scholarly journals The Influence of Curing Systems on the Cure Characteristics and Physical Properties of Styrene–Butadiene Elastomer

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5329
Author(s):  
Magdalena Maciejewska ◽  
Monika Siwek

The goal of this work is to study the influence of different curing systems on the cure characteristics and performance of styrene–butadiene elastomer (SBR) filled with carbon black or nanosized silica. A multifunctional additive for rubber compounds, namely Activ8, was applied as an additional activator and accelerator to increase the efficiency of sulfur vulcanization and to reduce the content of zinc oxide elastomers cured in the presence of 2-mercaptobenzothizole or 1,3-diphenylguanidine as a primary accelerator. The influence of the curing system composition on the crosslink density and physical properties of SBR vulcanizates, such as mechanical properties, thermal stability, and resistance to thermo-oxidative aging, is also reported. Activ8 effectively supports the vulcanization of SBR compounds, especially filled with nanosized silica. It reduces the optimal vulcanization time of SBR compounds and increases the crosslink density of the vulcanizates. Moreover, vulcanizates with Activ8 exhibit higher tensile strength and better damping properties than elastomer with zinc oxide. Activ8 allows the amount of ZnO to be reduced by 40% without detrimental effects on the crosslink density and mechanical performance compared to the vulcanizates conventionally crosslinked with ZnO. This is an important ecological goal since ZnO is classified as being toxic to aquatic species.

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1656
Author(s):  
Magdalena Maciejewska ◽  
Anna Sowińska

This work concerns the effect of fillers and ionic liquids on the cure characteristics of natural rubber (NR) compounds, as well as the mechanical and thermal properties of the vulcanizates. Three types of white filler were applied, such as cellulose, nanosized silica and hydrotalcite, to modify the performance of NR composites. Additionally, ionic liquids (ILs) with bromide anion and different cations, i.e., 1-butyl-3-methylimidazolium (Bmi) and 1-butyl-3-methylpyrrolidinium (Bmpyr), were used to improve the cure characteristics of NR compounds and functional properties of the vulcanizates. The type of filler and the structure of ILs were proved to affect the rheometric properties and cure characteristics of NR compounds as well as the performance of the NR vulcanizates. Owing to the adsorption of curatives onto the surface, silica reduced the activity of the crosslinking system, prolonging the optimal vulcanization time of NR compounds and reducing the crosslinking degree of the elastomer. However, silica-filled NR exhibited the highest thermal stability. Hydrotalcite increased the crosslink density and, consequently, the mechanical properties of the vulcanizates, but deteriorated their thermal stability. ILs beneficially influenced the cure characteristics of NR compounds, as well as the crosslink density and mechanical performance of the vulcanizates, particularly those filled with silica. Cellulose did not significantly affect the vulcanization of NR compounds and crosslink density of the vulcanizates compared to the unfilled elastomer, but deteriorated their tensile strength. On the other hand, cellulose improved the thermal stability and did not considerably alter the damping properties of the vulcanizates.


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.


2018 ◽  
Vol 197 ◽  
pp. 12006 ◽  
Author(s):  
Indra Surya ◽  
Hanafi Ismail

By using a semi-efficient sulphur vulcanisation system, the effects of alkanolamide (ALK) addition on cure characteristics, crosslink density and tensile properties of carbon black (CB)-filled styrene-butadiene rubber (SBR) compounds were investigated. The ALK was prepared from Refined Bleached Deodorized Palm Stearin and diethanolamine and added into the CB-filled SBR compounds. The ALK loadings were 1.0, 3.0, 5.0 and 7.0 phr. It was found that ALK decreased the scorch and cure times of the CB-filled SBR compounds. ALK also improved the tensile modulus and tensile strength; especially up to a 5.0 phr of loading. The crosslink density measurement proved that the 5.0 phr of ALK exhibited the highest degree of crosslink density which caused the highest in tensile modulus and tensile strength. Due to its plasticity effect, ALK increased the elongation at break of the CB-filled SBR vulcanisates.


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.


2006 ◽  
Vol 79 (5) ◽  
pp. 806-819 ◽  
Author(s):  
S. W. Kim ◽  
H. Y. Park ◽  
K. H. Seo

Abstract There has been a great deal of research on the effects of ground rubber (GR) on the cure characteristics of GR-filled rubber compounds. It has been known that the cure systems of the rubber matrix and GR also had an effect on the cure characteristics and physical properties of GR-filled compounds. In this study, the variation of the crosslink density and crosslink types of recured vulcanizates and fresh vulcanizates, with respect to the cure systems, were investigated by using a three-layered model. In addition, the adhesion forces between recured vulcanizates and fresh vulcanizates were measured, and the fracture surfaces were examined. Depending on the cure systems, the changes in the crosslink density and crosslink types of recured and fresh vulcanizates varied significantly and the failure modes of adhesion specimens were also different.


