<br/>Cellulose nanocrystals (CNCs) are renewable green materials and have been used as reinforcing agents in polymer composites. However, poor interaction and compatibility between CNCs and hydrophobic polymers lead to composites that have poor mechanical properties. Additionally, CNCs aggregate during drying, which reduces their dispersion in a matrix. To address these issues, composites of high lignin containing CNCs (HLCNCs), from hydrothermally treated poplar, and PLA were produced by compounding them together. Compared to the regular CNCs, the HLCNCs showed higher cellulose crystallinity, larger surface area, lower degree of agglomeration, more hydrophobic surface, and higher water contact angle. The effect of HLCNCs on the mechanical, thermal and viscoelastic properties and CNCs/polymer interfacial adhesion of nanocomposites was investigated with tensile test, DSC and DMA. Compared to neat PLA, the Young’s modulus, elongation to break, and toughness of PLA/2%HLCNCs were improved by 14, 77, and 30%, respectively.This compared to lignin-free PLA/2%CNCs values of 13, - 67, and - 30%, respectively.  Moreover, HLCNCs acted as nucleating fillers and increased crystallinity of PLA in the nanocomposites. The presence of lignin nanoparticles in the HLCNCs increased the compatibility/adhesion between CNCs and PLA matrix which increased the storage modulus.

Lignin-caused performance improvements of poly(lactic acid)/CNCs composites

255th National Meeting (2018)

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