Micro/nano Carbon Materials and Their Reinforced Composites

Transcription

1 Micro/nano Carbon Materials and Their Reinforced Composites Xiaodong (Chris) Li University of Virginia

2 Epoxy- SWCNT nanocomposites X. D. Li et al., Nanotechnology, 15 (2004) X. D. Li et al., J Nanoscience and Nanotechnology, 7 (2007)

3 Elastic modulus (GPa) CNT has disappointed us in its composites Upper boundary Lower boundary Experimental H-T model M-T model SWCNT concentration (wt.%) X. D. Li et al., Nanotechnology, 15 (2004) X. D. Li et al., J Nanoscience and Nanotechnology, 7 (2007)

4 Agarose-clay nanocomposite preparation Clay platelets (montmorillonite MMT) Length (Width): nm Thickness: ~ 1 nm Properties Elastic modulus: 178 GPa Density: 2.83 g/cm 3 Advantages High elastic modulus, aspect ratio, surface to volume ratio X. D. Li et al., Nanotechnology, 16 (2005)

5 Ductility Nanoclay - brittleness in its composites 200 Stress (MPa) Strain (mm/mm) 0% clay 30% clay 60% clay 80% clay Clay concentration (wt. %) X. D. Li et al., Nanotechnology, 16 (2005)

6 Hydrogen passivation induced dispersion of CNTs Ultrasonication only Coupled HP and ultrasonication X. D. Li et al., Advanced Materials, 24 (2012)

7 Hydrogen passivation induced dispersion of CNTs X. D. Li et al., Advanced Materials, 24 (2012)

8 Hydrogen passivation induced dispersion of CNTs X. D. Li et al., Advanced Materials, 24 (2012)

9 Hydrogen passivation induced dispersion of CNTs X. D. Li et al., Advanced Materials, 24 (2012)

10 Hydrogen passivation induced dispersion of CNTs X. D. Li et al., Advanced Materials, 24 (2012)

11 Hydrogen passivation induced dispersion of graphene X. D. Li et al., Scientific Reports, 3 (2013) 2086

12 Hydrogen passivation induced dispersion of graphene X. D. Li et al., Scientific Reports, 3 (2013) 2086

13 Hydrogen passivation induced dispersion of graphene X. D. Li et al., Scientific Reports, 3 (2013) 2086

14 The Shell of red abalone Nanoscale structure A nacre aragonite plate consists of thousands of nanograins! These nanograins are cobble-like polygons of approximately 32 nm in diameter, and are densely packed to form individual plates. X. D. Li et al., Nano Letters, 4 (2004)

15 Interlocking mechanism In-situ tensile load-time curve and AFM images Interlocking Mechanisms Nanoasperities Aragonite platelet pull-out Nanoasperites imposing arrangement - Increasing sliding resistance and absorbing energy R.Z. Wang et al., J. Mater. Res., 16 (2001)

16 How do nanonecklace fibers work in composites? X. D. Li et al., Advanced Materials, 20 (2008) 4091

17 Can we synthesize nanonecklace fibers? Nanonecklaces with SiO x beads in boron strings Formation mechanism of the nano/micro necklaces 50 mm X. D. Li et al., Applied Physics Letters, 89 (2006)

18 Superior reinforcing effect from B/SiO x nanoneklaces 0.5 wt% nanonecklace reinforced epoxy nanocomposite Control sample Hardness: 0.21± 0.01 GPa Elastic modulus: 3.59 ± 0.07 Gpa 0.5 wt% B/SiO x Nanocomposite Hardness: 0.34± 0.05 GPa 32% increase Elastic modulus: 4.75 ± 0.39 Gpa 62% increase Better than CNT in terms of reinforcing effect! 1 wt% CNT Nanocomposite Hardness: 8% increase Elastic modulus: 12% increase X. D. Li et al., Advanced Materials, 20 (2008) 4091

19 TEM characterization of B/SiO x nanonecklaces X. D. Li et al., Advanced Materials, 20 (2008) 4091

20 Elastic modulus of boron nanowires C.-H. Lin, H. Ni, X. N. Wang, M. Chang, Y. J. Chao, J. R. Deka, X. D. Li, Small, 6 (2010)

21 Convert a cotton T-shirt into a hybrid B 4 C/C composite X. D. Li. et al, Advanced Materials, 22 (2010)

22 Are B 4 C nanowires strong? X. D. Li. et al, Advanced Materials, 22 (2010)

23 New finding super-elasticity X. D. Li. et al, Advanced Materials, 22 (2010)

24 Outstanding UV irradiation blocking properties X. D. Li. et al, Advanced Materials, 22 (2010)

25 Superior mechanical reinforcing effect X. D. Li. et al, Advanced Materials, 22 (2010)

26 Bioinspired, multiscale reinforced composites X. D. Li et al., Nano Letters, (2018)

27 Bioinspired, multiscale reinforced composites X. D. Li et al., Nano Letters, (2018)

28 Bioinspired, multiscale reinforced composites X. D. Li et al., Nano Letters, (2018)

29 Bioinspired, multiscale reinforced composites X. D. Li et al., Nano Letters, (2018)

30 CNT/B 4 C composites X. D. Li et al., Advanced Engineering Materials, 16 (2014)

31 Summary - Coupled HP and ultrasonication effectively disperses CNTs and graphene. - Nanonecklaces are much better than CNTs in terms of reinforcing effect! - Micro/nano hybrid fillers are more powerful in reinforcing than nano filler alone. - There are still a lot to learn from nature.

32 Acknowledgments - National Science Foundation - NASA - Army Research Office - DOE - ACS Petroleum Research Fund