Table 4 - uploaded by Krzysztof Formela
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Physical properties of vulcanized rubber
Source publication
Ground tire rubber was devulcanized by extruding at 180°C and 300 rpm and blended with butadiene-styrene rubber, C biacii and other additives, cured at 750°C and 4.9 MPa and then studied for tensile strength, elongation at break, hardness, resilence, grindabliity and bending fatigue strength. The addn. of C black resulted in an improvement of the c...
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In this paper, the rubber with different carbon black content was designed and its properties were tested to verify its effects on rubber properties. The results showed that with the increase of carbon black content, the hardness of rubber increased gradually, and the tensile strength, elongation and tear strength firstly increased and then decreas...
This investigation addresses the evolution of the microscopic and mesoscopic structures distribution, and micro-defects of carbon black (CB) filled natural rubber (NR) under uniaxial tensile condition during the fatigue process. NR was filled with three different grades of CB in order to understand the impact of the structural degree and specific s...
Citations
... Thermomechanical reclaiming process was carried out using a co-rotating twin-screw extruder, in which the temperature of the barrel was 180-270 C, and the screw rotation speed was 400-1200 rpm. The results obtained by Si et al. [26] and in our previous works [27][28][29][30][31] confirmed the strong influence of the screw rotational speed (i.e., shear force) and temperature on the reclaiming process. Increase of barrel temperature and applying strong shear forces acting on processed material cause secondary cross-linking in the final product. ...
Thermomechanical reclaiming of ground tire rubber (GTR) was performed at different temperatures (60, 120, and 180°C) using a co-rotating twin-screw extruder. Obtained samples were used in styrene-butadiene rubber (SBR) blends. As reference samples, SBR compounds containing untreated GTR were used. Curing characteristics, static and dynamic mechanical properties, and morphology of the obtained blends were determined. The results show that the increase of barrel temperature during the thermomechanical reclaiming of GTR has a positive effect on the decrease of screw torque (lower machine load) and decrease of Mooney viscosity (better processing characteristics). However, mechanical properties and cross-link density of rubber revulcanizate decreased with increasing barrel temperature during the reclaiming process. SBR blends with 50 phr of reclaimed rubber showed increasing phase compatibility between SBR matrix and the reclaimed rubber, which was confirmed by mechanical properties and morphology measurements. J. VINYL ADDIT. TECHNOL., 2014. © 2014 Society of Plastics Engineers
... The use of scrap tires as as ubstitute for coal in cement kilns and power plants makes it possible to recover only about 37 % of the energy used in the production of new tires (Amari et al., 1999). Waste rubber materials, made of high quality rubber, are now widely used as af iller in rubber compounds (Ismail et al., 2011;Formela et al., 2012b;De et al., 2013), polyurethanes (Zhang et al., 2012a), epoxy resins (Fan and Lu, 2012), in the thermoplastic compositions and thermoplastic elastomers (Zhang et al., 2012b;Hassan et al., 2013;Tian et al., 2012). ...
Searching for new and cost-effective methods of waste rubber
recycling is a subject of research in many scientific centers in
the world. In this paper there are presented results of the research
of the extrusion process of cheap and environmentally
friendly thermoplastic compositions containing 50% wt. of
masses of ground tire rubber (GTR). The aim of this study
was to determine the relationship between the mixing conditions
and properties of obtained products, which is important
from a technological point of view. The mixing conditions
were determined by using two variables: the screw configuration
(co-rotating and counter-rotating) and the type of polyethylene.
In the case of both variables, thermoplastic compositions
were treated with various shear forces induced by
screw speed changes. The influence of mixing conditions on
the extrusion process was determined (screw torque, melt flow
rate) as well as static and dynamic mechanical properties of
obtained materials.
... Products obtained from the material recycling of reused tires, i.e., reclaimed rubber and GTR are commonly applied in rubber industry as rubber substitute and inactive fillers for rubber blends. However, the published studies focus mainly on rubber compounds based on natural rubber [20][21][22] or styrene-butadiene rubber (SBR) [23,24]. Ground tire rubber/carbon black mixture as hybrid filler for natural rubber has been investigated recently [25], indicating that the partial replacement of active filler, i.e., carbon black with GTR has a favorable influence on the mechanical properties and processing potential of the prepared vulcanizates. ...
The results on testing application of ground tire rubber (GTR), as potential filler for butyl rubber, are presented. The GTR content variation, within the range of 10–90 phr, was studied with respect to the vulcanization process, static mechanical properties (tensile strength, elongation-at-break, hardness and resilience), dynamic mechanical properties and the morphology of the obtained vulcanizates. Butyl rubber was characterized by its low compatibility to other elastomers [i.e., natural rubber and styrene–butadiene rubber (SBR)—the main ingredients of tires] and low degree of unsaturation. To evaluate the impact of these factors on curing characteristics and mechanical properties of butyl rubber vulcanizates filled with GTR, the same compositions of SBR compounds, cured under identical conditions, were used as reference samples. Based on the obtained data, it can be stated that butyl rubber vulcanizates containing 30 phr of GTR as filler revealed the highest tensile strength and elongation-at-break. The microstructural analysis of a sample containing 30 phr of GTR revealed strong interactions between the butyl rubber matrix and GTR. This phenomenon resulted mainly from two factors. First, the cross-link density of the butyl rubber matrix was affected by its competition against GTR for cross-linking agents. Secondly, the migration of carbon black particles from GTR into the butyl rubber matrix had a significant impact on properties of the obtained vulcanizates.
