Ultra High Density Polyethylene Research Articles

Measuring the ionic conductivity of solid polymer electrolyte powders

Ex-situ characterization of solid polymer electrolytes plays an important role in their development as materials for energy applications, with ionic conductivity being a crucial parameter to quantify. Conventional measurements of ionic conductivity often require the formation of a free-standing polymer film which in many instances is difficult to fabricate, thus there may be a need to quantify their ionic conductivity in powder form. In this work, we present a practical and reproducible method for measuring the ionic conductivity of solid polymer electrolytes (SPEs) in their powder form. By using a modified configuration of a through-plane cell, demonstrated with both a proton conducting- and an anion conducting-solid polymer electrolyte powder (SPEP), we are able to obtain ionic conductivity values under variable conditions in order to explore the influence of external parameters on the ionic conductivity of powders. Two types of SPEs in insoluble powder form were employed in this work: (1) a proton-exchange material (SPEP-H+) based on a hyperbranched, sulfo-phenylated poly(phenylene) SPEP (HB-sPPT-H+), with measured ionic conductivity of ⁓ 210 mS cm−1 at 80 °C and 95 % of relative humidity (RH); (2) an anion-exchange conducting polymer in its chloride form (SPEP-Cl-), consisting of a radiation-grafted ultra-high density polyethylene insoluble SPEP containing covalently-bonded benzyltrimethylammonium (BTMA) head-groups, with measured ionic conductivity of ⁓ 53 mS cm−1 at 80 °C and 95 % RH.

In Vitro Performance of Polymethyl-Methacrylate with Ultra High Density Poly Ethylene Fiber and Nano Zirconium Oxide Particles Composite

Background: Poly (methyl methacrylate) has been widely utilized for fabrication of dentures for many years as it has good advantages but not achieved all demands of the mechanical properties such as low transverse strength, low impact strength, low surface hardness, high water solubility and high water sorption. Material and method: To provide bonding between ZrO2 nanoparticles and PMMA matrix, the ZrO2 Nano-fillers were surface-treated with a saline coupling agent. Plasma surface treatment of polyethylene (PE) fiber was done to change surface fiber by using DC- glow discharge system. For characterization of interring any functional groups, the (FTIR) spectrum were done .then the mechanical properties studied to choose the appropriate percentages to complete study. Results: The results revealed that highly significant difference between groups in transverse strength, the highest mean value (96.1700 N/mm2) found in 2.0% polyethylene fibers and 1.5% salinized Zirconium oxide nanoparticles group, highly significant increase in impact strength (7.69 Kj/m2), surface hardness (92.35) and highly significant decrease in water sorption (0.0016 mg/cm2) and water solubility (0.0013 mg/cm2). Conclusion: the use of saline coupling agent with ZrO2 and oxygen plasma treatment PE fiber provided an effective procedure for getting good bonding with the PMMA matrix to give enhanced properties for the composite.

Evaporation, Lifetime, and Robustness Studies of Liquid Marbles for Collision-Based Computing.

Liquid marbles (LMs) have recently attracted interest for use as cargo carriers in digital microfluidics and have successfully been implemented as signal carriers in collision-based unconventional computing circuits. Both application domains require LMs to roll over substantial distances and to survive a certain number of collisions without degrading. To evaluate the lifetime of LMs being subjected to movement and impact stresses, we have selected four types of coating to investigate: polytetrafluoroethylene (PTFE), ultrahigh density polyethylene (PE), Ni, and a mixture of Ni with PE (Ni-PE). Hierarchies of robustness have been constructed which showed that pure PE LMs survived the longest when stationary and in motion. Pure PTFE LMs were shown to be the least resilient to multiple impacts. The PTFE coating provided minimal protection against evaporative losses for small LM volumes (2 and 5 μL) however, larger LMs (10 μL) were shown to have good evaporative stabilities when stationary. Conversely, PE LMs showed a remarkable ability to withstand multiple impacts and were also stable when considering just passive evaporation. Hybrid Ni-PE LMs exhibited more resilience to multiple impacts compared to Ni LMs. Thus, when designing LM devices, it is paramount to determine impact pathways and select appropriate coating materials.

