High-density polyethylene overview

This overview of the various cases of repercussions of chemicals on HDPE materials justifies the conclusion already addressed several times that, though HDPE geomembranes are not entirely inert, they are extraordinarily resistant to a broad spectrum of high-concentration chemicals at normal temperatures. This can also be seen by the assessment of chemical resistance as described in DIN 8075-Attachment 1 1984 High Density Polyethylene (HDPE) Pipes Chemical Resistance of Pipes and Fittings. The standard classifies for a large number of chemicals whether HDPE materials are resistant, only conditionally resistant or are not resistant at all... 

For polymers, anisotropic friction 10) was observed on lamellar crystals II -13 as well as on extended-chain crystals obtained by friction transfer deposition 14). The anisotropic friction for lamellar crystals was explained by the occurrence of chain-folding oriented preferentially in planes parallel to the corresponding crystal face. For extended-chain crystals friction anisotropy observed parallel and perpendicular to the chain direction was interpreted by the interlocking asperity model. In this paper we give an overview regarding our nanotribological observations on oriented high density polyethylene (HDPE), poly(tetrafluoroethylene) (PTFE) and on crystals of polyethylene (PE) and transcrystallized poly(ethylene oxide) (PEO). 

Plastics that are most often used as food packaging materials include polyolefines, polyesteres, polyvinyl chloride, polyvinyli-dene chloride, polystyrene, polyamide, various resins and so on. For example, the world plastic demand in 2011 was dominated by polyethylene, including low density polyethylene (PE-LD), linear low density polyethylene (PE-LLD, 17%) and high density polyethylene (PE-HD, 12%), polypropylene (PP, 19%), polyvinyl chloride (PVC, 11%), polystyrene solid (PS) and expandable (PS-E, 7.5%), polyethylene terephthalate (PET, 6.5%), polyurethane (PUR, 7%) and other plastic types (20%). An overview of the main types of polymeric packaging materials is given in Table 12.73. 

The book first focuses on commonly used industrial polymers, including polypropylenes, low- and high-density polyethylenes, and poly(vinyl chloride), as well as less widely used polymer types, such as acrylics, ether polymers, cellulosics, sulfide polymers, silicones, polysulfones, polyether ether ketones, and polybenzimidazoles. It then explores polymer derivatives and polymeric combinations that play special and often critical roles in diverse fields of human activities. The polymers covered include liquid crystal, electroactive, ionic, and shape memory polymers hydrogels and nanocomposites. The book concludes with a comprehensive overview of new developments in the use of polymers in a variety of areas. 

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