COMPOSITES and NANOSTRUCTURES #2 2016
CONTENS
V.I.Solodilov, I.V.Bessonov,
A.V.Kireinov, N.Yu.Taraskin, A.M.Kuperman
GLASS FIBER REINFORCED
PLASTIC WITH EPOXY MATRIX MODIFIED
BY FURFURAL-ACETONE RESIN AND POLYSULFONE...................................................... 77
The paper introduces a novel glass fiber reinforced plastic based on rowing RVMPN-10-420-80 and epoxy matrixes modified by thermosetting furanic resin, thermoplastic polysulfone, or both these components altogether. Data obtained confirm viability and promising outlook of epoxy-polysulfone matrixes modified by furanic co-monomer for manufacturing polymer-matrix composites by winding. Developed multi-component hybrid resins will permit to broaden substantially technological limits of filament winding. Introduction of 10 wt. % furanic resin into epoxy resin improves essentially its processability as a result of reducing viscosity by 2-3 times, and, hence, reducing processing temperature to 20°C. Both fracture and impact toughness Increase noticeable without negative impairing of glass transition temperature. Maximum efficiency from modification of epoxy matrix with polysulfone is observed at its concentration above 20 wt. % (p. 77-87; fig. 3).
CRACK PROBLEM FOR A UNIDIRECTIONAL COMPOSITE LAYER................................. 88
The paper is concerned with analysis of an infinite unidirectional composite layer reinforced with inextensible and absolutely flexible fibers. The layer has a finite crack in the matrix parallel to the fibers and is loaded with uniform tension in the direction orthogonal to the crack. The solution of the classical elasticity theory obtained in terms of complex variables specifies the deformed shape of the crack and demonstrates traditional singularity of stresses in the vicinity of the crack tip. Analogous solution found within the framework of the generalized theory of elasticity [1, 2] demonstrates the crack deformation which is different from the solution following from the classical theory and specifies the stresses that are not singular. An experimental approach allowing us to determine the structural parameter which enters the equations of the generalized theory is proposed. Numerical results demonstrating the dependences of the deformed crack shape and the stress distribution in the vicinity of the crack on the structural parameter value are presented. (p. 88-98; fig. 5).
V.A.Shcherbakov,
A.N.Gryadunov, A.M.Terekhin, N.V.Sachkova
EFFECT OF TIN
NANOPARTICLES ON STRUCTURE FORMATION
AND CHARACTERISTICS OF COMPOSITES BASED ON ZRB2-ZR...................................... 99
The article is devoted to obtaining by SHS compacting ceramic composites on the basis of ZrB2-Zr system with low a residual porosity (less than 1 %) and fine micristructure. The effect of TiN nanoparticles on the microstructure formation of the ceramic composites was studed. It was shown that introduction TiN nanoparticles in the reaction mixture results to formation solid solutions of a dispersed phase and a ceramic binder (Zr,Ti)B2 and (Zr,Ti)Nx accordingly. The particle size of dispersed phase is less than 0.1 microns and hardness of 1700 - 2200 MPa (p. 99-109; fig. 9).
RESISTANCE, RELIABILITY
AND DURABILITY OF COMPOSITES
AS CONSTRUCTIONAL MATERIALS.................................................................................. 110
Features (particularities) of behavior of composites under loading are considered. One proposes is the general approach making it possible to take into account the particularities. The realization gives the chance to estimate of the resistance of the failure, the reliability and longevity of the laminates containing glass fibers used at production of elements of designs is offered (p. 110-119).
M.A.Khaskov, K.R.Akhmadieva, A.N.Kudryavtseva, T.A.Grebeneva
AN EFFECT OF FULLERENE C60 ON THE CURING
KINETICS
OF EPOXY-BASED THERMOSET BINDERS........................................................................ 120
An effect of fullerene C60 on the curing kinetics of epoxy-based thermoset binders was studied by dielectric thermal analysis and differential scanning calorimeter. It was shown that the additives of C60 slow down the curing reaction in the chemical-controlled regime, probably, due to C60-amine adduct formation, which causes an increase of the activation energy ofthe curing reaction. The enhance rate of structural relaxation of C60-modified system may slow down the curing reaction in the diffusion-controlled regime (p. 120-132; fig. 2).
H.L.Gajera and S.Manocha
Preparation of Thermal Exfoliated Graphene and Studies of Effect of Graphene on Thermal Stability
of Graphene-Epoxy Nanocomposites................................................................................................................................ 133
Thermally Exfoliated graphene (TEG) was synthesized from graphite oxide by thermal exfoliation treatment of dried graphite oxide, synthesized by modified Hummer‘s method using natural graphite flakes as starting material. This thermal exfoliated graphene (TEG) was characterized using SEM, TEM, and XRD techniques. TEG based epoxy nano composites were fabricated by using solution mixing method. The influence of graphene on the thermal stability and glass transition temperature of nano composites was studied by using thermo gravimetric analysis and differential scanning calorimetry, respectively. The thermo gravimetric results showed higher thermal stability of composites in comparison with pure epoxy and also an increase in char yield with increase in graphene content. It shows that pure epoxy resin starts degradation at 341 °C and maximum degradation takes place at 370 °C temperature and in case of composite with 1.5% of TEG degradation starts at 368 °C and maximum degradation takes place at higher temperature of 390 °C (p. 133-140; fig. 7).
S.V.Madeev, A.S.Lovtsov, LN.Laptev, N.N.Sitnikov
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141 |
EVALUATION OF OPERATIONAL CHARACTERISTICS OF CARBON/CARBON COMPOSITES FOR GRIDS OF ION ENGINES
Keldysh Research Center investigates ion thrusters with extended lifetime capability. The lifetime depends on erosion resistance of material of accelerating grid of ion optics system (IOS). Carbon materials have the greatest erosion resistance. The grids of IOS must withstand launch vibration loads, therefore carbon/carbon composites look more promising. Mechanical and thermal properties of carbon composites depend on fabrication technology. Tests results, a complete description of the tests, and results of comparison of mechanical characteristics of carbon-carbon IOS and titanium IOS are presented herein (p. 141-150; fig. 6).