Polímeros: Ciência e Tecnologia
Polímeros: Ciência e Tecnologia
Original Article

Classification of natural rubber foam grades by optimising the azodicarbonamide content

Fateehah Baru; Sitisaiyidah Saiwari; Nabil Hayeemasae

Downloads: 1
Views: 50


This study aimed to focus on classifying rubber foam grades according to ASTM D1056. The natural rubber foams were prepared by varying the Azodicarbonamide (ADC) content from 2 - 10 phr. The results were evaluated on their physical and mechanical properties. The relative foam density of the foams decreased, and the expansion ratio increased with the addition of ADC. This was due to the increase in the gas phase raised by ADC. In addition, adding ADC also decreased hardness and compression-deflection of the foams, whereby the values obtained were higher after oven aging due to the radical recombination caused by chain breaking. According to ASTM D1056, the compression-deflection values of the foams were 2A2 and 2A3 grades, where the ADC content at 6 – 10 phr met the basic properties required by the same standard. Furthermore, the ADC content at 6 phr is strongly suggested when considering the foam morphology.




azodicarbonamide, compression-deflection, foam, natural rubber


1 Toncheva, A., Brison, L., Dubois, P., & Laoutid, F. (2021). Recycled tire rubber in additive manufacturing: selective laser sintering for polymer-ground rubber composites. Applied Sciences (Basel, Switzerland), 11(18), 8778. http://dx.doi.org/10.3390/app11188778.

2 Mutlu, İ., Sugözü, İ., & Keskin, A. (2015). The effects of porosity in friction performance of brake pad using waste tire dust. Polímeros: Ciência e Tecnologia, 25(5), 440-446. http://dx.doi.org/10.1590/0104-1428.1860.

3 Suethao, S., Phongphanphanee, S., Wong-ekkabut, J., & Smitthipong, W. (2021). The relationship between the morphology and elasticity of natural rubber foam based on the concentration of the chemical blowing agent. Polymers, 13(7), 1091. http://dx.doi.org/10.3390/polym13071091. PMid:33808133.

4 Najib, N. N., Ariff, Z. M., Bakar, A. A., & Sipaut, C. S. (2011). Correlation between the acoustic and dynamic mechanical properties of natural rubber foam: effect of foaming temperature. Materials & Design, 32(2), 505-511. http://dx.doi.org/10.1016/j.matdes.2010.08.030.

5 Ramasamy, S., Ismail, H., & Munusamy, Y. (2013). Effect of rice husk powder on compression behavior and thermal stability of natural rubber latex foam. BioResources, 8(3), 4258-4269. http://dx.doi.org/10.15376/biores.8.3.4258-4269.

6 Panploo, K., Chalermsinsuwan, B., & Poompradub, S. (2019). Natural rubber latex foam with particulate fillers for carbon dioxide adsorption and regeneration. RSC Advances, 9(50), 28916-28923. http://dx.doi.org/10.1039/C9RA06000F. PMid:35528441.

7 Ariff, Z. M., Zakaria, Z., Tay, L. H., & Lee, S. Y. (2007). Effect of foaming temperature and rubber grades on properties of natural rubber foams. Journal of Applied Polymer Science, 107(4), 2531-2538. http://dx.doi.org/10.1002/app.27375.

8 Pechurai, W., Muansupan, T., & Seawlee, P. (2014). Effect of foaming temperature and blowing agent content on cure characteristics, mechanical and morphological properties of natural rubber foams. Advanced Materials Research, 844, 454-457. https://doi.org/10.4028/www.scientific.net/AMR.844.454.

9 Charoeythornkhajhornchai, P., Samthong, C., Boonkerd, K., & Somwangthanaroj, A. (2016). Effect of azodicarbonamide on microstructure, cure kinetics and physical properties of natural rubber foam. Journal of Cellular Plastics, 53(3), 287-303. http://dx.doi.org/10.1177/0021955X16652101.

10 Lee, E.-K., & Choi, S.-Y. (2007). Preparation and characterization of natural rubber foams: effects of foaming temperature and carbon black content. Korean Journal of Chemical Engineering, 24(6), 1070-1075. http://dx.doi.org/10.1007/s11814-007-0123-6.

