Coatings with low surface energy can be promising in various fields of science and technology. It is well known that to achieve low surface energy, it is usually enough to form thin layer or even monolayer of hydrophobic compound on the surface of the coating. On the other hand, to increase stability, such monolayers should be covalently bonded with the surface. In this work, we have shown the possibility of the use of Piers–Rubinsztajn reaction for grafting of oligoorganosiloxane hydrophobic monolayer on the surface of phenol-formaldehyde, alkyd, and epoxy coating, most used in the paint and varnish industry. The organosilicon monolayers were studied by XPS, ellipsometry, and contact angle measurements. Additionally, coatings with grafted organosilicon monolayers were studied for the static effects of water. It was shown that the formed organosilicon monolayers exhibit good hydrophobic efficiency, with an increase in contact angle from 75° to 116° for phenol-formaldehyde coatings, from 82° to 107° for alkyd coatings, and from 84° to 100° for epoxy coatings.

A UV-curable alkyd-siloxane composition on a water basis was obtained, as an alternative to a similar composition based on an organic solvent. The emulsion was prepared using commercially available surfactants and free of volatile organic substances (VOCs). The most applicable technology for the production of alkyd-siloxane emulsions is direct emulsification at a temperature of 60°C, and using dynamic light scattering, the hydrodynamic radius of the particles was determined to be 132 ± 38 nm. The resulting emulsion has an aggregative and sedimentation stability during storage up to 3 months; however, the temperature difference causes the destruction of the colloidal system. The curing reaction occurs within 10 min to form a coating containing 95

Preparation of hydrophobic coatings is still a challenge for researchers in various fields of science. One of the easiest ways consists of the use of special modifiers. However, usually such modifiers are poorly compatible with organic polymeric matrixes, which leads to segregation of modifiers and deterioration of coating properties. In this work, we have synthesized a number of organosilicon copolymers and studied their compatibility with epoxy matrix and hydrophobic efficiency. It was shown that the increase of phenyl-containing units leads to increase of compatibility but decreases hydrophobic efficiency. Addition of small amounts of such modifiers into commercial epoxy paint material can lead to an increase of contact angle of the final coating from 63 to 87° without deterioration of other physico-mechanical properties. These results open new perspectives in preparation of organosilicon hydrophobic modifiers with directed properties for fields of application such as paints and coating materials.

An analysis of the influence of common modifiers on the kinetics of the curing process of epoxy-anhydride vitrimers was carried out. As common modifiers to enhance the “vitrimeric” nature of the material, zinc acetylacetonate as a transesterification catalyst and glycerol as a modifier of hydroxyl group content were chosen. The curing process of all obtained compositions was studied by differential scanning calorimetry (DSC) followed by the application of the isoconversional approach. It was shown that additives significantly affect the curing process. The resulting cured polymers were shown to be chemically recyclable by dissolution in the mixture of ethylene glycol and N-methylpirrolidone in a volume ratio of nine to one. The introduction of both zinc acethylacetonate and glycerol to the neat formulation led to a decrease in the dissolution time by 85.7% (from 35 h for the neat epoxy-anhydride formulation to 5 h for the modified formulation). In order to show the opportunity of the secondary use of recyclates, the mixtures based on the basic composition containing 10 wt. % of secondary polymers were also studied. The introduction of a recycled material to neat composition led to the same curing behavior as glycerol-containing systems.

Eugenol-containing oligoorganosilsesquioxanes were synthesized by the method of hydrolytic polycondensation in an active medium under various reaction conditions. The obtained products were characterized by 29Si NMR spectroscopy and MALDI-TOF spectrometry. It was shown that factors such as the reaction temperature, polycondensation duration, and molar ratio between the initial alkoxysilane monomer and acetic acid may affect the molecular weight characteristics and molecular structure of the formed oligomer, like the content of stressed cyclic units (T3, DTT, TDT) and unstressed silsesquioxane units TnDm. In particular, an increase in the ratio of the initial reagents led to an increase in the content of silsesquioxane Tn fragments from 28.2%mol to 41.7%mol, while the number of strained cyclic structures decreased by more than two times. An increase in the synthesis time is of no particular practical value since it was found that the composition of the oligomers synthesized for 6 h and 12 h was practically identical, as was that of the oligomers synthesized for 24 h and 48 h. A noticeable transition in the oligomer composition was observed only when the synthesis time was changed from 12 h to 24 h. Finally, it was shown that the choice of synthesis temperature had the strongest effect on the oligomer composition. The oligomer synthesized at 95 °C contained the highest amount of silsesquioxane Tn fragments, >77%mol, while a Tn fragment content of ~42%mol was observed during the synthesis at 117 °C. It was shown that silsesquioxanes are devitrified at room temperature (Tg from −6.4 to −10.6 °C), and their thermal stability in an inert atmosphere is 300 °C. The synthesized oligomers, due to the presence of hydroxyl-containing eugenol units, may be promising binders and additives for functional epoxy–silicone paints and coating materials.

