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Plastics
Published in Arthur Lyons, Materials for Architects and Builders, 2019
Polybutylene (polybutene-1, PB-1) is used for pipework as an alternative to copper. It has the advantage of flexibility, and the very smooth internal surface is resistant to the build-up of scale and deposits. It can withstand continuous operating temperatures up to 82°C. As polybutylene is slightly permeable to oxygen, some pipe manufacturers incorporate an ethyl vinyl alcohol copolymer (EVOH) barrier as an interlayer. The standard BS EN ISO 8986-1: 2009 describes the designation system for polybutene-1. Polybutylene pipes and fittings are described in BS 7291-2: 2010.
Biodegradability and ecotoxicity of polyurethane foams: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Kateřina Skleničková, Sabina Abbrent, Martin Halecký, Vladimír Kočí, Hynek Beneš
The soft segments derived from polyols are usually aliphatic, composed of either polyether or polyester chains (Hoyle & Kim, 1987). Polyester segments are rather photostable, therefore the (photo)oxidation of polyester PU takes place in the urethane (hard) aromatic segments (Xie et al., 2019). In contrast, polyether soft segments are very sensitive to photochemical oxidation which leads to a complete loss of all ether linkages in these materials as observed previously by FTIR (Wilhelm & Gardette, 1998). Majority of the used polyether polyols are based on polyethylene glycol, polypropylene glycol or polybutylene glycol (Ionescu, 2005). Their photooxidative degradation involves O2 radical attack on the Cα of polyether chains, formation of hydroperoxides, alkoxy radicals and β scission producing water, alcohols, carboxylic esters and acids functionalities (Figure 8) (Dannoux et al., 2008; Xie et al., 2019).
Modeling short- and long-term time-dependent nonlinear behavior of polyethylene
Published in Mechanics of Advanced Materials and Structures, 2018
Hossein Sepiani, Maria Anna Polak, Alexander Penlidis
Polymers are increasingly used in many aspects of our lives, including infrastructure, building, and pipeline construction. Thermoplastic polyethylene (PE) and unplasticised polyvinyl chloride are the predominant materials used for water and sewer pipes [1]. Other plastics for pipe production are polypropylene, polybutylene and acrylonitrile-butadiene-styrene, which are all thermoplastics [2]. The pipeline installation procedures, for example by horizontal directional drilling, impose tensile and bending deformations on the pipes and often result in significant amount of scratching of the pipe's outer surface. Subsequent utilization subjects the pipe to internal and external hoop stresses, often variable over time. The 3-D stress and strain under normal utilization conditions are relatively low due to high safety factors, which generally protect the pipes from failure under short-term conditions. However, adequate long-term strength of the PE pipes is a major concern in the design and construction of such pipeline systems. Therefore, theoretical and/or numerical modeling of the behavior of these materials is essential to complement experimental data and to allow for the structural analysis of polymeric elements and structures.
Effect of membrane parameters and filter structure on the efficiency of leukocyte removal by electrospun poly(ethylene-co-vinyl alcohol) membranes
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Mayuri P. V., Anugya Bhatt, Sabareeswaran A., Ramesh P.
Recent research in the past decade has recognized the technique of electrospinning as an ideal and inexpensive method for the fabrication of leukodepletion filter membranes [5, 6]. Although use of toxic solvents is disadvantageous, the ability to tune the membrane properties according to the filtration requirements by controlling the electrospinning parameters is one out of the most agreeable merits of electrospinning [7]. Plenty of polymers – inclusive of virgin or chemically modified versions of polypropylene (PP), polyethylene terephthalate (PET), polyvinyl alcohol (PVA), polyamide (PA), polyurethanes (PU), cellulose-based polymers and polybutylene terephthalate (PBT) – have been electrospun to filter membranes and carried trials on their leukodepletion capacities heretofore [8].