Impregnation of Ultra-High-Density Polyethylene with Unsymmetrical Disulfides in Subcritical Freon Media

For the first time, ultra-high-density polyethylene (UHDPE) samples impregnated with antibacterial unsymmetrical disulfides (allyl benzothiazol-2-yl disulfide and allyl 8-quinolyl disulfide) were obtained in subcritical freon R22 in the absence of organic solvents as modifiers. Freon R22 was completely removed from the impregnated samples that provided a high purity of the final material. Potential implants based on the UHDPE impregnated with unsymmetrical disulfides were shown to manifest antibacterial and antifungal activity.

Improved High Performance Recycling of Polymers by Means of Bi-Exponential Analysis of Their Fluorescence Lifetimes

Technical polymers could be identified by means of their remarkably strong auto fluorescence. The mono-exponentially obtained time constants of fluorescence decay were applied for a rough assignment of the polymeric materials whereas bi-exponential analysis allowed a fine classification such as for special batches and for preceding contaminations. Chemically similar materials such as LDPE (low-density polyethylene), HDPE (high-density polyethylene) and UHDPE (ultrahigh-density polyethylene) could be as well identified as contaminations of mineral oil in PET (polyethylene terephthalate). Furthermore, the fluorescence spectra could be characterized by means of five Gaussian functions in the visible allowing a redundant assignment to the fluorescence lifetimes. Thus, efficient sorting of polymers was possible for high performance recycling.

Physical characters and economics of acrylic and epoxy polymers as frame components of external skeletal fixator

Physical characters of acrylic and epoxy polymers used in constructing external skeletal fixator vis-à-vis economics were compared in the present study. The fixator constructs were prepared using acrylic/epoxy polymer, 1.5 mm K-wires and ultra high density polyethylene rods as a bone substitute. Observations on fabrication ease, weight, radiographic properties and economics of polymers were taken. The epoxy polymer being doughy, less heat producing and fumeless was easier to fabricate into constructs. Hardening time for acrylic was dependent on environmental temperature with an average of 11 min; whereas, epoxy putty hardened in about 22 min and the hardening was independent of environmental temperature. Acrylic fixators were radiolucent and significantly lower in weight. Preparation cost of epoxy constructs was significantly lower than acrylic constructs. Present study provides baseline benchmarks to choose polymers in constructing external skeletal fixators according to available resources, technical expertise and economics involved.

Comparative Evaluation of In Vitro Mechanical Properties of Different Designs of Epoxy‐Pin External Skeletal Fixation Systems

To compare in vitro biomechanical properties of different designs of epoxy-pin external skeletal fixator (ESF) constructs. Mechanical testing study. Four epoxy-pin ESF design constructs (uniplanar [EU], multiplanar-I [EM-I], multiplanar-II [EM-II], and circular [EC]) were mechanically tested in compression, bending, and torsion. Four different designs of free-form epoxy-pin external fixator constructs were developed using 1.5 mm K-wires and epoxy resin mounted in an ultra-high density polyethylene rod (20 mm diameter). Three-point fixation was done in each fragment, and the distance between fixation wires, and between the rod and the side bars was kept constant in all the designs. A 5 mm gap was maintained at the center of the fixation rod to simulate an unstable fracture condition. The fixator constructs (n = 12 of each design) were subjected to mechanical testing in axial compression, bending, or torsion. Load-deformation curves were generated and mechanical properties were compared between construct types. EU was the weakest design. Under compression, constructs EM-I, EM-II, and EC were similar. Under bending, EM-I and EM-II had similar strength, whereas EC was strongest. Under torsion, EC was strongest, followed by EM-II, EM-I, and EU; EM-II provided double the rotational stability of EM-I. Overall, EC followed by EM-II epoxy-pin fixator designs had better mechanical strength.

Thermal conductivity of highly crystallized polyethylene

We report thermal conductivity (κ) of low-density, high-density and ultra-high density polyethylene (PE) with different crystallinity and microstructures. PE was crystallized under high-pressure and high-temperature conditions which produce extended chain crystals. By applying a two-phase model, we estimate κ of 100% crystallized PE as a function of pressure and temperature. The increased crystallinity and lamellar thickness (fold length) reduce the thermal resistance, which is reflected not only in the absolute value of κ but also in more pronounced pressure and temperature dependencies approaching those of polycrystalline low-molecular weight materials. The results suggest that it is crucial to increase the lamellar thickness to significantly improve κ of PE with randomly oriented lamellae.

