Supermolecular structure and properties of polymers

Questions relating to methods of obtaining supermolecular structures and their effect on the properties of polymers are considered.Presented at 2nd All-Union Conference on Polymer Mechanics, Riga, November 10–12, 1971.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 409–415, May–June, 1972.     

Increasing the adhesion of polymers to metals by adding substances with conjugation systems

The electron-donor properties of polymers with conjugation systems (PCS) and their capability of forming -complexes with metals is of interest in relation to adhesion. Small amounts (0.01–0.1%) of substances with polyconjugation systems (polydiphenylbutadiene, polyphenylacetylene, and copolymers of naphthalene and anthracene with benzene) increase the adhesion between aluminum and polymers used as electrical insulation coatings (polyesters, polyimides, and their derivatives). With optimum PCS dosage, the resistance to peeling rises by 15–38%.Institute of Chemical Physics, Academy of Sciences of the USSR, Moscow. Translated from Mekhanika Polimerov, No. 2, pp. 365–367, March–April, 1974.     

Thermofrictional properties of self-lubricating antifriction plastics

New thermally stable polymers (polyimides, polyarylates, and phenolphthalein-phenolformaldehyde copolymers) were used in a study of the thermofrictional properties of their compositions with molybdenum disulfide. We established the existence of several temperature zones of friction and demonstrated their connection with the changes in the relaxation and autohesion properties of the polymers in these same temperature zones.Institute of Organoelement Compounds, Academy of Sciences of the USSR, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 481–485, May–June, 1970.     

Local compatibility and the adhesion of polymers

The role of the thermodynamic factor in creating an adhesion bond between partly or wholly compatible polymers is discussed. The importance of this factor depends on the fact that polymers brought into contact will diffuse into each other only if they are wholly or partly mutually soluble. This mutual solubility is confined to a surface layer and is determined by the local diffusion. In considering the mechanism of formation of an adhesion bond between two polymers it is necessary to take their surface properties into account. In the diffusion theory of adhesion diffusion is regarded as the motive force in the creation of an adhesion bond.Moscow Lomonosov Institute of Fine Chemical Technology. Translated from Mekhanika Polimerov, No. 3, pp. 455–459, May–June, 1969.     

Investigation of the energy effects accompanying the elastic deformation of uniaxially oriented crystalline polymers

The energy (thermal and mechanical) effects accompanying the elastic deformation of uniaxially oriented crystalline polymers have been investigated; it has been established that, when these polymers are stretched, heat is released. It is shown that the heat release in uniaxial tension is a consequence of localization of the elastic deformation in the poorly ordered regions of the polymer. The relation between the thermoelasticity of uniaxially oriented crystalline polymers and their supermolecular structure is examined.Institute of Heteroorganic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Mekhanika Polimerov, No. 5, pp. 785–798, September–October, 1970.     

Electret composite materials based on polymers: Main properties and new fields of application

Data are given on the effect of an electret charge on wetting, spreading, sorption, and diffusion of liquids in polymers and composites. The modification of polymers in electric fields or by electret and electrochemically active fillers improves the physical-mechanical and tribological characteristics of materials. It is shown that the electret composites used in machines for protecting the metal-polymer joints against corrosion increase their rigidity and tightness and improve their tribological characteristics. Electret composites are new-generation materials (smart or intelligent materials) since they respond to recent developments in technology and are capable of raising the efficiency of machines with simultaneous reduction in energy and consumption of materials.Submitted to the 10th International Conference on Mechanics of Composite Materials, April 20–23, 1998, Riga, Latvia.Belyi Metal-Polymer Research Institute, National Academy of Sciences, Gomel 246652, Belarus. Translated from Mekhanika Kompozitnykh Materialov, Vol. 34, No. 2, pp. 153–162, March–April, 1998.     

Effect of submicroscopic crack formation and relaxation phenomena in polymers

The development of submicrocracks and the changes taking place in their concentration during loading and unloading cycles were studied by the low-angle x-ray scattering method in oriented amorphous-crystalline polymers (capron and polypropylene). The deformation () of the polymers was compared with the changes in submicrocrack concentration (N_cr).A. F. Ioffe Physicotechnical Institute, Academy of Sciences of the USSR, Leningrad. Translated from Mekhanika Polimerov, No. 3, pp. 387–392, May–June, 1970.     

Physical and physicochemical modification of polymers

Research on the modification of the properties of crystalline polymers by changing their physical structure is reviewed. Two different modification principles are considered — the creation of a homogeneous physical structure (introduction of small amount of highly dispersed regulators of the structure-forming processes) and the creation of an inhomogeneous physical structure (by contact with large regulating surfaces) in order to differentiate the surface from the bulk properties and improve resistance to the development of defects. The question of regulation of the processes of physical structure formation by the introduction of chemically reacting substances is also investigated. The possibilities of using antioxidants as physical modifiers and the possibility of physical modification during both the processing and synthesis of polymers are stressed.L. Ya. Karpov Scientific-Research Physicochemical Institute, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 395–408, May–June, 1972.     

Viscoelastic parameters of certain polymers in the temperature interval 4.2–240°K

The principal elastic constants of Nylon 6, Nylon 7, Nylon 6.10, Nylon 11, Nylon 12, PVC, PMMA, polystyrene, and polyvinylfluoride have been calculated from data on the velocity of ultrasonic longitudinal and shear waves measured at a frequency of 5 MHz on the temperature interval 4.2–240°K. It is shown that at cryogenic temperatures the dynamic moduli of elasticity are, to a considerable extent, determined by the characteristics of the chemical structure of the polymers. It is suggested that the Poisson's ratios of the polymers depend on their free volume.Scientific-Research Institute of Plastics, Moscow. Translated from Mekhanika Polimerov, No. 4, pp. 604–609, July–August, 1973.     

