Abstracts

№4, 2016

Resistance to Thermal Oxidation of Ethylene-Propylene Rubber and Polyhydroxybutyrate Blends

Olkhov A.A. (Ph.D. [Techn.), Assist. Prof., Sen. Res.), Shibryaeva L.S. (Prof., D. Sc. [Chem.], Lead. Res.),

Tertyshnaya Yu.V. (Ph.D. [Chem.], Sen. Res.), Kovaleva A.N. (Ph.D. [Chem.], Assist. Prof.), Kucherenko E.L. (Ph.D. [Chem.], Res.),

Zhul`kina A.L. (Eng.- res.), Iordanskii A.L. (Prof., D. Sc. [Chem.], Head of Lab.)

Kinetics of thermal oxidation of blends based on polyhydroxybutyrate (PHB) and ethylene-propylene rubber (EPR) was studied. Mechanical properties were tested by tensile tester ZE-40 (Germany). Crystallization Тcr and meltin Тm temperatures PHB in blends were measured by DSC method (apparatus DSM-2M) at 16 оC/min sca nning rate. Film morphology was studied by SEM (HITACHI S-570, Japan). Thermooxidation of samples was determined by the amount of oxygen absorbed at 110 oC. Increase of PHB content results in decrease of elongation at rupture, increase of tensile strength and elongation modulus. At the changes of PHB content and oxidation time its Тcr and Тm changes insignificantly. High reactivity of EPR – PHB blends with respect to oxygen was observed at 20 to 40 wt% of PHB content. Maximum phase contact area was formed at these concentrations. It was shown that the phase inversion had occurred at 50 – 70 wt % of PHB content. It was determined that the kinetics of thermal oxidation of investigated blends can be controlled by changing of the ratio of EPR and PHB.

Key words: EPR, polyhydroxybutyrate, polymer blends, thermal oxidation, structure, mechanical properties, DSC, crystallization and meltin temperatures, morphology

Structure of Thermoplastic Vulcanizates Based on Various-Polar Rubbers and Polypropylene

Panfilova O.A. (Postgrad.Stud.), Volfson S.I. (Prof., D. Sc. [Techn.], Head of Dep.),

Okhotina N.A. (Ph. D. [Techn.], Prof.,), Sabirov R.K. (Assist. Prof., Ph. D. [Chem.]), Baranets I.V. (Ph. D. [Techn.], Sen. Res.)

Triple blends based on polypropylene, polar and non-polar rubbers were produced and studied to expand the thermoplastic elastomers assortment and properties range. To produce the mixed and dynamically cured materials the single-stage and double-stages methods with the use of rotary and screw mixers were applied. It was established that compositions based on TPV’s elastomer phase master-bathes (elastomer stocks) has the better properties. Improvement of various-polar polymers compatibility requires the use of functionalizes additives to modify the polypropylene.

Using the method of optic microscopy, the influence of formulation (the ratio of polymer phase components, absence or presence of compatibilizers) and processing (the method of production) parameters on structure and properties of mixed as well as dynamically cured thermoplastic elastomers have been studied. The study of mixed and cured TPE shown that at all times the areas reaches by rubber are disperses at different rate in the matrix of polypropylene. The polar rubber fragments locate at the polypropylene areas as well as areas reached by non-polar rubber. The range of dispersed phase particles depends on the method of production. The introduction of compatibilizer results in the significant increase of the uniformity of bulk components location, in the decrease of the range of dispersed phase particles and the thickness of extrudate (strand) surface layer reached by polypropylene. It should be noted that the polypropylene fibrils anisotropy along the extrusion direction are observed at the strand surface layer.

