The effect of temperature and strain rate on the mechanical properties of highly oriented polypropylene tapes and all-polypropylene composites

2007 ◽  
Vol 67 (10) ◽  
pp. 2061-2070 ◽  
Author(s):  
B. Alcock ◽  
N.O. Cabrera ◽  
N.-M. Barkoula ◽  
C.T. Reynolds ◽  
L.E. Govaert ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Effect Of Temperature ◽  
Polypropylene Composites ◽  
Oriented Polypropylene

scholarly journals Experimental Measurements of Mechanical Properties of PUR Foam Used for Testing Medical Devices and Instruments Depending on Temperature, Density and Strain Rate

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4560 ◽  
Author(s):  
Zdenek Horak ◽  
Karel Dvorak ◽  
Lucie Zarybnicka ◽  
Hana Vojackova ◽  
Jana Dvorakova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Mechanical Testing ◽  
Medical Devices ◽  
Optical Microscope ◽  
Surgical Instruments ◽  
Effect Of Temperature ◽  
Experimental Measurements ◽  
Compression Tests ◽  
Biomedical Material

Rigid polyurethane (PUR) foam is products used as a biomedical material for medical device testing. Thermal stability is a very important parameter for evaluating the feasibility of use for testing surgical instrument load during drilling. This work aimed to perform experimental measurements to determine the dependence of the mechanical properties of a certified PUR on temperature, strain rate and density. Experimental measurements were realised for three types of the PUR samples with different density 10, 25 and 40 pounds per cubic foot. The samples were characterised in terms of their mechanical properties evaluated from tensile and compression tests at temperatures of 25 °C, 90 °C and 155 °C. Furthermore, the structures of the samples were characterised using optical microscope, their thermal properties were characterised by thermogravimetric analysis, and their density and stiffness with the effect of temperature was monitored. The results show that it is optimal not only for mechanical testing but also for testing surgical instruments that generate heat during machining. On the basis of experimental measurements and evaluations of the obtained values, the tested materials are suitable for mechanical testing of medical devices. At the same time, this material is also suitable for testing surgical instruments that generate heat during machining.

Mechanical Properties of ZDTP Tribofilms Measured by Nanoindentation: Strain Rate and Temperature Effects

2008 ◽  
Author(s):  
S. Bec ◽  
K. Demmou ◽  
J.-L. Loubet
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Film Formation ◽  
Point Of View ◽  
Effect Of Temperature ◽  
Zinc Dialkyldithiophosphate ◽  
Wear Rates ◽  
Versus Strain ◽  
Antiwear Action

This study aims to contribute to better understand the antiwear action of zinc dialkyldithiophosphate (ZDTP) additives used in car engine lubrication. The antiwear action of ZDTP is associated to the formation of a protective tribofilm onto the rubbing surface. On a mechanical point of view, the efficiency of ZDTP tribofilms results from equilibrium between film formation and wear rates, associated with appropriate rheological properties. In this work, the mechanical properties of a ZDTP tribofilm have been measured by nanoindentation in different test conditions in order to investigate the effect of temperature and strain rate. A Nanoindenter XP® entirely set into a climatic chamber was used to perform the nanoindentation tests. For all tests, an increase of the elastic modulus was observed from a threshold contact pressure value. This effect is similar to the anvil effect observed on polymers: in confined geometry, the elastic modulus increases versus hydrostatic pressure. For the tribofilm, in the studied range, this effect is enhanced at high temperature and low strain rate. Furthermore, when the temperature increases, a change in the rheological behavior of the tribofilm is observed. Up to about 50°C, the tribofilm exhibits viscoplastic behavior — the hardness increases versus strain rate — and above 50°C, the hardness decreases versus strain rate (“shear thinning-like” behavior).

scholarly journals Compressive Behavior of Carbon Nanotube Reinforced Polypropylene Composites Under High Strain Rate: Insights From Molecular Dynamics

2021 ◽  
Author(s):  
Brijesh Mishra ◽  
Sumit Sharma
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Strain Rate ◽  
Compressive Strain ◽  
Md Simulations ◽  
Vital Role ◽  
Key Factors ◽  
Single Walled Carbon Nanotube ◽  
Vacancy Defects ◽  
Polypropylene Composites

Abstract Since the discovery of carbon nanotubes (CNTs), these have received a lot of attention because of their unusual mechanical electrical properties. Strain rate is one of the key factors that play a vital role in enhancing the mechanical properties of nanocomposites. In this study, (4, 4) armchair single-walled carbon nanotube (SWCNT) was employed with the polymer matrix as polypropylene (PP). The influence of compressive strain rate on SWCNT/PP nanocomposites was evaluated using MD simulations, and mechanical properties have been predicted. Stone-Wales (SW) and vacancy defects, were integrated on the SWCNT. The maximum Young’s modulus (E) of 81.501 GPa was found for the pristine SWCNT/PP composite for a strain rate of 1010 s-1. The least value of E was 45.073GPa for 6% SW defective/PP composite for a strain rate of 108 s-1. While the 6% vacancy defective CNT/PP composite showed the lowest value of E as 39.57GPa for strain rate 108 s-1. It was found that the mechanical properties of SWCNT/PP nanocomposites decrease with the increase in percent defect. It was also seen that the mechanical properties were enhanced with the increment in the applied strain rate. The results obtained from this study could be useful for the researchers designing PP-based materials for compression loading to be used for biomedical applications.

scholarly journals Effect of Temperature and Strain Rate on the Flexural Behavior of Wood-Polypropylene Composites

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3987 ◽  
Author(s):  
Wei Wang ◽  
Xiaomin Guo ◽  
Liu Liu ◽  
Ruiyun Zhang ◽  
Jianyong Yu
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Strain Rate ◽  
Storage Modulus ◽  
Master Curve ◽  
Wood Powder ◽  
Polypropylene Composites ◽  
Long Term Performance ◽  
Term Performance

The mechanical properties of wood-polypropylene composites exhibit typical viscoelasticity. However, there is little information on the mechanical properties of wood-polypropylene composites related to temperature and time, which limits the use of wood-polypropylene composites as structural components. Here, the effect of time (strain rate) and temperature on the flexural properties and the master curve of the storage modulus used to predict the long-term performance of wood-polypropylene composites were investigated. The results showed that the flexural strength and modulus increased linearly with the increase of wood contend, which can increase by 134% and 257% respectively when the mass fraction of wood powder reached 45%. Moreover, there was a positive linear relationship between flexural strength and ln strain rate, while the flexural strength and modulus decreased as temperature elevated. The storage modulus as a function of frequency (time) and temperature confirmed this trend. To evaluate the long-term performance, the storage modulus master curve was constructed and the respective activation energy was calculated, which revealed that the long-term performance of the samples depended on the matrix and the addition of an appropriate amount of wood powder was beneficial to improve their durability.

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