scholarly journals Investigating the Impact of Curing System on Structure-Property Relationship of Natural Rubber Modified with Brewery By-Product and Ground Tire Rubber

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 545 ◽  
Author(s):  
Łukasz Zedler ◽  
Xavier Colom ◽  
Javier Cañavate ◽  
Mohammad Reza Saeb ◽  
Józef T. Haponiuk ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Agricultural Waste ◽  
Structure Property ◽  
Hybrid Filler ◽  
Tire Rubber ◽  
Ground Tire Rubber ◽  
New Strategy ◽  
The Difference ◽  
Relationship Of ◽  
The Impact

The application of wastes as a filler/reinforcement phase in polymers is a new strategy to modify the performance properties and reduce the price of biocomposites. The use of these fillers, coming from agricultural waste (cellulose/lignocellulose-based fillers) and waste rubbers, constitutes a method for the management of post-consumer waste. In this paper, highly-filled biocomposites based on natural rubber (NR) and ground tire rubber (GTR)/brewers’ spent grain (BSG) hybrid reinforcements, were prepared using two different curing systems: (i) sulfur-based and (ii) dicumyl peroxide (DCP). The influence of the amount of fillers (in 100/0, 50/50, and 0/100 ratios in parts per hundred of rubber) and type of curing system on the final properties of biocomposites was evaluated by the oscillating disc rheometer, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, swelling behavior, tensile testing, and impedance tube measurements. The results show, that the scorch time and the optimum curing time values of sulfur cured biocomposites are affected by the change of the hybrid filler ratio while using the DCP curing system, and the obtained values do not show significant variations. The results conclude that the biocomposites cured with sulfur have better physico-mechanical and acoustic absorption, and that the type of curing system does not influence their thermal stability. The overall analysis indicates that the difference in final properties of highly filled biocomposites cured with two different systems is mainly affected by the: (i) cross-linking efficiency, (ii) partial absorption and reactions between fillers and used additives, and (iii) affinity of additives to applied fillers.

scholarly journals Preliminary Investigation on Auto-Thermal Extrusion of Ground Tire Rubber

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2090 ◽  
Author(s):  
Łukasz Zedler ◽  
Daria Kowalkowska-Zedler ◽  
Henri Vahabi ◽  
Mohammad Reza Saeb ◽  
Xavier Colom ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Preliminary Investigation ◽  
Fourier Transform Infrared ◽  
Gas Chromatography Mass Spectrometry ◽  
Tire Rubber ◽  
Ground Tire Rubber ◽  
The Impact ◽  
Thermal Extrusion

Ground tire rubber (GTR) was processed using an auto-thermal extrusion as a prerequisite to green reclaiming of waste rubbers. The reclaimed GTR underwent a series of tests: thermogravimetric analysis combined with Fourier-transform infrared spectroscopy (TGA-FTIR), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and static headspace and gas chromatography-mass spectrometry (SHS-GC-MS) in order to evaluate the impact of barrel heating conditions (with/without external barrel heating) on the reclaiming process of GTR. Moreover, samples were cured to assess the impact of reclaiming heating conditions on curing characteristics and physico-mechanical properties. Detailed analysis of the results indicated that the application of auto-thermal extrusion is a promising approach for the sustainable development of reclaiming technologies.

scholarly journals Beyond Neoclassical Economics: The Impact of Religion on the Economic Disparity Between Georgia and Estonia

2018 ◽  
Vol 8 (2) ◽  
pp. 24-43
Author(s):  
Anastasia Mgaloblishvili
Keyword(s):  
Economic Development ◽  
Good Governance ◽  
Free Market ◽  
Eastern Orthodoxy ◽  
Economic Divergence ◽  
The Difference ◽  
Relationship Of ◽  
Role Of Religion ◽  
The Impact

AbstractThe aim of this article is to examine the impact religion has had on the post-Soviet economic development of Georgia and Estonia. The role of religion in economic development has been neglected in the field of social sciences, in which political and economic theories dominate. Considering the difference in the religiosity of the two countries—Georgia is one of the most religious countries in Europe while Estonia is the most atheist—religion will be incorporated as a factor that could have directly or indirectly impacted the post-Soviet development of the two countries. By studying the relationship of the church and the state in the two countries and the population’s economic attitudes that may have been influenced by their religiosity, this paper will conclude that religion can be considered a contributing factor in the economic divergence between Estonia and Georgia. The article’s overall findings will suggest that the practice of Eastern Orthodoxy in Georgia impedes the development of good governance and a free market economy, whereas the opposite holds for Protestantism or atheism in Estonia.

scholarly journals The impact of personality on the success of prospecting behavior in changing landscapes

