Document Type : Original research
Authors
1 Chemical, Polymeric and Petrochemical Technology Development Research Division, Research Institute of Petroleum Industry, P.O. Box 14115-143, Tehran, Iran
2 Depertment of Elastomer Engineering, Iran Polymer and Petrochemical institute, 1497713115,Tehran, Iran
Abstract
Elastomer vulcanizates based on natural rubber (NR), NR reclaim (NRR) and layered silicates were compounded in an internal mixer and cured on a two-roll mill. Cure characteristics and mechanical properties of samples based on 50NR/50NRR reinforced with Cloisite 20A, Cloisite 30B and Nanolin DK1 were compared to those of conventional NR/NRR/kaolin microcomposites. Due to the light/soft nature of organoclays suppressing the friction forces, the minimum torque values decreased in the presence of organoclays, whereas the crosslink density, evidenced by the difference between the maximum and minimum torque values, increased in all samples and scorch times shortened by 37% to a minimum in the presence of Nanolin alkaline/catalytic role in the cure reaction. Fatigue resistance improved by about 10% benefiting the crack tips blunting/energy consuming hysteresis mechanisms motivated by the organoclays among which Nanolin DK1 provides the most efficient dispersion/distribution of nanolayers by faster intragallery crosslinking reactions that pushes the stacks apart. Higher states of dispersion in this sample would also promote strain-induced crystallization under deformation responsible for the improvements seen in the modulus and elongation-at-break. Two-step mixing sequence further improved the compound performance due to the dispersion state progress confirmed by X-ray diffraction and transmission electron microscopy (20% in fatigue resistance and 53% in tensile modulus). In-situ compatibilization through bis(triethoxysilylpropyl)tetrasulfide bi-functional silane coupling agent also promoted modulus and fatigue resistance. However, a prolonged scorch time was observed due to
the blinded NR cure-reactive sites as well as steric hindrance of large functional groups in the presence of this coupling agent.
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Main Subjects
- Junkong P, Cornish K, Ikeda Y (2017) Characteristics of mechanical properties of sulphur cross-linked guayule and dandelion natural rubbers. RSC advances 7: 50739-50752
- Gumede JI, Carson J, Hlangothi SP, Bolo LL (2020) Effect of single-walled carbon nanotubes on the cure and mechanical properties of reclaimed rubber/natural rubber blends. Mater Today Commun 23: 100852
- Rubber S (2016) Natural rubber and reclaimed Rubber composites–A Systematic Review. Polym Sci 2: 7
- Sombatsompop N, Kumnuantip C (2006) Comparison of physical and mechanical properties of NR/carbon black/reclaimed rubber blends vulcanized by conventional thermal and microwave irradiation methods. J Appl Polym Sci 100: 5039- 5048
- Hassan MM, Mahmoud GA, El-Nahas HH, Hegazy ESA (2007) Reinforced material from reclaimed rubber/natural rubber, using electron beam and thermal treatment. J Appl Polym Sci 104: 2569-2578
- Sombatsompop N, Kumnuantip C (2003) Rheol ogy, cure characteristics, physical and mechanical properties of tire tread reclaimed rubber/ natural rubber compounds. J Appl Polym Sci 87: 1723-1731
- Zhao X, Hu H, Zhang D, Zhang Z, Peng S, Sun Y (2019) Curing behaviors, mechanical properties, dynamic mechanical analysis and morphologies of natural rubber vulcanizates containing reclaimed rubber. e-Polymers 19: 482-488
- Thitithammawong A, Hayichelaeh C, Nakason W, Jehvoh N (2019) The use of reclaimed rubber from waste tires for production of dynamically cured natural rubber/reclaimed rubber/polypropylene blends: Effect of reclaimed rubber loading. J Met Mat Min 29: 98-104
- Paran S, Naderi G, Ghoreishy M, Heydari A (2018) Enhancement of mechanical, thermal and morphological properties of compatibilized graphene reinforced dynamically vulcanized thermoplastic elastomer vulcanizates based on polyethylene and reclaimed rubber. Compos Sci Technol 161: 57-65
- Choi D, Kader MA, Cho BH, Huh Yi, Nah C (2005) Vulcanization kinetics of nitrile rubber/ layered clay nanocomposites. J Appl Polym Sci 98: 1688-1696
- George SC, Rajan R, Aprem AS, Thomas S, Kim SS (2016) The fabrication and properties of natural rubber-clay nanocomposites. Polym Test 51: 165-173
- Chin KP, Wan NY, Saad CSM (2011) Microcellular rubber: A study on reclaimed natural rubber (NR) latex gloves/standard malaysian rubber (SMR) 20 blends. Pertanika J Sci Technol 19: 171-176
- Mostoni S, Milana P, Di Credico B, D’Arienzo M, Scotti R (2019) Zinc-based curing activators: new trends for reducing zinc content in rubber vulcanization process. Catalysts 9: 664-686
- Asif A, Rao VL, Ninan K (2011) Preparation, characterization, thermo-mechanical, and barrier properties of exfoliated thermoplastic toughened epoxy clay ternary nanocomposites. Polym Adv Technol 22: 437-447
- Dziemidkiewicz A, Maciejewska M, Pingot M (2019) Thermal analysis of halogenated rubber cured with a new cross-linking system. J Therm Anal Calorim 138: 4395-4405
- Dong B, Zhang L, Wu Y (2017) Influences of different dimensional carbon-based nanofillers on fracture and fatigue resistance of natural rubber composites. Polym Test 63: 281-288
- Momani B, Sen M, Endoh M, Wang X, Koga T, Winter HH (2016) Temperature dependent intercalation and self–exfoliation of clay/polymer nanocomposite. Polymer 93: 204-212
- Bokobza L (2019) Natural rubber nanocomposites: a review. Nanomaterials 9: 12-33
- Ghari HS, Arani AJ, Shakouri Z (2013) Mixing sequence in natural rubber containing organoclay and nano-calcium carbonate ternary hybrid nanocomposites. Rubber Chem Technol 86: 330- 341
- Roy K, Potiyaraj P (2019) Exploring the comparative effect of silane coupling agents with different functional groups on the cure, mechanical and thermal properties of nano-alumina (Al2O3)- based natural rubber (NR) compounds. Polym Bull 76: 883-902
- Sarkawi SS, Dierkes WK, Noordermeer JW (2015) Morphology of silica-reinforced natural rubber: The effect of silane coupling agent. Rubber Chem Technol 88: 359-372
- Nakhaei M, Ahmadi A, Naderi G (2020) Effect of process parameters on tensile strength of welds and modeling of laser welding of PA6/NBR/clay nanocomposite by response surface methodology. Polyolefins J 7: 99-110
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