Decomposition of ethylene-vinyl acetate

Table 9.15 Components from decomposition of ethylene-vinyl acetate copolymer...

Decomposition of Ethylene—Vinyl Acetate Copofymers Elxamined 1 Combined Thermogravimetiy, Gas Chromatography, and Infrared Spectroscopy... 

In this paper, the thermally induced decomposition of ethylene-vinyl acetate copolymers is examined. The analysis of the trapped effluents by GC/FT-IR is significantly different than that reported by other authors (4). These authors noted the formation of acetic acid and a polyolefin at 360 0 to 450 C, as is observed in... 

MCGRATTAN Decomposition of Ethylene--Vinyl Acetate Copotymers... 

T.R. Hull, D. Price, Y. Liu, C.L. Wills, and J. Brady, An investigation into the decomposition and burning behavior of ethylene-vinyl acetate copolymer nanocomposite materials. Polym. Degrad. Stab., 82, 365-371 (2003). 

Hull TR, Price D, Liu Y, Wills CL, Brady J (2003) An investigation into the decomposition and burning behaviour of Ethylene-vinyl acetate copol3mer nanocomposite materials. Polym Degrad Stab 82 365-371... 

HuU, T. R., Price, D., Liu, Y., Wills, C. L. and Brady, J. (2003) An investigation into the decomposition and hurning hehaviour of ethylene—vinyl acetate copolymer nanocomposite materials. Polymer Degradation and Stability, 82 (2), 365-371. 

When ethylene-vinyl acetate copolymers are manufactured, the decomposition products also contain carbon monoxide and carbon dioxide. When decomposition takes place in a tubular reactor or in a multi-chamber or cascade of autoclaves, up to 50% of the decomposition gases can consist of undecomposed ethylene. 

In a study of the flame retardance of styrene-methyl methacrylate copolymer with covalently bound pyrocatechol-vinyl phosphate, diethyl p-vinyl benzyl phosphonate, or di(2-phenyl ethyl phosphonate) groups. Ebdon and co-workers [23] obtained data on their decomposition behaviour. This was achieved by reducing the rate of liberation of flammable methyl methacrylate monomer during combustion. Possible mechanisms for these processes are suggested. Other methacrylate copolymers which have been the subject of thermal degradation studies include PMMA-N-methylmaleimide-styrene [24] and PMMA-ethylene vinyl acetate [25-27]. 

Another contamination issue stems from the adhesives which may be used to attach labels or base cups. Often, not all of the adhesive residue can be removed by washing. These residues can cause color changes in the PET. Further, the ethylene vinyl acetate can decompose, releasing acetic acid, which along with the rosin acids in some adhesives can catalyze PET decomposition. Thus, these contaminants also can detract from both performance and appearance of the recycled material. 

High-resolution TGA has been applied to decomposition studies on polymethyl methacrylate (PMMA), ethylene-vinyl acetate copolymer and acrylonitrile-butadiene-styrene terpolymer [47-50]. The results obtained on a supposedly pure sample of PMMA homopolymer indicated that a small quantity of impurity, possibly unreacted methyl monomer or even polyethylene methacrylate, is present. Conventional TGA does not resolve this impurity. 

The early hot melt adhesives were not strictly definable as rubber-based adhesives. Most rubber polymers such as natural rubber and random SBR are of such molecular weight and structure that they do not melt readily to a workable coating consistency at a temperature below which thermal degradation and decomposition take place. Certain synthetic polymers, however, lend themselves to the formulation of a wide range of hot melt adhesive compositions. Polyamide and polyester resins, ethylene-vinyl acetate (EVA) copolymers, ethylene-ethyl acrylate (EEA) copolymers, low molecular weight polyethylene and amorphous polypropylene, and certain vinyl ethers have found application in hot melt adhesives. These adhesives have found wide use in packaging, industrial, and construction applications. 

Infrared spectroscopy and thermogravimetry have been used in polymer analysis for many years. By coupling the effluent of thermogravimetry to an infrared gas cell, TG/IR (sometimes known as evolved gas analysis) has been used to examine the thermally induced decomposition products a variety of polymers including of poly(vinyl chloride) (7), polyacrylamide (2), tetrafluoroethylene-propylene (3) and ethylene-vinyl acetate (4) copolymers, as well as styrene-butadiene composite (5). 

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