Biodegradation behavior and tribological properties of ultrahigh molecular weight polyethylene stabilized with α-tocopherol

2019 ◽  
Vol 71 (3) ◽  
pp. 494-498
Author(s):  
Xueqin Kang ◽  
Chi Yao ◽  
Shirong Ge
Keyword(s):  
Molecular Weight ◽  
Tribological Properties ◽  
Design Methodology ◽  
Experimental Studies ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Tribological Test ◽  
Pressing Method ◽  
Content Type ◽  
Ultrahigh Molecular Weight ◽  
One Year

Purpose This paper aims to investigate the effect of simulated body fluid (SBF) on biodegradation and tribological properties of ultrahigh molecular weight polyethylene (UHMWPE) and UHMWPE stabilized with α-tocopherol. Design/methodology/approach The samples of UHMWPE and UHMWPE stabilized with α-tocopherol were prepared by a hot-pressing method, and then immersed in SBF for one year. Tribological test was performed on a UMT-2 tribometer. Findings The crystallinity and tribological properties increased slightly after UHMWPE stabilized with α-tocopherol, whereas the O/C ration decreased slightly. The crystallinity and O/C ratio increased after all samples immersed in SBF for one year. This resulted in the deterioration of tribological properties and the wear mechanism change. The tribological properties change was smaller in UHMWPE stabilized with α-tocopherol than that in UHMWPE, because the oxidation resistance of UHMWPE was increased by α-tocopherol. Originality/value The results of the experimental studies demonstrated and compared the biodegradation behavior and tribological properties of UHMWPE, UHMWPE stabilized with α-tocopherol, and after they immersed in SBF for one year.

Tribological properties of ultrahigh-molecular-weight polyethylene (UHMWPE) composites reinforced with different contents of glass and carbon fibers

2019 ◽  
Vol 71 (1) ◽  
pp. 22-30 ◽  
Author(s):  
Yanzhen Wang ◽  
Zhongwei Yin
Keyword(s):  
Molecular Weight ◽  
Wear Resistance ◽  
Friction Coefficient ◽  
High Performance ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Content Type ◽  
Ultrahigh Molecular Weight ◽  
Pin On Disc ◽  
Uhmwpe Composites ◽  
Uhmwpe Composite

PurposeThis purpose of this study was to investigate the effects of carbon fiber (CF) and/or glass fiber (GF) fillers on the tribological behaviors of ultrahigh-molecular-weight polyethylene (UHMWPE) composites to develop a high-performance water-lubricated journal bearing material.Design/methodology/approachTribological tests were conducted using a pin-on-disc tribometer using polished GCr15 steel pins against the UHMWPE composite discs under dry conditions with a contact pressure of 15 MPa and a sliding speed of 0.15 m/s. Scanning electron microscopy, laser 3D micro-imaging profile measurements and energy-dispersive X-ray spectrometry were used to analyze the morphologies and elemental distributions of the worn surfaces.FindingsThe results showed that hybrid CF and GF fillers effectively improved the wear resistance of the composites. The fiber fillers decreased the contact area, promoted transfer from the polymers and decreased the interlocking and plowing of material pairs, which contributed to the reduction of both the friction coefficient and the wear rate.Originality/valueThe UHMWPE composite containing 12.5 Wt.% CF and 12.5 Wt.% GF showed the best wear resistance of 2.61 × 10−5mm3/(N·m) and the lower friction coefficient of 0.12 under heavy loading. In addition, the fillers changed the worn surface morphology and the wear mechanism of the composites.

scholarly journals Usefulness of Sacral Sublaminar Wire for Low Transverse Sacral Fractures: Two Cases’ Report

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Tatsuro Sasaji ◽  
Hideki Imaizumi ◽  
Taishi Murakami
Keyword(s):  
Molecular Weight ◽  
Screw Fixation ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Sacral Fracture ◽  
Sacral Fractures ◽  
The Third ◽  
Ultrahigh Molecular Weight ◽  
Sacral Foramina ◽  
Bone Anchors ◽  
One Year

