Medium density polyethylene composites with functionalized carbon nanotubes.
A strong interface between the single-walled carbon nanotubes (SWNTs) and polymer matrix is necessary to achieve enhanced mechanical properties of composites. In this work a series of sidewall-functionalized SWNTs have been investigated in order to evaluate the effect of functionalization on SWNT aspect ratio and composite interfacial chemistry and their role on mechanical properties of a medium density polyethylene (MDPE) matrix. Fluorinated nanotubes (F-SWNTs) were used as precursors for subsequent sidewall functionalization with long chain alkyl groups to produce an F-SWNT- C(11)H(23) derivative. The latter was refluorinated to yield a new perfluorinated derivative, F-SWNT- C(11)F(x)H(y). The functionalized SWNTs as well as the pristine SWNTs were integrated into an MDPE matrix at a 1 wt% loading. The nanotubes and composite materials were characterized with FTIR, Raman spectroscopy, NMR, XPS, AFM, SEM, TGA, DSC and tensile tests. When incorporated into polyethylene, the new perfluorinated derivative, F-SWNT- C(11)F(x)H(y), yielded the highest tensile strength value among all nanotube/MDPE composite samples, showing a 52% enhancement in comparison with the neat MDPE. The 1 wt% SWNT/MDPE composite contained nanotubes with a larger aspect ratio but, due to a lack of interfacial chemistry, it resulted in less improvement in mechanical properties compared to the composites made with the fluorinated SWNT derivatives.
Pulikkathara
Merlyn X
MX
Department of Chemistry, Rice University, Houston, TX 77005, USA.
Kuznetsov
Oleksandr V
OV
Peralta
Ivana R G
IR
Wei
Xin
X
Khabashesku
Valery N
VN
D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008420:Manufactured Materials; D008422:Materials Testing; D008968:Molecular Conformation; D008970:Molecular Weight; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D020959:Polyethylene / Q000737:chemistry*; D013499:Surface Properties
D046911:Macromolecular Substances; D037742:Nanotubes, Carbon; D020959:Polyethylene