**4.3. Preparation of composite materials based on silicon carbide and carbon nanotubes**

The main process for obtaining dispersion-filled plastic masses (for the preparation of composites based on polyimide and CNT or nanostructured silicon carbide) is mixing. These are complex physicomechanical and physicochemical processes associated with the action of force fields, the displacement of the original components of the mixture in the reactor volume along complex trajectories, with the formation of a system characterized by a randomly distributed distribution of components.

As noted earlier, the polyimide matrices used are insoluble in organic solvents, and their softening temperature exceeds 300°C, which means that it is expedient to use the in-situ polymerization method as a basis.

The technologies of obtaining a composite material in the form of a powder and in the form of films were studied.

The process of obtaining a powder of composite material was divided into four stages:


The process of obtaining a film composite material was divided into five stages:


Experiments were carried out to produce composites based on nanostructured silicon carbide with a modified and unmodified surface, and also based on carbon nanotubes with a modified and unmodified surface. These experiments were conducted to study the effect of different contents of inorganic fillers with varying degrees of surface modification on the properties of the resulting composite materials (**Table 1**).

All the composites obtained were characterized by the methods of elemental analysis, IR spectrometry. Thermal and thermooxidative destruction was evaluated, and the glass transition temperature of the resulting materials was determined.

As initial polymer matrices, polyimide matrices with different degrees of structural rigidity were chosen.

**4.4. Properties of the resulting composite materials**

parameter for the success of this experiment.

*composite materials*

pPDA))

*4.4.1. Effect of nanosized filler on the viscosity of the precursor for the production of film* 

**Table 1.** Experiments of producing powders of composite materials based on nanostructured SiC and CNT.

**No. Type of inorganic filler Surface state of** 

Nanostructured SiC Unmodified 0.05%, 0.1%, 0.25%,

Nanostructured SiC Modified 0.05%, 0.1%, 0.25%,

Single-walled carbon nanotubes Unmodified 0.1%, 0.25%, 0.5%,

Single-walled carbon nanotubes Modified 0.1%, 0.25%, 0.5%,

Nanostructured SiC Unmodified 0.05%, 0.1%, 0.25%,

Nanostructured SiC Modified 0.05%, 0.1%, 0.25%,

Single-walled carbon nanotubes Unmodified 0.1%, 0.25%, 0.5%,

Single-walled carbon nanotubes Modified 0.1%, 0.25%, 0.5%,

Nanostructured SiC Unmodified 0.05%, 0.1%, 0.25%,

Nanostructured SiC Modified 0.05%, 0.1%, 0.25%,

Single-walled carbon nanotubes Unmodified 0.1%, 0.25%, 0.5%,

Single-walled carbon nanotubes Modified 0.1%, 0.25%, 0.5%,

3 Matrix No. 3 (pyromellitic dianhydride and 4-[4-(4-aminophenoxy)phenoxy] phenylamine (PMDA/AFFA))

2 Matrix No. 2 (3,3′, 4,4′-benzophenone tetracarboxylic acid dianhydride and p-phenylenediamine (BTDA/

1 Matrix No. 1 (pyromellitic dianhydride and 4,4′-oxydianiline (PMDA/ODA))

**inorganic filler**

**Inorganic filler content, wt.%**

Nanocomposite Polyimide Materials http://dx.doi.org/10.5772/intechopen.79889 97

0.5%, 1%, 2%

0.5%, 1%, 2%

0.75%, 1%, 2%

0.75%, 1%, 2%

0.5%, 1%, 2%

0.5%, 1%, 2%

0.75%, 1%, 2%

0.75%, 1%, 2%

0.5%, 1%, 2%

0.5%, 1%, 2%

0.75%, 1%, 2%

0.75%, 1%, 2%

viscosity of a precursor in the preparation of film composite materials was studied.

Solutions of polyamide acids (PAAs) are precursors in the preparation of polyimide films and composites based on them, and the degree of viscosity of this solution is an important

The effect of different contents of nanosized silicon carbide and carbon nanotubes on the



**Table 1.** Experiments of producing powders of composite materials based on nanostructured SiC and CNT.
