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L. V. Karabanova et al.
nanocomposites and also the impact of interfacial chemistry and interactions on the
matrix glass transition dynamics, as estimated by DMA and laser-interferometric
creep rate spectroscopy (CRS) techniques, were of essential interest and have been
performed herein.
8.2 Materials and Testing Methods
8.2.1 Materials
8.2.1.1 Carbon Nanotube Pretreatment
MWCNTs with an outer diameter of 10–30 nm, inner diameter of 5–10 nm and
length of 5–10 μm were purchased from TMSpetsmash (Ukraine), which were
grown using the CVD technique. Pristine MWCNTs (pMWCNTs) were prepared
from raw samples through low-temperature oxidation to remove surface amorphous
carbon and then refluxed in hydrochloric acid (HCl) to remove any residual metal
catalytic particles. Samples were then washed extensively in water and dried at
100 ◦ C.
8.2.1.2 Hemin-Coated MWCNTs
Hemin-coated MWCNTs (MWCNT-hemin) were prepared by sonicating pMWCNTs in a solution of excess hemin dissolved in tetrahydrofuran (THF). The mixture
was adjusted to pH 1 with the addition of HCl (2 M) and left for 8 hrs. MWCNTs
were separated from solution by centrifugation and washing with acidified methanol
(MeOH)-THF mixture until no further colouration of the supernatant was observed
(confirmed using UV-Vis analysis), then washed with MeOH and dried at 100 ◦ C.
8.2.1.3 Acid-Oxidized MWCNTs
Acid-oxidized MWCNTs (MWCNT-ox) were prepared by refluxing MWCNTs in
nitric acid (HNO 3 , 70%, 6 h) and then washed with water until a neutral pH.
Samples were then refluxed in sodium hydroxide (NaOH, 2 M, 1 h) to remove
surface-immobilised fulvic acids and then washed in NaOH solution until no further
colouration was obtained. The covalently attached surface groups were regenerated
by refluxing in HCl (2 M, 10 min). Samples were finally washed in water till pH 7
and dried at 100 ◦ C.
L. V. Karabanova et al.
nanocomposites and also the impact of interfacial chemistry and interactions on the
matrix glass transition dynamics, as estimated by DMA and laser-interferometric
creep rate spectroscopy (CRS) techniques, were of essential interest and have been
performed herein.
8.2 Materials and Testing Methods
8.2.1 Materials
8.2.1.1 Carbon Nanotube Pretreatment
MWCNTs with an outer diameter of 10–30 nm, inner diameter of 5–10 nm and
length of 5–10 μm were purchased from TMSpetsmash (Ukraine), which were
grown using the CVD technique. Pristine MWCNTs (pMWCNTs) were prepared
from raw samples through low-temperature oxidation to remove surface amorphous
carbon and then refluxed in hydrochloric acid (HCl) to remove any residual metal
catalytic particles. Samples were then washed extensively in water and dried at
100 ◦ C.
8.2.1.2 Hemin-Coated MWCNTs
Hemin-coated MWCNTs (MWCNT-hemin) were prepared by sonicating pMWCNTs in a solution of excess hemin dissolved in tetrahydrofuran (THF). The mixture
was adjusted to pH 1 with the addition of HCl (2 M) and left for 8 hrs. MWCNTs
were separated from solution by centrifugation and washing with acidified methanol
(MeOH)-THF mixture until no further colouration of the supernatant was observed
(confirmed using UV-Vis analysis), then washed with MeOH and dried at 100 ◦ C.
8.2.1.3 Acid-Oxidized MWCNTs
Acid-oxidized MWCNTs (MWCNT-ox) were prepared by refluxing MWCNTs in
nitric acid (HNO 3 , 70%, 6 h) and then washed with water until a neutral pH.
Samples were then refluxed in sodium hydroxide (NaOH, 2 M, 1 h) to remove
surface-immobilised fulvic acids and then washed in NaOH solution until no further
colouration was obtained. The covalently attached surface groups were regenerated
by refluxing in HCl (2 M, 10 min). Samples were finally washed in water till pH 7
and dried at 100 ◦ C.