Thermoplastics low-density polyethylene

A.M. Maysa, Radiation vulcanization of thermoplastic low-density polyethylene/bromobutyl rubber blends. J. Thermoplast. Compos. Mater. 27, 364—378 (2014)... 

Transfemoral sockets are typically rigid. Flexible sockets fabricated using a malleable thermoplastic [low-density polyethylene and Surlyn (Thermovac)] have recently been incorporated within a rigid or semirigid ftame (Fig. 33.14). The potential advantages of these flexible sockets include increased perceived comfort due to the flexible walls, improved proprioception, accommodation of minor volume changes, and enhanced suction suspension. 

Table II summarizes some thermal and mechanical properties of several soybean oil polymers and compares them with two of the most useful industrial thermoplastics, low density polyethylene (LDPE) and polystyrene (PS). The results show that the CLS polymers possess higher mechanical properties than the SOY and LSS polymers with the same stoichiometries. Also, the highest toughness of the resulting polymers is reached when the amount of the soybean oil is equivalent to the amount of alkene comonomers. With a proper choice of...

Commodity thermoplastics Low density polyethylenes (LDPE), polystyrenes (PS), cellulose acetate (CA). 

HDPE, high density polyethylene PP, polypropylene EVA, ethylene—vinyl alcohol SMC, sheet-molding compound ERP, fiber-reinforced plastic LDPE, low density polyethylene PE, polyethylene BMC, bulk mol ding compound TPE, thermoplastic elastomer. 

Chlorination may be carried out with both high-density and low-density polyethylene. When carried out in solution the chlorination is random but when carried out with the polymer in the form of a slurry the chlorination is uneven and due to residual crystalline zones of unchlorinated polyethylene the material remains a thermoplastic. 

Chattopadhyay S., Chaki T.K., and Bhowmick A.K., New thermoplastic elastomers from poly(ethyle-neoctene) (engage), poly(ethylene-vinyl acetate) and low-density polyethylene by electron beam technology structural characterization and mechanical properties. Rubber Chem. TechnoL, 74, 815, 2001. Roy Choudhury N. and Dutta N.K., Thermoplastic elastomeric natural rubber-polypropylene blends with reference to interaction between the components. Advances in Polymer Blends and Alloys Technology, Vol. 5 (K. Finlayson, ed.), Technomic Publishers, Pensylvania, 1994, 161. 

Crystalline thermoplastics—HDPE, linear low-density polyethylene (LLDPE)... 

PVC, another widely used polymer for wire and cable insulation, crosslinks under irradiation in an inert atmosphere. When irradiated in air, scission predominates.To make cross-linking dominant, multifunctional monomers, such as trifunctional acrylates and methacrylates, must be added. Fluoropolymers, such as copol5miers of ethylene and tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), are widely used in wire and cable insulations. They are relatively easy to process and have excellent chemical and thermal resistance, but tend to creep, crack, and possess low mechanical stress at temperatures near their melting points. Radiation has been found to improve their mechanical properties and crack resistance. Ethylene propylene rubber (EPR) has also been used for wire and cable insulation. When blended with thermoplastic polyefins, such as low density polyethylene (LDPE), its processibility improves significantly. The typical addition of LDPE is 10%. Ethylene propylene copolymers and terpolymers with high PE content can be cross-linked by irradiation. ... 

Fig. 1. US total sales and captive use of selected thermoplastic resins by major market for 2001. Major market volumes are derived from plastic resins sales and captive use data as compiled by VERIS Consulting, LLC and reported by the American Plastics Council s Plastic Industry Producers Statistics Group. Selected thermoplastics are low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, nylon, polyvinyl chloride, thermoplastic polyester, engineering resins, acrylonitrile-butadiene-styrene, styrene-acrylonitrile, other styrenics, polystyrene, and styrene butadiene latexes. (Data from ref. 25.)...

In addition to the polyolefin blends designed for thermoplastic elastomer applications, a great deal of interest also has centered on other kinds of blends of polyolefins as has been reviewed recently (see chapter 21 of Ref. 10 by Plochocki). In a recent paper (84), we showed that blends involving polypropylene-high density polyethylene-low density polyethylene in various proportions and combinations exhibit additivity of tensile strength however, there are serious losses in ductility in some cases such that the blends are less ductile than either pure component. It is interesting to note, however, that these losses in ductility can largely be restored by addition of rather small amounts of an amorphous ethylene-propylene rubber (84). 

A major step forward was taken in the area of base thermoplastics with the application of Union Carbide s Unipol process. Variations of this were subsequently offered by other low-density polyethylene (LDPE) producers such as Dow and CdF Chimie (now ORKEM). 

Within these 20 popular plastics there are five major families of thermoplastics that consume about two-thirds of all thermoplastics. They are the low density polyethylenes (LDPEs), high density polyethylenes (HDPEs), polypropylenes (PPs), polystyrenes (PSs), and polyvinyl... 

Within the family of polyolefins there are many individual families that include low density polyethylenes, linear low density polyethylenes, very low polyethylenes, ultra low polyethylenes, high molecular weight polyethylenes, ultra high molecular weight polyethylenes, polyethylene terephthalates, ethylene-vinyl acetate polyethylenes, chlorinated polyethylenes, crosslinked polyethylenes, polypropylenes, polybutylenes, polyisobutylene, ionomers, polymethylpentene, thermoplastic polyolefin elastomers (polyolefin elastomers, TP), and many others. 

Plastic polymers make up a high proportion of waste and the volume and range used is increasing dramatically. The two main types of plastic are thermoplastics which soften when heated and harden again when cooled and thermosets which harden by curing and cannot be remoulded. The six main plastics in municipal solid waste are, high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC) and polyethylene terephthalate (PET). In addition there are... 

Over a period of many years polymeric materials have gradually replaced metals in many applications. Among the five leading thermoplastics low and high density polyethylene, polyvinyl chloride, polypropylene, and polystyrene polyethylene is the largest volume plastic in the world. Polyethylene was initially made in the United States in 1943. In 1997, the estimated combined worldwide production of both low and high-density polyethylene was 1.230 x 1010 kg (2.712 x 1010 lb) [10]. Low density polyethylene is produced at pressures of 1030 to 3450 bar (1020 to 3400 atm) whereas high density polyethylene is produced at pressures of 103 to 345 bar (102 to 340 atm) [11]. 

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