Tire Black Sidewall Surface Discoloration and Non-Staining Technology: A Review

1998 ◽  
Vol 71 (3) ◽  
pp. 590-618 ◽  
Author(s):  
Walter H. Waddell
Keyword(s):  
Fatigue Life ◽  
Natural Rubber ◽  
Outer Surface ◽  
Chain Scission ◽  
Butadiene Rubber ◽  
Ethylene Propylene ◽  
Polymer Decomposition ◽  
Sidewall Surface

Abstract The tire black sidewall is the outer surface that protects the casing against weathering. It is formulated for resistance to weathering, ozone aging, abrasion, tearing and cracking, and for good fatigue life by using blends of natural rubber and cis-butadiene rubber. Protection against ozone aging is of particular interest since reaction with these olefinically unsaturated elastomers results in polymer decomposition via chain scission. Use of N-alkyl, N′-aryl-para-phenylenediamine antiozonants has proved most effective. However, their use also results in a surface discoloration, and thus they can be used in only limited amounts when tire appearance is also an important factor. A review is made of the literature describing this surface discoloration problem and approaches to formulate a black sidewall compound to eliminate this surface discoloration upon exposure to ozone. Methods include use of non-staining antiozonants, and uses of elastomers with saturated backbones such as ethylene-propylene-diene terpolymers, halobutyl rubbers and brominated-isobutylene- co-para-methylstyrene.

Mechanisms Involved in the Recycling of NR and EPDM

1999 ◽  
Vol 72 (4) ◽  
pp. 731-740 ◽  
Author(s):  
M. A. L. Verbruggen ◽  
L. van der Does ◽  
J. W. M. Noordermeer ◽  
M. van Duin ◽  
H. J. Manuel
Keyword(s):  
Natural Rubber ◽  
Crosslink Density ◽  
Main Chain ◽  
Chain Scission ◽  
Ethylene Propylene ◽  
Temperature Range ◽  
Lower Reactivity ◽  
Ethylene Propylene Diene Rubber ◽  
Diene Rubber ◽  
Crosslink Densities

Abstract The thermochemical recycling of natural rubber (NR) and ethylene-propylene-diene rubber (EPDM) vulcanizates with disulfides was studied. NR sulfur vulcanizates were completely plasticized when heated with diphenyldisulfide at 200 °C. It could be concluded that both main chain scission and crosslink scission caused the network breakdown. NR peroxide vulcanizates were less reactive towards disulfide at 200 °C, and only reacted through main chain scission. For EPDM a temperature range of 200–275 °C was studied. In the presence of diphenyldisulfide at 200 °C there was almost no devulcanization of EPDM sulfur vulcanizates, and at 225 and 250 °C there was only slightly more devulcanization. A decrease in crosslink density of 90% was found when 2×10−4 mol diphenyldisulfide/cm3 vulcanizate was added and the EPDM sulfur vulcanizates were heated to 275 °C. EPDM peroxide vulcanizates showed a decrease in crosslink density of ca. 40% under the same conditions. The lower reactivity of EPDM towards disulfide compared with NR is the result of higher crosslink densities, the presence of a higher percentage of more stable monosulfidic crosslinks and the fact that EPDM is less apt to main chain scission relative to NR.

Effect of Curing Systems on Fatigue of Natural Rubber Vulcanizates

1966 ◽  
Vol 39 (3) ◽  
pp. 785-797 ◽  
Author(s):  
W. L. Cox ◽  
C. R. Parks
Keyword(s):  
Fatigue Life ◽  
Natural Rubber ◽  
Main Chain ◽  
Accelerated Aging ◽  
Chain Scission ◽  
Rapid Loss ◽  
Effective Antioxidant ◽  
Natural Rubber Vulcanizates ◽  
Aging In Air ◽  
Oxidative Effect

Abstract The fatigue life of natural rubber-HAF black vulcanizates showed maxima when plotted as a function of crosslink concentration as did other properties related to a tearing process such as tensile strength, crack growth, and tear strength. Accelerated-sulfur vulcanizates were superior to peroxide and nonelemental-sulfur cures; this can be attributed to an exchange of polysulfide crosslinks under stress. An effective antioxidant was essential for maximum fatigue resistance. Accelerated-sulfur systems, although having a higher original fatigue life than peroxide or nonelemental-sulfur cures, showed a rapid loss on accelerated aging in air. This would indicate that an oxidative effect was involved. Sulfur group analyses of the flexed samples showed an increase in the concentration of RSSxSR linkages but a decrease in the total polysulfide sulfur, Sx, with no change in the crosslink densities. This suggests that the polysulfide linkages not only underwent exchange during the fatigue process but also homolytic cleavage to polythiyl radicals. These radicals can add to double bonds and in the presence of oxygen initiate oxidation chains which would lead to main chain scission.