A material capable of curing due to UV irradiation based on an alkyd oligomer and oligoorganosilsesquioxanes (OOSs) with functional thiol groups was obtained. Using microinterferometry, it was shown that the alkyd oligomer and OOS are completely compatible (mutually soluble). The resulting alkyd-siloxane composition was cured under the action of UV irradiation due to reaction between double bonds of alkyd oligomer and thiol-groups of silsesquioxane oligomer. The curing reaction takes 5 min with formation of coating, containing 99% of gel fraction, which is in 30 times faster in comparison with the classical method of alkyd curing in the presence of siccatives. The hydrophobicity of alkyd-siloxane coatings also increases and varies depending on the content of OOS. The introduction of 50% OOS into the alkyd oligomer makes it possible to increase the water contact angle by 10 degrees relative to the coating based on pure alkyd. A similar dependence is observed when studying the thermal stability of coatings. Thus, even with the introduction of 10% OOS into alkyd oligomer, the temperature at which a loss of 50% of mass occurs increases by 24 degrees C relative to coatings based on a pure alkyd oligomer.

The results of systematic studies on the surface energy γ and its polar γP and dispersion γD components of statistical copolymers of styrene and butadiene, acrylonitrile and butadiene, and butyl acrylate and vinyl acetate, with regard to their thermal prehistory, are generalized. Along with copolymers, the surfaces of their composing homopolymers were examined. We obtained the energy characteristics of the adhesive surfaces of copolymers that contacted with air, high-energy aluminium Al (γ = 160 mJ/m2), and the low-energy substrate surface of polytetrafluoroethylene F4 (PTFE) (γ = 18 mJ/m2). The surfaces of copolymers in contact with air, aluminium, and PTFE were investigated for the first time. It was found that the surface energy of these copolymers tended to occupy an intermediate value between the surface energy of the homopolymers. The additive nature of the change in the surface energy of the copolymers with their composition, as previously established in the works of Wu, extends to the dispersive component of the free surface energy γD and the critical surface energy γcr, according to Zisman. It was shown that a significant influence on the adhesive activity of copolymers was exerted by the substrate surface upon which the adhesive was formed. Thus, for the butadiene–nitrile copolymer (BNC) samples formed in contact with a high-energy substrate, their surface energy growth was associated with a significant increase in the polar component of the surface energy γP from 2 mJ/m2 for the samples formed in contact with air, to an increase from 10 to 11 mJ/m2 for the samples formed in contact with Al. The reason why the interface influenced the change in the energy characteristics of the adhesives was the selective interaction of each macromolecule fragment with the active centres of the substrate surface. As a result, the composition of the boundary layer changed and it became enriched with one of the components. The structure of such layers is nonequilibrium. The thermal annealing of copolymers in the mode of a stepwise temperature increase led to a convergence in the values of γ, asymptotically tending to the value characteristic of the surface of the copolymers formed in air. The activation energies for the processes of the conformational rearrangements of the macromolecules in the surface layers of the copolymers were calculated. It was found that the conformational rearrangements of the macromolecules in the surface layers occurred as a result of the internal rotation of the functional groups that determined the polar component of the surface energy.

Coatings with low surface energy can be promising in various fields of science and technology. It is well known that to achieve low surface energy it is usually enough to form thin layer or even monolayer of hydrophobic compound on the surface of the coating. On the other hand, to increase stability, such monolayers should be covalenly grafted on the surface. In this work we have shown the possibility of the use of Piers-Rubinsztajn reaction for grafting of oligosiloxane hydrophobic monolayer on the surface of phenol-formaldehyde coating. The monolayers were studied with by XPS, ellipsometry and contact angle measurenets. It was shown that the formed monolayers exhibit good hydrophobic efficiency, with increasing of contact angle from 75° to 116°, and good abrasion stability.

