Investigation of Rockwell hardness and Charpy impact test of injection molded multi-walled carbon nanotubes /poly methyl methacrylate nanocomposites

This paper studied the influence of Multiwalledcarbon nanotubes (MWCNT) concentration andinjection molding parameters on Rockwell H hardnessand Charpy impact testing of multi-walled carbonnanotubes/poly methyl methacrylate(MWCNT/PMMA) composite.Nanocomposites werefabricated through injection molding at varyingMWCNT concentration (0, 0.5, 1.0 and 1.5 wt. %). Itwas confirmed that the nanotubes were well dispersedin PMMA matrix according to scanning electronmicroscope (SEM) images.Design of experiments isperformed using full factorial method. Variable inputfactors are considered as MWCNT concentration infour levels, melt temperature in three levels (240, 250,260oC) and holding pressure in three levels (60, 80 and100 bar). Results proved that MWCNT concentrationis the most effective parameters on hardness and melttemperature has less effect. In addition, holdingpressure plays slight role on the hardness. In the caseof Charpy impact test, by increasing MWCNTconcentration within the PMMA matrix the resultswere improved up to 36.8%. Another significantparameter on impact testing is holding pressure that byincreasing it, the energy absorbed by specimensincreased up to 52.4%. Melt temperature enhancementalso increases the impact energy.

Keywords:

MWCNT , PMMA , Charpy Impact Test , Rockwell H hardness , Injection molding