The Effect of High Loaded Multiwall Carbon Nanotubes in Natural Rubber and Their Nonlinear Material Constants

Table 4

Repeatability and reproducibility of experimental data.

		Mean tensile strength (MPa)	Variance	Standard deviation
NR/5 phr MWCNT	Machine 1	5.6025	0.01103	0.105002
	Machine 2	5.5097	0.01493	0.122205
	Average of laboratory average = 5.5561 MPa
	SD of the laboratory averages = 0.0657
NR/10 phr MWCNT	Machine 1	7.5198	0.01613	0.126985
	Machine 2	7.5511	0.01233	0.111058
	Average of laboratory average = 7.5354 MPa
	SD of the laboratory averages = 0.0222
NR/20 phr MWCNT	Machine 1	14.788	0.04631	0.215192
	Machine 2	14.682	0.03282	0.181159
	Average of laboratory average = 14.735 MPa
	SD of the laboratory averages = 0.0753
NR/30 phr MWCNT	Machine 1	23.385	0.04913	0.221651
	Machine 2	23.317	0.05935	0.243615
	Average of laboratory average = 23.351 MPa
	SD of the laboratory averages = 0.0484