A comparison between mechanical properties of UHMWPE from ram extrusion process and UHMWPE from compression molding process for a hip joint liner

Wahyudi, Muhammad Sigit; Putra, Yohanes Eka Anggraita; Arrohman, Sigit; Jamari, J.; Ismail, Rifky

doi:10.1088/1757-899x/432/1/012007

Cited by 8 publications

(6 citation statements)

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“…Consequently, conventional meltprocessing techniques, such as extrusion or injection molding, normally are not suitable for UHMWPE. 1 Instead, sintering 2 is one of the preferred processing methods. There are many entanglement points in the amorphous region within highly entangled UHMWPE, and the topological structure of polymer chains affects their movement, resulting in a very slow diffusion process.…”

Section: ■ Introductionmentioning

confidence: 99%

Interplay of Particle Size and Temperature on Low-Entanglement Ultrahigh-Molecular-Weight Polyethylene Sintering in Blended Compositions: Analysis of Entanglement and Crystal Structure

Yan,

Zhang,

Tang

et al. 2023

Ind. Eng. Chem. Res.

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The present study focuses on improving the entanglement reconstruction of low-entanglement ultrahigh-molecularweight polyethylene (UHMWPE) through the incorporation of small particles into large particles in different sintering temperature environments. 10 wt % of small particles was added to the large particles, and the resulting entanglement degree of sintered products was examined through isothermal annealing experiments, high-temperature tensile tests, and rheological measurements. To gain insights into the entanglement formation process, the McLeish theory was employed to analyze the rheological results, and the chain dynamics of the bulk and interface domains in the particles were calculated. The analysis revealed that the addition of small particles significantly enhanced entanglement formation in both the interface and bulk domains of the particles. Regarding the characterization of the crystalline structures, it is found that the establishment of interphase has a positive correlation with entanglement construction, especially at a high sintering temperature. The tailored dimension of particle sizes and sintering temperatures result in optimized entanglement density and interphase content, leading to a substantial improvement in the tensile strength and breaking elongation of the material.

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Section: ■ Introductionmentioning

confidence: 99%

Interplay of Particle Size and Temperature on Low-Entanglement Ultrahigh-Molecular-Weight Polyethylene Sintering in Blended Compositions: Analysis of Entanglement and Crystal Structure

Yan,

Zhang,

Tang

et al. 2023

Ind. Eng. Chem. Res.

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“…However, the extremely high molecular weight and long chains, and high degree of molecular entanglement of UHMWPE also lead to poor melt processability. So far, compression molding and ram extrusion are the most widely used processing methods for UHMWPE 7 . Compression molding and ram extrusion are non‐continuous processes, and further machining is needed to obtain the final part geometry.…”

Section: Introductionmentioning

confidence: 99%

“…So far, compression molding and ram extrusion are the most widely used processing methods for UHMWPE. 7 Compression molding and ram extrusion are non-continuous processes, and further machining is needed to obtain the final part geometry. Machining will leave machine marks on the part surface and might affect its mechanical properties and surface aesthetics.…”

Section: Introductionmentioning

confidence: 99%

Thermal, rheological, and mechanical characterization of compression and injection molded ultra‐high molecular weight polyethylene, high density polyethylene, and their blends

Yang

Yilmaz

Jiang

et al. 2022

J of Applied Polymer Sci

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Tensile and impact test samples of ultra‐high molecular weight polyethylene (UHMWPE), high‐density polyethylene (HDPE), and their blends at various UHMWPE/HDPE weight ratios were prepared via compression molding and injection molding for thermal, rheological, and mechanical characterization. A twin‐screw extruder with either a tapered die with air‐cooling or a regular die was used to compound and extrude the materials prior to pelletization and molding. To the best of our knowledge, there has been no publication on pelletizing neat UHMWPE using a regular extruder. The differential scanning calorimetry analysis suggested the occurrence of re‐crystallization and co‐crystallization for all the blends. The rheology test confirmed that all the blends exhibited a solid‐like behavior and the degree of compatibility increased with increasing HDPE content in the blends. A strong synergistic effect was observed the blends possessed a higher tensile and impact strength than their neat UHMWPE and HDPE counterparts. The compression molded (95/5) UHMWPE/HDPE samples extruded using the tapered die yielded the highest tensile strength (50.1 MPa), which was about 40% higher than that of the neat UHMWPE samples. The best composition of these blends for compression and injection molded parts is 10% HD and 50% HD, respectively.

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“…11 Polymer molded products within a processable melting point could be prepared through heating to a molten state followed by binding together in the cooling process. Many high-performance polymers, such as polytetrafluoroethylene (PTFE), 12,13 ultrahigh molecular weight polyethylene (UHMWPE), 14,15 and meltable PIs, [16][17][18] are molded based on this fabricating pathway either by pressing or extrusion. Zalaznik 19 also demonstrated that the processing temperature below the melting point for polyetheretherketone (PEEK) greatly influenced the crystallinity and hardness, thus determining its tribological behavior.…”

Section: Introductionmentioning

confidence: 99%

Property investigation for high-Performance Polyimides fabricated via compression molding in solid-like state

Wan

Jia

Zhan

et al. 2022

High Performance Polymers

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A compacted body was fabricated by pulverulent polyimide (PI) block copolymers using solid-like state compression molding (SCM) technique. Polymer heated to solid-like state, i.e. the high-elastic non-melting state above the glass transition temperature ( Tg) and well below melting temperature, could achieve plasticity due to dramatic decreases in elastic modulus. Tensile properties were taken as response values, and the results of single-factor experiments indicated that molding temperature was the dominant parameter on mechanical performances, followed by molding pressure and holding time. Within this context, the SCM process possesses a longer processing time window whereas the processing temperature is narrow. The manufacturing defects induced by inappropriate processing conditions also hurt the tribological performance of PIs. Particles in a solid-like state could coalesce tightly only by exerting both high temperature and pressure in the SCM process. Thermoforming mechanism examined by atomic-scale molecular dynamics simulation indicated that non-bonding interaction forces, especially van der Waals forces play a key role in fusing among polymeric particles. This study is devoted to establishing the interdependence of structure-formability-property for high-temperature polymers that are not melt processible.

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A comparison between mechanical properties of UHMWPE from ram extrusion process and UHMWPE from compression molding process for a hip joint liner

Cited by 8 publications

References 0 publications

Interplay of Particle Size and Temperature on Low-Entanglement Ultrahigh-Molecular-Weight Polyethylene Sintering in Blended Compositions: Analysis of Entanglement and Crystal Structure

Interplay of Particle Size and Temperature on Low-Entanglement Ultrahigh-Molecular-Weight Polyethylene Sintering in Blended Compositions: Analysis of Entanglement and Crystal Structure

Thermal, rheological, and mechanical characterization of compression and injection molded ultra‐high molecular weight polyethylene, high density polyethylene, and their blends

Property investigation for high-Performance Polyimides fabricated via compression molding in solid-like state

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