Sorption-active modified chemical fibres

Abstract

The effect of topochemistry on polymer-analog transformations of graft copolymers of polycaproamide, hydrated cellulose, and polyvinyl alcohol with polyglycidyl methacrylate under the effect of different amines was established. The amine-containing sorption-active fibres exhibit high activity with respect to heavy metals and platinum-group metals.Chemisorbents, in particular, sorption-active fibres, play an important role in solving environmental problems (treatment of gas--air emissions and wastewaters from industrial enterprises, separation and concentration of valuable metals) and problems in occupational safety (creation of devices for protecting the respiratory organs) [1][2][3]. These fibres are a promising alternative to granulated ion-exchange resins due to the developed specific surface.The Chemical Fibre Technology Department at Moscow State Textile University has developed a large group of sorption-active fibres of different composite and chellfical composition based on graft copolymers [4, 5] using ionogenic monomers and polymer-analog transformations of highly reactive o~-oxide groups of graft polyglycidyl methacrylate (PGM) in amination and sulfonation reactions (Scheme 1).An efficient graft polymerization process has not yet been developed due to the specific features of polymerization of ionized monomers. For this reason, the method based on graft polymerization of nonionogenic monomers and chemical transformations of the graft polymer is preferred in industry. The method of initiation utilizing the CUk--H202 redox system proposed for these purposes, which allows fixing the copper complex in the fibre and subsequently formation ofa macroradical, makes it possible to synthesize graft copolymers of the fibre-forming polymers listed above with PGMA with a degree of conversion of 95-97% and without formation of homopolymer; this makes this stage of production of chemisorption fibres highly efficient.In studying the characteristics of graft polymerization, a topochemical effect was found. According to electron microscopic data, the layer of graft polymer almost does not touch the central part ofpolycaproamide (PCA) fibre even for an almost 100% PGMA content in the fibre, while in grafting of GMA to hydrated cellulose (HC) fibre, the graft polymer is distributed over the entire section, as indicated by the absence of a cavity in the fibre after etching. This distribution of the graft polymer affects both the occurrence of the reactions of chemical transformations of PGMA and the sorption activity of the fibre chemisorbents obtained.We used a large group of nitrogen-and sulfur-containing compounds for incorporation of sorption-active groups. The systematic studies of the chemical transformations of graft PGMA in different polymer matrices and under the effect of a broad spectrum of nitrogen-and sulfur-containing compounds were directed toward revealing the characteristics of this process and formulating fundamental scientific premises which would allow more successfully solving practical problems in cre...

Specific features of amination of poly(glycidyl methacrylate) chains grafted onto polypropylene fibers

“…In addition, it was found that the degree of conversion of epoxy rings decreased with an increase in the degree of GMA graft polymerization [4][5][6][7][8]. These facts were also attributed to the effect of steric factors [8].Thus, PGMA amination by opening of epoxy rings in reactions with amines and polyamines is characterized by a steric effect infl uencing the density of the incorporated amino groups and the conversion of epoxy groups. However, this matter has been studied insuffi ciently.…”

“…Experiments on amination of PGMA chains grafted onto the surface of polymer fi bers by reactions of these chains with aliphatic polyamines also showed that the density of the incorporated amino groups decreased with an increase in the length of the reacting polyamine molecule [4][5][6][7][8]. In addition, it was found that the degree of conversion of epoxy rings decreased with an increase in the degree of GMA graft polymerization [4][5][6][7][8].…”

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Amination with diethylenetriamine of poly(glycidyl methacrylate) chains grafted onto polypropylene fi bers by the radiation-chemical procedure was studied.Adsorbents containing amino groups show high selectivity and performance in preconcentration and selective recovery of heavy metal ions from multicomponent solutions [1][2][3][4][5][6][7][8][9]. A widely used route to amine-containing adsorbents is amination of poly(glycidyl methacrylate) (PGMA) as a component of polymeric matrix, or of PGMA chains grafted onto the surface of polymer fi bers of various chemical structures.

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Sorption Properties of Materials Based on Graft Polycaproamide Copolymers

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Sorption of metal ions with a cation exchanger based on a graft polycaproamide copolymer was studied, and the sorption power of the material was evaluated.Polymer-analogous transformations in grafted copolymer chains are a promising route for introducing new functional groups into pendant chains of polymeric materials [1,2]. A characteristic example is phosphorylation of grafted polycaproamide (PCA) chains.

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“…Polymer-analogous transformations in grafted copolymer chains are a promising route for introducing new functional groups into pendant chains of polymeric materials [1,2]. A characteristic example is phosphorylation of grafted polycaproamide (PCA) chains.…”