The example of solving the complex problem of polymer synthesis belongs to the analysis of the chemical structure of one of the representatives of polymer networks - phenol-formaldehyde resin widely applied, in particular, to production of pressed woody articles.

Before analyzing the structure of a polymer network based on phenol formaldehyde resin, it should be noted that although phenol formaldehyde resins (PFR) are one of the oldest representatives of high cross-linked polymer networks, their structure is still of great interest [201]. There is a broad list of works devoted to the analysis of the structure and properties of PFR. However, there is still no general point of view on the chemical structure of the network formed by these resins. The reason is, apparently, in the fact that due to proceeding of the PFR curing the network structure obtained may be different. Another reason is associated with the fact that OH-groups capable of forming hydrogen bonds are present in the network structure. These hydrogen bonds may be displayed in both intermolecular interaction of these groups disposed in neighboring PFR chains and at the sacrifice of the same interaction OH-groups disposed in the same repeat unit.

The meaning of the notions of 'intermolecular interaction' and 'intramolecular interaction' in the context of the approach under discussion should be explained with the help of a simplified scheme represented in Figure A-3-1. Figure A-3-1a demonstrates the case corresponding to the intermolecular interaction, which leads to the formation of a network of physical (hydrogen) bonds linking...