Ethylene-co-methacrylic acid

In most ionomers, it is customary to fully convert to the metal salt form but, in some instances, particularly for ionomers based on a partially crystalline homopolymer, a partial degree of conversion may provide the best mechanical properties. For example, as shown in Fig. 4, a significant increase in modulus occurs with increasing percent conversion for both Na and Ca salts of a poly(-ethylene-co-methacrylic acid) ionomer and in both cases, at a partial conversion of 30-50%, a maximum value, some 5-6 times higher than that of the acid copolymer, is obtained and this is followed by a subsequent decrease in the property [12]. The tensile strength of these ionomers also increases significantly with increasing conversion but values tend to level off at about 60% conversion. 

Sodium ionomers are commercially recognized as the most effective nucleating agents for PET compounds. The typical use rate of sodium ionomer-based nucleating agents is 3-4 wt%. The sodium salt of poly(ethylene-co-methacrylic acid) is a particularly effective nucleating agent for PET. 

Other examples of interpolymer complexation due to hydrogen bonding include complexes of poly(ethylene-co-methacrylic acid) with polyethers, poly(2-vinylpyridine), and polyethyloxazoline [107-109], and PAA with poly(vinyl alcohol-co-vinyl acetate) [110]. PAA has even been shown to form stable interchain hydrogen bonded association under high shear flow [111]. 

Phase behavior studies with poly(ethylene-co-methyl acrylate), poly (ethylene-co-butyl acrylate), poly(ethylene-co-acrylic add), and poly(ethylene-co-methacrylic acid) were performed in the normal alkanes, their olefinic analogs, dimethyl ether, chlorodifluoromethane, and carbon dioxide up to 250 °C and 2,700 bar. The backbone architecture of the copolymers as well as the solvent quality greatly influences the solution behavior in supercritical fluids. The effect of cosolvent was also studied using dimethyl ether and ethanol as cosolvent in butane at varying concentrations of cosolvent, exhibiting that the cosolvent effect diminishes with increasing cosolvent concentrations. 

Poly(ethylene-co-methacrylic acid) (EMAA)-Butane-Cosolvent... 

Ionomers consist of statistical copolymers of a non-polar monomer, such as ethylene, with (usually) a small proportion of ioniz-able units, like methacrylic acid. Ethylene-co-methacrylic acid copolymers (-5% methacrylic acid) are used to make cut-proof golf balls (see Fascinating Polymers opposite). The protons on the carboxylic acid groups are exchanged with metal ions to form salts. These ionic species phase-separate into microdomains or clusters which act as crosslinks, or, more accurately, junction zones (Figure 6-4). (We discuss interactions in a little more detail in Chapter 8.)... 

Pyrolysis of poly(ethylene-co-methacrylic acid) (10% wt. methacrylic acid), CAS 25053-53-6, also is dominated by the pyrolysis products of polyethylene. The pyrogram of this copolymer obtained at 600° C in He with separation of a Carbowax column is given in Figure 6.1.10, and for comparison, the pyrogram for polyethylene is shown in the same... 

Figure 6.1.10. Pyrogram of poly(ethylene-co-methacrylic acid) 10% wt. methacrylic acid (upper trace) and of high-density polyethylene (lower trace). Pyrolysis done on 0.4 mg material at 60(f C in He, with the separation on a Carbowax type column.

Table 6.1.6. Identification of peaks corresponding to compounds bearing carboxyl groups in the pyrolysate of poly(ethylene-co-methacrylic acid).

Weng, Y.M., Chen, M.J., and Chen, W. 1999. Antimicrobial food packaging materials from poly(ethylene-co-methacrylic acid). Lebensmittel-Wissenschaft und-Technologie 32 191-195. 

Fig. 1 Important ionomers (A) poly(ethylene-co-methacrylic acid), the free acid form of Surlyn, (B) Nafion, (C) SPS, and (D) poly(styrene-co-methacrylie acid). For the sake of simplicity, all polymers are shown in the acid form. In the ionomers, the acids are partly or fully neutralized with cations such as Na, NH4, or Zn. ...

