Dynamic mechanical properties of multicomponent polymeric compositions

The mechanical relaxation processes in rubber-polymer compositions have been investigated by the forced nonresonance vibration method. A method of evaluating black-filled polymer mixtures with advantages over microscopic methods is proposed.Scientific-Research Institute of the Tire Industry, Moscow. V. I. Lenin Moscow State Pedagogical Institute, Laboratory of Problems in Polymer Physics. Translated from Mekhanika Polimerov, No. 1, pp. 138–141, January–February, 1970.     

The dynamic mechanical behavior of heterogeneous polymer systems

The dynamic mechanical properties of copolymers, block polymers, and blends of rubbers based on butadiene and isoprene have been studied over a wide range of temperatures. The principal laws governing the dynamic behavior of heterogeneous polymer systems are established. The method can be used to determine the mutual compatibility of polymers and their concentration in mixtures and to analyze the composition of copolymers.Mekhanika Polimerov, Vol. 1, No. 5, pp. 85–89, 1965     

Instrument for investigating the dynamic mechanical properties of polymers by the resonance vibration method

The RUIZ-2T instrument for automatically measuring the dynamic modulus of elasticity and decrement of plastics in the resonance vibration regime is described.Rostov-on-Don Institute of Railroad Transport Engineers. V. I. Lenin Moscow State Pedagogical Institute, Problem Laboratory of Polymer Physics. Translated from Mekhanika Polimerov, No. 6, pp. 1100–1101, November–December, 1971.     

A nondestructive method of testing the mechanical strength anisotropy of cellulose compositions

A nondestructive method of testing the mechanical tensile strength anisotropy of cellulose compositions from the coefficients of reflection of polarized shf waves is described. Equations for finding the reflection coefficient from the measured value of the SWR of the shf wave are presented. It is shown that there is a close linear correlation between the mechanical strength anisotropy and the anisotropy of the shfwave reflection coefficient.     

Antifriction and mechanical properties of polymer compositions based on silicone adhesives

A comparative investigation has been made of the antifriction and mechanical properties of polymer compositions based on K-400 silicone adhesive and fillers in the form of finely dispersed powdered polymers (tetrafluoroethylene, Kapron, polyethylene), graphite, sawdust, B-83 babbitt, and a lubricant^–US-2 grease. The antifriction properties of these materials are not inferior to those of some common nonferrous metals (B-83 babbitt, TsAM9-1.5 zinc alloy, OTsS5-5-5 bronze). The rational range of application of the compositions investigated is indicated.Rostov-on-Don Institute of Railroad Transport Engineers. Translated from Mekhanika Polimerov, No. 5, pp. 937–940, September–October, 1969.     

Natural aging and dynamic mechanical properties of polymer matrices

The influence of natural six-month aging at 293 K of two kinds of epoxy resins with different network density on their dynamical properties was studied. All the samples were examined by forced resonance oscillations at a frequency of 200 Hz in the range of 120–520 K. The components of the complex Young's modulus E, E, tan , and low-frequency velocity of sound were measured. The basic temperature transitions including T_g and the network density were determined from the experimental data. It was established that after aging of epoxy resins cured by the cross-linking agent meta-phenylenediamine their network density decreased (cold degradation). By using the cross-linking agent 2,6-diaminopyridine, and T_g increased. An attempt is made to explain the nature of this phenomenon.Presented at the 10th International Conference on the Mechanics of Composite Materials (Riga, April 20–23, 1998).Moscow State Technical University, Russia. Translated from Mechanika Kompozitnykh Materialov, Vol. 34, No. 3, pp. 407–412, May–June, 1998.     

Relationship of some mechanical and thermophysical properties of polymer compositions on reduced filler concentration

The dependences of the modulus of elasticity, coefficient of linear expansion, glass transition temperature, and decomposition temperature of epoxide compositions on the concentrations of four fillers of differing physical and chemical natures have been studied. The experimental data were interpreted from the point of view of a lowered mobility of the segments of the polymer molecules as a result of interaction with the filler surface. It was shown to be possible to construct universal curves for each of the studied properties, which were invariant with respect to the nature of the filler.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, Vol. 9, No. 3, pp. 487–491, May–June, 1973.     