Remplacement total de l’articulation temporo-mandibulaire par prothèse

Summary Introduction The temporomandibular joint (TMJ) may be the location for tumoral, post-traumatic, degenerative, inflammatory, or congenital diseases requiring a prosthetic replacement. We present a technical note for total TMJ replacement with a Biomet ® Microfixation prosthesis (Jacksonville, FL, USA). Technical note The preoperative data includes dental panoramic X-ray, MRI of the TMJ, and CT-scan (or cone beam) of the facial skeleton. The last two mentioned examinations allow three-dimensional reconstructions and stereo-lithographic models required for surgical planning. The prosthetic device includes a temporal ultra-high density polyethylene component and a mandibular chrome-cobalt-molybdenum-titanium alloy component; in case of allergy the prosthesis is made in titanium. These components may be standard size or custom made. The surgery requires through two common surgical approaches: pre-auricular and sub-mandibular. When a custom-made prosthesis is used, osteotomies are performed using surgical guides provided by the manufacturer. After intermaxillary fixation, the various prosthetic components are positioned and fixed with specific titanium screws, 2 mm (temporal component) and 2.7 mm (mandibular component) in diameter. The occlusion and prosthesis functionality are tested after releasing the intermaxillary fixation. Soft food intake is recommended for 21 days and physiotherapy is initiated on the second postoperative week for at least 1 year. Discussion The total replacement technique with a Biomet Microfixation ® prosthesis is a simple procedure. It allows recovering a good articular function and relieves the patient.

Development of Textile Laminates for Improved Cut Resistance

Fiber structures, yarn structures, and mechanical properties of fibers namely tensile modulus, tenacity, and elongation, are the key performance indicators of fabric cut resistance. p-aramid and UHDPE (Ultra High Density Polyethylene) based high performance fibers are most commonly used for protection against mechanical risks. Specially engineered composite yarns and fabrics enhance cut resistance. This paper discusses the influence of textile structure configuration on the performance of cut resistant textiles. A three tier laminate composite was made using knitted Kevlar fabric, (p-aramid) as the outer surface, polyurethane foam in the middle and a knitted nylon fabric as the skin contact layer. This specially engineered laminate showed a 20% increase in cut resistance when compared with the Kevlar fabric used for lamination. The combination of breathable PU foam and knitted fabric yielded high stretch with improved breathability and dexterity.

Evaluation of total hip replacement

This prospective study was made to asses the results of total hip replacement done primarily at Dhaka Medical College Hospital by the surgical team from its orthopaedic department. Eight patients were selected randomly from April/2005 to December/2005. Six patients were male and two females. Age of the patients was ranging from 22 to 67 years with average of 37.4+/-5.12 (mean+/-SE) years. Majority of the patients (75%) were diagnosed as Aseptic necrosis of femoral head with secondary osteoarthritis. The femoral head was replaced by metallic component with C-stem and the acetabular cup made up of Ultra-High density Polyethylene. Both the components were cemented (methylmethacrylate) by hand-packing. The patients were followed-up for 7.75+/-6.1 months (mean+/-SE) ranging from 4 months to 1 year. The results were evaluated on the basis of Harris Hip Score(2). 75 % had good to excellent and 12.5% had fair results. One patient complicated with dislocation and ultimately had poor result. The quality of life in seven patients (87.5%) improved much for which they were grateful.

An axisymmetric model of acetabular components in total hip arthroplasty

An axisymmetric finite element model with nonaxisymmetric loading of an acetabular arthroplasty and the surrounding pelvic bone is presented. Model variations include ultra high density polyethylene acetabular components of varying wall thicknesses and metal backed ultra high density polyethylene components. Each of the two component types is modeled as implanted within an acetabulum with intact subchondral bone and within an acetabulum without subchondral bone. Thin wall polyethylene acetabular prostheses are predicted to increase, relative to thick wall components, maximum stresses in the cement-bone composite. Trabecular bone stresses are predicted to increase with the removal of subchondral bone. Stiffer metal-backed acetabular components are predicted to reduce maximum cement and bone stresses and to abridge the effects of altered component wall thickness and of subchondral bone removal.