The possibility of using thermoplastic polymers in photopolymer compositions for SLA and DLP is discussed in this article. The diffusion and mutual solubility of uncured systems based on tert-butyl acrylate (tBA) and ethylene-vinyl acetate copolymers (EVA) or low-density polyethylene (LDPE) were studied. The solubility and diffusion of tBA with EVA containing 7, 20, and 40 wt.% vinyl acetate (VA) and with LDPE in the temperature range 20–75 °C were studied by optical micro-interferometry method. Phase diagrams of LDPE–tBA, EVA-7–tBA, and EVA-20–tBA systems were obtained. It is shown that the compositions are characterized by the phase-state diagrams of amorphous separation with the upper critical solution temperature (UCST). The concentration dependences of the interdiffusion coefficients as well as dependences of the self-diffusion coefficients on VA content and on temperature were plotted. The activation energy of self-diffusion of EVA and LDPE was calculated. It was shown that the most promising tBA modifier is EVA-40, which is completely soluble at all studied temperature ranges. The obtained data on the mixing of the initial components is valuable for further studies of the processes of structure formation during photocuring of compositions, regulation of the phase structure and, as a consequence, the performance characteristics of the 3D printable materials.

1. Castro VA, Thrasher AN, Healy M, Ott CM, Pierson DL. Microbial characterization during the early habitation of the International Space Station. Microb Ecol. 2004;47(2):119-126. doi:10.1007/s00248-003-1030-y CrossRef Pubmed Google Scholar

A methodological approach has been proposed for studying the effect of solvent nature on the adhesive properties of films of binary copolymers with different chain microstructures. The approach is based on a complex analysis of the thermodynamic work of adhesion in polymer–liquid model systems and the results of mechanical tests in combination with quantum-chemical calculations. The approach has been used for the first time for copolymers of styrene and n-butyl acrylate having gradient and random distributions of comonomer units over the chains, with the copolymers being synthesized by radical polymerization with reversible chain transfer. The results obtained have shown that the adhesive properties of the binary copolymer films may be regulated by varying the chemical nature of solvents from which they are formed.

Phase equilibria in the mixtures of polyvinyl alcohol (PVA) and chitosan were revealed. Structures of the phases were identified. The temperature and concentration dependences for the chitosan—PVA and chitosan—PVA—water systems were determined. The phase state diagram was built. It is shown that the polymer mixtures are characterized by a complex supramolecular organization, which corresponds to their phase diagram.

The adhesive properties of Polylen (Russia), Polyken (United States), Nitto (Italy), and Furukawa (Japan) insulating tapes and wrappers are described. The contribution is evaluated that primer layers make to the service properties of the insulating tapes providing the necessary adhesion bond between polyethylene tapes and a metal substrate. It is shown that the tackiness and creep of a Polylen tape butyl rubber layer exceeds the corresponding characteristics of other tapes.

Phase behavior and structure formation was studied using optical interferometry, nephelometry, and refractometry in the polymer–solvent–nonsolvent system for DMF solutions of two poly(amic acids): based on 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride and meta-phenylenediamine (PAA-1) and pyromellitic acid dianhydride and 4,4′-oxydianiline (PAA-2). Distilled water and its mixtures with DMF were used as a nonsolvent. According to the results of the study, isothermal cross sections of the phase state diagram in the threecomponent system were plotted, the position of the critical point, the spinodal, and the conodes were determined, the movement of the figurative points in the system was traced depending on the nonsolvent composition.

Phase equilibria in polystyrene-poly(n-butyl acrylate) systems containing polystyrene of various molecular masses were studied for the first time via optical interferometry at temperatures between 280 and 500 K. The phase diagrams of the systems were obtained, the pair interaction parameters were determined, and the dependences of the parameters on the molecular mass of polystyrene and temperature were found. The possibility of thermodynamic analysis of phase diagrams in terms of the classical Flory-Huggins-Scott theory and the possibility to predict generalized phase diagrams of polystyrene-poly(n-butyl acrylate) systems on the basis of the experimental values of the pair interaction parameters were shown.