Mixing, Curing and Reinforcement of NR/BR/EPDM Blends for Tire Sidewall Applications

2009 ◽  
Vol 82 (3) ◽  
pp. 379-399 ◽  
Author(s):  
H. Zhang ◽  
R. N. Datta ◽  
A. G. Talma ◽  
J. W. M. Noordermeer
Keyword(s):  
Natural Rubber ◽  
Butadiene Rubber ◽  
High Concentration ◽  
Ethylene Propylene ◽  
Ethylene Propylene Diene Rubber ◽  
Filler Distribution ◽  
Diene Rubber ◽  
Ozone Resistance

Abstract Tire sidewalls generally consist of blends of natural rubber (NR) and butadiene rubber (BR), containing a high concentration of antiozonants to provide ozone resistance. However, the most widely used antiozonant, N-(1, 3-dimethyl-butyl)-N'-phenyl-p-phenylenediamine (6PPD), is a staining, toxic and environmentally unfriendly substance. Incorporation of Ethylene-Propylene-Diene rubber (EPDM) into NR/BR is a way of achieving non-staining ozone resistance. But blending of dissimilar rubbers is severely restricted due to viscosity mismatch, thermodynamic incompatibility, cure incompatibility and heterogeneous filler distribution. This chapter gives an overview of the various research approaches in the field of blending dissimilar rubbers so far, as well as the mechanism of ozone protection by incorporation of EPDM in tire sidewall applications.

A Peroxide Curing Butyl Rubber

1969 ◽  
Vol 42 (4) ◽  
pp. 1147-1154 ◽  
Author(s):  
C. E. Oxley ◽  
G. J. Wilson
Keyword(s):  
Natural Rubber ◽  
Chain Scission ◽  
Butyl Rubber ◽  
Polymer Chains ◽  
The Other ◽  
Cross Linking ◽  
Ethylene Propylene ◽  
Peroxide Curing ◽  
Polymer Reactions ◽  
Crosslinking Reactions

Abstract The reactions of peroxides with polymers have been studied for some time. They form an extensive part of vulcanization technology. Two types of reactions are generally recognized, those leading to crosslinking between polymer chains and those leading to scission of the chains. Natural rubber, polybutadiene and ethylene-propylene rubber are examples of polymers in which crosslinking reactions take place to a greater extent than reactions leading to chain scission and these polymer reactions with peroxides form a useful method of vulcanization. On the other hand, polyisobutene is an example of a polymer which degrades extensively and for polyisobutene and butyl rubber, peroxides have not found use as cross-linking agents.

Pengaruh penambahan natural rubber (NR), epoxidation natural rubber (ENR-46) dan chlorprene rubber (CR) pada sifat kompon termoplastik

2020 ◽  
Vol 26 (2) ◽  
pp. 62-69
Author(s):  
Farida Ali ◽  
Tuti I. Sari ◽  
Andi A. Siahaan ◽  
Al-Kautsar D. Arya ◽  
Tri Susanto
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Vinyl Chloride ◽  
Butadiene Rubber ◽  
Elongation At Break ◽  
Nitrile Butadiene Rubber ◽  
Poly Vinyl Chloride

Penelitian ini untuk mengetahui pengaruh penambahan Natural Rubber (NR) dan Epoxidation Natural Rubber (ENR-46) dengan kompatibiliser Chlorprene Rubber (CR) pada aplikasi kompon termoplastik Poly Vinyl Chloride (PVC) dan Nitrile Butadiene Rubber (NBR), variabel penelitian meliputi ENR-46/PVC/NBR/CR, NR/PVC/NBR/CR dan CR-NR/PVC/NBR, CR-ENR-46/PVC/NBR. Parameter pengujian sifat fisik-mekanik : Hardness (Shore A), Tensile Strength (Mpa), Elongation at Break (%) dan ketahanan terhadap pelarut minyak (n-Pentane, Toluene, Hexane dan Pertalite). Hasil penelitian didapatkan untuk sifat fisik-mekanik, semakin banyak penambahan NR Kekerasan kompon termoplastik akan menurun, Tensile Strength dan Elongation at Break kompon akan meningkat begitu juga dengan CR-NR. Tetapi berbanding terbalik hasilnya untuk ENR-46 dan CR-ENR-46. Pengujian Ketahanan terhadap pelarut minyak semakin banyak penambahan ENR-46 Ketahanan kompon termoplastik terhadap pelarut akan meningkat, hasil yang sama juga pada CR-ENR-46. Tetapi berbanding terbalik hasilnya dengan penambahan NR dan CR-NR pada kompon termoplastik.

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