Effect of vulcanizing system on the crosslink density of nitrile rubber compounds

2005 ◽  
Vol 96 (6) ◽  
pp. 2440-2445 ◽  
Author(s):  
S. N. Lawandy ◽  
S. F. Halim
Keyword(s):  
Crosslink Density ◽  
Nitrile Rubber ◽  
Rubber Compounds

scholarly journals Ionic Liquids and Calcium Oxide Grafted with Allylmalonic Acid Applied to Support the Peroxide Crosslinking of an Ethylene–Propylene Copolymer

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3260
Author(s):  
Magdalena Maciejewska
Keyword(s):  
Ionic Liquids ◽  
Silica Nanoparticles ◽  
Calcium Oxide ◽  
Crosslink Density ◽  
Ethylene Propylene ◽  
Rubber Compounds ◽  
Curing Characteristics ◽  
And Performance ◽  
Crosslinking Reactions ◽  
Thermal Stability Of

Nanosized calcium oxide (CaO) featuring a surface grafted with allylmalonic acid (ALA) was used to increase the efficiency of the peroxide crosslinking of an ethylene–propylene copolymer (EPM) filled with silica nanoparticles. In this study, 1-butyl-3-methylimidazolium ionic liquids (ILs) with different anions were applied to improve the dispersion of CaO/ALA and silica nanoparticles in the EPM copolymer, as well as to catalyze the interfacial crosslinking reactions. In this article, we discuss the effects of CaO/ALA and ILs on the curing characteristics, vulcanization temperature, crosslink density, mechanical properties, and thermal stability of EPM, as well as the resistance of EPM to weather aging. The CaO/ALA with ILs reduced the vulcanization time of the rubber compounds without a significant effect on the vulcanization temperature. Their application resulted in an increased vulcanizate crosslink density, as well as improved tensile strength compared to the pure peroxide system. The influence of 1-butyl-3-methylimidazolium ILs on EPM vulcanization and performance depends on the anion present in the molecules of the ionic liquid. The most active IL seems to be that with the tetrafluoroborate anion.

Effect of nitrile rubber on properties of silica-filled natural rubber compounds

2005 ◽  
Vol 24 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Hexiang Yan ◽  
Kang Sun ◽  
Yong Zhang ◽  
Yinxi Zhang
Keyword(s):  
Natural Rubber ◽  
Nitrile Rubber ◽  
Rubber Compounds

Effect of Curing Temperature on the Technical Properties of Nitrile Rubber and Carboxylated Nitrile Rubber

1980 ◽  
Vol 53 (1) ◽  
pp. 107-115 ◽  
Author(s):  
A. K. Bhowmick ◽  
S. K. De
Keyword(s):  
Metal Ion ◽  
Crosslink Density ◽  
Nitrile Rubber ◽  
Curing Temperature ◽  
Aging Studies ◽  
Aging Resistance ◽  
Technical Properties ◽  
Low Sulfur ◽  
Better Than ◽  
Sulfur Donor

Abstract In a mixed crosslink system (sulfur and metal carboxylate) of XNBR vulcanizate, the variations of the proportions of curatives (low sulfur/high accelerator or high sulfur/low accelerator) have little effect on the vulcanizate properties. But aging studies indicate that the metal ion crosslinks are modified in the presence of a sulfur vulcanizing system. NBR vulcanizates with a comparable recipe have less crosslink density than the corresponding XNBR ones. In general, the technical properties and aging resistance of mixed crosslink systems using ZnO2 and sulfur donor-sulfur are better than the NBR vulcanizates. Increase of curing temperature does not always lower the technical properties of XNBR and NBR vulcanizates. Addition of XNBR to NBR in XNBR-NBR blends lowers most of the technical properties, possibly due to different vulcanization characteristics.

