Ethylene acrylic acid-starch copolymer

Otey has studied the interactions between the ethylene-acrylic acid (EAA) copolymer and gelatinised starch since 1977 [7-83]. 

Ethylene-acrylic acid copolymer Thermoplastic starch + NH OH Otey, 1979... 

Otey has studied the interactions between ethylene-acrylic acid copolymer (EAA) and gelatinized starch since 1977 [77-83]. 

Other compositions contain starch, an ethylene acrylic acid copolymer, stearic acid salt and as a glycerol based lubricant. Increasing the temperature gelatinizes the starch and melts the copolymer. Excess moisture is removed imder reduced pressure and the plastic material is extruded (12). An example illustrates starch pol5nner composites in Table 7.3. 

Otey F.H., Westhoff R.P., Russell C.R., Biodegradable films from starch and ethylene-acrylic acid copolymer, Ind. Eng. Chem. Prod. Res. Dev., 16, 1977, 305-308. 

Otey has studied EAA (ethylene-acrylic acid copolymer)/ thermoplastic starch composites since 1977 [95-106] and has demonstrated that the addition of ammonium hydroxide to EAA makes it compatible with starch. Urea, in these formulations, enhances the film tear propagation resistance and reduces ageing phenomena due to segmental motions in amorphous starch [107,108]. The films obtained with a content of plasticized starch of about 50% showed good tensile properties (Table 6.1) [101]. The sensitivity to environmental... 

To increase the starch load up to 40-60% in PO a gelatinized starch is used in the films of poly(ethylene-co-acrylic acid) (EAA) or a mixture of EAA/LDPE or LDPE/EMA (ethylene-maleic anhydride). The difficulty with this system is that the high level of filler seriously impairs the mechanical properties, especially in thin films, and the starch is subjected to moisture-absorption problems. LDPE Mn stea-rate/starch showed a decrease of MW during thermo-oxidation and an increase of MW during UV irradiation. In the mixtures, it has been estabhshed that ethylene-acrylic acid copolymer accelerates LDPE oxidative degradation while plasticized starch inhibits it [62]. 

Proposed polysaccharide-derived materials as biodegradable fillers include a variety of starches, cellulose, lignin, sawdust, casein, mannitol, lactose, and other materials. These fillers have been tried in compositions of as much as 80% in a wide range of synthetic resins, including PE, PP, PS, ethylene-acrylic acid copolymers, PVC, and vinyl alcohol copolymers. Often additional additives such as fatty acids and processing aids are incorporated to improve the biodegradability of the finished product. Starch-based polymers are discussed further in Chapter 3 of this handbook. 

Considerable attention has been generated in the commercial sector on blends and composites consisting of synthetic polymers and natural degradable materials. These include starch-polyethylene and starch-ethylene-acrylic acid copolymers. Other natural polymers have also been considered.Until the main concern is addressed that the polyalkene is actually degraded, instead of the specimen having physically disintegrated, this remains a questionable approach. 

Starch has been used as a filler in degradable materials, in blends such as starch-urethanes, and starch-polyethylene with ethylene-acrylic acid copolymer. 

Superabsorbent polymers are now commonly made from the polymerization of acrylic acid blended with sodium hydroxide in the presence of an initiator to form a polyacrylic acid, sodium salt (sometimes referred to as cross-linked sodium polyacrylate). Some of the polymers include polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxy-methyl-cellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and starch grafted copolymer of polyacrylonitrile to name a few. The latter is one of the oldest SAP forms created. 

Poly(vinyl alcohol) is utilized as a component of starch-based adhesives.11121114 Other patents report the use of partially oxidized starch,1115 dextrins,1116 dextrins and urea,1117 borax,1118 boric acid,1119 and vinyl methyl ether-maleic acid copolymers.1120 Other patents indicate the use of poly (vinyl alcohol) with partially hydrolyzed poly(vinyl acetate),1121 nonhy-drolyzed poly(vinyl acetate),1122 and poly(vinyl chloride).1123 A few patents have reported such poly acrylic additives as poly (acrylic acid)1124 and its salts,1125 poly(acrylamide),1126 1127 A-methylacrylamide or poly(A-acryl-amide),1128 and polyethyleneimine.1129 Polystyrene has also been used,1130 as well as more complex copolymers such as a maleic acid monobutyl ester-methyl vinyl ether copolymer, together with dextrin and polyacrylamide),1131 carboxylated ethyl acrylate-styrene zinc salt copolymer,1132 ethylene-methyl acrylate-vinyl acetate copolymer,1133 vinyl acetate-vinyl pyr-rolidone copolymer,1134 and ethylene-vinyl acetate copolymer.1135 Some adhesives are compounded with SBR latex1136 1138 and phenol-formaldehyde resins.1139... 

Starch utilization in plastic and rubber compositions began in the 60s and 70s, with oxidised starch in rubber and other polymers, such as urethane foams, poly(vinyl alcohol) and copolymers of poly(ethylene-co-acrylic acid) formulations, and as a filler in plasticized polyvinyl chloride (PVC) [37,39]. In another technique, gelatinized starch was mixed with PVC latex and the water was removed to give a PVC-starch composition, which was mixed with a PVC plasticizer such as dioctyl phthalate (DOP). 

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