Acrylic acid-based ionomers ethylene

This versatile technique is generally used where a ply of polyethylene or copolymer thereof is required in a structure. Other polymers may be used in specialized areas but the handling can become more difficult. The process is widely used within the Packaging Industry for the coating of paper, board, foils, cellulose film and thermoplastic films. The most common coating resin used is low-density polyethylene, but this now extends to copolymers such as Ethylene-vinyl acetate, ethylene-acrylic acid, polypropylene, high density polyethylene and ionomers (e.g. Surlyn). The acrylic acid-based materials and ionomers are used in areas in which enhanced adhesive strength is required, such as resistance to difficult environments. 

Ionomer resins consisting of ethylene—methacrylic acid copolymers partially neutralized with sodium or zinc were commercially introduced in 1964 by Du Pont under the Sudyn trademark (1). More recently, a similar line of products, sold as Hi-Mdan resins, has been commercialized by Mitsui—Du Pont in Japan. lolon ionomeric resins, based on ethylene—acrylic acid, are produced by Exxon in Belgium. Ionomers containing about 1 mol % of carboxylate groups are offered by BP in Europe as Novex resins. Low molecular weight, waxy Aclyn ionomers are produced and sold by AHiedSignal. 

A variety of ionomers have been described in the research literature, including copolymers of a) styrene with acrylic acid, b) ethyl acrylate with methacrylic acid, and (c) ethylene with methacrylic acid. A relatively recent development has been that of fluorinated sulfonate ionomers known as Nafions, a trade name of the Du Pont company. These ionomers have the general structure illustrated (10.1) and are used commercially as membranes. These ionomers are made by copolymerisation of the hydrocarbon or fluorocarbon monomers with minor amounts of the appropriate acid or ester. Copolymerisation is followed by either neutralisation or hydrolysis with a base, a process that may be carried out either in solution or in the melt. 

Here we report the synthesis of inorganic tin II and tin IV ionomers based on a copolymer of ethylene and acrylic acid. 

Despite tlte broad scope of the held and the unusual property combinations obtainable, commercial exploitation has been confined mainly to the original family based on ethylene copolymers. Within certain industries, such as llexihle packaging, the word ionomer is understood to mean a copolymer of ethylene with methacrylic or acrylic acid, partly neutralized with sodium or zinc. 

Within the scope of the original definition, a very wide variety of ionomers can be obtained by the introduction of acidic groups at molar concentrations below 10% into the important addition polymer families., followed by partial neutralization with metal cations or amines. Extensive studies have been reported, and useful reviews of the polymers have appeared (3—8). Despite the broad scope of the field and the unusual property combinations obtainable, commercial exploitation has been confined mainly to the original family based on ethylene copolymers. The reasons for this situation have been discussed (9). Within certain industries, such as flexible packaging, the word ionomer is understood to mean a copolymer of ethylene with methacrylic or acrylic acid, partly neutralized with sodium or zinc. 

Arguably the most important amorphous ionomer is sulfonated polystyrene (SPS). Other ionomers include poly(styrene-rfln-methacrylic acid) (SMAA), polyurethanes, siloxanes, butadiene-based elastomers, ethylene-propylene-diene terpolymers, acrylates and methacrylates, polyphosphoesters, polyimides, and many others. ... 

The grafting functionalization of a poly(vinylidene fluoride) powder by y-irradiation was achieved by Valenza et aL The amoimt of grafted meth-acrylic acid onto poly(vinylidene fluoride) (PVDF) powder was 19.7 w%. The grafted polymer was then blended at different ratios with an ionomer based on ethylene-methacrylic acid copolymer, partially neutralized (Surlyn 9970). Nongrafted PVDF and this ionomer are highly immiscible. The functionalization of the PVDF with methacrylic acid allows to compatibilize both... 

Nevertheless, several conunercial grades of moderate impact strength polyamides have been produced for a long time by simple melt blending with such impact modifiers as ethylene-ethyl acrylate, ethylene-acrylic acid copolymers and ionomers based on zinc neutralized, ethylene-methacrylic acid copolymers [15-16]. However, in the case of the PA-6, the zinc ionomers have been found to be particularly effective as impact modifiers... 

Typically, carboxylate ionomers are prepared by direct copolymerization of acrylic or methacrylic acid with ethylene, styrene or similar comonomers by free radical copolymerization (65). More recently, a number of copolymerizations involving sulfonated monomers have been described. For example, Weiss et al. (66-69) prepared ionomers by a free-radical, emulsion copolymerization of sodium sulfonated styrene with butadiene or styrene. Similarly, Allen et al. (70) copolymerized n-butyl acrylate with salts of sulfonated styrene. The ionomers prepared by this route, however, were reported to be "blocky" with regard to the incorporation of the sulfonated styrene monomer. Salamone et al. (71-76) prepared ionomers based on the copolymerization of a neutral monomer, such as styrene, methyl methacrylate, or n-butyl acrylate, with a cationic-anionic monomer pair, 3-methacrylamidopropyl-trimethylammonium 2-acrylamlde-2-methylpropane sulfonate. 

Poly(urethane)/poly(olefin) blend compositions are compatibi-lized using a zinc ionomer, based upon an ethylene/methacrylic acid/alkyl acrylate polymer, or a maleic anhydride-grafted ethylene oxide poly (olefin) elastomer (45). 

---