skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Manufacturing of stereolithographic 3D printed boron nitride nanotube-reinforced ceramic composites with improved thermal and mechanical performance
Title: Manufacturing of stereolithographic 3D printed boron nitride nanotube-reinforced ceramic composites with improved thermal and mechanical performance
Abstract Boron nitride nanotubes (BNNTs) are the perfect candidate for nanofillers in high-temperature multifunctional ceramics due to their high thermal stability, oxidation resistance, good mechanical properties, high thermal conductivity, and radiation shielding. In this paper, 3D printed ceramic nanocomposite with 0.1 wt% of BNNT was prepared by fusing it at high temperatures. Samples were built with three different print directions to study the effect of print layers on mechanical performance along with BNNT addition. Dynamic mechanical analysis is performed to study the length effect of nanoscale reinforcements on the mechanical properties of the printed ceramic composites reporting significant improvements up to 55% in bending strength and 72% in bending modulus with just 0.1 wt% BNNT addition. A 63% thermal diffusivity improvement of ceramic by adding BNNTs is observed using laser flash analysis. The bridging and pull-out effect of nanotubes with a longer aspect ratio was observed with high-resolution microscopy. Such composites’ modeling and simulation approaches are crucial for virtual testing and industrial applications. Understanding the effect of nanoscale synthetic fillers for 3D printed high-temperature ceramics can revolutionize future extreme environment structures.  more » « less
Award ID(s):
1950500
PAR ID:
10410588
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Functional Composites and Structures
Volume:
5
Issue:
1
ISSN:
2631-6331
Page Range / eLocation ID:
015001
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; (, Nanotechnology)
    Abstract Controlling the thermal expansion of ceramic materials is important for many of their applications that involve high-temperature processing and/or working conditions. In this study, we investigate the thermal expansion properties of additively manufactured alumina that is reinforced with boron nitride nanotubes (BNNTs) over a broad temperature range, from room temperature to 900 °C. The coefficient of thermal expansion (CTE) of the BNNT-alumina nanocomposite increases with temperature but decreases with an increase in BNNT loading. The introduction of 0.6% BNNTs results in an approximate 16% reduction in the CTE of alumina. The observed significant CTE reduction of ceramics is attributed to the BNNT’s low CTE and ultrahigh Young’s modulus, and effective interfacial load transfer at the BNNT-ceramic interface. Micromechanical analysis, based onin situRaman measurements, reveals the transition of thermal-expansion-induced interface straining of nanotubes, which shifts from compression to tension inside the ceramic matrix under thermal loadings. This study provides valuable insights into the thermomechanical behavior of BNNT-reinforced ceramic nanocomposites and contributes to the optimal design of ceramic materials with tunable and zero CTE. 
    more » « less
  2. ; ; ; ; ; (, Advanced Materials)
    Abstract Boron nitride nanotubes (BNNT) uniformly dispersed in stretchable materials, such as poly(dimethylsiloxane) (PDMS), could create the next generation of composites with augmented mechanical, thermal, and piezoelectric characteristics. This work reports tunable piezoelectricity of multifunctional BNNT/PDMS stretchable composites prepared via co‐solvent blending with tetrahydrofuran (THF) to disperse BNNTs in PDMS while avoiding sonication or functionalization. The resultant stretchable BNNT/PDMS composites demonstrate augmented Young's modulus (200% increase at 9 wt% BNNT) and thermal conductivity (120% increase at 9 wt% BNNT) without losing stretchability. Furthermore, BNNT/PDMS composites demonstrate piezoelectric responses that are linearly proportional to BNNT wt%, achieving a piezoelectric constant (|d33|) of 18 pmV−1at 9 wt% BNNT without poling, which is competitive with commercial piezoelectric polymers. Uniquely, BNNT/PDMS accommodates tensile strains up to 60% without plastic deformation by aligning BNNTs, which enhances the composites’ piezoelectric response approximately five times. Finally, the combined stretchable and piezoelectric nature of the composite was exploited to produce a vibration sensor sensitive to low‐frequency (≈1 kHz) excitation. This is the first demonstration of multifunctional, stretchable BNNT/PDMS composites with enhanced mechanical strength and thermal conductivity and furthermore tunable piezoelectric response by varying BNNT wt% and applied strain, permitting applications in soft actuators and vibration sensors. 
    more » « less
  3. ; ; (, Journal of Physics D: Applied Physics)
    Abstract Cellulose nanofibers (NFCs) have emerged as a preferred choice for fabricating nanomaterials with exceptional mechanical properties. At the same time, boron nitride nanotubes (BNNTs) have long been favored in thermal management devices due to their superior thermal conductivity (k). This study uses reverse non-equilibrium molecular dynamics (MD) simulations to investigatekfor a hybrid material based on NFCs and BNNTs. The result is then compared with pure NFC and BNNT-based structures with equivalent total weight content to elucidate how incorporating BNNT fillers enhanceskfor the hybrid system. Furthermore, the fundamental phonon vibration modes responsible for driving thermal transport in NFC-based materials upon incorporating BNNTS are identified by computing the vibrational density of states from the Fourier transform analysis of the averaged mass-weighted velocity autocorrelation function. Additionally, MD simulations demonstrate how both NFCs and BNNTs synergistically improve the constituting hybrid structure’s mechanical properties (e.g. tensile strength and stiffness). The overarching aim is to contribute towards the engineered design of novel functional materials based on nanocellulose that simultaneously improve crucial physical properties pertaining to thermal transport and mechanics. 
    more » « less
  4. ; ; ; ; (, Journal of Materials Research)
    Abstract Boron nitride nanotubes (BNNTs) are emerging nanomaterials with analogous structures and similarly impressive mechanical properties to carbon nanotubes (CNTs), but unique chemistry and complimentary multifunctional properties, including higher thermal stability, electrical insulation, optical transparency, neutron absorption capability, and piezoelectricity. Over the past decade, advances in synthesis have made BNNTs more broadly accessible to the nanomaterials and other research communities, removing a major barrier to their utilization and research. Therefore, the field is poised to grow rapidly and see the emergence of BNNT applications ranging from electronics to aerospace materials. A key challenge, that is being gradually overcome, is the development of manufacturing processes to make “neat” BNNT materials. This overview highlights the history and current status of the field, providing both an introduction to this Focus Issue—BNNTs: Synthesis to Applications—as well as a perspective on advances, challenges, and opportunities for this emerging material. Graphical abstract 
    more » « less
  5. ; ; ; (, Journal of Composite Materials)
    null (Ed.)
    Semi-crystalline carbon biochar is derived from spent coffee grounds (SCG) by a controlled pyrolysis process at high temperature/pressure conditions. Obtained biochar is characterized using XRD, SEM, and TEM techniques. Biochar particles are in the micrometer range with nanostructured morphologies. The SCG biochar thus produced is used as reinforcement in epoxy resin to 3 D print samples using the direct-write (DW) method with 1 and 3 wt. % loadings. Rheology results show that the addition of biochar makes resin viscous, enabling it to be stable soon after print; however, it could also lead to clogging of resin in printer head. The printed samples are characterized for chemical, thermal and mechanical properties using FTIR, TGA, DMA and flexure tests. Storage modulus improved with 1 wt. % biochar addition up to 27.5% and flexural modulus and strength increased up to 55.55% and 43.30% respectively. However, with higher loading of 3 wt. % both viscoelastic and flexural properties of 3D printed samples drastically reduced thus undermining the feasibility of 3D printing biochar reinforced epoxies at higher loadings. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email