Department of Polymer Engineering (2018 - Present)
Polymer Engineering
Polymer Engineering, Tarbiat Modares University, Tehran, Iran
Polymer Science and Technology
Rubber Processing, Iran Polymer & Petrochemical Instuitute, Tehran, Iran
Applied Chemistry
Chemistry, Ferdowsi University of Mashhad, Mashhad, Iran
I received my PhD in polymer engineering at Tarbiat Modares University (Tehran, Iran) in 2017. Since September 2018, I worked as an assistant professor in the department of polymer engineering at Tarbiat Modares University. Understanding the mechanisms of fracture and failure in polymer composites and its relation to the attributes of reinforcing filler is one of the research interests. Rubber microstructural modification to obtain self-healable, toughened and sustainable rubbers is also pursued. Two master courses, namely Design and Engineering of Rubber Parts and Rubber Chemistry are taught.
The tear strength (TS) of rubber-silica composites is inevitably lowered by the reduction of viscoelastic dissipation imparted by the use of bifunctional silanes. It is of interest to find out whether promoting crack tip deviation represented by a slip-stick tearing can compensate for such a loss in the tear strength. Here, the phenomenon of crack growth in terms of the TS and also the tearing type is considered for both the untreated and silane-treated silica rubber composites to figure out the microstructure parameters affecting the slip-stick tearing. It was realized that within a certain volume fraction of the reinforcing filler, deviation whether in the form of slip-stick or knotty tearing can be found for both cases. Tearing for silan
The reinforcement degree offered by silica as a spherical filler with low aspect ratio and high filler–filler interaction was compared with mica as a platelet filler with higher aspect ratio and lower filler–filler interaction. By replacing half of the carbon black with silica or mica in a typical formulation, rubber composites were prepared and their properties were evaluated under two conditions: In the first one, the impact of increasing the amount of a chemical surface modifier, namely silane TESPT (bis triethoxysilylpropyl tetrasulfide), was investigated and in the second one, the increasing amount of a physical modifier namely DPG (diphenyl guanidine) on the performance of the two fillers was explored. The resulting composites wer
The distinction between abrasion resistance of carbon black and silica reinforced tire tread compounds has drawn attention to the indispensable role of interfacial phenomena on crack growth resistance of rubber composites. Attempts to determine the dependence of interface bonding (from covalent to non-covalent) on crack growth resistance of rubber composites are insufficient without knowledge of the contributions resulting from the interphase (ie the volume of rubber chains with restricted mobility). For highly-filled rubbers, the interphase is mainly formed by strong filler-filler interaction and entrapment of rubbers among filler aggregates. Working on the silane-treated silica reinforced rubber, here the alkyl length and the grafting den
Vol. 30, No. 6, 489-500 February-March 2018 ISSN: 1016-3255 Online ISSN: 2008-0883 DOI: 10.22063/JIPST. 2018.1539 styrene butadiene rubber, silica, silane-spacer length, tribology, polymer-filler interactionHypothesis: Substitution of carbon black by surface-modified silica in tire tread compound formulation often brings a lower friction coefficient and inadequate vehicle safety. Through modifying polymer-filler interactions, silane chain length is capable of altering viscoelastic properties. The connection between tribological properties and viscoelastic dissipation can be regarded as an important factor to control the frictional behavior of tire tread compounds. It has always been speculated that silane chain length dictates the propertie
The idea of partitioning the equilibrium fracture strength (G 0) of adhesive joints into the contributions of cohesive (R), Interfacial (I) and Substrate (S) failures in is extended here for filled polymer composites. Using the silane spacer length and grafting density as tuning parameters, composites of silane treated silica-Solution Styrene Butadiene Rubber (SSBR) are prepared with controlled filler-polymer interfacial phenomena, and the mechanisms through which silane length modifies the fracture of composites is extracted. It was shown that chain length of silane greatly modifies the filler-filler and the filler-polymer energetic interactions. Tearing energy was assessed in trousers geometry and the share of matrix and the interface on
