scholarly journals Organic Zinc Salts as Pro-Ecological Activators for Sulfur Vulcanization of Styrene–Butadiene Rubber

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.

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3804
Author(s):  
Magdalena Maciejewska ◽  
Anna Sowińska ◽  
Agata Grocholewicz

Zinc oxide nanoparticles (N-ZnO) and zinc complexes with 1,3-diketones of different structures were applied instead of microsized zinc oxide (M-ZnO) to activate the sulfur vulcanization of styrene-butadiene rubber (SBR). The influence of vulcanization activators on the cure characteristics of rubber compounds, as well as crosslink density and functional properties of SBR vulcanizates, such as tensile properties, hardness, damping behavior, thermal stability and resistance to thermo-oxidative aging was explored. Applying N-ZnO allowed to reduce the content of zinc by 40% compared to M-ZnO without detrimental influence on the cure characteristic and performance of SBR composites. The activity of zinc complexes in vulcanization seems to strongly depend on their structure, i.e., availability of zinc to react with curatives. The lower the steric hindrance of the substituents and thus the better the availability of zinc ions, the greater was the activity of the zinc complex and consequently the higher the crosslink density of the vulcanizates. Zinc complexes had no detrimental effect on the time and temperature of SBR vulcanization. Despite lower crosslink density, most vulcanizates with zinc complexes demonstrated similar or improved functional properties in comparison with SBR containing M-ZnO. Most importantly, zinc complexes allowed the content of zinc in SBR compounds to be reduced by approximately 90% compared to M-ZnO.


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 ◽  
...  

1974 ◽  
Vol 47 (2) ◽  
pp. 266-281 ◽  
Author(s):  
C. K. Das ◽  
S. Banerjee

Abstract The effect of sulfur, MBT, zinc oxide, and stearic acid on the DCP vulcanization of SBR has been studied. DCP decomposition obeys first order kinetics in all cases, but its rate constant is higher in presence of MBT. Sulfur and MBT reduce the crosslink density due to DCP. In the mixes containing sulfur, MBT, zinc oxide, and stearic acid in presence of DCP the crosslink density is initially additive. Here oxidation of some pendent vinyl groups are effected by DCP, and these groups also take part in thiol addition reaction with MBT. The thiazole accelerated sulfuration of SBR proceeds fundamentally by the same mechanism as reported for NR, but the details show slight difference chiefly due to the presence of pendent vinyl groups and styrene units in the chain and due to the absence of pendent methyl groups in SBR.


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.


2013 ◽  
Vol 594-595 ◽  
pp. 634-638 ◽  
Author(s):  
N.Z. Nik Yahya ◽  
N.Z. Noimam ◽  
Hanafi Ismail ◽  
Mohd Arif Anuar Mohd Salleh ◽  
Santiagoo Ragunathan

Curing characteristics and swelling behavior of natural rubber/styrene butadiene rubber/recycled nitrile glove (NR/SBR/rNBRg) blends were investigated. Eleven composition ratio; 50/50/0, 50/40/10, 50/30/20, 50/20/30, 50/10/40, 50/0/50, 40/50/10, 30/50/20, 20/50/30, 10/50/40, and 0/50/50 of SMRL/SBR/rNBRg with the size of rNBRg ; 2.5 3.0 cm2 were prepared by using two roll mill at room temperature. Cure characteristics such as scorch time,t2, cure time,t90, minimum torque, ML, maximum torque, MH, and swelling behavior of SMRL/SBR/rNBRg ternary blends were examined. Results indicated that the scorch time and maximum torque of the NR/SBR/rNBRg blends decreased with increasing rNBRg content. The minimum torque of the blends increased as rNBRg content increased. The cure time of NR/SBR/rNBRg blends show a unique trend, which are depending on the domain rubber content. The increment in rNBRg content decreased the crosslink density of NR/SBR/rNBRg blends.


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