8589356487

L. Kozhitov, A. Kostikova. V. Kozlov, Zh. Myrkhalykow A. Saipow FEATURES OF FeNi3 NANOPARTICLES IN POLYACRYLONITR/LE FORMATION UNDER INF RA RED HEAT1NG

where k is the constant, k= 0.89;

B is the diffraction-angle half-width of the

peak;

X is the CuK_a-radiation length equal to 1.54056 A;

0 (degree) is the diffraction-angle.

The calculation accuracy of particie sizes from the Debye-Scherrer equation is equal to 5% [4]. The FeNij/C composite structure is studied by SEM JEOL-JSM-6490 LV with an energy dispersive X-ray analyzer INCA350 for an elemental sample analysis.

RESULTS AND DISCUSSION

PAN is a chemically stable polymer at Iow temperaturę. In the rangę of 70-150°C H₂0 desorption takes place only. At 300°C PAN destruction starts. When further temperaturę increasing the poly-conjugated system in PAN is formed, and the cyclization providing the thermal stability of the pyrolyzed polymer to 300°C in the air starts (Fig. 1) [10].

CH

CH

2\

CH

DMF

60 C, 6 hours.

air

* /^CH2\

CH

CH

2\

CH

300 °C, 20 min, vacuum ^

CH

CH

CH

CH

CH

Fig. 1 - Chemical transformations in PAN under IR-heating

When FeCl₃-6H₂0 and NiCl₂-6H₂0 injection the PAN transformation acceleration is provided due to both the catalytic metal activity and the possibility of forming the complex with transition metal coordinated by-polymer nitrile groups -C=N. This significantly changes Chemical PAN conversion under the thermal treatment [10, 11]. In contrast to the pure polymer, nitrile groups bonded to the metal do not participatc in the cyclization reaction, hence the stage of C=N conjugated bond formation is eliminated. As a result of the dehydration backbone reaction, the conjugated double bond system has the length bigger than that obtained in the absence of transition metals.

Thermodynamic analyses of FeCl₃ and NiCl₂ reduction by H₂ emitted under the PAN destruction (reactions 2 and 3) and of the FeCl₃ and NiCl₂ decomposition (reactions 4-6) were fulfilled in the system FeCl₃-NiCl₂-PAN at temperatures higher than 300 °C (Table 1):

2FeCl₃ + 3H₂ —• 2Fe + 6HC1    (2)

NiCl₂+H₂ —Ni + 2HC1    (3)

2FeCl₃ —► 2FeCl₂+ Cl₂    (4)

FeCl₂ —► Fe-ł- Cl₂    (5)

NiCl₂ — Ni + Cl₂    (6)

6

Journal of Industrial Technology and Engineering, 2012, 2(3): 5-10