In nano-dispersed filler containing rubbers, mechanical properties of composites are dictated by the characteristics of surface layers in the interphase as well as the manner in which rubber interacts with filler at the interface. In the present contribution, surface-related and volume-related effects of filler on the reinforcement were distinctively considered in the finite element prediction of mechanical and fracture properties. A unit-cell containing three phases of a single particle, an interphase perfectly bonded to the particle, and the rubber matrix was built. The particle represents the total volume fraction of the filler, and the interphase symbolizes all surface related phenomena of the filler including filler surface area, fille
The present study discusses that filler–filler mechanical engagement resulting from the grafted long-chain silanes on the silica surface is indeed a reinforcing mechanism in rubber composites, as already speculated by nonlinear viscoelastic properties in our previous study. The existence and severity of such a phenomenon are assessed purely by isolating the energetic contribution of reinforcement from interfering with filler mechanical engagement in the silica network formation and breakdown processes. In a novel approach, the driving force of fillers to flocculate energetically at elevated temperatures was defined using surface energy theories, and it was adjusted to be similar in two composites having silica treated by short- and
The idea of partitioning the equilibrium fracture strength (G 0) of adhesive joints into the contributions of cohesive (R), Interfacial (I) and Substrate (S) failures in is extended here for filled polymer composites. Using the silane spacer length and grafting density as tuning parameters, composites of silane treated silica-Solution Styrene Butadiene Rubber (SSBR) are prepared with controlled filler-polymer interfacial phenomena, and the mechanisms through which silane length modifies the fracture of composites is extracted. It was shown that chain length of silane greatly modifies the filler-filler and the filler-polymer energetic interactions. Tearing energy was assessed in trousers geometry and the share of matrix and the interface on
We evaluated the significance of mechanical engagement and energetic interaction between a polymer and a filler as two reinforcing mechanisms in SBR composites containing silica modified by short- and long-chain silanes. To exclude mechanical contributions of reinforcement from that of energetic contributions, surface energy of silica particles was systematically adjusted to prepare fillers of identical and diverse surface energies. Having analyzed interactions using a temperature sweep in a small-strain oscillatory test and a uniaxial tension test, results indicated that the chain length of the silane has remarkable influence on energetic filler–filler and filler–polymer interactions, but no detectable difference associated with f
In present contribution two main methods of Washburn capillary rise (WCR) and sessile drop technique on non-porous and smooth surfaces are to be compared in evaluating the surface energy of powder materials. Pristine silica and silane modified powders are used to assess the influence of silane nature and silane spacer length of 3-carbon and 16-carbon chain upon the surface energy of these powders. Having examined the surface modification of silica using infrared spectroscopy, an innovative method for preparing non-penetrable surface based on a combinatory press technique encompassing hydraulic and isostatic press is introduced. Using silane of high spacer length leads to an extremely hydrophobic surface where a contact angle of 47 degree fo
The present review focuses on the properties and developing applications of carboxylated styrene butadiene rubber (XSBR) as a modified grade of styrene butadiene rubber (SBR). Carboxylated polymers, and particularly carboxylated rubbers, are regarded as a new class of polymers with superior physical and mechanical properties over non-carboxylated counterparts. Upon introducing carboxyl groups, the properties such as elasticity range, strength, compatibility towards functional fillers and polymers, resistance to hydrocarbon solvents enhance and cross-linking by non-sulfur reagents becomes possible. The XSBR latex benefits from excellent mechanical and chemical stability, excellent liquidity, high bond and conjunction strength, high toughness
INTRODUCTION: PURPOSE OF THIS STUDY WAS TO EVALUATION ORGANIZATIONAL ENTREPRENEURSHIP IN EMPLOYEES HEAD OFFICE OF SPORT AND YOUTH, QOM PROVINCE.METHODOLOGY: THIS INVESTIGATION WAS AMONG DESCRIPTIVE AND COMPARATIVE TYPES. STATISTICAL POPULATION OF THE STUDY INCLUDED ALL THE EMPLOYEES OF HEAD OFFICE OF SPORT AND YOUTH IN QOM PROVINCE WHO WERE 55 PERSONS. DUE TO THE LOW NUMBER OF THIS STATISTICAL POPULATION, HOLISTIC SAMPLING METHOD WAS USED. THIS STUDY MEASUREMENT TOOLS OF WAS SAMADAGHAI'S ORGANIZATIONAL ENTREPRENEURSHIP QUESTIONNAIRE AND PERSONAL INFORMATION QUESTIONNAIRE. TO ANALYZE THE DATA, DESCRIPTIVE AND INFERENTIAL STATISTICS (KOLMOGROV-SMIRNOV TEST, T TEST AND ANOVA TEST) WERE APPLIED AT SIGNIFICANCE LEVEL OF 0.05. DATA ANALYSIS WAS D
