Tamás Barany | Budapest University of Technology and Economics (original) (raw)

Papers by Tamás Barany

Journal of Polymer Research

We prepared different thermoplastic elastomers (TPEs) using an internal mixer. We investigated th... more We prepared different thermoplastic elastomers (TPEs) using an internal mixer. We investigated the properties of thermoplastic polyurethanes (TPUs) produced from prepolymers with various isocyanate content and two different chain extenders to select the most appropriate TPU matrix for preparing thermoplastic vulcanizates (TPVs). Based on the results, we selected a prepolymer with moderate isocyanate content (10%) and the more flexible 1,6-hexanediol as a chain extender and prepared TPVs by dynamic vulcanization with in situ produced TPU. The rubber phase was acrylonitrile-butadiene rubber (NBR) with peroxidic and sulfuric curing with different accelerators. Dynamical mechanical analysis (DMA) results show that the room temperature storage modulus of the TPVs decreases due to the rubber phase. The TPU/NBR-CBS TPV with delayed action accelerator yields the highest tensile and tear strength and elongation at break. TPU/NBR-DCP made with a peroxide-based rubber blend shows similar tensi...

The goal of this study is to produce injection molded all-polypropylene composites at a low injec... more The goal of this study is to produce injection molded all-polypropylene composites at a low injection temperature. As a matrix, we used an amorphous poly-alpha-olefin-based melt-adhesive, as its melting temperature is significantly lower than the melting temperature of the polypropylene homopolymer reinforcement. The composites were produced by injection molding of an impregnated pre-product, and by overmolding of the reinforcing fabric. The composites made of the impregnated pre-product showed unsatisfactory mechanical properties, so the latter method seems to be more promising. Kivonat A kutatas celja alacsony hőmersekleten froccsonthető onerősitett kompozitok kifejlesztese. Matrixkent amorf poli-alfa-olefin tartalmu omledekragasztot hasznaltunk, amelynek az olvadasi hőmerseklete a polipropilen homopolimer erősitőanyagenal lenyegesen alacsonyabb. A kompozitokat extruzios impregnalassal keszult előgyartmany froccsontesevel, valamint a matrix szovetre tortenő rafrocssontesevel allit...

Periodica Polytechnica Chemical Engineering, 2017

In this work the effect of cyclic butylene terephthalate (CBT) was studied on the curing, rheolog... more In this work the effect of cyclic butylene terephthalate (CBT) was studied on the curing, rheological, morphological and mechanical properties of styrene butadiene rubber (SBR), oil extended styrene butadiene rubber (oSBR), acrylonitrile butadiene rubbers (NBR) with various acrylonitrile (AN) content and a carboxylated acrylonitrile butadiene rubber (XNBR). The effect of CBT on the oil resistance of the NBR and XNBR based compounds was also investigated. Viscosities of the uncured compounds were signiicantly decreased by CBT and it also acted as a semi-active iller, effectively reinforcing the tested rubbers, therefore it is suggested to be a bifunctional additive for tested rubbers. CBT also showed to have a positive effect on the oil resistance of NBR compounds.

Materials, 2020

Fibrous carbon nanotubes (CNTs) and lamellar graphene oxide (GO) exhibit significant advantages f... more Fibrous carbon nanotubes (CNTs) and lamellar graphene oxide (GO) exhibit significant advantages for improving the fatigue properties of rubber composites. In this work, the synergistic effect of CNTs and GO on the modification of the microstructure and fatigue properties of natural rubber (NR) was comprehensively investigated. Results showed that CNTs and GO were interspersed, and they formed a strong filler network in the NR matrix. Compared with those of CNT/NR and GO/NR composites, the CNT-GO/NR composites showed the smallest crack precursor sizes, the lowest crack growth rates, more branching and deflections, and the longest fatigue life.

Scientific Reports, 2020

We devulcanized ground tire rubber (GTR) in a laboratory microwave oven and an internal mixer, me... more We devulcanized ground tire rubber (GTR) in a laboratory microwave oven and an internal mixer, measured the soluble content and the cross-link density of the samples, and then used Horikx’s analysis. The results showed that microwave treatment caused severe degradation of the polymer chains, while in the case of thermomechanical devulcanization, the selective scission of covalent cross-links is more common. Four devulcanized ground tire rubber (dGTR) samples were chosen for further study and three groups of samples were produced: dGTR samples containing vulcanizing agents and different amounts of paraffin oil (dGTR-based mixtures), natural rubber-based rubber mixtures with different dGTR contents and reference rubber mixtures with dGTR-based mixtures (increased vulcanizing agent contents). Cure characteristics showed a plasticizer-like effect of dGTR. Tensile and tear strength decreased drastically with increasing dGTR content; however, elongation at break values did not follow such...

