scholarly journals Nano-Indentation Response of Ultrahigh Molecular Weight Polyethylene (UHMWPE): A Detailed Analysis

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 795
Author(s):  
Tanveer Iqbal ◽  
S. S. Camargo ◽  
Saima Yasin ◽  
Ujala Farooq ◽  
Ahmad Shakeel
Keyword(s):  
Molecular Weight ◽  
Strain Rate ◽  
Peak Load ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Holding Time ◽  
Creep Model ◽  
Depth Sensing ◽  
Nano Indentation ◽  
Wide Range ◽  
Ultrahigh Molecular Weight

Nano-indentation, a depth sensing technique, is a useful and exciting tool to investigate the surface mechanical properties of a wide range of materials, particularly polymers. Knowledge of the influence of experimental conditions employed during nano-indentation on the resultant nano-mechanical response is very important for the successful design of engineering components with appropriate surface properties. In this work, nano-indentation experiments were carried out by selecting various values of frequency, amplitude, contact depth, strain rate, holding time, and peak load. The results showed a significant effect of amplitude, frequency, and strain rate on the hardness and modulus of the considered polymer, ultrahigh molecular weight polyethylene (UHMWPE). Load-displacement curves showed a shift towards the lower indentation depths along with an increase in peak load by increasing the indentation amplitude or strain rate. The results also revealed the strong dependence of hardness and modulus on the holding time. The experimental data of creep depth as a function of holding time was successfully fitted with a logarithmic creep model (R2 ≥ 0.98). In order to remove the creeping effect and the nose problem, recommended holding times were proposed for the investigated polymer as a function of different applied loads.

Study of dynamic compressive behaviour of aramid and ultrahigh molecular weight polyethylene composites using Split Hopkinson Pressure Bar

2016 ◽  
Vol 51 (1) ◽  
pp. 81-94 ◽  
Author(s):  
Khubab Shaker ◽  
Abdul Jabbar ◽  
Mehmet Karahan ◽  
Nevin Karahan ◽  
Yasir Nawab
Keyword(s):  
Molecular Weight ◽  
Strain Rate ◽  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Hopkinson Pressure Bar ◽  
Ultrahigh Molecular Weight ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Polyethylene Composites

In this paper, high strain rate compression properties of aramid and ultrahigh molecular weight polyethylene composites in the out-of-plane direction are tested at room temperature on a Split Hopkinson Pressure Bar apparatus. Tests were conducted on composites reinforced with woven or Uni-Directional (UD) fabrics made from aramid or ultrahigh molecular weight polyethylene as well as on composites reinforced with hybrid reinforcement. The strain rate is varied in the tests by changing the projectile shooting pressure. Four different pressures 2, 4, 6 and 8 bar were selected to change the strain rate. Stress–strain and energy absorption behaviour of eight type of samples were noted. Hybrid samples showed better performance in the energy absorption compared with other samples.

scholarly journals Закономерности микродеформации сверхвысокомолекулярного полиэтилена, модифицированного добавками галлуазита

2018 ◽  
Vol 60 (7) ◽  
pp. 1341
Author(s):  
В.В. Шпейзман ◽  
П.Н. Якушев ◽  
В.М. Егоров ◽  
С.В. Васильева ◽  
А.С. Смолянский
Keyword(s):  
Molecular Weight ◽  
Strain Rate ◽  
Transition Energy ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Degree Of Crystallinity ◽  
Effect Of Additives ◽  
Calorimetric Measurements ◽  
Ultrahigh Molecular Weight ◽  
Interference Measurement ◽  
The Degree Of Crystallinity

AbstractThe effect of additives of 1 and 3 wt % of halloysite on the rate and small jumps of deformation under uniaxial compression of ultrahigh-molecular-weight polyethylene was investigated. A procedure for precision interference measurement with a resolution of 325 nm for displacement and 1 kHz for frequency enabled the detection of several levels of deformation in the micro- and nanometer ranges. The addition of halloysite results in a decrease in the strain rate under the same loading conditions and a change in the characteristics of the strain jumps. Calorimetric measurements showed that melting of polyethylene with a different concentration of halloysite causes a change in the transition energy and the degree of crystallinity.

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