Key words: polypropylene, polyisoprene, butadiene and acrylonitrile copolymers, mixed thermoplastic elastomers, thermoplastic vulcanizates, optic microscopy, morphology

Some Features of Abrasive Wear of Rubbers Containing Complex Antidegradant PRS-1N

Puchkov A.F. (Ph. D. [Techn.]), Spiridonova M.P. (Ph. D. [Techn.]), Lapin S.V. (Postgrad. Stud.), Kiba A.A. (Student)

Abrasive wear of tread rubber containing complex antiager - antidegradant PRS-1N has been studied by apparatus MIR-2 and optical microscope MBI-3 in comparison with rubber containing antiager IPPD (N-isopropyl-N-phenyl-p-phenylendiamin). Rubber containing PRS-1N (ε-caprolactam-N-isopropyl-N-phenyl-p-phenylendiamin-zincodisalicilat) has the much better wear resistance. The cause of this effect is connected with content of ε-caprolactam in composition of PRS-1N and its interaction with other components of complex antiagers. Washing data support the strong connection of ε-caprolactam with other components. Important is the polarity of PRS-1N resulting in its incompatibility with general-purpose rubbers in composition of tread rubber. Some considerations on mechanism of antidegradant effect of PRS-1N were presented.

Key words: abrasive wear, abrasion resistance, deterioration, complex antidegradant, tread rubber, compatibility, IPPD, PRS-1N

The study of the influence of schungite (karelit) on the properties of vulcanizates based on EPDM, obtained by the ultra-high frequency vulcanization

Boksha M.Yu. (Ph. D. [Techn.], Head of Sector), Potapov E.E. (Prof., D. Sc. [Chem.]),

Reznichenko S.V. (Prof., D. Sc. [Techn.], Head of Dep., Gen. director), Bobrov, A.P. (Ph.D. [Techn.], Head of Scientific Dep.),

Smal V.A. (Chairman of Board), Lyakin Yu.I. (Ph. D. [Techn.] Sen. Res.)

Physical, mechanical and processing properties as well as different types of aging of EPDM-based rubber filled with carbon black and schungite (karelit) have been studied. Ultra-high frequency vulcanization is shown to be especially effective for rubber compounds containing schungite because uniform distribution of the heat convection in the curing process. It provides a uniformity product, high surface quality at extrusion, and the optimum combination of properties. Application of shungite reduces rubber content of rubber compounds and the dosage of carbon black. The possibility to maintain the level of mechanical properties of vulcanizates is shown. Application of shungite improves ozone resistance and reduces the change in the color of products in the process of UV-ageing. Improvement of sealing and other service characteristics as well as environmental properties of rubber articles are shown. Improve of economic of rubber articles production is also possible.

Key words: natural mineral fillers, schungite, carbon black, EPDM, non-molded vulcanization method, ultra-high frequency vulcanization, extrusion, mechanical properties, ozone resistance, UV-ageing

Chlorinated Isoprene Rubber in Adhesive Compounds

Zuev A.A. (Postgrad. Stud.), Lyusova L.R. (Prof., D. Sc. [Techn.]), Head of Dep.), Boreiko N.P. (D. Sc. [Techn.], Deputy Director)

Today any field of the industry doesn't do without elastomeric adhesive materials. Compositions based on synthetic polymers make 75 % of total amount of adhesive materials produced because of a complex of the unique properties of elastomeric base of an adhesive. The majority of import glues for rubber-to-metal bonding is based on the chlorinated NR. The chlorinated isoprene rubber developed at the Scientific Research Institute of Synthetic Rubber in St. Petersburg is offered as an alternative. Properties of adhesive compositions of the chlorinated isoprene rubber and that of import chlorinated NR are compared. Physical and mechanical properties of compositions based on blends of chlorinated isoprene rubber and butadiene acrylonitrile rubber (BNR) were studied. The chlorinated NR Pergut S20, the chlorinated isoprene rubber SKI-3 and BNR of different brands have been chosen for comparison. Influence of the ratio chlorinated SKI-3/BNR in compositions as well as processing factors on the properties of films is established. The level of the results show the possibility to use chlorinated instead of chlorinated NR Pergut S20.

