G V Kozlov

This new book explores the consideration of relationships that connect the structural and basic mechanical properties of polymeric mediums within the frameworks of fractal analysis with cluster model representations attraction. Incidentally, the choice of any structural model of medium or their combinations is defined by expediency and further usage convenience only. This book presents leading-edge research in this rapidly changing and evolving field. The book presents descriptions of the main reactions of high-molecular substances within the frameworks of fractal analysis and irreversible aggregation models. Synergetics and percolation theory were also used. In spite of the enormous number of papers dealing with the influence of the medium on the rate of chemical reactions (including synthesis of polymers), no strict quantitative theory capable of "universal" application has been put forward up until now. It is now possible to describe the relationship between the reaction rate constants and the equilibrium constants with the nature of the medium in which the reactions take place by means of a single equation. This important book for the first time gives structural and physical grounds of polymers synthesis and curing, and the fractal analysis is used for this purpose.This new book: • Highlights some important areas of current interest in polymer products and chemical processes• Focuses on topics with more advanced methods• Emphasizes precise mathematical development and actual experimental details• Analyzes theories to formulate and prove the physicochemical principles• Provides an up-to-date and thorough exposition of the present state of the art of complex polymeric materials

This new book explores the consideration of relationships that connect the structural and basic mechanical properties of polymeric mediums within the frameworks of fractal analysis with cluster model representations attraction. Incidentally, the choice of any structural model of medium or their combinations is defined by expediency and further usage convenience only. This book presents leading-edge research in this rapidly changing and evolving field. The book presents descriptions of the main reactions of high-molecular substances within the frameworks of fractal analysis and irreversible aggregation models. Synergetics and percolation theory were also used. In spite of the enormous number of papers dealing with the influence of the medium on the rate of chemical reactions (including synthesis of polymers), no strict quantitative theory capable of "universal" application has been put forward up until now. It is now possible to describe the relationship between the reaction rate constants and the equilibrium constants with the nature of the medium in which the reactions take place by means of a single equation. This important book for the first time gives structural and physical grounds of polymers synthesis and curing, and the fractal analysis is used for this purpose.This new book: • Highlights some important areas of current interest in polymer products and chemical processes• Focuses on topics with more advanced methods• Emphasizes precise mathematical development and actual experimental details• Analyzes theories to formulate and prove the physicochemical principles• Provides an up-to-date and thorough exposition of the present state of the art of complex polymeric materials

The interest in polymer composites research is due to their enlarged application. Filling with hard particles gives to polymers a number of desirable properties: increases hardness, decreases heat expansion coefficient, improves resistance to creep and fracture toughness. Difficulties in structure-properties relationships researching for polymer composites are due to their structure complexity. Till now, composites studies were conducted within the frameworks of continuum mechanics and thermodynamic conceptions. However, these conceptions applications does not allow satisfactory descriptions nor predictions of such materials properties. As a matter of fact, an experimental data set dictates one or another physical model of structure choice for composites macroscopic properties description.

Fractal analysis gives just general mathematical description of polymers, i.e. it does not identify structural units (elements), from which any real polymer is formed. Physical description of thermodynamically non-equilibrium polymer structure in the framework of the local order ideas gives the cluster model of the polymer amorphous state structure that quantitatively identify its elements. Since these models consider the polymer structure somewhat from two sides, they are excellent completing one another. It is common knowledge that structures displaying fractal behaviour on small length scale and being homogeneous on large length scale are named homogeneous fractals. These fractals are percolation clusters at the percolation threshold. As shown below, the cluster structure represents the percolation system and, due to the above-said, the homogeneous fractal. To put it differently, the presence of the local order in the condensed phase of polymers determines fractality of their structures.

Nanochemistry is a science connected with obtaining and studying of physical-chemical properties of particles having sizes on the nanometer scale. This book addresses polymer synthesis which, according to Melikhov's classification, is automatically part of nanochemistry. This is determined as far as polymeric macromolecules (more precisely macromolecular coils) belong to nanoparticles and polymeric sols and gels - to nanosystems. Catalysis on nanoparticles is one of the most important sections of nanochemistry. The majority of catalytic systems are nanosystems. At heterogeneous catalysis the active substance is tried to deposit on carrier in nanoparticles form in order to increase their specific surface. At homogeneous catalysis active substance molecules have often in themselves nanometer sizes. The most favorable conditions for homogeneous catalysis are created when reagent molecules are adsorbed rapidly by nanoparticles and are desorbed slowly but have high surface mobility and, consequently, high reaction rate on the surface and at the reaction molecules of such structure are formed at which desorption rate is increased sharply. If these conditions are realised in nanosystem with larger probability than in macrosystem, then nanocatalyst has the raising activity that was observed for many systems.

Fractals & Local Order in Polymeric Materials