Utilizing turbidimetry data, an examination is conducted on the behavior of solutions containing N-vinylpyrrolidone and vinyl propyl ether copolymer within a temperature range coinciding with the occurrence of a phase transition. The investigation reveals that within specific conditions prevailing in this domain, the emergence of entities denoted as hydrophobic–hydrophilic associates is conceivable. These entities are characterized by the presence of a relatively dense core, upheld by hydrophobic interplays, and they are proficient in effectively dispersing irradiation within the optical spectrum. Encircling this core is a hydrophilic periphery that impedes the formation of insoluble precipitates. The development of such associates transpires when hydrophobic interactions have attained a discernible prominence, although they remain inadequate to counteract the forces that drive the expansion of macromolecular coils. Under these circumstances, the energetically favored course of action entails the constitution of a core for the aforementioned associates, involving discrete segments from diverse macromolecules. Notably, the introduction of an additional constituent (ethanol) to the solution, which selectively mitigates hydrophobic interactions, serves to stabilize the hydrophobic–hydrophilic associations.

New design of a viscometer based on the s tokes viscosity measurement method is proposed. The principle of operation of this viscosimetr is based on the use of ball periodic alternated movement in a horizontally positioned cuvette that filled with the test liquid. The movement appears under the in fluence of a magnetic field that created by two electromagnets. Registration of the ball movement inside the cuvette is carried out using an optoelectronic pair. A distinctive feature of the proposed design is control by using a program that installed on t he user's smartphone, which also carries out the primary data processing. Data transmission is carried out over the radio channel using a Bluetooth module. Disposable cuvettes are used for measurements. This approach makes it possible to significantly redu ce both the device production costs and operating costs by eliminating most of the operations for the device preparing for working (the vast majority of existing types of viscometers require thorough flushing of all units in contact with the test medium). In addition, the proposed approach excludes the occurrence of measurement errors associated with insufficiently thorough preparation of the device for operation.

Mixtures containing polyvinyl alcohol (PVA) and methylcellulose (MC) were obtained and used to synthesize hydrogels in various ratios of components. The swelling kinetics of the resulting hydrogels were studied, revealing that the equilibrium swelling degree in artificial saliva is nearly twice as high as in water. It was found that increasing the volumetric content of PVA in the mixture leads to a higher swelling degree. The kinetics of active pharmaceutical ingredient (API) sorption and release from the hydrogels were also investigated. It was demonstrated that hydrogels with a higher PVA content exhibit greater sorption capacity; however, the release of the API from such samples occurs at a slower rate. For the first time, the mucoadhesive properties of PVA-MC-based hydrogels were studied. It was established that the PVA-MC hydrogel with a ratio of 6:4 vol.% remained on the surface of the porcine cheek mucosa for two days, the 5.5:4.5 vol.% sample detached after 24 h, and the 5:5 vol.% sample adhered for approximately 10 h. These findings confirm the mucoadhesive potential of the hydrogels and their suitability for buccal drug delivery forms. The synthesized PVA-MC hydrogels are promising for applications in medicine and pharmacology.

The influence of a new filler of natural origin on the thermal oxidation process of high-pressure polyethylene has been studied. The studied filler is carbonized rice husk, a waste product of agricultural production. It has been established that CSF exhibits some thermostabilising effect, preventing the decrease of deformation and strength characteristics of the polymer after its exposure for 3 hours at 170ºC. The introduction of CSF allows to keep the yield strength at the level of 77% (10% wt. CSF) and 46% (5% wt. CSF), while for unfilled aged LDPE this index does not exceed 3% of the initial sample. The breaking stress of the filled samples remains at the level of the unoxidized ones. A synergetic effect was revealed when the investigated filler and standard antioxidant Irganox 1010 were used. At the introduction of 10% wt. of CSF and 0,2% wt. of phenolic stabilizer, there is no decrease in destructive stress after the thermal aging of the material.

Study of the physico-chemical properties of novel water-soluble copolymers of cationic type based on N-isopropylacrylamide