Kinetic thermal behavior of nanocellulose filled polylactic acid filament for fused filament fabrication 3D printing

Abstract

Fused filament fabrication (FFF) with thermoplastic filaments is the most popular 3D printing technology. The continuous polymer filaments undergo a series of thermal processes, including heating, melting, cooling, and solidification. Therefore, it is necessary to investigate the thermal behavior of polymer filaments. The present study aims to provide a fundamental study of the thermal decomposition behavior and the isothermal melting crystallization behavior of nanocellulose filled polylactic acid (PLA) filaments. The influences of nanocellulose contents on the thermal decomposition properties such as onset temperature (T onset ), the temperature at 20-wt % conversion (T α20 ), and the temperature at the peak decomposition rate (T p ) were examined by thermogravimetric analysis (TGA). The effects of nanocellulose contents on the glass transition temperature (T g ) and the melting temperature (T m ) were studied by differential scanning calorimetry (DSC). Effects of nanocellulose and polyethylene glycol (PEG) incorporation on the thermal decomposition activation energy, isothermal melting crystallization rate, and semi-crystallization time are also investigated. The addition of nanocellulose improves the thermal stability of PLA filament, whereas the addition of plasticizer PEG decreases the thermal stability. TGA and DSC kinetic analyses indicate that nanocellulose alone or together with PEG could drastically increase the crystallization rate and shorten the semi-crystallization time.

Structure and Properties of Polylactic Acid Biocomposite Films Reinforced with Cellulose Nanofibrils

“…PLA/CNF biocomposites started to crystallize easily than neat PLA films. The mobility of PLA chains was altered by the incorporation of CNF [ 34 ]. Slightly lower T cc was detected for PLA/CNF biocomposite films.…”

“…CNF was isolated following the protocol developed in our previous studies [ 34 , 37 , 38 ]. Briefly, enzymatic pretreatment of MCC was conducted at 10 wt % MCC loading, 12.8 FPU/g MCC, and 50 °C for 2 h in the acetic buffer (pH 4.6).…”

Recent advances in 3D printing of nanocellulose: structure, preparation, and application prospects

“…177,178 Wang and her co-workers have utilized polylactic acid (PLA) filled with nanocellulose and polyethylene glycol (PEG) as filament for FDM printing. 180 The inclusion of nanocellulose has improved the thermal stability, mechanical strength of the PLA composite filament, and provided synergistic effect with PEG on the crystallization rate with semi-crystallization time shortened from 12.2 min at 120 o C for pure PLA filament to 1.5 min at 100 o C for nanocellulose-incorporated PLA/PEG composite that is used as filament in FDM printing. Ambone et al also demonstrated the improvement of 3Dprinted PLA structure in tensile strength and modulus by 84 % and 73 % respectively, with just 1 wt% CNFs extracted from sisal fiber.…”

Extending Cellulose-Based Polymers Application in Additive Manufacturing Technology: A Review of Recent Approaches

“…The other type of surface modifier that can be used is PEG that acts as a plasticizer to nanocellulose as it can promote uniform adhesion and dispersion of nanocellulose in the PLA matrix. Addition of nanocellulose was able to improve the composite thermal stability, whereas nanocellulose/PEG addition improved the crystallization rate, which is vital during printing for the buildability of printed products [ 88 ]. Furthermore, 3,6-dimethyl-1,4-dioxane-2,5-dione as L-lactide monomer was surface grafted on CNF also was able to improve the homogeneity in the PLA matrix, and it was found that the crystallinity of the extruded filaments increased about 100% [ 89 ].…”