Melt Spinning of Cellulose Nanofibril/Polylactic Acid (CNF/PLA) Composite Fibers For High Stiffness

Abstract

Nanocellulose has potential as a reinforcing agent to improve stiffness and strength in polymer fiber; however, the inherent difference in hydrophilicity makes it challenging to incorporate it into nonhydrophilic polymers, and the composite properties are strongly anisotropic. In the present work, a dual approach was employed to incorporate cellulose nanofibrils (CNFs) into polylactic acid (PLA). Polyethylene glycol (PEG) acted as a compatibilizating agent to enable the melt spinning of CNF/PLA composite fibers without water/solvent, and CNFs were surface modified to improve compatibility, increase nanoparticle thermal stability, and increase CNF dispersion in PLA. While no significant difference was observed in strength, the stiffness improved up to 600% (1.3 wt % CNF, maximum draw) in the composite fibers. This improvement was correlated with the crystallinity and fiber orientation (Herman's order parameter) for as-spun and hot-drawn fibers.

Functional Properties and Molecular Degradation of Schizostachyum Brachycladum Bamboo Cellulose Nanofibre in PLA-Chitosan Bionanocomposites

“…Also, the band at 1500 to 2000 cm −1 is assigned to C-H, and that at 1050 cm −1 is C-O stretching. These functional group bonds represent cellulose nanofibre, as reported in previous studies [ 28 , 34 ]. The functional group analysis confirmed the successful isolation of CNF using combined supercritical carbon dioxide and high-pressure homogenisation [ 33 ].…”

“…It possesses a good strength enhancement to other biopolymers [ 7 ]. PLA-cellulose nanofibre biocomposite film properties have been researched with several agglomeration reports because of the difference in PLA and CNF [ 27 , 28 , 29 ]. CNF is hydrophilic, while PLA is hydrophobic.…”

Evaluation of the Suitability of Poly(Lactide)/Poly(Butylene-Adipate-co-Terephthalate) Blown Films for Chilled and Frozen Food Packaging Applications

“…PLA is a compostable and bio-based polymer, it is a linear aliphatic polyester, and its properties can be turned varying the relative content of D-and L-enantiomers [11]. It can be easily processed with conventional process such as extrusion, spinning, injection and compression molding [12][13][14][15]. However, its high brittleness limits its use, thus different strategies are tested in order to improve its toughness [16][17][18][19].…”

Synthesis and characterization of carbon black modified by polylactic acid (PLA‐g‐CB) as pigment for dope dyeing of black PLA fibers

“…The second heating DSC curve showed some peaks at 104 and 168 °C, which were temperatures of cold‐crystallization peak and melting peak of PLA fiber, respectively. Compared to white PLA fiber, cold crystallization temperature and glass transition temperature of dope dyed black PLA fiber had shifted to lower temperature, which indicated a higher initial crystallinity . According to ΔH m and ΔH c values, crystallinity of PLA fiber had been calculated.…”

“…On the other hand, at a high loading level, the PLA‐ g ‐CB (I) pigment tended to reunite, and the further addition of the PLA ‐g‐ CB (I) pigment might hinder the regular arrangements of the PLA chains which led to the declined crystallinity of the fiber . As shown in Figure (b), two melting endotherm peeks were observed at 160–170 °C in DSC thermogram of dope dyed black PLA fiber containing 3% PLA‐ g‐ CB (I) pigment, indicating that there were phase separation or various crystalline morphology due to the excessive amount of PLA ‐g‐ CB (I) pigment …”