Conclusions and future scope
E. Biocompatibility studies on composites
5.2 Scope of future work
The work presented in this thesis opens up several avenues for further development of the composites for future application of carbon nanotube based composites for orthopedic application. The scope of future work is outlined as follows:
1. The effect of different aspect ratio of MWCNTs on the properties of the composites can be studied. Such studies would provide a better insight into the proper selection of MWCNTs for optimum mechanical properties of the composites.
2. Sandwich composites can be prepared with MWCNTs composite as core and virgin UHMWPE as skin to improve the fracture toughness. The same can also be explored by varying the concentration of T at skin and core prior to irradiation.
3. The influence of ion irradiation can be compared with that of gamma irradiation in composites/polymer by following accelerated ageing protocol.
4. Wear studies can be performed under simulated body fluid or bovine calf serum lubricating condition to replicate the human physiological condition in a pin-on-disc machine. Such a study would enable to assess the wear performance of the composites in a more realistic human body environment.
5. Hip simulator studies can be performed to exactly replicate the physiological loading conditions, which can influence the wear mechanisms. Such a study would greatly enhance to envisage the performance of the developed composites.
6. Elaborate biocompatibility studies can be performed confirming to ISO 10993 standards to completely assess the behaviour of developed composites in a biological system.
2000 4000 6000
8000 10000 25 kGy 50 kGy 75 kGy 100 kGy
Work to failure (m J)
100200300 400 500 600 700 800 25 kGy 50 kGy 75 kGy 100 kGy
% Strain at fracture
H H H
C C C C H H H
H H H H H H
C C C C H H H H H H H
H H
C C C C H H H H
H H H
H H
C C C C H H H H
H H H
. .
..
..
. .
..
..
0 20 40 60 80 100
k=3.274x10-7 N/mm3 k=5.361x10-7 N/mm3 k=6.635x10-7 N/mm3
k=8.635x10-7 N/mm3 GI100NC2.0
GI100NC0.0
GI100αT0.1
NC2.0
% Wear volume
A
Virgin UHMWPEk=1.208x10-6 N/mm3
25 50 75 100
0.125 0.130 0.135 0.140 0.145 0.150 0.155 0.160 0.165 0.170 0.175 0.180
CLD (mol/dm3)
Irradiation dose (kGy) pure
0.5 wt.%
1.0 wt.%
1.5 wt.%
2.0 wt.%
40 60 80 100 120 140 160 180
% Enhancement
Yield stress Strain at fracture Fracture stress Work to failure
0.4 0.5
y=0.488-0.036x
Plasticity index
ASP samples SLR samples
y=0.485-0.036x
0.5 1.0 1.5
2.0 y=0.741+0.281x
Young's modulus (GPa)
ASP samples SLR samples
y=0.683+0.275x
0.0 0.5 1.0 1.5 2.0
10 20 30 40 50 60 70 80
y=18.50*exp(-x/0.84)+18.81 y=38.46*exp(-x/0.51)+18.51
y=42.22*exp(-x/0.84)+34.72 Work to failure Strain at fracture Yield stress
% Reduction
MWCNTs wt. %
H
H H
C C C C
H H
H
H H H H H H
C C C
H H H
H H H H
H H
C C C C
H H H
H
H H H
H H
C C C
H H H
H
H H H
C C
0.0 0.5 1.0 1.5 2.0
0 20 40 60 80 100 120 140
10 Days 60 Days 120 Days
Relative intensity
MWCNTs wt.%
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