of cellulose nanofibrils. The resultant composites showed high thermal stability and very low degrees of water absorption and water vapour transmission rate were obtained for the composites. The water vapour barrier efficiency of the LCNF composites increased dramatically. For applications in adhesives system, LCNF dramatically improved the pMDI adhesive gap-filling properties by serving as a reactive medium to bridge the bonding gaps and helped to form a continuous bondline in the adhesive joints. The LCNF usage allows pMDI to become a more versatile and sustainable wood adhesive with broader applications.<br/>

Lignin containing nanocellulose fibrils: A promising biomaterial for performance enhancement in polymeric systems

2019 Spring National Meeting

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