Permolecular structure

Synchronous processes represent the most demonstrative and unique example of chemical reaction ensembles, arranged in time and space. Interest in synchronous chemical reactions is also so much keener, because in biological systems many processes are synchronous. This means that biochemical reactions are arranged and performed in systems with molecular and permolecular structures, which is the chemist s pipe dream . Studies performed in recent decades have allowed the development of the interaction theory for synchronous chemical reactions at two levels—microscopic and macroscopic. Strictly speaking, parallel reactions may also be taken as synchronous reactions although proceeding simultaneously in the reaction system, they are characterized by the absence of any interaction between them. However, such synchronous reactions are trivial and of no special interest for chemistry. It is of much more importance when they interact and, therefore, induce oscillations in yields of synchronous reaction products. 

The polarity of macromolecules and the solvent determine the effect of organic solvents on polymer materials. Polymers containing polar groups are resistant to non-polar substances but can swell and be dissolved in polar substances. The polymer permolecular structure exerts a considerable effect on its stability under aging as well. Crystalline polymers dissolve slower than non-crystalline ones, which is due to different diffusion velocities of low-molecular-weight components in the crystalline and amorphous polymers. 

The permolecular structure of polymers exerts a perceptible effect on permeability. Thermoplasts whose structure is not spherulitic and materials with a coarse-spherulitic structure are highly permeable because of different development levels of the microcapillary system of permolecular formations. 

Structural formers (oxides, carbides, nitrides, salts of organic acids, fine-dispersed powders, surfactants) exert an effect on the permolecular structure formation and assist in yielding materials with a given microstructure. A number of powder Cl can be related to active structuring agents. In particular, impregnation of small amounts of fine-dispersed Cl (NDA, G-2, 5-PhTet) in the polymer film materials improves their strength and barrier properties (see Sect. 2.3). 

Film formation is a specific property of polymers that distinguishes them from low-molecular matter. This is a considerable length and asymmetry of macromolecules capable of forming a strong oriented permolecular structure during stretching of polymer bodies that lies at the base of this property [2]. So far, polymers are considered to utterly suit to a raw material for production of the films. 

Destruction of macromolecules and distortion of the permolecular structure lead to changes in their properties, especially solubility, resistance to chemical agents, strength, fatigue and impact viscosity, as well as elasticity and plasticity. From the practical viewpoint, variations in polymer properties induced by the tribochemical destruction raise interest in two respects first, as unavoidable phenomena that accompany any mechanical effect on the polymers during their treatment or operation and, second, as a deliberate change of properties of solid pol3uners to obtain materials with specific characteristics. 

Physico-structural inhomogeneity. In contrast to low-molecular substances, the reactivity of solid polymers depends greatlyon the structure of the electron shells and to a greater extent on molecular d3mamics and imperfections of the permolecular structure. Physical-structural inhomogeneity of polymers may bring about the following phenomena that are critical for tribochemical reactions [80]. 

The kinetics of tribochemical transformations. The role of mechanical stresses consists of not only the initiation of radical processes but in kinetic changes of the elemental stages of the chemical reactions with the participation of macromolecules as well. Plastic deformations increase reaction velocities that have been limited by travel of the reacting particles in the material bulk. Shear and tension accelerate the decay of the radicals with a free valence in the chain center. Chemical reactions are also affected by variations in the intra-molecular mobility and permolecular structure during pol3Tner deformation. 

The cases considered above, when the reaction rate is restricted by the distribution of elastic stresses in the polymer, do not describe in full the kinetics of complex multistage tribochemical reactions in pol3Tuers. The limiting stage may happen to be the displacement of reacting particles, formation of a new friction surface and so on. The reaction velocity constant may vary during the friction process as it depends upon the pol3mier permolecular structure, molecular-mass distribution and other factors. 

It was proposed to use the thermodynamics of small systems and Avrami equations to describe the formation processes of carbon nanostructures during recrystallization (graphitization) [6,7]. These equations are successfully applied [8] to forecast permolecular structures and prognosticate the conditions on the level of parameters resulting in the obtaining of nanostructures of definite size and shape. The equation was also used to forecast the formation of fibers [9]. The application of Avrami equations in the processes of nanostructure formation (a) embryo formation and crystal growth in polymers [8]—... 

The results obtained show that stabilizer injection causes a significant (over two times) deceleration of thermal oxidation in LCP. Of interest is the effect of additives on polymer morphology, determined during studying stabilized and non-stabilized samples (before and after thermal oxidation in air) by the X-ray difiraction analysis. It is found that crystalline reflex is preserved in stabilized polymers, whereas it disappears in non-stabilized samples. The stabilization effect on the physical structure of polymers was not studied well with respect to chemistry of degradation processes. Only complex consideration of the problem (chemistry + change of physical permolecular structure) may cause the increase of thermal stability of prepared product and extension of the material lifetime in articles. 

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