11 Yang, H.-H., & Han, C. D. (1984). The effect of nucleating agents on the foam extrusion characteristics. Journal of Applied Polymer Science, 29(12), 4465-4470. http://dx.doi.org/10.1002/app.1984.070291281.

12 Ehabé, E., Bonfils, F., Aymard, C., Akinlabi, A. K., & Sainte Beuve, J. (2005). Modelling of Mooney viscosity relaxation in natural rubber. Polymer Testing, 24(5), 620-627. http://dx.doi.org/10.1016/j.polymertesting.2005.03.006.

13 Kramer, O., & Good, W. R. (1972). Correlating Mooney viscosity to average molecular weight. Journal of Applied Polymer Science, 16(10), 2677-2684. http://dx.doi.org/10.1002/app.1972.070161020.

14 Ismail, H., & Anuar, H. (2000). Palm oil fatty acid as an activator in carbon black filled natural rubber compounds: dynamic proper- ties, curing characteristics, reversion and fatigue studies. Polymer Testing, 19(3), 349-359. http://dx.doi.org/10.1016/S0142-9418(98)00102-0.

15 Reyes-Labarta, J. A., & Marcilla, A. (2007). Kinetic study of the decompositions involved in the thermal degradation of commercial azodicarbonamide. Journal of Applied Polymer Science, 107(1), 339-346. http://dx.doi.org/10.1002/app.26922.

16 Harpell, G. A., Gallagher, R. B., & Novits, M. F. (1977). Use of azo foaming agents to produce reinforced elastomeric foams. Rubber Chemistry and Technology, 50(4), 678-687. http://dx.doi.org/10.5254/1.3535165.

17 Bhatti, A. S., Dollimore, D., Goddard, R. J., & O’Donnell, G. (1984). The thermal decomposition of azodicarbonamide. Thermochimica Acta, 76(1-2), 63-77. http://dx.doi.org/10.1016/0040-6031(84)87004-5.

18 Ballard, D. G. H., Myatt, J., & Richter, J. F. P. Some observations on the mechanism of action of retarders in rubber vulcanization. A new class of retarder. Journal of Applied Polymer Science, 16(10), 2647-2655. http://dx.doi.org/10.1002/app.1972.070161017.

19 Guan, L. T., Du, F. G., Wang, G. Z., Chen, Y. K., Xiao, M., Wang, S. J., & Meng, Y. Z. (2007). Foaming and chain extension of completely biodegradable poly(propylene carbonate) using DPT as blowing agent. Journal of Polymer Research, 14(3), 245-251. http://dx.doi.org/10.1007/s10965-007-9103-0.

20 Yamsaengsung, W., & Sombatsompop, N. (2009). Effect of chemical blowing agent on cell structure and mechanical properties of EPDM foam, and peel strength and thermal conductivity of wood/NR composite–EPDM foam laminates. Composites. Part B, Engineering, 40(7), 594-600. http://dx.doi.org/10.1016/j.compositesb.2009.04.003.

21 Zhang, G., Wu, Y., Chen, W., Han, D., Lin, X., Xu, G., & Zhang, Q. (2019). Open-cell rigid polyurethane foams from peanut shell-derived polyols prepared under different post-processing conditions. Polymers, 11(9), 1392. http://dx.doi.org/10.3390/polym11091392. PMid:31450807.

22 Azevedo, J. B., Chávez, M. A., & Rabello, M. S. (2011). Efeito de reticulante na morfologia e propriedades físico-mecânicas de espumas poliméricas obtidas com EVA e EPDM. Polímeros, 20(5), 407-414. http://dx.doi.org/10.1590/S0104-14282011005000002.

23 Motiee, F., & Bigdeli, T. (2020). Prediction of mechanical and functional features of aged rubber composites based on BR/SBR; structure-properties correlation. Materials Research, 22(6), e20190226. http://dx.doi.org/10.1590/1980-5373-mr-2019-0226.

24 Hayeemasae, N., & Masa, A. (2020). Relationship between stress relaxation behavior and thermal stability of natural rubber vulcanizates. Polímeros: Ciência e Tecnologia, 30(2), e2020016. http://dx.doi.org/10.1590/0104-1428.03120.

6356f4e4a9539535006ee2c2 polimeros Articles
Links & Downloads

Polímeros: Ciência e Tecnologia

Share this page
Page Sections