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Interfacial improvements in cellulose nanofibers reinforced polylactide bionanocomposites prepared by in situ reactive extrusion
Author(s) -
Li FengJiao,
Yu XiTong,
Huang Zan,
Liu DingFu
Publication year - 2021
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.5264
Subject(s) - materials science , reactive extrusion , ultimate tensile strength , nanocomposite , crystallinity , nanofiber , composite material , grafting , nucleation , crystallization , extrusion , chemical engineering , polymer chemistry , polymer , organic chemistry , chemistry , engineering
Grafting of polylactide (PLA) onto the cellulose nanofiber (CNF) (CNF‐g‐PLA) was prepared by in situ reactive extrusion using dicumyl peroxide (DCP) as a free radical initiator to improve the interfacial adhesion between CNFs and PLA. The effect of DCP content on the dynamic rheological properties, crystallization behavior, mechanical properties, and micromorphology of PLA/CNF (95/5) bionanocomposite was systematically investigated. FTIR spectra confirmed that PLA chains were successfully grafted onto the CNF surface by forming CC bonds. The presence of such CC crosslinks improved stress transfer at the CNF–PLA interface; SEM and TEM observations and adhesion factor calculated from DMA data confirmed that the synthesized graft copolymers improved the interfacial interaction between CNFs and PLA matrix, thus enhancing the mechanical properties of CNF‐g‐PLA nanocomposites. Compared with PLA/CNF (95/5) bionanocomposite, the maximum tensile modulus, tensile strength, elongation at break, and V‐notched Izod impact strength of CNF‐g‐PLA nanocomposites were increased by 31.8%, 20.0%, 12.0%, and 27.9%, respectively. WAXD and DSC analyses indicated that the crystallinity degree of the grafted CNF‐g‐PLA was higher than that of PLA/CNF (95/5) bionanocomposite, and first increased and then decreased with increasing DCP content. The polarized optical micrographs confirmed that DCP‐initiated grafting significantly increased the nucleation density but decreased the spherulite size of PLA. The melt strength of CNF‐g‐PLA nanocomposites was improved due to stronger intermolecular interaction by grafting. This one‐step in situ reactive extrusion technology provides an efficient and economical way to enhance the properties of PLA/CNF bionanocomposites.