V. F. Babich

Some peculiarities of viscoelastic properties in the system polymer-polymeric filler of the same chemical nature

Abstract The temperature and frequency dependences of complex shear modulus and mechanical losses were studied for epoxide resin filled with the same epoxide resin, i.e. using filler of the same chemical nature. Samples with different amounts of the filler have different physical structures. Experimental results have been discussed on the basis of WLF-method and the free volume concept. It was shown that the viscoelastic properties of the epoxy binder hardened in the presence of the same resin hardened beforehand differ from the properties of the resin hardened without filler. The fractional free volume at the glass temperature was found not to be a universal constant but depends on the physical structure of the system.

Adhesion of Polymer Blends. I. Phenomenological Model

Abstract A phenomenological model based on the Takayanagi approach is proposed to describe the adhesion of polymer blends to a solid support. The model consists of three elements corresponding to two components of the blend and a solid surface. The conditions for failure of the adhesion joints at the interface between the solid surface and the polymer blend are found to depend on the blend composition and the moduli and adhesion joint strength of each component to the solid.

Determination of strength of adhesion contacts in filled elastomers from elastic modulus change

Abstract The concentration of particles of the filler that have separated from the binder is determined by comparing the values of the modulus of elasticity of a filled polymer for the initial sample and after loading with a measured load. Analyzing the curve of the dependence of the concentration of the debonded filler on the stress that has caused the debonding makes it possible to estimate the adhesion strength of the binder-to-filler bond.

Effect of the boundary layer thickness on the viscoelastic properties of filled polymers

The viscoelastic properties of a composite, when the thickness of the boundary layer and filler concentration were varied, were analyzed by a theoretical calculation method.

The structure-sensitive viscoelastic characteristics of polymers☆

An attempt to calculate theoretically the structure-sensitive viscoelastic characteristics of a gravity-type polymer has been made for the simplest model of a 2 component system within the limits of linear viscoelasticity, using the Takanayagi model for polymer mixtures. It was shown that not all mechanical properties correlated synonymously with structural parameters. Consequently the viscoelastic characteristics depend on structure only in a defined range of properties of structural elements and this dependence may be changed according to the ratio of these properties.

Effect of filler on relaxation-time spectra of filled polymers

The frequency and temperature dependence of the complex shear modulus G* and tan δ of epoxide compositions with various fillers have been studied. Relaxation-time spectra of filled polymers with various fillers have been plotted by the Ninomi-Ferry method. The principles governing changes in the shape of the spectrum curves with increase in filler concentration have been observed, enabling conclusions to be drawn on the effect of the filler on the change in properties of a polymer matrix and the deformation conditions of the polymer layers between the filler particles.

Investigation of viscoelastic behaviour and the concept of iso-free volume during glass transition as applied to systems containing a polymer and polymeric filler of like nature☆

Abstract The method of deformation and harmonic analysis provided a basis for investigation of filled epoxy systems containing ED-5 and polyethylenepolyamine to determined the temperature and frequency dependences of the complex shear modulus and the phase angle between stress and deformation. The filler was a powder of the same ED-5 polymer, which made it possible for samples to be prepared with variations in their physical structure, while the chemical compositions of the samples remained identical. Experimental results were analyzed by the method of Williams-Landell-Ferry applying the concept of free volume. It was found that the free volume fraction of the polymer is not a constant at the glass transition temperature, and is a function of the physical structure of the polymer. It is seen that in the case of rigid network polymers the free volume theory with respect to glass transition processes retains its importance solely from a qualitative standpoint, but is unacceptable from a quantitative point of view.

Superimposition of “frequency-filler concentration” in filled polymers☆

Experimental studies were made of the temperature and frequency relations of the complex elasticity modulus E and the tangent of mechanical loss angle tan δ of polyurethane acrylate filled with quartz powder. The concentration and the size of filler particles were varied. Results were analysed by the Williams-Landel-Ferri method using the concept of free volume. It was shown that the addition of a filler creates new relations in mechanical behaviour. On increasing the concentration of the filler in particular the actual flexibility decreases in the same way as on increasing the frequency of deformation.

Rheological, Mechanical and Adhesive Properties of the Filled LCP-Thermoplastics Blends

Rheological, mechanical and adhesive properties of two-phase polymer blends containing of liquid crystal copolyester of poly(ethylene terephthalate) and p-hydroxybenzoic acid plus three regular thermoplastics (polypropylene or polysulfone or poly(methyl methacrylate)) with varying compositions and concentrations of short fibers (glass fibers, aluminum borate whiskers) have been studied.

Effect of fillers of varied nature on change in the thermodynamics of the interactions and physical chemical properties of binary polymeric systems in the region of extremal changes in properties

Abstract Reverse gas chromatography and mechanical dynamic spectroscopy have been used to study the effect of fillers of varied nature on the thermodynamics of the interactions and visco-elastic properties of binary PE-POM and PS-PBMA blends over a wide concentration region of the blends and contents of fillers in the regions of extremal changes in properties. The introduction of a filler into the system leads in a certain region of compositions to rise in the thermodynamic stability of the blend. In this region of compositions and contents of fillers smoothing or disappearance of the maxima are observed in the concentration dependence of the real part of the complex shear modulus. A clear relationship has been established between the thermodynamic state of the filled blends of polymers in the melt and their physicomechanical characteristics in the solid state.