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Fused filament fabrication (FFF) of composites with compliant high-strength fibers could expand opportunities for the design and fabrication of complex flexible structures, but this topic has received limited attention. This study pursued the development of filaments consisting of ultra-high molecular weight polyethylene yarn (UHMWPE) embedded in a matrix of polycaprolactone (UPE/PCL) and successful 3D printing. The physical characteristics and printability of the filament were evaluated in terms of key parameters including spooling speed, temperature, fiber distribution (consolidated vs dispersed), and fiber volume fraction (4≤ Vf ≤30 %). An evaluation of the microstructure and tensile properties of the UPE/PCL was performed after processing and printing. Prior to printing, the filament exhibited an ultimate tensile strength (UTS) of 590±40 MPa with apparent fiber strength of 2.4 GPa. For the printed condition, the UTS reached 470±60 MPa and apparent fiber strength of 1.9 GPa. Fiber dispersion in the filament plays an important role on the printed properties and the potential for fiber degradation. Nevertheless, the strength of the UPE/PCL represents a new performance benchmark for compliant composites printed by FFF. This new material system can support applications where strength and toughness are key performance metrics in addition to flexibility.
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Scalable Manufacturing of Polymer Multi‐Nanofiber Twisted Yarns
Continuous high‐strength polymer nanofiber yarns can be assembled into textiles suitable for numerous applications that benefit from the high surface‐area‐to‐volume ratio of the component nanofibers. Electrospun nanofibers have been used to make multifiber twisted yarns (MFTYs). Traditionally, electrospun nanoyarns are made using self‐bundling methods or cone spinning. However, these approaches inhibit ordered fiber architecture or postprocessing of filaments prior to yarn fabrication limiting yarn length, uniformity, and mechanical strength. A spinning process utilizing automated parallel track collection is capable of manufacturing MFTYs with microarchitecture control and integration of individual fiber postdrawing prior to yarn assembly. The advantage of this process is the ability to optimize electrospinning parameters, postprocessing parameters, and yarn spinning parameters independently. Polycaprolactone (PCL) fibers are electrospun with various parameters and made into long MFTYs that retain up to 50% of the strength of individual component nanofibers. Mechanical testing shows relationships between spinning parameters and yarn strength. The tenacity of PCL MFTYs exceeds the tenacity of most reported self‐bundled nanofiber yarns by an order of magnitude or more. Thus, the alternative nanoyarn fabrication method presented in this work is able to produce yarns with highly tunable parameters with a significant increase in mechanical strength compared to other electrospun nanoyarns.
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- Award ID(s):
- 2345785
- PAR ID:
- 10661751
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Advanced Engineering Materials
- Volume:
- 27
- Issue:
- 7
- ISSN:
- 1438-1656
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Fused filament fabrication (FFF) of composites with compliant high-strength fibers could expand opportunities for the design and fabrication of complex flexible structures, but this topic has received limited attention. This study pursued the development of filaments consisting of ultra-high molecular weight polyethylene yarn (UHMWPE) embedded in a matrix of polycaprolactone (UPE/PCL) and successful 3D printing. The physical characteristics and printability of the filament were evaluated in terms of key parameters including spooling speed, temperature, fiber distribution (consolidated vs dispersed), and fiber volume fraction (4≤ Vf ≤30 %). An evaluation of the microstructure and tensile properties of the UPE/PCL was performed after processing and printing. Prior to printing, the filament exhibited an ultimate tensile strength (UTS) of 590±40 MPa with apparent fiber strength of 2.4 GPa. For the printed condition, the UTS reached 470±60 MPa and apparent fiber strength of 1.9 GPa. Fiber dispersion in the filament plays an important role on the printed properties and the potential for fiber degradation. Nevertheless, the strength of the UPE/PCL represents a new performance benchmark for compliant composites printed by FFF. This new material system can support applications where strength and toughness are key performance metrics in addition to flexibility.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/adem.202401897
