Biography:

In the past Yu.S. Lipatov has collaborated on articles with S.V. Laptij and V.P. Privalko. One of their most recent publications is Some peculiarities of viscoelastic properties in the system polymer-polymeric filler of the same chemical nature. Which was published in journal European Polymer Journal.

More information about Yu.S. Lipatov research including statistics on their citations can be found on their Copernicus Academic profile page.

Yu.S. Lipatov's Articles: (62)

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

AbstractThe 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.

Some peculiarities of thermodynamic behaviour of oligomeric mixtures with specific interactions between components

AbstractUsing inverse gas chromatography, the temperature and concentration dependences of the interaction parameter χ23 were estimated for mixtures of various oligomers capable of specific interaction. Mixtures of polyethylene glycol with polypropylene glycol and polyethylene glycol adipate were studied, including mixtures of polyethylene glycol fractions of different molecular weights. It was found that there is a maximum and a minimum in the temperature dependence of χ23, and the bimodal character phase diagrams was established. Experimental data were explained by aggregation or association phenomena in mixtures. The comparison of experimental values of χ23 with those calculated on the basis of the new Flory theory shows essential differences, especially for enthalpy and entropy contributions, this being explained by the specific interaction between components.

Influence of solid surface on equilibria in polymer mixtures

AbstractThe influence of solid disperse particles (aerosil) on phase equilibria in ternary (polymer-polymer-solvent) and binary (polymer-polymer) systems has been investigated using adsorption and gas chromatography techniques. The change in position and shape of the binodal for the ternary systems has been established. The region of thermodynamic compatibility of two polymers in a common solvent is broadened due to the selective adsorption of high molecular weight fraction of one of the polymers, this effect being dependent on the amount of solid particles introduced into the system. For binary systems, the thermodynamic interaction parameters χ23 have been determined and increasing thermodynamic stability of the mixture in the presence of the solid phase has been discovered. The complicated dependences of the interaction parameters on mixture composition are connected with differences in selectivity of adsorption for various compositions. It is supposed that increased thermodynamic stability of a mixture of two incompatible polymers in the presence of solid is due to the transition of both polymers into adsorption and border layers.

Polymer paperInversion of infra-red dichroism in linear crystallizable polyurethanes

AbstractInfar-red spectroscopic and calorimetric data for a number of linear crystallizable polyurethanes based on n-tetramethylene glycol oligomers (n = 1,2,3,4) and hexamethylene diisocyanate are given. A degree of similarity has been found in the orientation behaviour of stretching vibration bands of NH groups (inversion of dichroism with elongation) and of CH2 groups (no inversion) in the spectra of polyurethanes studied and in the spectra of segmented polyurethanes. It is concluded that in polyurethanes with a glycol ether component of relatively small length a somewhat independent behaviour of segments of different nature localized in separate micro-regions may take place. A supposition is made that the polyurethanes examined, except for the first member of a series (n = 1), can be considered as segregated systems with an ether glycol unit enriched amorphous phase in which crystallites formed mainly by urethane chain fragments are distributed.

Polymer paperMiscible polymer blends: 1. Thermodynamics of the blend melts poly(methyl methacrylate)-poly(ethylene oxide) and poly(methyl methacrylate)-poly(vinylidene fluoride)

AbstractThe composition, temperature and pressure dependences of thermodynamic characteristics have been studied for the melts of blends of poly(methyl methacrylate) (PMMA) with poly(ethylene oxide) (PEO) and poly(vinylidene fluoride) (PVDF). The experimental data have been treated in terms of the Sanchez-Lacombe equation of state, and the parameter X12 has been calculated. In addition, the SAXS patterns of these blends have been examined above the melting temperature (Tm) for PEO and PVDF.

Polymer paperThe kinetic peculiarities of interpenetrating polymer network formation

AbstractUsing the method of attenuated total internal reflection, infra-red spectroscopy has been used to study the kinetics of formation of the interpenetrating polymer network (IPN) formed between polyurethane and polyesteracrylate. It was found that the curing rates of the different networks are related and an increase in the polymerization rate of oligoesteracrylate leads to changes in the rate of polyurethane formation in IPN. The effects observed are explained in terms of the interdependence of the processes of network formation and microphase separation. The degree of segregation of the components in the IPN depends on the rate of formation of each of the networks.

Viscosity studies of filled oligo-ester melts☆

AbstractThe viscosities of the oligo-ester (OE) melts containing various amounts of aerosil were studied over a wide range of temperatures. The thickness of the boundary layer of the oligomer was evaluated on the solid particles. The analysis of the temperature dependence of viscosity forms the basis of the assumption that glass formation and an “iso-entropic” transition applies to the filled polymers.

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