Effect of fillers on the structure and properties of cured resins

It is shown for the first time that the increased strength of filled plastics is associated with an increase of the internal pressure in the resin determined by the nature of the filler surface and the curing conditions.For communication 1, see [1].Moscow. Translated from Mekhanika Polimerov, No. 1, pp. 54–58, January–February, 1970.     

Effect of disperse mineral fillers on the strain-strength properties and crack resistance of cured polyesters

Conclusion The tendency of disperse mineral fillers toward aggregation, with the formation of a continuous framework of particles, when filler content is greater than the SCC is manifest in a sharp increase in the difference between the relative viscosity of polyester binder-pastes in the uncured state and the relative elastic modulus in the cured state. It is also manifest in an increase in the relative modulus and a reduction in crack growth energy in cured composites. In this case, there is an especially large increase in the size of the characteristic defect, which ultimately determines the reduction in the breaking stress. The modification of binder-pastes with surfactants increases filler dispersion and makes it possible to increase the strength of cured composites.Presented at the Sixth All-Union Conference on the Mechanics of Polymer and Composite Materials (Riga, November, 1986).Translated from Mekhanika Kompozitnykh Materialov, No. 5, pp. 819–824, September–October, 1987.     

Effect of elevated temperatures on the strength of cured resins and resin-based materials

An analysis of the relationship between the relative changes of compressive strength and weight loss for glass laminates has shown that at elevated temperatures (to 600° C) the changes in strength are primarily caused by processes of mechanical destruction of the resin phase. The process of thermo-oxidative degradation of the resin in the laminate is described by the same stages as were detected in studying cured resins.Moscow Aviation-Engineering Institute. Translated from Mekhanika Polimerov, Vol. 4, No. 5, pp. 832–838, September–October, 1968.     

Effect of elevated temperatures on the strength of cured resins and resin-based materials

Measurement of the loss of weight and ultimate compressive strength of phenol-formaldehyde resins under the influence of elevated temperatures has shown that during thermal degradation there is an abrupt transition from a first to a second and third structural stage with steadily increasing stabilization of the strength properties. Apart from the dependence on the heat treatment conditions, all the resins investigated were found to give a straight-line relation between the relative change in ultimate compressive strength and the relative change in weight for each structural stage. The investigation was conducted on standard specimens obtained by molding a mixture of hardening resin and the same resin in precured powdered form.     

Effect of elevated temperatures on the strength of cured resins and resin-based materials

An investigation of the thermal stability of polycondensation cured resins has confirmed the previously established linear relationship between loss of strength and loss of weight. In the process of thermal degradation three qualitatively different stages are observed. The first is characterized by a fall in strength at low weight loss, pointing to a highly stressed structural network. The second stage, characterized by smooth variation of strength and weight, corresponds to thermo-oxidative degradation, which in the case of organophosphorous and melamine-formaldehyde resins ends in the formation of stable structures (third stage) with a residual strength of 8–10%. It is proposed to estimate the thermal stability of resins from three-dimensional diagrams in strength-temperature-time coordinates. Plane diagrams can be used for the rapid comparative evaluation of different resins.Mekhanika Polimerov, Vol. 2, No. 5, pp. 746–754, 1966     

Effect of fillers and solvents on the properties of polystyrene coatings

The mechanism of coating formation from solutions of atactic polystyrene in xylene and carbon tetrachloride has been investigated. It has been established that, as the filler content increases, in coatings formed from polystyrene solutions containing an evaporating solvent the growth of the internal stresses and the thermophysical characteristics is characterized by similarity of slope, as distinct from the case of coatings obtained from systems containing a polymerizing solvent. It is shown that the nature of the solvent has an important effect on the character of the interaction at the polymer—filler interface and on the structure and properties of the coatings.Kucherenko Central Scientific-Research Institute of Structural Design. Institute of Physical Chemistry, AS USSR, Moscow. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1127–1129, November–December, 1968.     

Stresses in various resins cured on glass films

By using Sanzharovskii's method for determining the stresses in lacquer coatings and employing as a model a layer of resin deposited on a glass film, it is possible to simulate the processes that take place in glass-reinforced plastics and determine the stresses that develop in different resins cured under various conditions. The method proposed makes it possible to estimate the effect on the stresses of the shrinkage of the resin, its elasticity, and the difference in the coefficients of thermal expansion of the resin and the glass. Such an investigation is desirable before selecting the composition of the resin, additional organic or mineral fillers and elasticizers, and the optimal curing regime for glass-reinforced plastics.All-Union Scientific-Research Institute of Aviation Materials, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 481–486, May–June, 1969.     

Effect of mineral fillers on properties of composite matrix material

The influence of mineral fillers on thermomechanical properties of matrix material of composites is investigated. Different methods to determine elastic properties and thermal expansion coefficients of composite materials have been considered and compared. Injection moulded polyester samples containing varying concentrations of talc filler are tested and properties such as Young 's modulus, thermal expansion coefficients, and volumetric shrinkage during cure are measured. Results obtained by theoretical models and from experiments are compared and discussed.To be presented at the Ninth International Conference on the Mechanics of Composite Materials (Riga, October 1995).Published in Mekhanika Kompozitnykh Materialov, Vol. 31, No. 4, pp. 435–445, July–August, 1995.     

Effect of an electron beam on the structure of epoxy resins

It is shown that exposing a cured epoxy resin to the action of an electron beam leads to a change in the structure outside the zone of direct action of the beam; this is accompanied by the formation of diffraction rings in the electron diffraction pattern and a change in microhardness.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 523–525, May–June, 1976.     

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.     

Effect of powdered mineral fillers on the crosslinking of phenol-formaldehyde oligomers and the mechanical properties of the molding materials

By investigating the effect of various powdered oxides on network formation in phenolformaldehyde oligomers, it has been established that nonionogenic oxides increase the number of network defects in proportion to the surface energy of the powder. Small amounts of ionogenic oxides with a divalent cation cause the formation of new ionic or ionic-coordination linkages in the polymer network. The effect of mineral powders on polymer network formation is correlated with the mechanical properties of molding materials based on phenol-formaldehyde polymers with different network densities.Moscow Aviation Technological Institute. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1033–1042, November–December, 1968.     

Effect of fillers on the hardness and structural order of polymers

The effect of various finely dispersed filler particles differing in size, structure, and the chemical nature of the surface, on the hardness of one crystalline (polycaproamide) and two amorphous (polystyrene and polymethylmethacrylate) polymers has been experimentally investigated. The observed changes in hardness are related with a change in the structural order of the polymer under the influence of the filler and with the formation of structures of different strength by the fillers in the polymer.Kiev Shevchenko State University. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1077–1081, November–December, 1968.     

Effect of molding conditions on the structure and properties of polyformaldehyde

The effect of molding conditions-melt temperature, dwell time in molten state, and cooling rate-on the structure and mechanical properties of polyformaldehyde is investigated.Mekhanika Polimerov, Vol. 3, No. 5, pp. 782–786, 1967