Key words: adhesion, adhesives, rubber-to-metal bonding, chlorinated NR, chlorinated SKI-3, BNR, bond strength

Some Features of Adhesive Properties of Rubber/Metal Systems with Modified Silica Fillers

Krotova O.A. (Postgrad. Stud.), Kasperovich A.V. (Assist. Prof., Ph. D. [Techn.], Head of department),

Shashok Zh.S. (Ph. D. [Techn.], Assist. Prof.), Potapov E.E. (Prof., D. Sc. [Chem.]), Reznichenko S.V. (Prof., D. Sc. [Techn.], Head of department)

The effect of specially synthesized adhesion promoters on the structure and properties of filled elastomer compositions based on NR have been studied. Adhesion promoters are silica modified by ions of cobalt and/or nickel which contains on the surface a reduced number ions of metals of variable valence (compared to the industrial adhesion modifier cobalt stearate). The use of new promoters of 7.3 and 9.3 wt. % Co allows obtaining a rubber of nearly the same vulcanization structure as rubbers of cobalt stearate. The adhesive properties of the rubber/steel cord system under normal test conditions are also nearly the same as for sample with cobalt stearate. However rubber-to-steel cord bond after various types of aging is higher then for sample with cobalt stearate. The use of silica of 5.8 wt. % Со and 1.2 wt. % Ni results in increase of rubber-to-steel cord bond of rubber at 100°С by factor 1.25 in comparison with the use of cobalt stearate. Advantages of new promoters are evident also under thermal, salt and vapor aging. Resistance of rubber/steel cord system to aggressive factors is also increases. Effect of the changes of number of Со and Ni ions on the properties of rubber/metal systems is studied.

Key words: adhesion promoter, modified silica, cobalt stearate, structure of vulcanizate, steel cord, rubber-to-steel cord bond, Со and Ni ions, aging

Non-Isothermal Flow of Viscoelastic Elastomeric Compounds in Convergent Channel

Baranov A.V. (Prof., D. Sc. [Phys.-Mat.])

Highly filled polymer composites are widely used in various processes of modern industry, therefore much attention is paid to the investigation of flow of such media in various channels of processing equipment. Mathematical model of non-isothermal flow of non-Newtonian fluid in convergent channel is presented. All important factors to be taken into account in the development of the model have been noted. Many assumptions were made on the basis of the fact that the flow occurs at low values of the Reynolds number and at a high Peclet number. Upper convected Maxwell model is used as a rheological model. In a search for a series solution, all stress components are expressed in terms of the powers. Thermal boundary conditions of the first kind, temperature dependence of the viscosity and the energy dissipation are taken into account. The solution of the temperature profiles problem was carried out by the iteration scheme, at each step of which collocation method was applied. Results of calculations have been presented.

Key words: mathematical modeling, viscoelastic fluid, non-isothermal flow, elastomeric composition

To the Dynamic Endurance of Cross-Linked Elastomers

Dorozhkin V.P. (D. Sc.[Chem.], Prof.), Mokhnatkin A.M. (Ph. D. [Techn.]),

Salaev M.V. (Postgrad. Stud.), Mokhnatkina E.G. (Ph. D. [Techn.], Head of Dep.)

The mathematical model describing the dynamic endurance of cross-linked elastomers, based on statistical failure theory of polymers is developed. Model is applied to description of results on dynamic endurance obtained in laboratory of “Nizhnekamskshina”. Dynamic endurance of tread rubbers Nр was usually tested under elongation ε = 150 % and frequency ν = 250 r.p.m. Semiquntitative connection between Nр and ratio ƒ100/ƒр (stresses at ε = 100 % and at rupture) is established. Data on Nр and ƒ100/ƒр were obtained for compounds of different ratio of fillers content (carbon black, carbon nanotubes and silica). Probability of rupture of some numbers of joints and number of joints resistant to rupture mK were calculated. Calculated and experimental data are under comparison. Some calculations on kinetics of rupture of tread rubbers of different fillers were presented. Conclusion on homogeneity of physical structure of silica-filled rubber was maid.

