SYNTHESIS OF SULFUR-CONTAINED MICROCAPSULES AND POTENTIAL APPLICATION IN RUBBER
Keywords:melamine urea-formaldehyde, microcapsules, self-healing, sulfur
Microcapsule-based material is potentially utilized in a variety of fields such as pharmaceuticals, food, biology, self-healing materials, etc. More remarkedly, in the rubber-related fields, this outstanding material is able to have a crucial role to play as an alternative of sulfur in compounding and vulcanizing process with regard to the self-healing ability after cracking. In this research, the interface polymerization was applied to generate microcapsules, whose shell was synthesized from Urea-formaldehyde pre-polymer modified by 0.25 wt% melamine containing sulfur (S) as a core substance. When the synthesizing process was carried out at 80 C and stirring rate of 300 rpm in 2 hours, the microcapsule product was spherical with the average size of 115 m and contained 60% of core content that was examined by FTIR, DLS, SEM, TGA and experimented the potential application. As a result, the amount of 8 phr of produced microcapsules utilized in NBR rubber compounds necessitated a longer time to vulcanize rubber at 160 C compared to using 5 phr free S. Besides, the mechanical strength of the microcapsules-contained product was insignificantly changed but bloom-like phenomenon on the rubber surface was markedly improved. It is noticeable that the vulcanized NBR rubber with the presence of these microcapsules are well able to heal its crack or cut when heated up to 150 C in 10 minutes while the free S-vulcanized NBR rubber is definitely unable to be self-healing in the same conditions.
Khorasani, S. N., Ataei, S. & Neisiany, R. E. Microencapsulation of a coconut oil-based alkyd resin into poly(melamine–urea–formaldehyde) as shell for self-healing purposes. Prog. Org. Coatings 111, 99–106 (2017).
Ha, L. T. T. & Mai, C. N. Assessment of alkyd paint ’ s self-healing ability with microcapsules foly ( melamine-urea-formaldehyde ) walled alkyd resin. 57, 195–201 (2019).
Yuan, H., Li, G., Yang, L., Yan, X. & Yang, D. Development of melamine-formaldehyde resin microcapsules with low formaldehyde emission suited for seed treatment. Colloids Surfaces B Biointerfaces 128, 149–154 (2015).
Shinzo, K. & Ikeda, Y. Chemistry, Manufacture and Applications of Natural Rubber. (2014).
Herculano, R. D. et al. Natural rubber latex used as drug delivery system in guided bone regeneration (GBR). Mater. Res. 12, 253–256 (2009).
Popescu, R. C., Popescu, D. & Grumezescu, A. M. Applications of rubber-based blends. Recent Developments in Polymer Macro, Micro and Nano Blends: Preparation and Characterisation (Elsevier Ltd, 2016). doi:10.1016/B978-0-08-100408-1.00004-2
Benko, I. D. A. et al. United States Patent ( 19 ). (1990).
Thulasiram Gobinath, Hudson, OH (US); James Oral Hunt, Akron, O. (US); W. P. & Francik, Akron, OH (US); Carl Trevor Ross Pulford, Akron, O. (US). ( 12 ) Patent Application Publication ( 10 ) Pub . No .: US 2008 / 0033593 A1. 1, (2008).
Nah, S. H. & Thomas, A. G. Migration and Blooming of Waxes to the Surface of Rubber Vulcanizates. Rubber Chem. Technol. 54, 255–265 (2011).
Ayers, W. J. K. and K. B. The Solubility of Sulfur in Rubber. 16, 148–150 (1922).
Aziz, Y.B. ; Hepbrun, C. Problems of Bloom Experienced When Insoluble Sulphur is used in Natural Rubber. J. Rubber Res. Inst. Malaysia 2, 57–67 (1979).
Li, J., Wang, S. J., Liu, H. Y., You, L. & Wang, S. K. Microencapsulation of sulphur in polyurea. Plast. Rubber Compos. 40, 433–437 (2011).
Li, J., Wang, S.-J., Liu, H.-Y., Wang, S.-K. & You, L. Microencapsulation of sulfur in poly(urea-formaldehyde). J. Appl. Polym. Sci. 122, 767–773 (2011).
Taylor, P. et al. Preparation and Application of Poly ( melamine-urea- formaldehyde ) Microcapsules Filled with Sulfur. Polym. Plast. Technol. Eng. 50, 37–41 (2011).
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