REINFORCEMENT OF NATURAL RUBBER BY SILICA/SILANE IN DEPENDENCE OF DIFFERENT AMINE TYPES

2017 ◽  
Vol 90 (4) ◽  
pp. 651-666 ◽  
Author(s):  
C. Hayichelaeh ◽  
L. A. E. M. Reuvekamp ◽  
W. K. Dierkes ◽  
A. Blume ◽  
J. W. M. Noordermeer ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Natural Rubber ◽  
Health And Safety ◽  
Aliphatic Amines ◽  
Shielding Effect ◽  
Processing Temperature ◽  
Rubber Content ◽  
Payne Effect ◽  
Rubber Compounds ◽  
Bound Rubber

ABSTRACT Diphenyl guanidine (DPG) is the most commonly used secondary accelerator in silica-reinforced rubber compounds because of its additional positive effect on the silanization reaction and deactivation of free silanol groups that are left over after the silanization. However, because of health and safety concerns about the use of DPG, which decomposes to give highly toxic aniline during high processing temperature, safe alternatives are required. This work investigates the effect of various types of aliphatic amines having alkyl or cyclic structures and similar pKa (i.e., hexylamine [HEX], decylamine [DEC], octadecylamine [OCT], cyclohexylamine [CYC], dicyclohexylamine [DIC], and quinuclidine [QUI]) on the properties of silica-reinforced natural rubber (NR) compounds by taking the ones with DPG and without amine as references. When compared with the compound without amine, the use of all amine types reduces filler–filler interaction (i.e., the Payne effect) and enhances filler–rubber interaction, as indicated by bound rubber content and decreased heat capacity increment. The amines with alkyl chains can reduce the Payne effect and enhance cure rate to a greater extent compared with the amines with cyclic rings as a result of better accessibility toward the silica surface and a shielding effect because of less steric hindrance. The longer carbon tails on linear aliphatic amines ranging from HEX, DEC, to OCT lead to a lower Payne effect, lower heat capacity increment, higher bound rubber content, and higher modulus as well as tensile strength. Overall, the use of OCT provides silica-reinforced NR compounds with properties closest to the reference one with DPG and can act as a potential alternative for DPG.

Influence of Fillers Surface Characteristics on Bound Rubber Properties of Filled Natural Rubber Compounds

2013 ◽  
Vol 845 ◽  
pp. 412-416 ◽  
Author(s):  
Mustafa Kamal Mazlina
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Surface Activity ◽  
Specific Activity ◽  
Filler Particle ◽  
Surface Characteristics ◽  
Rubber Content ◽  
Rubber Compounds ◽  
Bound Rubber ◽  
Service Application

One of the most important phenomena in rubber science is the reinforcement by rigid entities, such as carbon black, clays, silicates and calcium carbonate. Thus, these fillers are added to rubber formulations to optimise properties that meet a given service application or set of performance parameters. Fillers can be divided into three categories reinforcing, semi-reinforcing and non-reinforcing. For a given elastomer and state of mix, bound rubber can be considered as a measurement of a surface activity of a filler and is considered as one of major factors in reinforcement. A strong rubber: filler interaction results in a large bound rubber content. Good dispersions and distribution of filler aggregates is also important for the full reinforcing potential of fillers to be reached. In this study, the influence of fillers on bound rubber content of Natural Rubber compounds were determined and compared. Results showed that the bound rubber content followed the trend of Carbon Black>Silica>Carbon Black>Starch. The two main filler characteristics that affect the bound rubber properties are the filler particle size and surface activity. The specific activity of the filler is determined by the physical and chemical nature of the filler surface in relation to that of elastomer. Keywords: reinforcement, surface energy

Influence of carbon black on the Payne effect of filled natural rubber compounds

2020 ◽  
pp. 108586
Author(s):  
Xuanyu Shi ◽  
Shihao Sun ◽  
An Zhao ◽  
Haimo Zhang ◽  
Min Zuo ◽  
...  
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Payne Effect ◽  
Rubber Compounds

Effect of Methyl Methacrylate Content in Carbon Black Filled Natural Rubber Compounds

2012 ◽  
Vol 501 ◽  
pp. 3-7
Author(s):  
Abu Bakar Rohani ◽  
Mustafa Kamal Mazlina ◽  
Fauzi Mohd Som
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Proton Nuclear Magnetic Resonance ◽  
Performance Parameters ◽  
Rubber Content ◽  
Elongation At Break ◽  
Compression Set ◽  
Rubber Compounds ◽  
Emulsion Polymerisation

