Determining the Mechanical Characteristics of Composite Nanostructured Materials based on Recovered Silicone Rubber

This paper presents the mechanical characteristics of some nanocomposite materials based on recovered silicone rubber and different calcium carbonate nanopowders. The influence of the powders on the mechanical properties was studied by means of resistance at breakage, elongation at break and hardness.

Using the same base matrix there were obtained variants of composite nanostructured materials by combining silicone rubber recovered from the coating of used composite electrical insulators with powders obtained from egg shells, snail shells and filtered conch.

Determining The Mechanical Characteristics In Case Of Breaking Strain For Composite Nanostructured Material Based On Silicone Rubber Matrix
The material used as base matrix was silicone rubber recovered from used silicone rubber from the coating of discarded 24 KV composite electrical insulators in the form of silicone powder combined with liquid silicone rubber in different ratios and nanopowders obtained by recycling, yielding the following combinations: In case of pure silicone rubber the results were: Liquid silicone rubber (70%) combined with silicone powder (30%): Liquid silicone rubber (68%) combined with silicone powder (29%) and snail shell powder (3%), (Fig. 1): Fig. 1 -Technical plate from liquid silicone rubber (68%) + silicone powder (29%) + snail shell powder (3%);  Research has determined the maximum amount of silicone powder absorbed by the liquid silicone rubber (liquid silicone rubber 42,6% and silicone powder 57,4%):   The mechanical properties of the evaluated composite samples (resistance at breakage, elongation at break, respectively hardness) vary from the sample made of pure silicone rubber and 30% recovered silicone powder.The resistance at breakage decreases with the addition of the calcium carbonate nanoparticles, while the elongation at break increases for the case of egg shell powder.Regarding the resistance at breakage, the behavior is different: an increased hardness is recorded for all of the composite samples, the snail shell samples showing the best characteristics.

Conclusions
The new material is based on a matrix of silicone rubber recovered from 24 KV composite electrical insulators.
The largest value of the unit breaking force ır appears in case of "pure" silicone rubber, and decreases with the introduction of nanostructured components: snail shell powder 38 daN/cm 2 , filtered conch powder 29 daN/cm 2 and egg shell powder 36 daN/cm 2 .
Elongation at break įr also decreases from 540% in case of pure silicone rubber to 340% for the egg shell powder, 320% for silicone powder, 300% snail shell powder and 260% in case of filtered conch powder.

Fig. 4 -
Fig. 4-Resistance at breakage for samples with different percents of recovered silicone powder and nanopowder;

TABLE 6 -
EVALUATION OF MECHANICAL PROPERTIES (RESISTANCE AT BREAKAGE, ELONGATION AT BREAK AND HARDNESS) FOR SAMPLES OF LIQUID SILICONE RUBBER(42,6%) + SILICONE POWDER (57,6%) Fig. 2-Resistance at breakage for samples with different percents of recovered silicone powder and nanopowder; Fig. 3-Elongation at break for samples with different percents of recovered silicone powder and nanopowder;

TABLE . 5
-EVALUATION OF MECHANICAL PROPERTIES (RESISTANCE AT BREAKAGE,