scholarly journals Microwave Devulcanized Crumb Rubbers in Polypropylene Based Thermoplastic Dynamic Vulcanizates

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 767 ◽  
Author(s):  
Dániel Simon ◽  
István Halász ◽  
József Karger-Kocsis ◽  
Tamás Bárány

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/dCR = 40/60/0…50/35/15) and processing parameters (different screw configurations, temperature profiles, the feeding method of PP) were investigated. Results showed that the fresh rubber compound can be replaced up to 10 wt % without compromising the mechanical properties of the resulting TDV.


2020 ◽  
Vol 39 (1) ◽  
pp. 81-90
Author(s):  
An Zhao ◽  
Xuan-Yu Shi ◽  
Shi-Hao Sun ◽  
Hai-Mo Zhang ◽  
Min Zuo ◽  
...  


1999 ◽  
Vol 35 (9) ◽  
pp. 1687-1693 ◽  
Author(s):  
N.S. Saxena ◽  
P. Pradeep ◽  
G. Mathew ◽  
S. Thomas ◽  
M. Gustafsson ◽  
...  


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1723 ◽  
Author(s):  
Magdalena Maciejewska ◽  
Anna Sowińska ◽  
Judyta Kucharska

Organic zinc salts and complexes were applied as activators for sulfur vulcanization of styrene–butadiene elastomer (SBR) in order to reduce the content of zinc ions in rubber compounds as compared with conventionally used zinc oxide. In this article, the effects of different organic zinc activators on the curing characteristics, crosslink densities, and mechanical properties of SBR as well as the aging resistance and thermal behavior of vulcanizates are discussed. Organic zinc salts seem to be good substitutes for zinc oxide as activators for sulfur vulcanization of SBR rubber, without detrimental effects to the vulcanization time and temperature. Moreover, vulcanizates containing organic zinc salts exhibit higher tensile strength and better damping properties than vulcanizate crosslinked with zinc oxide. The application of organic zinc activators allows the amount of zinc ions in SBR compounds to be reduced by 70–90 wt % compared to vulcanizate with zinc oxide. This is very important for ecological reasons, since zinc oxide is classified as being toxic to aquatic species.



2007 ◽  
Vol 18 (2) ◽  
pp. 122-127 ◽  
Author(s):  
P. Konečný ◽  
M. Černý ◽  
J. Voldánová ◽  
J. Maláč ◽  
J. Šimoník


2020 ◽  
Vol 13 (1) ◽  
pp. 1-5
Author(s):  
Patrik Macúrik ◽  
Rafal Anyszka ◽  
Ivan Hudec ◽  
Terézia Malčeková ◽  
Ján Kruželák

AbstractThe study was focused on the investigation of trans-polyoctylene (TOR) influence on cross-linking as well as mechanical and rheological properties of rubber compounds based on styrene-butadiene rubber (SBR). SBR was compounded with different proportions of TOR in the concentration range from 0 to 30 phr. Integration of TOR into rubber leads to the prolongation of the optimum curing time and scorch time and thus the decrease of the curing rate. Higher content of TOR led to less viscous rubber due to the plasticizing effect. Cross-link density of vulcanizates was reduced, which correlates with higher elongation at break. Tensile strength and hardness of vulcanizates increased with the increasing TOR content, probably due to the increasing amount of the crystalline phase.



Author(s):  
Daniela B. García ◽  
Marcela A. Mansilla ◽  
Matías Crisnejo ◽  
Hernán Farabollini ◽  
Mariano M. Escobar


2018 ◽  
Vol 45 (1) ◽  
pp. 5-9
Author(s):  
A.M. Mokhnatkin ◽  
V.P. Dorozhkin ◽  
E.G. Mokhnatkina ◽  
V.E. Muradyan ◽  
L.A. Zotov ◽  
...  

A specially designed relaxometer was used to measure the stress relaxation under 30% elongation for tread rubber compounds based on a blend of three rubbers: natural rubber, neodymium butadiene rubber, and oil-extended styrene butadiene rubber. The rubber compounds were filled with carbon black and silica in different ratios: with 80 parts carbon black only, with 80 parts silica only, and with different ratios of carbon black and silica. The method proposed by Bartenev was used to calculate the relaxation specta. The maxima of the spectra at different relaxation times were assigned to different types of interaction: rubber-filler interaction, carbon black-carbon black interaction, silica-silica interaction, carbon black-silica interaction. New maxima were obtained for specimens containing roughly equal amounts of carbon black and silica. These results were compared with data obtained using transmission electron microscopy. The existence of three levels of structure of filled elastomers and the presence of ‘rigid’ rubber around filler particles are suggested.



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