Physico-chemical nanomaterials science

Approaches for improving physical and mechanical properties of hydrogels 
N. Fihurka, N.Nosova, S. Hermanovych, A. Stasyuk, V. Samaryk 
Department of organic chemistry, Lviv Polytechnic National University, 12, Stepan Bandera str., Lviv-79013, Ukraine. 
E-mail: figurka.nataliia@gmail.com

Hydrogels have an increasing application in various fields. The urgency of their application is associated with several factors. First of all, hydrogels possess biocompatible properties, do not cause irritation and reactions in the body tissues after the contact. One of the disadvantages that essentially inhibits the use of hydrogels is insufficient mechanical properties, especially at the high levels of swelling. Therefore, increasing the physical and mechanical properties of hydrogel materials is an urgent task.
In this paper, we consider methods for increasing the physical and mechanical properties of hydrogels via reinforcing them with polymer scaffolds while preserving their basic properties. Reinforcing the hydrogel with polypropylene network leads to a significant increase in  Young's modulus of the hydrogel. At the same time, it should be noted that from the point of view of industrial use a significant increase in the physical and mechanical properties of reinforced hydrogels (at all loading types) is observed only when the gelling polymer forms links with the scaffold material. In this paper, the influence on the physical and mechanical properties of hydrogels on the formation of covalent bonds between the gel-forming polymer and previously modified polypropylene surface is investigated. The modification of polypropylene surface is carried out due to the attaching of nanometric reactive polyperoxide layer [1,2].
The resulting reinforced hydrogel should be considered as a polymer composite material with clearly separated functions of the components at close interaction between them, which ensures the formation of unified integral properties. The main operational properties of resulting materials are determined by the hydrogel matrix, and the reinforcement element provides an increased physical and mechanical properties. This feature significantly distinguishes such composite materials from similar materials.
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2.	V.Samaryk, A.Voronov, I.Tarnavchyk, S.Varvarenko, N.Nosova, O.Budishevskaya,  A.Kohut, S.Voronov   Formation of Coatings with Tailored Properties on Polyperoxide-Modified Polymeric Surfaces // Progress in Organic Coatings. -2012. -74(4). - Р.  687–696.