This study focuses on the preparation and rheological investigations of carboxylated styrene butadiene rubber latex (XSBR) – multiwall carbon nanotube (CNT) nanocomposites. Two types of non-functionalized CNT and hydroxyl functionalized multiwall carbon nanotube (CNTOH) were used. A new approach based on concurrent ball milling of CNT and XSBR latex was applied to embed the nano material into the carboxylated latex. To do so, first of all, the effect of ball milling on the colloidal stability of the carboxylated latex was examined by the use of Dynamic Light Scattering (DLS) method. The results of DLS revealed that the particle size of the carboxylated latex did not seriously alter during ball milling, implying that the milling process ha
This research study was devoted to the modeling of the mechanical behavior of three carbon black/silica natural rubber/butadiene rubber (NR/BR) compounds under a tensile load. These compounds were prepared on a two‐roll mill, and the tensile testes were carried out on a dumbbell‐shaped specimen and three rubber‐strip specimens with different widths. Heat buildup tests were also performed, and the temperature rise was determined. The time‐independent behavior of the rubber was described by traditional hyperelastic models, including those of Marlow and Yeoh. The viscoelastic behavior was studied with two linear (Prony series) and nonlinear [Bergstrom–Boyce (BB)] models. A previously developed methodology by the authors, which was b
In the current paper, effects of heat treatment of nanodiamond particles on the scratch behavior of polyacrylic/diamond nanocomposite coatings were studied. Two types of nanodiamond, i.e. one produced by detonation synthesis (DND) and the other produced by nondetonation synthesis (NDND) were used as reinforcement phase to increase scratch resistance of polyacrylic base polymeric clear coat. Heat treatment was used as the surface modification route. Coatings containing both types of particles in two surface conditions (as-received and heat treated) were compared to each other and also to the neat polyacrylic coating. The results showed strong effect of heat treatment on scratch resistance of coatings based on the scratch width criterion. The
This chapter deals with different applications of natural rubber based blends and IPNs mainly in the automotive industry but also in other fields. First a brief description of the physical and mechanical properties of natural rubber, as well as principles of rubber compounding, will be briefly addressed. Subsequently, as the global natural rubber consumption is split among tyres, automotive mechanical products, seismic isolation bearings, membrane technology, and miscellaneous applications such as retreading of tyres, improvement of plastic properties, etc., the application of natural rubber blends and IPNs in nearly each of which will concisely be presented.
This study deals with the preparation of carboxylated styrene butadiene rubber (XSBR)/multiwall carbon nanotubes (MWCNTs) nanocomposites prepared in the latex form by means of a ball mill. Two types of CNTs, i.e., non-functionalized and OH-functionalized (CNT–OH) were used. The rheological properties, FTIR spectrums, SEM micrographs and stress relaxation experiments were exploited to evaluate the resulting nanocomposites. For a given frequency, both the viscosity and storage modulus increased as the concentration of CNT was augmented with the greatest value for the nanocomposites loaded with CNT–OH. The viscosity of nanocomposites exhibited a shear thinning behavior throughout applied frequency and indicated a power law i
In present contribution two main methods of Washburn capillary rise (WCR) and sessile drop technique on non-porous and smooth surfaces are to be compared in evaluating the surface energy of powder materials. Pristine silica and silane modified powders are used to assess the influence of silane nature and silane spacer length of 3-carbon and 16-carbon chain upon the surface energy of these powders. Having examined the surface modification of silica using infrared spectroscopy, an innovative method for preparing non-penetrable surface based on a combinatory press technique encompassing hydraulic and isostatic press is introduced. Using silane of high spacer length leads to an extremely hydrophobic surface where a contact angle of 47 degree fo
Vol. 32, No. 5, 397-409 December 2019-January 2020 ISSN: 1016-3255 Online ISSN: 2008-0883 DOI: 10.22063/JIPST. 2020.1692 fatigue crack growth, interface bonding, filler-filler interaction, rubber, silicaHypothesis: Fatigue crack growth (FCG) of rubber composites as controlled by the viscoelastic losses, is strongly dependent on the polymer-filler interfacial phenomena. The type of filler-polymer bonding at the interface and the extent of mobility restriction of rubber chains resulting from the interaction by the filler are of the critical ones. In highly filled rubber compound, the amount of mobility restriction is almost dictated by the filler-filler interaction. Regulating the surface energy of the filler can be an effective method to con
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