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

the open soil environment, living microorganisms such as need for further research. One way to improve interfacial
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aerobic bacteria were found to decompose organic matter adhesion is by overcoming the hydrophilic characteristic
via microbial activity. The degradation rate of such of natural fibers, which will also positively contribute to
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biocomposite 3D-printed parts in marine environments the enhancement of their overall dimensional stability.
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was found to depend on the surface roughness of the Another target is to achieve a homogeneous NFRCF, which
printed parts, the extent of crystallinity in their structure, will be decisive in the future development of biodegradable
and the ratio of wet to dry cycles during the cyclic products in the AM field. Further research needs to be
submersion test. The cause of the embrittlement effect, conducted on NFRCFs to fill in the gap of information
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which was predominantly observed in the PLA-PHA- arising due to a lack of data about their mechanical
printed biocomposite parts following the cyclic submersion behavior. 117
test, was linked to environmental stress cracking resulting The significant growth observed in the AM field and
from the penetration of salt crystals and other impurities the increasing demand for AM-manufactured products
in the failure regions. In another study, the degradation are calling for further optimization of the NFRCF
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rate of PF-PHA biocomposite filament was monitored by filament. The current targets set by material scientists and
assessing their weight loss in the soil burial test. 103 engineers in the field of AM are high-quality 3D prints,
For 3D-printed materials with reduced biodegradability, reduced printing time, and low cost of production.
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other alternative options of reuse and recycling are To achieve the set targets, optimization of the process
being considered. With projected growth in AM and parameters through design of experiment was found
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the corresponding upward surge in the use of filament to be essential. Other techniques which could be
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materials in the coming years and decades, other aspects considered to analyze and optimize the process efficiency
in the large-scale utilization of such materials, namely their in AM are the Taguchi method and the response surface
recycling, have to be considered to ensure a sustainable methodology. 73
approach. The recycling and reuse of end-of-service- The hybridization of natural fibers is a proven technique
life products is imperative in today’s society as there is a that has yielded conclusive results when applied to
growing need for better waste management and disposal for improve the strength of NFRCs. 118,119 The hybridization of
a reduced impact on the environment. The various means natural fibers is a technique to combine two or more types
to recycle filament materials include shredding, melting, of fibers with the aim of achieving maximum mechanical
and re-extruding, among other means. The recycling of performance in terms of toughness and strength. In past
filament materials not only reduces the amount of energy literature, satisfactory results were obtained when the
and carbon emissions required to produce new materials hybridization technique was applied to a variety of natural
but also conserves resources and reduces wastes. 113,114
fibers, namely pineapple leaf fiber, kenaf, jute, hemp, sugar
Besides enabling effective waste utilization, the potential of palm, and coir. Moreover, to reduce the delamination
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repurposing polymeric materials from recycled NFRCFs as new and fiber pull-outs during machinability, the hybrid
consumer products is providing an alternative means for material natural fiber composite could be further enhanced by the
valorization. In one study, the mechanical recycling of printed addition of specific filler materials. The aforementioned
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products made from commercial-grade PLA was conducted via observations about the hybridization of natural fibers for
shredding prior to re-extrusion into new filament material for NFRCs have not been well explored and considered for the
reuse. As revealed from the results of a life cycle assessment, this development of advanced NFRCFs and will thus require
approach, termed as closed-loop recycling, was found to be a further attention.
better alternative than landfill disposal. Moreover, the process
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of reprocessing the filament material led to a reduction in their 7. Conclusion
viscosity, which indicates a deterioration in their performance With the increasing use of AM technologies for product
for the FDM process. One proposed solution to enhance their development in recent years, there is a growing need to look
viscosity was to blend virgin PLA with recycled ones to enable into alternative and more sustainable materials bearing a
their re-utilization in filament materials. 116 lower carbon footprint. This review addresses this gap by

6. Future works to optimize NFRCF probing into the latest progress made in the development
performance of biodegradable NFRCFs for 3D printing. The rationale
for using NFRCFs in modern AM processes is covered
The inferior mechanical performance observed in in this review. Factors contributing to the performance
NFRCFs as a result of poor bonding strength and adhesion attributes of NFRCFs, namely their fabrication procedure,
prevailing between the fiber-matrix interfaces is signaling a fibers and matrix selection, the fiber-matrix interaction,

Volume 4 Issue 1 (2025) 14 doi: 10.36922/msam.8533