Natural rubber-grafted-poly(methyl methacrylate) containing 30 and 50 percent of methyl methacrylate (MMA) monomer per 100 parts by weight of the dry rubber content denoted as NR-g-PMMA 30 and NR-g-PMMA 50, respectively were prepared via emulsion polymerisation technique. The occurrences of graft copolymerisation of PMMA onto NR were confirmed by proton Nuclear Magnetic Resonance (1H NMR) and Fourier Transform Infrared (FTIR) following purifications. The reinforcement of rubber by fillers is of great practical and technical importance. Thus, these fillers are added to rubber formulations to optimize the properties to meet a given application or set of performance parameters. In this study, the effect of carbon black in NR-g-PMMA 30 and NR-g-PMMA 50 rubber compounds were evaluated. Our results demonstrated that tensile strength, elongation at break and compression set reduced, while the hardness and solvent resistance increased in the presence of carbon black filler in comparison to the unfilled compound.

Flocculation in Silica Reinforced Rubber Compounds

2009 ◽  
Vol 82 (5) ◽  
pp. 524-540 ◽  
Author(s):  
S. Mihara ◽  
R. N. Datta ◽  
J. W. M. Noordermeer
Keyword(s):  
Activation Energy ◽  
Coupling Agent ◽  
Physical Phenomenon ◽  
Interfacial Interaction ◽  
Shielding Effect ◽  
Interaction Layer ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
Bound Rubber ◽  
Flocculation Rate

Abstract Flocculation plays an important role in reinforcement of silica filled rubber compounds, even if coupling agents are applied. It is well known that silica tends to flocculate during the early stages of vulcanization, when no dense rubber network has been formed yet. In the present study, flocculation was monitored by following the change in storage modulus at low strain, the so-called Payne effect, using a RPA2000 dynamic mechanical tester. The kinetic parameters: the rate constant and the activation energy of the silica flocculation were calculated according to the well-known Arrhenius equation. On basis of the value of the activation energy obtained for flocculation, it can be concluded that the silica flocculation is a purely physical phenomenon. Bound rubber measurements were also done in order to estimate the interfacial interaction layer between silica and polymer resulting from the coupling agent. The silica flocculation rate decreases with increasing interfacial interaction layer on the silica surface. This indicates that the decrease of the flocculation rate is due to the shielding effect of the coupling agent. It is argued that the attractive flux from forces related to polarity differences between the silica and the rubber is the determining factor for silica flocculation.

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.

Payne effect of carbon black filled natural rubber compounds and their carbon black gels

Polymer ◽  
2019 ◽  
Vol 185 ◽  
pp. 121953 ◽  
Author(s):  
Zhongjia Xu ◽  
Yihu Song ◽  
Qiang Zheng
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Payne Effect ◽  
Rubber Compounds

SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUNDS CONTAINING BIO-BASED PROCESS OILS. I: ASPECTS OF MIXING SEQUENCE AND EPOXIDE CONTENT

2019 ◽  
Vol 93 (2) ◽  
pp. 360-377
Author(s):  
C. Hayichelaeh ◽  
L. A. E. M. Reuvekamp ◽  
W. K. Dierkes ◽  
A. Blume ◽  
J. W. M. Noordermeer ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Rate Constant ◽  
Silica Surface ◽  
Early Stage ◽  
Shielding Effect ◽  
Cure Reaction ◽  
Silanol Groups ◽  
Rubber Compounds ◽  
Tan Δ ◽  
Flocculation Rate

