Polyethylene terephthalate comonomers

The concept of polymeric soil release agents has been around for well over 25 years. The initial polymer chemistries (polyethylene terephthalate-polyoxyethylene terephthalate, PET-POET) were designed to deposit on fabrics and facilitate oily soil removal upon subsequent washing [98,133,134], The limitation of this chemistry was its effectiveness on synthetics (polyester) alone, with limited benefits being observed on cotton and synthetic blends. In recent years the focus has shifted to delivering soil release on cotton. Two classes of polymer chemistries have been disclosed in the recent patent literature for cotton soil release one based on hydrophobically modified polycarboxylates derived from acrylic acid and hydrophobic comonomers at defined molar ratios [188] and the other based on modified polyamines [189-193],... 

A. Polyakova, D. M. Connor, D. M. Collard, D. A. Schiraldi, A. Hiltner, and E. Baer. Oxygen-barrier properties of polyethylene terephthalate modified with a small amount of aromatic comonomer. J. Polym. Sci., Part B Polym. Phys., 39(16) 1900-1910, August 2001. 

FIGURE 12.9 X-ray diffraction patterns of (a) commercial acrylic and (b) polyethylene terephthalate fibers. The acrylic fiber was a commercial sample containing 7% vinyl acetate comonomer. In both cases, the fiber axis is vertical. 

Polyester fibers are composed of linear chains of polyethylene terephthalate (PET), which produces benzene, benzoic acid, biphenyl, and vinyl terephthalate on pyrolysis. Acrylic fibers comprise chains made up of acrylonitrile units, usually copolymerized with less than 15% by weight of other monomers, e.g., methyl acrylate, methyl methacrylate, or vinylpyrrolidone. Thermolysis results in the formation of acrylonitrile monomer, dimers, and trimers with a small amount of the copolymer or its pyrolysis product. In this case, the acrylic is Orion 28, which contains methyl vinyl pyridine as comonomer. Residual dimethyl formamide solvent from the manufacturing process is also found in the pyrolysis products. Cotton, which is almost pure cellulose, comprises chains of glucose units. The pyrolysis products of cellulose, identified by GC/MS, include carbonyl compounds, acids, methyl esters, furans, pyrans, anhydrosugars, and hydrocarbons. The major pyrolysis products are levoglucosan (1,6-anhydro-B-D-glucopyranose) and substituted furans. 

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