Polymers, 2020

We developed polypropylene-based single-polymer composites (PP-SPC) with blends of amorphous poly... more We developed polypropylene-based single-polymer composites (PP-SPC) with blends of amorphous poly-alpha-olefin (APAO) and random polypropylene copolymer (rPP) as matrix material and polypropylene (PP) woven fabric as reinforcement. Our goal was to utilize the lower melting temperature of APAO/rPP blends to increase the consolidation of the composites and decrease the heat load of the PP reinforcement. We produced the composites by film-stacking at 160 °C, and characterized the composites with density, peel, static tensile and dynamic falling weight impact tests, and by scanning electron microscopy. The results indicate that consolidation can be enhanced by increasing the APAO content of the matrix. We found that the APAO content of 50% is optimal for tensile properties. With increasing APAO content, the perforation energy decreased, but even the well-consolidated composites showed very high perforation energy. In the case of a pure APAO matrix, fiber content can be increased up to 8...

Polymers, 2019

The aim of this paper was the detailed investigation of the properties of one-shot bulk polymeriz... more The aim of this paper was the detailed investigation of the properties of one-shot bulk polymerized thermoplastic polyurethanes (TPUs) produced with different processing temperatures and the properties of thermoplastic dynamic vulcanizates (TDVs) made by utilizing such in situ synthetized TPUs as their matrix polymer. We combined TPUs and conventional crosslinked rubbers in order to create TDVs by dynamic vulcanization in an internal mixer. The rubber phase was based on three different rubber types: acrylonitrile butadiene rubber (NBR), carboxylated acrylonitrile butadiene rubber (XNBR), and epoxidized natural rubber (ENR). Our goal was to investigate the effect of different processing conditions and material combinations on the properties of the resulting TDVs with the opportunity of improving the interfacial connection between the two phases by chemically bonding the crosslinked rubber phase to the TPU matrix. Therefore, the matrix TPU was synthesized in situ during compounding fr...

Journal of Applied Polymer Science, 2019

Polymers, 2018

Because of the chemically crosslinked 3D molecular structure of rubbers, their recycling is a cha... more Because of the chemically crosslinked 3D molecular structure of rubbers, their recycling is a challenging task, especially when cost efficiency is also considered. One of the most straightforward procedures is the grinding of discarded rubber products with subsequent devulcanization. The devulcanized rubber can be used as a feedstock for fresh rubber compounds or can be blended with uncured virgin rubber and thermoplastic polymers to form thermoplastic dynamic vulcanizates (TDVs). TDVs combine the beneficial (re)processability of thermoplastics and the elastic properties of rubbers. Our current work focuses on the development of polypropylene (PP)-based TDVs with the use of a tire model rubber (MR) composed of natural rubber (NR) and styrene-butadiene rubber (SBR) in a ratio of 70/30. The research target was the partial substitution of the above fresh MR by microwave devulcanized crumb rubber (dCR). TDVs were produced by continuous extrusion, and the effects of composition (PP/MR/dC...

Periodica Polytechnica Mechanical Engineering, 2015

Express Polymer Letters, 2015

Handbook of Engineering Biopolymers, 2007

Express Polymer Letters, 2013

Composites Part A: Applied Science and Manufacturing, 2015

Materials Science Forum, 2010

In the present work the weldability of self-reinforced composite was investigated. As reinforceme... more In the present work the weldability of self-reinforced composite was investigated. As reinforcement a fabric, woven from highly stretched split PP yarns, whereas as matrix materials of two kinds of random polypropylene copolymer (with ethylene) were used. The composite sheets were produced by film-stacking method and compression molded with different thickness (1 mm, 2 mm) with different contents at different processing temperatures keeping the holding time and pressure constant. The SRPPC sheets were welded by ultrasonic welding machine with different welding parameters. The welds were qualified by mechanical and microscopic tests. The results showed that the thermoplastic reinforcement has not got melted; therefore the reinforcement was kept the strength-increasing effect.

$Research paper thumbnail of Plane-stress fracture behavior of syndiotactic polypropylenes of various crystallinity as assessed by the essential work of fracture method$

Polymer Engineering & Science, 2002

The fracture behavior of 1-mm-thick syndiotactic polypropylene (sPP) sheets of various crystallin... more The fracture behavior of 1-mm-thick syndiotactic polypropylene (sPP) sheets of various crystallinity (owing the various stereo- and regioregularity) was studied by the essential work of fracture (EWF) concept. The specific work of fracture parameters were determined on tensile-loaded deeply double-edge notched (DDEN-T) specimens at various deformation rates (v = 1, 10 and 100 mm/min) at ambient temperature. As the DDEN-T specimens showed full ligament yielding prior to subsequent necking, the energy partitioning method was adopted for data reduction. The specific essential work of fracture slightly increased as a function of crystallinity. Its yielding-related constituent increased with both crystallinity and deformation rate similarly to that of the yield strength and E-modulus. The specific plastic work parameters were less sensitive to crystallinity and deformation rate. The strain-induced crystalline phase transition from helical toward all-trans conformation was accompanied by voiding and crazing.