Furan-acrylonitrile copolymers

Scheme 6 The structures of five residues derived from fuian in acrylonitrile (AN) copolymers, and the meth furan radical...

An anionic technique by indirect grafting was proposed for N-metallation of Nylon by Yamaguchi (153-155), in which alcali metals dissolved in liquid ammonia displace the amidic hydrogen atoms. Nylon derivatives and graft copolymers can be synthetized from the N-metallated Nylon (153). For ethylene oxide as grafting monomer, the metallated fibers were soaked in a tetrahydro-furan solution of the monomer, at 60° C (154). Methyl methacrylate is grafted on Nylon with a conversion over 90% by this technique (155). Other procedures involve the use of sodium methoxide in methanol solution and subsequent anionic graft copolymerization of acrylonitrile in a tetrahydrofuran solution (156). 

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. 

Similar to furan and benzofuran monomers,thiophene and 1-benzothiophene " are also known to copolymerize in a 1 1 fashion with MA. Thiophene will not undergo free-radical homopolymerization or copolymerization with monomers such as styrene, methyl methacrylate, or acrylonitrile. However, when an equimolar mixture of thiophene and MA are combined with chloroform containing AIBN and heated at 60°C, a white copolymer starts to precipitate after only a few minutes reaction time. Varying the molar feed ratios showed that both yields and reduced viscosities were maximum for equimolar feeds. Copolymerizations in solution from 1 bar to 3 kbars show that rates and yields are increased with pressure.Through composition studies and comparing the NMR spectrum of the copolymer with the NMR spectra of 2,3- and 2,5-dihydrothiophene, structure 88 was assigned to the copolymer. 

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