Prediction of the short-term strength of polymer materials based on equations of state

The possibility is analyzed of using equations of state for predicting the mechanical properties of linear amorphous polymers with short-term loading from data for their compressibility.D. I. Mendeleev Chemical Technology Institute, Moscow. Translated from Mekhanika Kompozitnykh Materialov, Vol. 33, No. 2, pp. 258–262, March–April, 1997.     

Friction properties of physically modified polymers

The effectiveness of using physical methods of modifying the surface layers of polymers in order to improve their friction properties is demonstrated.Institute of Mechanics of Metal—Polymer Systems, Academy of Sciences of the Belorussian SSR, Gomel'. L. Ya.Karpov Scientific-Research Physicochemical Institute, Moscow. Translated from Mekhanika Polimerov, No. 5, pp. 839–842, September–October, 1974.     

Relation between the microstructure of block amorphous polymers and certain mechanical properties of the specimens

The structures of PMMA, PS, and PC are considered in relation to the mechanical properties. The part played by the individual elements of the microstructure and their influence on the mechanical strength and deformability of the material are determined. The experimental data obtained by various authors are interpreted on the basis of the microstructural characteristics of polymers.Institute of Problems of Mechanics, Academy of Sciences of the USSR, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 416–421, May–June, 1972.     

Fundamental theories and methods of polymer mechanics

The fundamental theories and methods of polymer mechanics are analyzed in the light of modern ideas about the structure and mechanical properties of polymers.Lomonosov Moscow State University. Translated from Mekhanika Polimerov, Vol. 5, No. 1, pp. 3–13, January–February, 1969.     

Structure and properties of polymers

The history of the development of the structural mechanics of polymers is reviewed and the more important of its future tasks are noted.Institute of Heteroorganic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 387–394, May–June, 1972.     

Changes in the structure of polymeric materials in a magnetic field

It is shown that the action of a magnetic field leads to a change in the supermolecular structure of crystalline polymers. The creation of an oriented state in amorphous thermoplastics and thermosets is accompanied by an increase in their hardness and the homogeneity of the structural state.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 4, pp. 737–739, July–August, 1973.     

Analysis of the Adhesion and Adhesion Strength of Two-Layer Polymer Films and Coatings

The formation of adhesion bonds during the creation of two-layer polymer films and coatings capable of acid–base interaction is considered. The coatings are obtained from polymer solutions, and the second layer is formed from the polymer solutions and their mixtures on a hard polymer coating. As a result of absorption by the coating of a considerable amount of solvents (to 14%), polymer macrochains are able to approach one another at a distance necessary for the formation of acid–base (hydrogen) bonds and a transition layer. The polar component of the work of adhesion is equal to about 50% of the whole work W _a. There is no interrelation of the thermodynamic work W _a between the films and the work of their separation into layers. The main part of the external work upon the separation is spent (if strong donor–acceptor bonds are formed) for extracting the segments and macrochains of polymers out of the films.     

Strength and deformability of reinforced polymers in tension normal to the fibers

The strength and deformability of reinforced polymers in tension across the fibers is investigated. It is assumed that the polymer deforms as an ideal elastoplastic body. Relations are obtained for the nature of the deformation of the polymer between the fibers and the strength and deformability of the composite with allowance for the structural distribution of the components. Theoretical stress-strain diagrams are presented for composites with different reinforcement densities and resin elasticities. The theoretical values of the strength and deformation of reinforced polymers with the load applied across the fibers are compared with the results of experiments on model specimens of epoxy-Thiokol polymers.Leningrad Mechanical Institute. Translated from Mekhanika Polimerov, No. 4, pp. 682–687, July–August, 1970.     

Determination of the thickness of the surface layer on polymer blocks

A dependence of the thickness of the surface layer on the mechanical and wave characteristics of polymers has been obtained from joint solution of the equations of surface-wave motion and surface-layer equilibrium. From the dependence derived, the thicknesses of the surface layers have been calculated for four polymers. The dependence of surface-layer thickness on mechanical properties of the polymers and loading characteristics has been established.Institute of the Chemistry of High-Molecular-Weight Compounds, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 2, pp. 195–201, March–April, 1972.     

Theory of filled polymers and the problem of modifying the structure and properties of polymers with fillers

An attempt is made to explain the effect of fillers on the structure and properties of polymers. The effect of fillers on the state of thermodynamic equilibrium and the stability of polymer structure and properties is also considered.Kiev Shevchenko State University. Translated from Mekhanika Polimerov, No. 6, pp. 1031–1041, November–December, 1970.     

Intermolecular interactions in fiber-forming linear polymers and certain of their mechanical properties

Values of the specific volumetric intermolecular interaction energies of a series of linear polymers have been calculated on the basis of data on the interatomic and intermolecular interactions of the functional groups in the polymer molecules. It is shown that the specific volumetric intermolecular interaction energy is closely correlated with the elastic and relaxation properties of the polymers, which makes it possible to predict a series of mechanical properties of chemical fibers.Leningrad Branch, All-Union Scientific-Research Institute of Synthetic Fibers. Translated from Mekhanika Polimerov, No. 5, pp. 790–795, September–October, 1971.