Quasi-static method of investigating the dynamic properties of rigid polymers

The mechanical properties of polymers have been investigated at medium impact velocities. The various experimental methods of constructing stress-strain diagrams are compared.     

Investigation of the mechanical behavior of two-component granular composites in terms of structural models

A structural model is suggested for elastomers filled with particles of two fractions — with diameters exceeding 10 μm and submicronic ones. In each fraction, the particle diameter varies randomly, but between the fractions, the average particle diameter differs by several orders of magnitude. It is assumed that the small particles, together with the matrix, behave as a homogeneous medium relative to the large ones. By using this model, the mechanical behavior of composites based on elastomers filled with different volume contents of solid particles is investigated. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 43, No. 2, pp. 191–200, March–April, 2007.     

Conditional Monte Carlo method for dynamic systems with random properties

A method is developed for calculating moments and other properties of states X(t) of dynamic systems with random coefficients depending on semi-Markov processes ξ(t) and subjected to Gaussian white noise. Random vibration theory is used to find probability laws of conditional processes X(t)∣ξ(·). Unconditional properties of X(t) are estimated by averaging conditional statistics of this process corresponding to samples of ξ(t). The method is particularly efficient for linear systems since X(t)∣ξ(·) is Gaussian during periods of constant values of ξ(t), so that and its probability law is completely defined by the process mean and covariance functions that can be obtained simply from equations of linear random vibration. The method is applied to find statistics of an Ornstein-Uhlenbeck process X(t) whose decay parameter is a semi-Markov process ξ(t). Numerical results show that X(t) is not Gaussian and that the law of this process depends essentially on features of ξ(t). A version of the method is used to calculate the failure probability for an oscillator with degrading stiffness subjected to Gaussian white noise.     

关于正整数有序分拆的一些恒等式和n-colour有序分拆的两个组合性质

研究了正整数的无序分拆与有序分拆的关系.给出了正整数的无序分拆与有序分拆的一些恒等式.并且利用菲波拉契数与正整数n分拆成不含分部量1的有序分拆数的关系给出了n-colour有序分拆的两个组合性质.     

Study of the thermophysical and antifriction properties of polyethylene-based compositions

The results of a study of the effect of the filler properties (thermal conductivity, density, particle shape and size, percentage content) on the thermal conductivity of the composite are presented; the factors responsible for the increase in the thermal conductivity of the polymer are indicated. Formulas are recommended for calculating the thermal conductivity of composites based on polyethlene and various fillers.Institute of Polymer Mechanics, Academy of Sciences of the LatvianSSR, Riga. Translated from Mekhanika Polimerov, No. 2, pp. 259–266, March–April, 1973.     

Investigation of the thermophysical and antifriction properties of polyethylene compositions

The coefficient of linear expansion of polyethylene compositions has been determined. Metals, oxides, and silicates were used as fillers. The coefficient depends significantly on the geometry of the filler particles. Powdered fillers reduce the coefficient by 10–20% (an amount somewhat greater than their volume concentration). Fillers consisting of material with a low coefficient of linear expansion and a high modulus of elasticity in chopped-fiber form may reduce the coefficient of linear expansion by one order as compared with pure polyethylene.Mekhanika Polimerov, Vol. 3, No. 5, pp. 873–880, 1967     

Study of the thermophysical and antifriction properties of polyethylene-based compositions

The mechanical and antifriction properties of polyethylene filled with various, relatively hard fillers are determined. Filling with oxides and silicates produces the greatest increase in wear resistance. The coefficient of friction decreases with increase in the stiffness of the compositions.Mekhanika Polimerov, Vol. 3, No. 6, pp. 1070–1077, 1967