Uniaxial tensile creep behaviour of ultra high molecular weight linear polyethylene

Polymer ◽  
1981 ◽  
Vol 22 (1) ◽  
pp. 23-28 ◽  
Author(s):  
S.K. Bhateja
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Creep Behaviour ◽  
Tensile Creep ◽  
Uniaxial Tensile ◽  
Linear Polyethylene ◽  
Ultra High Molecular Weight ◽  
Uniaxial Tensile Creep

Fabrication of Kevlar®-reinforced ultra-high molecular weight polyethylene composite through microwave-assisted compression molding for body armor applications

2020 ◽  
pp. 073168442095944
Author(s):  
Taresh Guleria ◽  
Nishant Verma ◽  
Sunny Zafar ◽  
Vivek Jain
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Energy Absorption ◽  
Compression Molding ◽  
High Energy ◽  
Impact Testing ◽  
Uniaxial Tensile ◽  
Microwave Assisted ◽  
Uniaxial Tensile Testing ◽  
Ultra High Molecular Weight

Kevlar®-reinforced composites are used in high energy absorption applications. In the present work, Kevlar®-reinforced ultra-high molecular weight polyethylene composites were fabricated through microwave-assisted compression molding. The microwave-assisted compression molding parameters were optimized through trial and error method. Analysis of mechanical behavior of composites was accessed through uniaxial tensile testing, flexural testing, impact testing, and nano-indentation. The fractured specimens were observed using scanning electron microscopy. An increment of 92.2% was observed in the ultimate tensile strength of the ultra-high molecular weight polyethylene/Kevlar® composite compared to neat ultra-high molecular weight polyethylene. Flexural properties, impact energy absorption rate, and hardness property of the composite were increased by 27.1%, 91.6%, and 4.77%, respectively, compared to pure ultra-high molecular weight polyethylene. Enhanced mechanical properties may be attributed to unique microwave heating phenomena during microwave-assisted compression molding.

Short-term creep and recovery behavior of medical grade ultra-high molecular weight polyethylene (UHMWPE)

2016 ◽  
Vol 78 (2) ◽  
pp. 65-70 ◽  
Author(s):  
F. Metin ◽  
M. Cengil
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Viscoelastic Material ◽  
Material Properties ◽  
Polymeric Materials ◽  
Tensile Creep ◽  
Short Term ◽  
Creep And Recovery ◽  
Ultra High Molecular Weight ◽  
Medical Grade

Purpose: In this study, short-term tensile creep and recovery behaviors of medical gradeultra-high molecular weight polyethylene (UHMWPE) were investigated to contributedeformation behaviour of UHMWPE components in knee and hip prosthesis during daily lifeactivities of patients.Design/methodology/approach: Tensile test specimens were machined fromcompression molded UHMWPE sheets having commercial brand name: Chirulen 1020 andthey were prepared according to ASTM 527-2. The tensile creep tests were performed atconstant stress levels of 5, 9, 13, 18 and 21 MPa as long as 1 hour for each test. Then, thespecimens were allowed to recover unloaded for 1 hour. Automatic extensometer was usedto measure the deformations precisely for each test.Findings: Results show that creep rate linearly increased with increasing the stress levels.Permanent deformations were observed after recovery. Recovery of the material becamedifficult with increasing the applied load at intended time interval.Research limitations/implications: UHMWPE components used in prosthesis havebeen subjected to complex loading conditions during service life. Polymeric materials showthe viscoelastic material properties like strain rate sensitivity, relaxation, creep and recoveryat room temperature. Because of the viscoelastic material properties of the UHMWPE,it makes difficult to predict the failure of the UHMWPE components in hip and knee prosthesis.Therefore, deformation behavior of medical grade UHMWPE should be investigated in manydifferent loading conditions.Practical implications: Medical grade ultra-high molecular weight polyethylene(UHMWPE) have been used commonly in total hip replacements as acetabular cup and intotal knee replacements as tibial insert since early 1960s.

scholarly journals Cryogenic machining to enhance surface finish of a biomedical grade ultra-high-molecular weight polyethylene

2021 ◽  
Author(s):  
Rachele Bertolini ◽  
Andrea Ghiotti ◽  
Stefania Bruschi
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Surface Finish ◽  
Polymeric Materials ◽  
Uniaxial Tensile ◽  
Cryogenic Machining ◽  
Dry Cutting ◽  
Crystallinity Degree ◽  
Wide Range ◽  
Ultra High Molecular Weight

In recent years, polymeric materials are being used at an increasing rate in the biomedical industry. In particular, Ultra-High-Molecular Weight Polyethylene (UHMWPE), a thermoplastic polymer characterized by high toughness, good chemical stability and self-lubricating properties, is an ideal candidate for the manufacture of bearing implants used in hip or knee replacements. Nevertheless, it is difficult to achieve a good level of surface finish when turning it, because of its high instability at increasing temperature. In the present study, cryogenic machining was applied instead of dry cutting to machine a biomedical grade UHMWPE at different cutting speeds. The surface finish was assessed in terms of surface roughness, crystallinity degree and hardness in correspondence of the surface. To correlate machinability results with the UHMWPE mechanical behaviour, uniaxial tensile tests were performed in a wide range of temperatures. The obtained results showed that the application of cryogenic machining was an efficient mean to increase the surface finish: in fact, smoother and harder surfaces were obtained regardless of the adopted cutting parameters.

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