Effects of Cure Systems of Ground Rubber and Rubber Matrix on their Adhesion and Crosslink Structures

2006 ◽  
Vol 79 (5) ◽  
pp. 806-819 ◽  
Author(s):  
S. W. Kim ◽  
H. Y. Park ◽  
K. H. Seo
Keyword(s):  
Physical Properties ◽  
Crosslink Density ◽  
Failure Modes ◽  
Rubber Matrix ◽  
Adhesion Forces ◽  
Layered Model ◽  
Cure Characteristics ◽  
Filled Rubber ◽  
Ground Rubber ◽  
Rubber Compounds

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.

PROMOTING INTERFACIAL COMPATIBILITY OF SILICA-REINFORCED NATURAL RUBBER TIRE COMPOUNDS BY ALIPHATIC AMINE

2018 ◽  
Vol 91 (2) ◽  
pp. 433-452 ◽  
Author(s):  
C. Hayichelaeh ◽  
L. A. E. M. Reuvekamp ◽  
W. K. Dierkes ◽  
A. Blume ◽  
J. W. M. Noordermeer ◽  
...  
Keyword(s):  
Crosslink Density ◽  
Silica Surface ◽  
Shielding Effect ◽  
Polymer Layer ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Bound Rubber ◽  
Interfacial Compatibility ◽  
Physical Interactions ◽  
Tan Δ

ABSTRACT Octadecylamine (OCT) as an alternative for diphenyl guanidine (DPG) in silica-reinforced NR tire compounds with bis-(triethoxysilyl-propyl)tetrasulfide (TESPT) as silane coupling agent was investigated with focus on the improvement of compatibility between the silica surface and rubber molecules, by taking the amine-free rubber compound as a reference. The quantity of OCT and DPG was varied in a range of 2.4–9.5 mmol per 100 parts of rubber by weight (i.e., 0.5–2.5 phr). Bound rubber contents, changes in heat capacity (ΔCp), and immobilized polymer layer (χim) data prove an enhanced interfacial compatibility as the amines are absorbed on the polar silica surface and catalyze the silanization reaction. Comparing the two different amine types, the rubber compounds with OCT show higher interfacial compatibility than the ones with DPG, because of an additional shielding effect promoted by the long alkyl chain that leads to more hydrophobicity. Thus, the rubber compounds with OCT show higher physically bound rubber contents and consequently higher total bound rubber, a higher immobilized polymer layer, as well as a lower Payne effect. However, the compounds with OCT show a higher flocculation rate constant because the physical interactions between amine and silanol groups decrease under thermal treatment. The compounds with OCT show a lower cure torque difference that indicates a lower crosslink density, but because of the good interfacial interaction combining both chemical and physical interactions, the vulcanized rubber with OCT at optimum loading shows better mechanical properties and tan δ at 60 °C when compared with the DPG counterpart. At high (excessive) loading of amines, the compounds with DPG clearly have higher crosslink density and thus higher modulus as well as tensile strength compared with the use of OCT.

Comparative Study on Effect of Natural and Synthetic Antioxidants on Curing Characteristic and Properties of Different Natural Rubber Origin Compounds

2013 ◽  
Vol 812 ◽  
pp. 93-99
Author(s):  
N.H.H. Shuhaimi ◽  
Nadras Othman ◽  
Hanafi Ismail ◽  
S. Sasidharan
Keyword(s):  
Molecular Weight ◽  
Fatigue Life ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Processing Time ◽  
The Other ◽  
Synthetic Antioxidants ◽  
Compression Set ◽  
Rubber Compounds ◽  
Natural And Synthetic

Effect of natural and synthetic antioxidants on curing characteristic and properties of different natural rubber (NR) origin compounds were performed in this study. The evaluations of natural antioxidant (NA) performance in different NR origins were conducted and the changes in curing characteristic, crosslink density, fatigue life and compression set were recorded. The results indicated that Standard Thailand Rubber (STR) compound has longer processing time in curing characteristic due to a longer chain which is high molecular weight. Because of that, crosslink density, fatigue life cycle (Kc) and compression set (%) of STR compound show better result compared to other origins. On the other hand, NR compounds with NA have show better fatigue and compression set compared with trimethylquinoline (TMQ) especially for STR 5L. Thus, NA can be used as an alternative to the commercial antioxidant in all rubber compounds.