ABSTRACT A bio-based process oil for rubber compounds is one of the compounding ingredients to be used toward an eco-friendly and more sustainable rubber technology. This work investigates epoxidized palm oil (EPO) as an alternative for petroleum-based process oil in silica-reinforced natural rubber (NR) tire tread compounds. The effect of different incorporating steps of EPO on the properties of the rubber compounds is first studied, taking into account that the polar functional groups in the oil molecules may interact with the silanol groups on the silica surface. The properties of silica-reinforced NR compounds with EPO oil are compared with that of reference mixes with treated distillate aromatic extract (TDAE) and without oil. The compounds with EPO show a lower viscosity, filler–filler interaction, and flocculation rate constant but higher cure reaction rate constants compared with the compound with TDAE. The results indicate that the epoxide groups in EPO interact with the silanol groups on the silica surface, promoting a greater shielding effect on the polar surface and thus better silica dispersion and less interference with the vulcanization reaction. The different incorporating steps of EPO show no significant effect on the viscosity, filler–filler interaction, or flocculation rate constant but clearly affect the extent of crosslinking, as indicated by the cure torque difference. The presence of EPO in an early stage of the mixing together with the first half addition of silica and silane results in the lowest cure torque difference, modulus, and tensile strength (i.e., the highest tan δ at 60 °C), which indicates a possible obstruction for the interaction between the silanol groups and silane coupling agent by the EPO molecules. Comparing EPO with different epoxide contents in the range of 1–3 mol%, the increase in epoxide content gives similar Payne effects but enhances the cure reaction, resulting in improved tensile properties and tan δ at 60 °C. The results clearly prove that EPO can be used as a TDAE alternative.

Studies on reinforcing effect of industrial nano silica in chloroprene vulcanizates containing carboxy-terminated liquid natural rubber

2021 ◽  
pp. 009524432110635
Author(s):  
Gopika Sudhakaran ◽  
Shanti A Avirah
Keyword(s):  
Maleic Anhydride ◽  
Natural Rubber ◽  
Cost Effective ◽  
Cross Linking ◽  
Nano Silica ◽  
Rubber Content ◽  
Reinforcing Effect ◽  
Bound Rubber ◽  
Liquid Natural Rubber ◽  
Rubber Filler

Maleic anhydride was chemically attached to depolymerized natural rubber, and the product was named as carboxy-terminated liquid natural rubber (CTNR). The CTNR can act as a potential plasticizer in chloroprene (CR) vulcanizates. This paper describes the use of commercial nano silica (NS) as a promising cost-effective filler, which can enhance the tensile properties and ageing resistance of the CR vulcanizates incorporated with CTNR (CR-CTNR). The enhancement in properties may be attributed to the increased bound-rubber content owing to the large surface area of the nano-sized filler. The characteristics of the NS-filled CR vulcanizates containing CTNR (NS CR-CTNR) were compared with those containing amorphous silica. The NS CR-CTNR vulcanizates showed superior ageing and oil resistance due to the finer rubber filler interaction modified by ionic cross linking.

Viscoelastic Behaviors of Carbon Black Gel Extracted from Highly Filled Natural Rubber Compounds: Insights into the Payne Effect

2016 ◽  
Vol 49 (4) ◽  
pp. 1454-1463 ◽  
Author(s):  
Shunchang Gan ◽  
Zi Liang Wu ◽  
Huilong Xu ◽  
Yihu Song ◽  
Qiang Zheng
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Payne Effect ◽  
Rubber Compounds ◽  
Viscoelastic Behaviors

Thermoelastic Phenomena in Natural Rubber Compounds during Cyclic Deformation

1959 ◽  
Vol 32 (4) ◽  
pp. 1020-1026
Author(s):  
M. P. Votinov ◽  
L. L. Sulzhenko ◽  
E. V. Kuvshinskiĭ
Keyword(s):  
Heat Capacity ◽  
Quantitative Analysis ◽  
Natural Rubber ◽  
Silica Gel ◽  
Cyclic Deformation ◽  
Heat Effect ◽  
Relaxation Cycle ◽  
Adiabatic Conditions ◽  
Rubber Compounds ◽  
Work Of Deformation

Abstract 1. The initial stages of stretching of natural rubber gum compounds ((λ≦4.5)) and of filled compounds ((λ=1.8−4)) are characterized by liberation of heat equivalent to the work of deformation according to Equation (lb). Further deformation takes place with liberation of surplus heat caused by- crystallization of the rubber. The relation between the work of deformation and the heat effect is given by Equation (1a) 2. The beginning of crystallization and its degree at a given elongation depend on the degree of vulcanization and on the nature of the dispersed fillers. The rubbers with the highest modulus crystallize the poorest. Active fillers such as channel black promote crystallization to a greater degree than silica gel and chalk. 3. A rate of deformation of 100% per second assures adiabatic conditions without taking special measures. 4. It was determined that errors in the quantitative analysis of the process of adiabatic stretching of rubbers result from lack of knowledge of the true heat capacity of the compound and especially from inaccuracy of measurement of elongation during the relaxation cycle.

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