Low transverse sacral fractures are rare, with only two published reports regarding their surgery. The complication associated with surgery for sacral fractures is the prominence of implants. In addition, screw fixation below S3 is impractical. We performed posterior sacral fixation using S2 alar iliac (S2AI) screws and sacral sublaminar wires for low transverse sacral fractures. Case 1 was 65-year-old male with an S2-3 transverse sacral fracture. We performed laminectomy (S2-3) and passed ultrahigh molecular weight polyethylene (UHMWPE) cables from laminectomy area to the third posterior sacral foramina. We inserted S2AI screws and connected rods. We also tightened the UHMWPE cables. The implants did not protrude into skin. One year after surgery, the sacral fracture healed without any displacement. Case 2 was a 42-year-old female with an S2 transverse sacral fracture. We performed laminectomy (S1–3) and passed UHMWPE cables from laminectomy area to the third and fourth posterior sacral foramina. We inserted S1 pedicular screws and S2AI screws and connected rods. We also tightened UHMWPE cables. The implants did not protrude into skin. One year after surgery, the sacral fracture healed without any displacement. We consider sacral sublaminar wires to be useful bone anchors in lower sacrum.

Biomimetic surface design for ultrahigh molecular weight polyethylene to improve the tribological properties

2012 ◽  
Vol 226 (8) ◽  
pp. 705-713 ◽  
Author(s):  
Bo Zhang ◽  
Wei Huang ◽  
Xiaolei Wang
Keyword(s):  
Molecular Weight ◽  
Tribological Properties ◽  
Articular Surface ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Industrial Applications ◽  
Wear Depth ◽  
Surface Design ◽  
Area Density ◽  
Ultrahigh Molecular Weight ◽  
Average Wear

Tribological problem is a major obstacle that limits the using of ultrahigh molecular weight polyethylene (UHMWPE) in industrial applications and orthopedic surgeries. Many efforts have been made to improve the tribological properties of UHMWPE, such as promoting the structure, morphology, and mechanical properties of the polymer. Inspired by the features of articular surface, micro-scaled texture is introduced to improve the tribological properties of UHMWPE using micro-imprint lithography. Friction and wear experiments are conducted on textured and untextured specimens using ring-on-disc test apparatus under water lubrication. The experimental results demonstrate that the micro-scaled surface texture can remarkably improve the tribological properties of UHMWPE. Friction force can be effectively reduced by selecting suitable dimple parameters. Compared with an untextured UHMWPE, the textured one with optimum parameters shows a reduction in the friction coefficient as much as 66.7–85.7% on different load–speed conditions. The optimized area density of surface textured UHMWPE ranges from 22.9% to 29.9%, which is obviously higher than that of stiff materials such as metals and ceramics. The textured UHMWPE with area density 29.9%, diameter 50 µm, and depth 15 µm presents a significant effect of wear resistance. The average wear depth of textured UHMWPE is 35.5% of that of untextured one.

scholarly journals Effect of Powder on Tribological and Electrochemical Properties of Nylon 66 and Ultra-High Molecular Weight Polyethylene in Water and Seawater Environments

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2874
Author(s):  
Wanxing Xu ◽  
Tian Yang ◽  
Shengpeng Zhan ◽  
Dan Jia ◽  
Lixin Ma ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Synergistic Effect ◽  
Tribological Properties ◽  
Pure Water ◽  
Water Environment ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Polymer Materials ◽  
Nylon 66 ◽  
Ultrahigh Molecular Weight ◽  
Seawater Environment

Polymer materials are used increasingly in marine machinery and equipment; their tribological properties and effect on the water environment have garnered significant attention. We investigate the effect of water or seawater environment containing powder on tribology and electrochemistry of polymer materials. A friction test involving nylon 66 (PA66) and an ultrahigh molecular weight polyethylene (UHMWPE) pin–disc (aluminum alloy) is performed in seawater or water with/without polymer powder, and the solution is analyzed electrochemically. The results show that the tribological properties of the UHMWPE improved by adding the powder to the solution, whereas the PA66 powder demonstrates abrasive wear in a pure water environment, which elucidates that the synergistic effect of powder and seawater on UHMWPE reduces the wear, and the synergistic effect of pure water and powder aggravates the wear. The results of electrochemical experiments show that after adding powder in the friction and wear tests, the powder can protect the pin by forming a physical barrier on the surface and reducing corrosion, and the changes are more obvious in seawater with powder in it. Through electrochemical and tribological experiments, the synergistic effect of solution environment and powder was proved.

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