Nanocomposites and nanomaterial

Carbon-carbon composite material
thermo-expanded graphite – carbon nanotubes
Grebelna J.A., Makhno S.M., Sementsov Yu.I., Kartel M.T.
Chuiko Institute of Surface Chemistry, NAS of Ukraine,
17 General Naumov Str., Kyiv 03164, Ukraine. liza50@ukr.net

The aim of the work was to develop technology and create carbon-carbon composites from thermo-expanded graphite filled with carbon nanotubes in order to obtain outging materials  for the production  by anodic oxidation of graphene na-
noparticles and composite filler carbon nanotubes (CNT) – graphene nanoparticles.
Effective deagglomeration agent for CNT is strong acids and oxidizing agents. Processes of deagglomeration of CNT and intercalation of natural graphite are performed simultaneously.
Fig.1 shows thermo-expanded graphite (TEG) samples that have a folded structure. It is seen that CNT “are embedded” in the body of the TEG (shown with arrows).	
	
The hardness for stretching of TEG samples, obtained by different methods and the TEG-CNT composite material, are presented in the Table. It is estimated that the introduction of 1% by weight CNT in natural graphite, provided that its anodic oxidation is combined with CNT, leads to the hardness increase in the hardness for stretching of rolled samples from the resulting TEG by about 22%.

Sample	Density,
g/cm3	Specific surface for desorption of argon, m2/g	Hardness limit for stretching,
MPa	The ratio of hardness limit to density	
TEG + CNT еcо	0.35	92	1.2  0.2	3.4  0.6	
TEG + CNT еcо	0.60	92	1,9  0.4	3.2  0.4	
TEG еcо	0.62	33	1.0  0.2	2.7  0.6	
TEG еcо	0.54	62	1.3  0.5	2.3  0.9	

It is obtained that the most defective structure is in TEG, synthesized by chemical oxidation in a solution of potassium bichromate in sulfuric acid with a ratio of 1 g К2Сr2O7 to 10 cm3 H2SO4, 2 dm3 solution per 1 kg of graphite.