Influence of the silanes on the crosslink density and crosslink structure of silica-filled solution styrene butadiene rubber compounds

2016 ◽  
Vol 24 (7) ◽  
pp. 711-727 ◽  
Author(s):  
Jong-Yeop Lee ◽  
Nam Park ◽  
Seokhwan Lim ◽  
Byeongkyu Ahn ◽  
Woong Kim ◽  
...  
Keyword(s):  
Crosslink Density ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Rubber Compounds ◽  
Styrene Butadiene

Effect of Compounding Ingredients and Crosslink Concentration on Blooming Rate of Natural Rubber Compounds

2015 ◽  
Vol 1134 ◽  
pp. 50-55 ◽  
Author(s):  
Ummu Qani’ah Yasin ◽  
Dzaraini Kamarun ◽  
Che Mohd Som Said ◽  
Azemi Samsuri
Keyword(s):  
Diffusion Process ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Crystalline Material ◽  
Rubber Matrix ◽  
Opposite Trend ◽  
Rubber Compounds ◽  
Rubber Surface ◽  
Different Types ◽  
High Peroxide

Blooming is a diffusion process whereby compounding ingredients dispersed in rubber matrix migrate to the rubber surface and appears as a layer of white crystalline material. Blooming is a typical phenomenon observed in rubber compounds which could lead to problems such as discoloration and poor appearance of products as well as loss of adhesion. Cause of blooming was still unclear and this research was carried out to identify the effect of compounding ingredients and crosslink concentration on blooming rate in natural rubber compounds. In this project 6 natural rubber formulations based on three different types of compounding ingredients at two different concentrations of crosslinker were compounded and tested for their blooming characteristics. Sulphur, wax and dithiocarbamate as the compounding ingredients were mixed with natural rubber in the presence of 1 and 6 phr of peroxide as the vulcanizing agents. The effect of crosslink concentration on blooming rate of the compounded rubber was then determined. The blooming rate was determined by the weight of the blooming material on the rubber surface as a function of time. The blooming rate was found to be affected by the types of compounding ingredients and crosslink density of rubber. Wax with 6 phr of peroxide showed the highest amount of bloom and the highest blooming rate while the dithiocarbamate accelerator with 1 phr peroxide showed the lowest amount of bloom and the lower blooming rate. As expected, all the compounding ingredients showed an increase of crosslink concentration as the loading of peroxide increases. The blooming rate was also found to be affected by the crosslink concentration of rubber. As the crosslink concentration increases, the rate of blooming increases as were shown by wax and dithiocarbamate accelerator. However, sulphur showed the opposite trend whereby the crosslink concentration increases but the blooming rate decrease. This could be due to the high peroxide level retarding the sulphur blooming process.

Effect of Curing System on Mechanical Properties of NBR/Nylon-PET Cord Composite

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
G. R. Bakhshandeh ◽  
T. Darestani Farahani ◽  
M. Emamikia
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Stearic Acid ◽  
Linear Function ◽  
Acid Concentration ◽  
Crosslink Density ◽  
Nitrile Rubber ◽  
Coating Adhesion ◽  
High Level

AbstractFrom the results of this study it can be concluded that higher stearic acid concentration as a part of curing activator and high level of curative (i.e. sulfur and accelerator) causes higher crosslink density, tensile strength, modulus and hardness, and lower NBR to nylon-PET cord adhesion. Accelerator type also affects NBR/nylon-PET cord adhesion and using NOBS the highest coating adhesion is achieved. Using semi-efficient vulcanizing (i.e. accelerator/sulfur ratio around 1) is the most suitable way for achieving high NBR/nylon cord adhesion. And finally, independent from accelerator type, sulfur amount and efficiency of vulcanizing system, coating adhesion is a semi-linear function of crosslink density of nitrile rubber.

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