... Formela i współpr. 101,102) badali wpływ prędkości obrotowej i temperatury na właściwości dewulkanizatów. Proces dewulkanizacji prowadzono przy możliwie najniższych temperaturach cylindra i przy jak największych prędkościach obrotowych ślimaków, co umożliwiło generowanie znacznych sił ścinających działających na miał gumowy. ...
A review, with 104 refs., of uses of ground rubber waste in polymer matrix composites, rubber formulations, road bitumens, concretes and insulating masses as well as in prodn. of fuel, oils and monomers.
Searching for newways to utilize rubber and polymerwaste has been the focus of many studies
conducted by research centers and companies worldwide. In this study, the influence of extrusion conditions
on the properties of thermoplastic compositions containing post-production recycled high density
polyethylene (PE-HD) and ground tire rubber (GTR) at 50:50 mass ratiowas examined. Response Surface
Methodology (RSM) was used to determine the effects of the barrel temperature (160—240 °C), screw
speed (250—650 rpm) and feed rate of extrusion (1—2.5 kg/h) on the quality of the obtained products.
Empirical models for determining the relationship between extrusion conditions, mechanical properties
and the mass flow rate of obtained thermoplastic compositions were developed. It has been determined
that tensile strength, elongation at break, hardness and the mass flow rate of thermoplastic compositions
depend mainly on the barrel temperature. Properties of PE-HD/GTR blends deteriorated with increased
barrel temperature, which was due to degradation of polyethylene and reclaiming of ground tire rubber.
In studied extrusion conditions the influence of screw speed and feed rate on the properties of recycled
high density polyethylene/ground tire rubber compositions was negligible.
Ground tire rubber (GTR) was devulcanized in twin-screw extruder at 180-220°C and 200-500 rpm, and blended (1:1) with low d. polyethylene (PE-LD) at 180°C and 80 rpm. Similariy, GTR/PE-LD composites were prepd. by coextrusion of components at 780°C and 20-500 rpm. The composite materials were studied for tensile strength, elongation at break, hardness, abrasibility, dynamic mech. properties and morphology. The devulcanization of GTR resulted in improving the mechanical properties of the GTR/PE-LD composites.
High-d. polyethylene was blended with comp. maleic anhydride-grafted polyethylene and ground tire rubber (40:10:50 by mass) in a co-rotating twin screw extruder at 180°C and studied for static and dynamic mech. properties, processing parameters, thermal anal, and morphol. The addn. of grafted polyethylene resulted in decreasing the mass flow and abrasivity of the blends and in increasing their tensile strength and elongation at break because of improving the compatibility of the blend components.
SBR rubber was blended with a rubber devulcanizate and C black and then vulcanized under std. conditions. The devulcanizate was prepd. by extrusion of ground tire rubber. Addn. of the devuicanizate resuited in decreasing the sweliing degree and increasing crosslink d., storage modulus and mass loss at above 500°C.
In this article the results of research on a continuous thermomechanical reclaiming process of ground tire rubber (GTR) conducted in a twin screw extruder are presented. The effects of the rotation direction (co-rotating/counter-rotating), design of co-rotating plasticizing units and the rotational speed of the screws on the extruder working parameters, sol fraction and the degree of reclaiming in the obtained products were described. The influence of secondary vulcanization on cure characteristics as well as mechanical properties of revulcanizates, and blends of reclaimed rubber and styrene-butadiene rubber (SBR) were determined. Based on the obtained results, it was concluded that the application of counter-rotating plasticizing system (i.e. screw profile A), consisting mainly of transport elements with different pitch, increases the time during which ground tire rubber is exposed to the barrel temperature. The use of co-rotating plasticizing system, equipped with kneading elements and characterized by constant pitch, causes that the retention time of ground tire rubber in the extruder barrel is much shorter. In the case of co-rotating plasticizing system, it is also higher shear forces (then in counter-rotating screw configuration), besides temperature, acts on ground tire rubber, and converts mechanical energy into heat. Testing of styrene-butadiene rubber-ground tire rubber/reclaimed ground tire rubber (SBR-GTR/dGTR) compounds confirmed that the reclaiming process has positive influence on properties of obtained products.
Slightly crosslinked butyl rubber, (PhMe2CO)2 and maleic anhydride were added as compatibilizer to the recycled polyethylene-ground tire rubber blends. Recycled post-prodn. and postconsumer (shredded bottle caps) polyethylene wastes were used. The thermoplastic compns. were studied for statistic and dynamic mech. properties and morphol. The addn. of butyl rubber resulted in a decrease of the tensile strength and hardness of the blends and an Increase In compatibility of the blend components. Use of (PhMe2CO)2 and maleic anhydride resulted in an improvement of mech. strength of the blends.
