This study aimed to investigate the dependence of the biocidal activity of polyguanidine (co)polymers on their structure during the formation of biofilms by active PE-degrading cultures of model microorganisms. The Bc-2 copolymer of methacryloyl guanidine hydrochloride (MGHC) and diallyldimethylammonium chloride (DADMAC), which suppressed both the formation of biofilms and the growth of planktonic cultures, exhibited the highest activity. When PE was exposed in tropical soil, the composition of the microbial community on the PE surface differed significantly from that of the community in the surrounding soil. In particular, the proportion of Actinobacteria increased from 7% to 29%, while the proportion of Bacteroidetes decreased from 38% to 8%. Keywords: biofilms, polyhexamethylene guanidine salts, dynamics of biofilm formation, antibiofilm effect, composite materials

During radical polymerization of novel biocidal methacrylate guanidine monomers, a cyclic byproduct was discovered and identified as 2-imino-5-methyltetrahydropyrimidin-4(1H)-one (THP). Its methacrylate salt (MTHP) was synthesized and characterized via 1H and 13C NMR and pyrolysis chromatography. Synthesis conditions of both THP and MTHP were optimized to high yields, and both MTHP homopolymerization (in aqua) and copolymerization with diallyldimethylammonium chloride (in aqua in salt form) were successfully carried out with middle to high yields, providing a promising platform for potential tailored biocide polymers.

The effect of the chemical structure of crosslinking agents on the activity of proteins in hydrogels obtained by the copolymerization of acrylamide, a crosslinking agent, and an unsaturated protein derivative is studied. It is shown that interaction between units of the hydrophobic crosslinking agent which increases with an increase in the length of the aliphatic region between the double bonds of the crosslinking agent leads to an additional "hydrophobic crosslinking" of macromolecules and causes a decrease in the activity of the immobilized protein.

The copolymers of methacryloylguanidine hydrochloride with methacrylamide and diallyldimethylammonium chloride are synthesized by radical polymerization. The reactivity ratios of these monomers are determined, and the dependence of the biocidal activity of the copolymers on the structure of the macromolecule chain is studied. It is shown that manifestation of the biocidal activity is determined not only by the composition of the copolymer but also by the nature of the distribution of methacryloylguanidine hydrochloride units along the macromolecule chain.

Patterns of formation of three-species biofilms on the surface of an LDPE-based composite material were studied using a mixture of pure planktonic cultures of microorganisms capable of degrading this polymer. This is the first report of the role of the ascomyceteYarrowia lipolyticaas a primary colonizer in this system, forming aggregates with gram-negative bacteriaPseudomonas aeruginosaorChromobacterium violaceum. Addition of biocidal compounds of the guanidine family to LDPE as a component of the filler was shown to result in selective suppression of biofilm growth of some microorganisms, while it had no effect on the initial stages of adhesion and on planktonic growth of the cultures. Gram-positive bacteria of the genusKocuriaexhibited the highest sensitivity to these biocidal agents.

Radical copolymerization of methacryloylguanidine trifloroaceatate with styrene has been studied in acetone and dimethylsulfoxide in a wide range of the monomer mixture compositions. For the first time, copolymers (with the yield up to 90%) have been obtained from monomer mixtures with a high total concentration of comonomers (up to 1.7 mol/L). The preliminary biological tests have shown sufficiently high biocide and fungicide activity of the synthesized copolymers.

For production and application of novel biocidal guanidine polymer compounds techniques for monitoring the toxic monomer and oligomer components in polymer aqueous solutions are required. A direct spectroscopic method is offered for determination of methacryloyl guanidine salts, polymer and copolymer in water solutions at native pH. The impact of unsubstituted guanidine and methacrylate guanidine contaminants is also discussed. The spectroscopic method offered is simple, rapid and effective for monitoring contamination of polymethacryloylguanidines with toxic monomer components during synthesis of polymers and copolymers from different monomer salts, during dialysis and other manufacturing stages of biocidal polymers.

The reaction of the amino group of α-chymotrypsin with poly(N,N-diethylacrylamides) bearing terminal carboxyl groups which have the degree of polymerization ranging from 30 to 180 and which possess an LCST of 34–29°C affords polymer derivatives of the enzyme. It is found that, upon an increase in the temperature of the aqueous solution of the resulting derivatives to 40°C, the derivative with a degree of polymerization of 180 precipitates at 34°C, while the derivatives with a degree of polymerization of 30–80 remain in solution. The activity of α-chymotrypsin as a part of the derivatives with a degree of polymerization of 30 does not change with increasing temperature, whereas the activity of the enzyme as a part of the derivatives with degrees of polymerization of 60 and 80 decays almost to zero near the LCST of the initial polymers. Such a change in the enzyme activity is reversible (the activity fully recovers with a decrease in temperature).

A method for the synthesis of methacryloylguanidine trifluoroacetate was developed for the first time and its radical (co)polymerization was carried out in various solvents. The polymerization proceeds homogeneously in water, methanol, and DMSO up to high conversion and heterogeneously in acetone after reaching 20% conversion. For the first time, methacryloylguanidine trifluoroacetate and methylmethacrylate copolymers were synthesized in acetone and DMSO; the copolymerization constants for this system in acetone were determined to be r1 = 1.41 ± 0.24 and r2 = 0.11 ± 0.01. Preliminary biological tests showed a fairly high biocidal and fungicidal activity of the synthesized copolymers.

New methods for the preparation of guanidine methacrylate, methacryloyl guanidine, and its hydrochloride have been proposed, and the physicochemical characteristics of the products have been studied. A number of kinetic parameters of the radical polymerization of these monomers have been determined (the rate and the rate constant in the initial section as well as the order of the reaction rate with respect to the concentration of the initiator for methacryloyl guanidine hydrochloride). It has been found that the classical general rules are followed: The conversion increases with an increase in temperature, while the characteristic viscosity decreases. The main NMR spectroscopic parameters of polymethacryloyl guanidine hydrochloride have been determined. According to preliminary biological tests, polymers have sufficiently high bactericidal activity and can be used as stand-alone biocidal preparations or as functional additives in composite materials.

The absorption and spatial structuring of modifiers in the interplanar space were studied, and the methods of chemical binding of guanidine-containing monomers and polymers to montmorillonite were elaborated. It was shown that a polymer chemically absorbed on clay very slowly desorbs in water during great dilution and has a greater thermal stability than that of the initial polymer. Guanidine-containing compounds bound to clay may be used as biocidal fillers in various polymers. Nanocomposites with marked biocidal properties were obtained on the basis of montmorillonite modified with biocidal polymers and gutta-percha.

The N-pentafluorophenyl-exo-endo-norbornene-5,6-dicarboximide (2a) and N-phenyl-exo-endo-nor-bornene-5,6-dicarboximide (2b) monomers were synthesized and polymerized via ring-opening metathesis polymerization (ROMP) using bis(tricyclohexylphosphine) benzylidene ruthenium(IV) dichloride (I) and tricyclohexylphosphine [1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidene] ruthenium dichloride (II). Both catalysts were used to synthesize random and block high molecular weight copolymers which were further hydrogenated using a Wilkinson’s catalyst. Then, the saturated copolymers were modified by reacting with sodium 4-hydroxybenzene-sulfonate dihydrate to generate new ionomers with fluoro-sulfonic acid pendant groups.