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Báo cáo hóa học: " Influence of Surface Modified MWCNTs on the Mechanical, Electrical and Thermal Properties of Polyimide Nanocomposites"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Influence of Surface Modified MWCNTs on the Mechanical, Electrical and Thermal Properties of Polyimide Nanocomposites | Nanoscale Res Lett 2008 3 444-453 DOI 10.1007 S11671-008-9179-4 NANO EXPRESS Influence of Surface Modified MWCNTs on the Mechanical Electrical and Thermal Properties of Polyimide Nanocomposites B. P. Singh Deepankar Singh R. B. Mathur T. L. Dhami Received 30 June 2008 Accepted 16 September 2008 Published online 15 October 2008 to the authors 2008 Abstract Polyamic acid the precursor of polyimide was used for the preparation of polyimide multiwalled carbon nanotubes MWCNTs nanocomposite films by solvent casting technique. In order to enhance the chemical compatibility between polyimide matrix and MWCNTs the latter was surface modified by incorporating acidic and amide groups by chemical treatment with nitric acid and octadecylamine C18H39N respectively. While the amide-MWCNT polyimide composite shows higher mechanical properties at low loadings 3 wt the acid-MWCNT polyimide composites perform better at higher loadings 5 wt . The tensile strength TS and the Young s modulus YM values of the acid-MWCNT polyimide composites at 5 wt MWCNT loadings was 151 and 3360 MPa respectively an improvement of 54 in TS and 35 in YM over the neat polyimide film TS 98 MPa YM 2492 MPa . These MWCNT-reinforced composites show remarkable improvement in terms of thermal stability as compared to that for pure polyimide film. The electrical conductivity of 5 wt acid modified MWCNTs polyimide nanocomposites improved to 0.94 S cm 1 6.67 X 10 18 S cm-1 for pure polyimide the maximum achieved so far for MWCNT-polyimide composites. Keywords Multiwalled carbon nanotubes Polyimide Nanocomposites Electrical properties Mechanical properties B. P. Singh R. B. Mathur H T. L. Dhami Carbon Technology Unit Engineering Materials Division National Physical Laboratory New Delhi 110012 India e-mail rbmathur@mail.nplindia.ernet.in D. Singh Central Institute for Plastics Engineering and Technology Chennai 600 032 India Introduction After their discovery in 1991 by Iijima 1 carbon nanotubes CNTs have attracted