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.

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.

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.

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.

SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUNDS CONTAINING BIO-BASED PROCESS OILS. II: INFLUENCE OF EPOXIDE AND AMINO FUNCTIONAL GROUPS

2020 ◽  
Vol 93 (1) ◽  
pp. 195-207
Author(s):  
C. Hayichelaeh ◽  
L. A. E. M. Reuvekamp ◽  
W. K. Dierkes ◽  
A. Blume ◽  
J. W. M. Noordermeer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Palm Oil ◽  
Proton Nuclear Magnetic Resonance ◽  
Elastic Response ◽  
Shielding Effect ◽  
Resonance Spectroscopy ◽  
Chemical Structures ◽  
Epoxidized Palm Oil ◽  
Rubber Compounds

ABSTRACT The feasibility of the use of epoxidized palm oil (EPO) and amine-modified epoxidized palm oil (mEPO) as process oils in silica-reinforced natural rubber compounds is studied. The chemical structures of EPO and mEPO are characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy (1H-NMR). Amine modification for 3 and 5 h leads to mEPOs with 0.03 and 0.04 mmol of amine in 1 g of oil, referred to as 0.03 mEPO and 0.04 mEPO, respectively. The properties of rubber compounds containing modified palm oils are investigated by taking those with TDAE oil and those without oil as references. The use of process oils clearly enhances the processibility (i.e., lower mixing torque and complex viscosity) and mechanical and dynamic mechanical properties of the rubber compounds as compared with compounds without oil. The rubber compounds with EPO and 0.03 mEPO show a lower Payne effect (i.e., less filler–filler interaction) than the rubber compound with TDAE because of the shielding effect of the oils on the silica surface. The use of mEPO boosts the vulcanization reaction, resulting in much better cure torque difference, which indicates a higher crosslink density due to the amino groups present in mEPO as compared with TDAE. Therefore, rubber compounds with mEPOs have better mechanical properties (i.e., reinforcement index, tensile strength, and elongation at break) and better elastic response under dynamic deformation, as indicated by a lower loss tangent at 60 °C as compared with the mix with TDAE.

scholarly journals Combination of Self-Healing Butyl Rubber and Natural Rubber Composites for Improving the Stability

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 443
Author(s):  
Kunakorn Chumnum ◽  
Ekwipoo Kalkornsurapranee ◽  
Jobish Johns ◽  
Karnda Sengloyluan ◽  
Yeampon Nakaramontri
Keyword(s):  
Natural Rubber ◽  
Dynamic Mechanical Properties ◽  
Attenuated Total Reflection ◽  
Rubber Matrix ◽  
Self Healing ◽  
Mechanical And Electrical Properties ◽  
Natural Rubber Composites ◽  
Tan Δ ◽  
The Stability ◽  
Physical And Chemical

The self-healing composites were prepared from the combination of bromobutyl rubber (BIIR) and natural rubber (NR) blends filled with carbon nanotubes (CNT) and carbon black (CB). To reach the optimized self-healing propagation, the BIIR was modified with ionic liquid (IL) and butylimidazole (IM), and blended with NR using the ratios of 70:30 and 80:20 BIIR:NR. Physical and chemical modifications were confirmed from the mixing torque and attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR). It was found that the BIIR/NR-CNTCB with IL and IM effectively improved the cure properties with enhanced tensile properties relative to pure BIIR/NR blends. For the healed composites, BIIR/NR-CNTCB-IM exhibited superior mechanical and electrical properties due to the existing ionic linkages in rubber matrix. For the abrasion resistances, puncture stress and electrical recyclability were examined to know the possibility of inner liner applications and Taber abrasion with dynamic mechanical properties were elucidated for tire tread applications. Based on the obtained Tg and Tan δ values, the composites are proposed for tire applications in the future with a simplified preparation procedure.

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