Critical considerations for the accelerated ageing of high-density polyethylene potable water materials

2009 ◽  
Vol 94 (7) ◽  
pp. 1163-1175 ◽  
Author(s):  
Andrew J. Whelton ◽  
Andrea M. Dietrich
Keyword(s):  
High Density Polyethylene ◽  
Potable Water ◽  
High Density ◽  
Accelerated Ageing

scholarly journals Durability of Basalt/Hemp Hybrid Thermoplastic Composites

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 603 ◽  
Author(s):  
Claudia Sergi ◽  
Jacopo Tirillò ◽  
Maria Carolina Seghini ◽  
Fabrizio Sarasini ◽  
Vincenzo Fiore ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Uv Radiation ◽  
High Density Polyethylene ◽  
High Density ◽  
Thermoplastic Composites ◽  
Accelerated Ageing ◽  
Special Focus ◽  
Scanning Calorimetry ◽  
Hemp Fibre ◽  
Fibre Composites

The Achilles heel of thermoplastic natural fibre composites is their limited durability. The environmental degradation of the mechanical properties of hemp and hemp/basalt hybrid-reinforced high-density polyethylene (HDPE) composites has been investigated with a special focus on the effects of water ageing and accelerated ageing, including hygrothermal and UV radiation. Modification of the matrix was carried out using a maleic anhydride high-density polyethylene copolymer (MAPE) as a compatibilizer. Hybridization of hemp fibres with basalt fibres and the incorporation of MAPE were found to significantly decrease the water uptake (up to 75%) and increase the retention of mechanical properties after accelerated ageing. Secondary crystallization phenomena occurring in the composites, as confirmed by differential scanning calorimetry (DSC) analysis, were able to counteract the severe combined effects of hygrothermal stress and UV radiation, with the exception of hemp-fibre composites where permanent damage to the fibres occurred, with 2% and 20% reduction in tensile strength and modulus, respectively, for a 30 wt % hemp fibre-reinforced HDPE.

Effects of exposure conditions on the depletion of antioxidants from high-density polyethylene (HDPE) geomembranes

2002 ◽  
Vol 39 (6) ◽  
pp. 1221-1230 ◽  
Author(s):  
Henri P Sangam ◽  
R Kerry Rowe
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Induction Time ◽  
High Density Polyethylene ◽  
High Density ◽  
Accelerated Ageing ◽  
Time Intervals ◽  
Msw Landfill ◽  
Exposure Conditions

Laboratory-accelerated ageing tests have been conducted to examine the depletion of antioxidants from high-density polyethylene (HDPE) geomembranes as a result of their exposure to various environments. Samples of 2.0 mm thick geomembrane were exposed to air, water, and municipal solid waste (MSW) leachate at temperatures of 22, 40, 55, 70, and 85°C. At various time intervals, samples were collected and the oxidative induction time (OIT) was evaluated. The results indicated that the antioxidants are depleted at rates 1.6 to 2.4 times faster for samples in water than for air-exposed samples. For samples in leachate, the depletion is about 4 times faster than that in air and 1.6–3.2 times faster than that in water. Using these rates, it is estimated that if the geomembrane examined were used as an MSW landfill primary liner, it would take at least 40 years to deplete the antioxidants from the geomembrane at a temperature of 33°C and over 150 years at a temperature of 13°C.Key words: ageing, antioxidants, durability, oxidative induction time, HDPE geomembrane, antioxidant depletion time.

Case Study on Failures of Thermoplastics Pipeline Systems

2015 ◽  
Vol 1111 ◽  
pp. 275-282
Author(s):  
Marius Cocard ◽  
Alin Constantin Murariu ◽  
Emil Moldovan ◽  
Claudiu Burian
Keyword(s):  
Natural Gas ◽  
High Density Polyethylene ◽  
Potable Water ◽  
High Density ◽  
Manufacturing Companies ◽  
Pipeline Systems ◽  
Pipeline Networks ◽  
Water Pipeline

The paper presents some of the most significant situations of tests realised on high density polyethylene pipeline networks from Romania, designed for fluids and gases, which failed during 2008-2014. The inspected objects were assemblies or welded components made of pipes and fittings, as parts of the natural gas and potable water pipeline. The inspections on various assemblies and weldments have identified a number of nonconformities, which have led to failures, generally recorded after welding, during operation. Based on the investigation results, a number of comments and recommendations have emerged, useful for manufacturing companies and for the clients, which could ensue increasing the safety in operation of the high density polyethylene pipeline systems.

Composition and Surface Topography Effects on Apatite-Forming Ability of Ceramic-Polymer Composites

2003 ◽  
Vol 774 ◽  
Author(s):  
Susan M. Rea ◽  
Serena M. Best ◽  
William Bonfield
Keyword(s):  
Surface Topography ◽  
High Density Polyethylene ◽  
High Density ◽  
Apatite Layer ◽  
Biologically Active ◽  
Human Blood Plasma ◽  
Apatite Formation ◽  
Polyethylene Matrix ◽  
Composite Surface ◽  
X Ray

AbstractHAPEXTM (40 vol% hydroxyapatite in a high-density polyethylene matrix) and AWPEX (40 vol% apatite-wollastonite glass ceramic in a high density polyethylene matrix) are composites designed to provide bioactivity and to match the mechanical properties of human cortical bone. HAPEXTM has had clinical success in middle ear and orbital implants, and there is great potential for further orthopaedic applications of these materials. However, more detailed in vitro investigations must be performed to better understand the biological interactions of the composites and so the bioactivity of each material was assessed in this study. Specifically, the effects of controlled surface topography and ceramic filler composition on apatite layer formation in acellular simulated body fluid (SBF) with ion concentration similar to those of human blood plasma were examined. Samples were prepared as 1 cm × 1 cm × 1 mm tiles with polished, roughened, or parallel-grooved surface finishes, and were incubated in 20 ml of SBF at 36.5 °C for 1, 3, 7, or 14 days. The formation of a biologically active apatite layer on the composite surface after immersion was demonstrated by thin-film x-ray diffraction (TF-XRD), environmental scanning electron microscopy (ESEM) imaging and energy dispersive x-ray (EDX) analysis. Variations in sample weight and solution pH over the period of incubation were also recorded. Significant differences were found between the two materials tested, with greater bioactivity in AWPEX than HAPEXTM overall. Results also indicate that within each material the surface topography is highly important, with rougher samples correlated to earlier apatite formation.

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