2015 ◽  
Vol 1107 ◽  
pp. 113-118
Author(s):  
Ahmad Kifli Che Aziz ◽  
Teku Zakwan Zaeimoedin ◽  
Mazlina Mustafa Kamal

The challenges of using Epoxidised Natural Rubber (ENR) in truck tyre tread are to achieve good cure reversion resistant and physical properties especially on abrasion resistance towards long vulcanization time. The objectives of the project are to study the effects of vulcanization additive on cure characteristics and physical properties of silica filled ENR compound. In this work, a variation of curing systems were employed and a standard carbon black filled Natural Rubber/Butadiene Rubber (NR/BR) compound as a comparison. Greater reversion resistance and physical properties were observed with inclusion of vulcanization additive in the silica compound as compared to compound containing any. The abrasion resistance on the hand improved in spite of long vulcanisation time which commonly practices in truck tyre manufacturing.Keywords: ENR, silica, vulcanization additive, cure reversion, abrasion resistance


2015 ◽  
Vol 815 ◽  
pp. 44-48
Author(s):  
M.H. Fatin ◽  
N.Z. Noriman ◽  
Kamarudin Husin ◽  
M.Z. Salihin ◽  
N.R. Munirah ◽  
...  

The potential of activated carbon as a filler in rubber compound has been reviewed .Cure characteristics and physical properties ofImperataCylindricaactivated carbon filled natural rubber of Standard Malaysian Rubber (SMR L) were studied. SMR L was used as the elastomer and the composition of filler loading were varied from 0-50 parts per hundred rubber (phr). A semi-efficient vulcanization system was used throughout the study. The cure characteristics of the rubber compound was determined by using rheometer. The samples of hardness and resilience were measured by durometer shore A and Wallace Dunlop Tripsometer. Cure characteristics showed that cure time, t90and scorch time,t2increased as increased filler loading which indicate poor interaction between rubber and filler which slow down the vulcanization time. Minimum torque,MLand maximum torque,MHincreased as increased filler loading due to the low processability of the SMR L compounds. Crosslink density and hardness exhibit increment as increased filler loading due to increase rigidity of the SMR L compounds. The resilience will decrease correspondingly as increased in rigidity of the compounds.


2015 ◽  
Vol 815 ◽  
pp. 24-28
Author(s):  
N.R. Munirah ◽  
N.Z. Noriman ◽  
M.Z. Salihin ◽  
H. Kamarudin ◽  
M.H. Fatin ◽  
...  

The role of activated carbon (AC) in rubber compounds was investigated to better understand the reinforcing mechanism. The activated carbon filled styrene butadiene rubber vulcanizates (SBR-AC) using bamboo activated carbon as filler were prepared by using two-roll mill and cured at 160 °C. AC filler loading from 10 to 50 phr (part per hundred rubber) were used in this study. Study into the influences of filler loading on the cure characteristics, swelling behaviour and physical properties (hardness and resilience) of SBR-AC vulcanizates were carried out. It was observed that SBR-AC vulcanizates has better cure characteristics compared to the styrene butadiene rubber gum vulcanizate (SBR-GV) which is a non-filled vulcanizate. The results showed that the scorch time (ts2) decreased with increasing filler loading. The cure time (tc90) slightly decreased up to 20 phr before a rise as the filler loading increased. The minimum torque (ML) of SBR vulcanizate increased and the maximum torque (MH) decreased up to 20 phr but then increased with increasing filler loading. The cure rate index (CRI) of SBR-GV vulcanizate was higher than that of all SBR-AC vulcanizates. Up to 20 phr of filler loading, the CRI increased before a decline occurred as the filler loading increased. As expected, the hardness value of SBR-AC vulcanizates was higher compared to SBR-GV vulcanizate which has lower resilience. The hardness and crosslink density showed an increasing trend meanwhile the resilience was adversely affected by the increase in filler loading. Bamboo activated carbon showed some potential enhancement on the reinforcing and physical properties of the vulcanizates.


2021 ◽  
Vol 22 (7) ◽  
pp. 3678
Author(s):  
Anna Sowińska ◽  
Magdalena Maciejewska ◽  
Anna Grajewska

The goal of this work was to apply ionic liquids (ILs) with bis(trifluoromethylsulfonyl)imide anion (TFSI) for fine-tuning the cure characteristics and physico-chemical properties of elastomer composites based on a biodegradable natural rubber (NR) matrix. ILs with TFSI anion and different cations, such as alkylpyrrolidinium, alkylammonium, and alkylsulfonium cations, were applied to increase the efficiency of sulfur vulcanization and to improve the performance of NR composites. Thus, the influence of ILs on the vulcanization of NR compounds, as well as crosslink density and physical properties of NR vulcanizates, including tensile properties, thermal stability, and resistance to thermo-oxidative aging was explored. The activity of ILs seems to be strongly dependent on their cation. Pyrrolidinium and ammonium ILs effectively supported the vulcanization, reducing the optimal vulcanization time and temperature of NR compounds and increasing the crosslink density of the vulcanizates. Consequently, vulcanizates with these ILs exhibited higher tensile strength than the benchmark without IL. On the other hand, sulfonium ILs reduced the torque increment owing to the lower crosslinking degree of elastomer but significantly improved the resistance of NR composites to thermo-oxidation. Thus, TFSI ILs can be used to align the curing behavior and performance of NR composites for particular applications.


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