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Materials Science in Additive Manufacturing Natural composite filaments for 3D-Print

A B C

D E F G

Figure 10. The generation of biofilament material from CNF and PLA using the extrusion process. Key stages of the investigation include: (A) enzymatic
hydrolysis of cellulose with high-pressure homogenization, (B) CNF powder, (C) extrusion process via the Wellzoom desktop extruder, (D) extrusion
of composite filament material with a diameter of 1.75 mm, (E) specimen generation via the M3036 FDM desktop 3D printer, (F) tensile testing of
specimens with 10% and 35% infill, and (G) testing of tensile strength of composite filament material with varying CNF composition. Illustration
reproduced from ref. – an open-access article distributed under the CC BY License of MDPI (Basel, Switzerland)
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Abbreviations: CNF: Cellulose nanofibrils; PLA: Polylactic acid
its material composition. The strength and homogeneity in provides limited information pertaining to the surface of
filament material could also be enhanced by including a the observed specimen only. 109
pre-mixing stage to produce a homogeneous mix, which
will also minimize the frequent clogging of the nozzle 5. Natural degradation and recycling of
in the FDM process. 73,86 For instance, the addition of NFRCFs
additives, such as compatibilizer and coupling agents The integration of natural fibers as reinforcement in filament
through customized treatments, was found to improve material has not only enhanced their mechanical attributes
the interfacial bonding between the polymer matrices and 49
filler components, thus affecting the homogeneity of the but has also improved their biodegradability trait. The
filament material. In another study, the consideration transition toward using biodegradable products in the
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of continuous natural fiber with PLA for biofilament field of AM is also being propelled by the incorporation
fabrication evidenced a homogeneous distribution within of PLA-based filament materials into usage. Besides, in
the cross-section. 95 terms of benefits, biodegradable filaments made of PLA
and polyvinyl alcohol (PVA) have been reported to be non-
In previous studies, several techniques have been toxic. On the downside, biodegradable filaments, namely
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considered to examine the homogeneity of composite PLA and PHA, have been reported to have a brittle nature,
filament materials. One such technique, namely the while PVA and polyethylene terephthalate were found to be
Thermogravimetric Analysis, was utilized to verify the susceptible to moisture absorption. Moreover, similar to
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composition of composite-based filament material, such neat polymeric-based biodegradable filaments, fabricated
as polymer-ceramic and PLA–potato thermoplastic starch NFRCF should also be stored in a controlled environment
filament materials. 105,106 Other microscopy techniques, to avoid degradation to external factors such as ultraviolet,
such as scanning electron microscopy (SEM), have been temperature, and moisture content. 67
considered to study the fractured surface of the composite
filament, whereby the distribution of the reinforcement To determine the biodegradable characteristics of
components could also be clearly examined. 107,108 To biodegradable material, the soil burial test, also known
closely study the internal morphological characteristics as the soil degradability test, has been previously
of 3D-printed composite filament, the X-ray microscopy considered. 110-112 In such experiments, the rate of
technique was even considered it could afford additional degradation of biocomposite filaments can be monitored
information as compared to the SEM technique, which by assessing their weight loss. In this method involving
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Volume 4 Issue 1 (2025) 13 doi: 10.36922/msam.8533