Sauer, B.B. McLean, R.S. AFM and x-ray studies of crystal and ionic domain morphology in poly(ethylene-co-methacrylic acid) ionomers. Macromolecules 2000, 33, 7939. 

The addition of a copolymer has been shown to be a method of improving the mechanical properties of polyethylene/polyamide blends. One copolymer which has had particular success is poly(ethylene-co-methacrylic acid) (EMA) where the acid groups are partially neutralized by metal ions (EMA-salt). 

The LOPE S were obtained from Monsanto (LDPE-M8011) and Dow Chemical (LDPE-493C) the poly(ethylene-co-methacrylic acid)) (Nucrel -1214) and ionomers (Surlyn -8660 and Surlyn -9950) were graciously provided by the Dupont Chemical Company. 

PE-g-maleic anhydride Styrene-co-ethylene-co-butadiene-co-styrene-g-maleic anhydride Sodium-neutralized ethylene-co-methacrylic acid PE-g-glycidyl methacrylate St3Tene-co-ethylene-co-butadiene-co-styrene-g-glycidyl methacrylate St3Tene-co-ethylene-co-butadiene-co-styrene Styrene-co-ethylene-co-butadiene-co-styrene-g-maleic anhydride PE-g-maleic anhydride EPR-g-maleic anhydride PE-g-maleic anhydride PP-g-maleic anhydride Styrene-co-ethylene-co-butadiene-co-styrene Styrene-co-butadiene... 

Table 2.5 Interfacial Tensions between Polymer Melt Pairs Including Compatibilizing Agents. MAH-PP Maleic Anhydride Grafted Polypropylene SEES Hydrogenated Triblock Copolymer of Styrene and Butadiene MAH-g-SEBS Maleic Anhydride Grafted SEES PEMA-Zn Poly(ethylene-co-methacrylic Acid) lonomer Neutralized by Zinc.

Because the free radical initiated graft reaction can also lead to the cross-linking of polyethylene, copolymers of ethylene and with acrylic acid (184,185), glycidyl methacrylate (184,186), methacrylic acid and 10-undecenoic acid (187-189) were synthesized to compatibilize polyethylene/polyamide blends. The poly (ethylene-co-methacrylic acid) ionomers neutralized by sodium (184) and zinc (45,118,190-192) has also used as compatibilizers. High energy irradiation, used to modify the surface of fibers or films at beginning, was also used to compatibilize the polyethylene/polyamide blends (193-196). 

FIGURE 5.60 Melt viscosities (160°C) at various shear rates of poly(ethylene-co-methacrylic acid) with 3.5 mole% comonomer and its sodium salt. 

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. 

LEE Lee, S.-H. and McHugh, M.A., Phase behaviom studies with poty(ethylene-co-methacrylic acid) at high pressures, Polymer, 38, 1317, 1997. 

Poly (ethylene-chlorotrifluoroethylene). See Ethylene/chlorotrifluoroethylene copolymer Poly (ethylene-co-acrylic acid). See Ethylene/acrylic acid copolymer Poly (ethylene-co-1-butene). See Ethylene/butene-1 copolymer Poly (ethylene-co-butyl acrylate). See Ethylene/butyl acrylate copolymer Poly (ethylene-co-carbon monoxide). See Ethylene/carbon monoxide copolymer Poly (ethylene-co-ethyl acrylate). See Ethylene/ethyl acrylate copolymer Poly (ethylene-co-methacrylic acid). See Ethylene/methacrylic acid copolymer Poly (ethylene-co-methyl acrylate). See Ethylene/methyl acrylate copolymer Poly (ethylene-co-methyl acrylate-co-acrylic acid). See Ethylene/methyl acrylate/acrylic acid terpolymer... 

The interfacial reaction of immiscible polymeric systems containing oxazoline and carboxylic acid groups, respectively, was studied by FTIR spectroscopy and FTIR microscopy. A poly(butadiene-co-acrylonitrile) rubber, where the nitrile groups are partially converted to oxazoline groups, was thermally annealed in a two-layer specimen with poly(ethylene-co-methacrylic acid). The formation of the esteramide in the interface was measured quantitatively by FTIR difference spectroscopy. 33 refs. 

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