• La Thi Thai Ha Ho Chi Minh City University of Technology
  • Chau Ngoc Mai Graduate School of Engineering, Nagasaki University



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.


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Author Biographies

La Thi Thai Ha, Ho Chi Minh City University of Technology

La Thi Thai Ha is an lecturer of Polymer and Composite at Ho Chi Minh City University of Technology. She received her doctorate in Vietnam in the year 2005. Her recent publications include: Structural, optical and gas sensing properties of vertically well-aligned ZnO nanowires grown on graphene/Si substrate by thermal evaporation method (Materials Characterization, 2018); Synthesis of microcapsules from pre-polyurethanes (Vietnam Journal of Science and Technology, 2017); Catalyst-free groeth of well-aliged ZnO nanowires graphene-Si Substrate bu thermal evaporation (Vietnam Journal of Science and Technology, 2017); Factors affecting antibacterial activity of acrylic resin containing silver nanoparticles (Vietnam Journal of Science and Technology, 2016). Her research interests are related to biopolymer, nanocomposite materials as well as smart materials. In the recent time, she has carried out lots of projects mainly about Anticorrosion inorganic polymer Aluminum Phosphate and Constructive paints based on core-shell butylacrylate and styrene.

Chau Ngoc Mai, Graduate School of Engineering, Nagasaki University

Ms. Chau Ngoc Mai graduated at Ho Chi Minh City University of Technology in Vietnam with the main major in Polymer Materials. Now, she is a master student at Nagasaki University, Japan. Mai is a co-author of three papers in Vietnam Journal such as Modifying Chitosan with n-butyl acrylate - The antibacterial activity in Science and Technology Development Journal (2018), SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF COMPOSITE BASED ON CHITOSAN-GRAFTED-(N-BUTYL ACRYLATE) AND SILVER NANOPARTICLES in Vietnam Journal of Science and Technology (2019) and Assessment of alkyd paint’s self-healing ability with microcapsules poly(melamine-urea-formaldehyde) walled alkyd resin in Vietnam Journal of Chemistry (2019).

She is going to receive her B. Eng. in Nov. 2018. She has a paper entitled Modifying Chitosan with n-butyl acrylate - The antibacterial activity in Vietnam Journal of Science and Technology (2018).


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).