2015 ◽  
Vol 61 (3) ◽  
pp. 557-568 ◽  
Author(s):  
John Curtis Burkhalter ◽  
Nina H. Fefferman ◽  
Julie L. Lockwood
Keyword(s):  
Landscape Composition ◽  
Breeding Habitat ◽  
Relative Fitness ◽  
Costs And Benefits ◽  
Large Role ◽  
High Quality ◽  
New Strategy ◽  
The Difference ◽  
The Impact ◽  
Very High

Abstract Personality can play a large role in dispersal decisions, influencing how each individual estimates and values expected costs versus benefits of venturing out to explore the unknown. We contrast the impact of persistence on fitness using decision theory models to examine the relative success of prospecting movement (which is a widespread behavior used by animals to explore available breeding habitat before determining where to settle) in different landscapes among individuals with different personalities. While evaluating trends in the costs and benefits of movement we provide a quantifiable measure of the impacts of relative tenacity in prospecting behavior on fitness gains/losses. Our model results predict that, regardless of landscape composition, individuals with greater tenacity in prospecting strategy have reduced fitness gains relative to individuals who are more willing to both initiate novel strategies, but then also abandon the new strategy rapidly if initial search does not seem fruitful. We show that fitness gains from choosing an appropriate prospecting strategy (i.e. abandoning poor habitat or staying in rich habitat) can be very high, indicating a potentially large influence from personality on fitness. Importantly, the model predicts that relative fitness gains are highly dependent on the availability of high quality habitat in the landscape, even if the difference under varying fitness outcomes between poor and rich habitat was substantial.

scholarly journals Structural and physico-mechanical properties of natural rubber/GTR composites devulcanized by microwaves: Influence of GTR source and irradiation time

2018 ◽  
Vol 52 (22) ◽  
pp. 3099-3108 ◽  
Author(s):  
Xavier Colom ◽  
Marc Marín-Genescà ◽  
Ramon Mujal ◽  
Krzysztof Formela ◽  
Javier Cañavate
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Natural Rubber ◽  
Irradiation Time ◽  
Rubber Composites ◽  
Tire Rubber ◽  
Ground Tire Rubber ◽  
Scanning Electron

Ground tire rubber from car and truck was modified using microwave irradiation at variable time. The irradiated ground tire rubber was used as filler in composites based on natural rubber. The composites, with high content of ground tire rubber, were prepared using an internal batch mixer and subsequently cross-linked at 160℃. The influence of the ground tire rubber source (car/truck) and irradiation time on structure, physico-mechanical behaviour, thermal properties and morphology of natural rubber/ground tire rubber composites was studied. The interfacial interactions between ground tire rubber and natural rubber as function of ground tire rubber source and irradiation time were evaluated by Fourier transform infrared spectroscopy, thermogravimetric analysis, tensile tests, swelling measurements and scanning electron microscopy. The results showed that irradiation of ground tire rubber slightly enhanced tensile properties and cross-link density of natural rubber/ground tire rubber composites. This effect was more evident in the case of ground tire rubbertruck because of its higher content of natural rubber and was reflected in changes in the interfacial adhesion, which were confirmed by the results of Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy analysis.

scholarly journals The Impact of Ground Tire Rubber Oxidation with H2O2 and KMnO4 on the Structure and Performance of Flexible Polyurethane/Ground Tire Rubber Composite Foams

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 499
Author(s):  
Aleksander Hejna ◽  
Adam Olszewski ◽  
Łukasz Zedler ◽  
Paulina Kosmela ◽  
Krzysztof Formela
Keyword(s):  
Mechanical Performance ◽  
Hydroxyl Groups ◽  
Tire Rubber ◽  
Economic Implications ◽  
Ground Tire Rubber ◽  
Polyurethane Composite ◽  
Composite Foams ◽  
And Performance ◽  
Flexible Polyurethane ◽  
The Impact

The use of waste tires is a very critical issue, considering their environmental and economic implications. One of the simplest and the least harmful methods is conversion of tires into ground tire rubber (GTR), which can be introduced into different polymer matrices as a filler. However, these applications often require proper modifications to provide compatibility with the polymer matrix. In this study, we examined the impact of GTR oxidation with hydrogen peroxide and potassium permanganate on the processing and properties of flexible polyurethane/GTR composite foams. Applied treatments caused oxidation and introduction of hydroxyl groups onto the surface of rubber particles, expressed by the broad range of their hydroxyl numbers. It resulted in noticeable differences in the processing of the polyurethane system and affected the structure of flexible composite foams. Treatment with H2O2 resulted in a 31% rise of apparent density, while the catalytic activity of potassium ions enhanced foaming of system decreased density by 25% and increased the open cell content. Better mechanical performance was noted for H2O2 modifications (even by 100% higher normalized compressive strength), because of the voids in cell walls and incompletely developed structure during polymerization, accelerated by KMnO4 treatment. This paper shows that modification of ground tire rubber is a very promising approach, and when properly performed may be applied to engineer the structure and performance of polyurethane composite foams.

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