## 1 Introduction  
Functional synthetic polymers are increasingly prominent materials due to their unique properties and applications [1; 2; 3]. The specific application fields of functional synthetic polymers are determined by the nature of the functional groups and their locations and the structure of the polymer matrix [4]. One of the groups of functionalized polymers comprises polymers possessing a phosphoric function. The phosphorus-containing polymers have been successfully applied in biotechnology and biomedical engineering, nanotechnology, the food industry, hydrometallurgy, catalysis and the purification of various industrial and wastewaters, and as polymer supports, adsorbents and ion exchange resins [5; 6; 7; 8; 9]. Some phosphorus polymers possess a phosphorus function in the main chain (polymoghphaarenes [10], polyphosphoesters [11]). Most common are polymers containing a phosphorus moiety in the side part of the main chain (phosphinic acid derivatives [12], phosphonate derivatives [13], phosphorus-containing fluoropolymers [14]). Materials with special topologies or architectures, such as stars, hyperbranched polymers or dendrimers (treelike structures), are also of great interest [15]. Functional synthetic polymers can be prepared either via the chemical modification of already defined polymers [16] or via the direct polymerization or copolymerization of functionalized monomers [17; 18; 19; 20]. The first method has the drawback of lacking control over the molecular weight and functional group distribution, while the second requires careful adaptation of the polymerization technique to avoid side reactions of the desired functional groups. The copolymerization process allows the easy and direct introduction of the functional group into the polymer structure. The functional group exists in all volumes of the polymer structure. Polymers with a phosphine oxide function are readily synthesized via free radical copolymerization with common monomers, e.g., styrene or methyl methacrylate. The resulting copolymers can be used as potential flame-retardant materials [21; 22]. Phosphorus-containing polymers also are used as sorbents [8; 22; 23; 24; 25; 26; 27; 28]. Resins are particularly useful in the removal, preconcentration and determination of various metal ions in aqueous solutions and in metal recovery [23]. A silica-based octyl(phenyl)-\(N\),\(N\)-diisobutylcarbamoyl-methylphosphine oxide (CMPO) resin (CMPO/SiO\({}_{2}\)-P) was applied for Nd(III) removal from a nitric acid medium [24]. Modification of silica by the impregnation and immobilization of two chelating agents, such as \(N\),\(N\),\(N\),\(N\)-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) and octyl(phenyl)-\(N\),\(N\)-diisobutylcarbamoylmethylphosphine oxide (CMPO), made it possible to obtain chelating polymeric resins for actinide and lanthanide (Am(III), Cm(III), Gd(III), Sm(III)) preconcentration [25]. A phosphine-functionalized PVA/SiO\({}_{2}\) composite nanofiber adsorbent of a porous structure was evaluated for manganese and nickel ion removal from an aqueous solution at various pH values by [PERSON] et al. [26]. [PERSON] et al. [27] synthesized a new type of phosphine-based covalent organic material (P-COFs) for iodine adsorption. A phosphine-functionalized magnetic nanocomposite (Fe\({}_{3}\)O\({}_{4}\)/SiO\({}_{2}\)/OPPh\({}_{2}\)) was used as a palladium ion adsorbent [28]. A phosphorus-containing polymer sorbent obtained by the chemical modification (oxidative chlorophosphorylation reaction) of an industrial polymer--butadiene rubber--was also applied for the removal of the toxic azo dye arsenazo III by [PERSON] [29]. The chloromethylated styrene-divinylbenzene copolymers modified with iso-propylamine and diethylphosphite were tested for phenol and its derivatives' uptake from water [30]. Dyes are applied in several industries, such as the textile, plastic, paper, leather, food, pharmaceutical, cosmetic or rubber industries [31]. These industrial sectors are among the world's greatest polluters.