Key words: dynamic endurance, cross-linked elastomers, mathematical model, kinetics of rupture, tread rubbers, carbon black, silica, carbon nanotubes

Rubber Compounds. The Practice of Database Development

Drabkin S.S. (Eng.)

The software complex «Rubber compounds» based on Microsoft Access 2010 has been developed. Functional capabilities: 1) search for a certain product with a review of the all properties of rubber compounds; 2) search for a certain Technical Specifications standard (TU) or other documents for reviewing their contents, as well as properties of the compounds included. (Depending on the TU’s classification, there are two texture modifications – by the type of rubber or by the function of the rubber compound); 3) a comparable analysis of rubber compounds by one property; 4) search of a rubber compound by several pre-set parameters, for example: type of rubber, operating environment and temperature intervals, durability, tensile strength, elongation at rupture, hardness, low temperature resistance, brittleness and other physical and mechanical properties; 5) the forming of various references. Short description of the developed textures is presented. Development of an industry-wide register of the function of rubber compounds is proposed.

Key words: rubber compounds, database, Access, functional capabilities, multi-parameter search

Effect of Mechanical Plastication of Unfilled Cured NBR Compounds on their Structure and Properties

Suzdaltseva E.S., Klochkov V.I., Bulkina A.K., Kurlyand S.K.

Mechanical degradation of unfilled cured rubbers of different acrylonitrile unit content have been studied. Destructive mechanical action (“plasticizing”) was carried out through milling of vulcanized rubber plate at the narrow opening of the roll at room temperature during different time (0–40 min). It was followed by the second curing for 40 min at 143 0C without addition of curing agent. Parameters of molecular structure Mw and Mn, gel/sol content, intrinsic viscosity and vulcanizing properties of “plasticized” samples, as well as vulcanizing mechanical properties of secondary vulcanizates have been examined. Structure formation processes have been found to predominate at “plasticizing” of vulcanizates, unlike in plasticizing of raw rubber. The efficiency of the processes is dependent on acrylonitrile unit content. Mechanical characteristics are dependent on the time of milling. Moreover, the secondary vulcanizate is superior over the initial one by strength characteristics. The suggestion is made that physical bonds, not chemical ones, play more active part in the mechanism of reinforcement.

Key words: NBR, unfilled vulcanizates, degradation, structure formation, Mw, Mn, gel/sol content, intrinsic viscosity, vulcanizing properties, mechanical properties

Crucial Outbreak in the Field of Recycling of Rubber Wastes

Beirach L.Ya. (Dr., Scientific Chief.)

«GREENGUM RECYCLING»,Israel

Analysis of the state of recycling of rubber wastes is presented. Advantages and disadvantages of ultra small size crumb are under discussion. The main disadvantages of the use of the ultra small size crumb are shown. Mechanism of action of crumb in rubber compounds is considered. Existing processes of modification of crumb by amines and sulfides at not too high temperatures resulting in surface devulcanization of crumb particles are reviewed. Process developed by company «GREENGUM RECYCLING», is some sort of continues of these developments. It included: the study of the physical and mathematical dependencies of properties of crumb and crumb-containing compounds on temperature and other processing parameters; development of monitoring of devulcanization degree based on mathematical models; development of 23 recipes of modifiers; development of modified equipment for processes of simultaneous crumbing and surface devulcanization under one step; development of recipes of different modified crumb-containing compounds; providing of testing equipment.

Key words: ultra small size crumb, rubber compounds, modification, surface devulcanization, mathematical models, processing, testing equipment

Physical Chemistry of Reinforcing of Rubber by Carbon Blacks

Razdyakonova G.I. (Ph. D. [Chem.], Sen. Res.)

Review devoted to results obtained by author on mechanism of reinforcing of rubber by carbon blacks. Effect of the relief of the surface of filler, morphology of aggregates and oxygen-containing functional groups on the parameters of the sorption of elastomers is shown.

Key words: carbon black, morphology, oxygen-containing functional groups, elastomers, adsorptionKey words: rubber compounds, database, Access, functional capabilities, multi-parameter search