Ionomers polyethylene

Transparency Examples of maximum transparency is available in acrylic, polycarbonate, polyethylene, ionomer, and styrene compounds. Many other TPs may have adequate transparency. 

Gao, Y. A study of a polyethylene ionomer, its nanocomposites and hybrids, PhD Thesis, The University of South Australia, April 2003. 

Polyethyleneimine (PEI), 16 14, 15 molecular formula, 5 713t Polyethylene ionomers, properties of, 14 413—415... 

FAIRLEY PRUD HOMME Rheology of Polyethylene—Ionomer Blends 215... 

Another benefit of copolyermization of ethylene is incorporation of appropriate polar groups such as carboxylic acid groups or salt groups in the ionomers. Du Pont is still the only producer of the Surlyn-type of polyethylene ionomers. However, several companies produce copolymers of ethylene with acrylic acid (EAA). Such copolymers offer improved thermal properties with retention of clarity, improved heat-seal strength, and impact strength, as well as improved adhesion to a variety of substances, such as aluminum foil, glass fibers, and mineral fibers. 

Some physical properties of polyethylene ionomers are compared with those of polyethylene and the acid copolymer, poly(ethylene-co-methacrylic acid) in Table 5.15. lonomer is generally tougher and, as shown in Table 5.15, relative to the acid copolymer, its tensile strength is increased by 27—53% and its stiffness is nearly tripled. 

Carboxylated polybutadiene ionomers, which are close relatives of the polyethylene ionomers described above, have an essentially polybutadiene backbone that contains some acrylonitrile and styrene to adjust its flexibility and toughness, and, in addition, up to 6% by weight of acrylic or methacrylic acid. Like the polyethylene ionomers, they are usually made by direct copolymerization with the carboxylic acid monomer using, however, emulsion methods. Typically the monomers are slurried in water with sodium dodecylbenzene sulfonate as the emulsifier and potassium persulfate as the free-radical initiator. The tendency of the carboxyhc add monomer to dissolve in the aqueous phase instead of remaining in the butadiene-rich phase is suppressed by making the aqueous phase acidic so that the monomer remains in the nonionized form. 

TABLE 5.15 Comparative Physical Properties of Polyethylene Ionomers and Their Acid Precursor... 

The presence of the comonomer breaks up the crystallinity of the polyethylene, so that ionomer films have lower crystallinity and better clarity compared to polyethylene. Ionomers are known for their toughness and abrasion resistance, and the polar nature of the polymer improves both its bondability and paintability. Ionomers have good low-temperature flexibility and resistance to oils and organic solvents. Ionomers show a yield point with considerable cold drawing. In... 

Further modification of polyethylene is possible by chemical substitution of hydrogen atoms this occurs preferentially at the tertiary carbons of a branching point and primarily involves chlorination, sulfonation, phosphorylination, and intermediate combinations. (See chlorinated polyethylene chlorosulfonated polyethylene phosphorylated polyethylene ionomer.)... 

Vibration welding is ideally suited to parts injection molded or extruded in engineering thermoplastics as well as acetal, nylon, polyethylene, ionomer, and acrylic resins. Almost any thermoplastic can be vibration welded. Unlike other welding methods, vibration welding is applicable to crystalline or amorphous or filled. 

Poly(ethylene-co-vinylacetate) EVA, Polyethylene ionomer EIM, Cycloolefine copolymer COC [Poly(ethylene-co-norbornene)], Poly(ethylene-co-acrylic acid) EAA Polyolefines III... 

Polyethylene ionomer, EIM. Applications transparent tubes for water and liquid foods, transparent films, bottles, transparent coatings, adhesion promoters. 

Table 3.3-ir Poly(ethylene-co-vinyl acetate), EVA polyethylene ionomer, EIM cyclooleflne copolymer, COC (poly-(ethylene-co-norbomene)) poly(ethylene-co-acrylic acid), EAA... 

Figure 2 shows another interesting compound crosslinked system, the idealized morphology of the polyethylene ionomer known commercially as Surlyn. This polymer contains about 5% of sodium methacrylate as a random comonomer. The ionomeric groups phase-separate into small domains of about 70A in size, the crystallites occupy a second region of space, and the amorphous portion occupies a third region of space. 

DTA has been used for the measurement of crystallinity of random and block ethylene-propylene copolymers [27], polybutene [28], polyethylene terephthalate [16, 29, 30], 1,4-cyclohexane dimethyl terephthalate [29], polypropylene [29, 30], and polyethylene ionomers [31]. 

Its tensile strength was increased by addition of polyethylene ionomer [204]. 

HDPE-I-acrylonitrile/methyl acrylate 75/25-g-butadiene/acrylonitrile rubber was compatibilized by adding polyethylene ionomer [63]. 

HDPE + nylon 6 was compatibilized by adding polyethylene ionomer, which gave finer domain size due to emulsification and lower interfacial tension [70]. LLDPE + polyvinyl chloride was compatibilized by adding up to 5% of isoprene-4-vinyl pyridine diblock copolymer, acting as an emulsifier to reduce phase diameter and interfacial tension. Polystyrene-acrylic acid diblock copolymer was somewhat less effective [49]. 

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