ИСТИНА

Poly(vinyl alcohol) cryogels (PVACGs) are the macroporous physical gels of crystallization type that are formed as a result of a single or several cycles of freezing, holding in the frozen state and thawing of the polymer solutions. Owing to both the simple preparation technique and excellent properties of PVACGs they are of interest for the use in medicine, biotechnology, food industry, and construction. The imparting of new properties, in particular, rigidity and heat endurance of PVACGs can be reached by the introduction of disperse fillers. The aim of this study was to find the ways for selecting the fillers capable of tailor-made changing the properties of composite PVA cryogels (cPVACGs). Disperse particles of different chemical nature (hydrophilic and hydrophobic, mineral and organic) and of different porosity were used in the work. Rheological experiments with respect of initial suspensions revealed that adhesion contacts arise between the filler particles, as well as discrete and continuous phases, already at the stage of suspension preparation, thus affecting the properties of the resultant composite cryogels. These effects were more pronounced in the case of the fillers with a larger pore size. Thereby, the possibility for poly(vinyl alcohol) macromolecules to penetrate inside the filler particles and to form there the cryogel phase, which is connected through the gross pores with bulk continuous cryogel phase, is the major mechanism facilitating the observed increase in the rigidity of such composites.