Sains Malaysiana 53(9)(2024): 3135-3147

http://doi.org/10.17576/jsm-2024-5309-18

Diimide-Mediated Hydrogenation of Nitrile Butadiene Rubber

(Penghidrogenan Pengantaraan Diimida bagi Getah Nitril Butadiena)

AMIRA SHAFIQA SALLEH HUDDIN¹, YI-FAN GOH², NAHARULLAH JAMALUDDIN³ & SITI FAIRUS MOHD YUSOFF^1,4,*

¹Department of Chemical Sciences, Faculty of Science andTechnology, Universiti Kebangsaan Malaysia, 43600UKM Bangi, Selangor, Malaysia

²Asia Innovation Centre (AIC), Synthomer Sdn Bhd, Kawasan Perindustrian i-Park, Bandar Indahpura, 81000 Kulai, Johor, Malaysia

³Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia

⁴Polymer Research Centre (PORCE), Faculty of Science andTechnology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

Received: 19 January 2024/Accepted: 19 July 2024

Abstract

The hydrogenation of nitrile butadiene rubber (NBR) has shown great potential for improving its physical, thermal, mechanical, and chemical stability. Hydrogenation process of NBR in this work involved the utilization of diimide produced from the interaction between hydrazine hydrate (N₂H₄) and hydrogen peroxide (H₂O₂), with the addition of boric acid as a promoter. Attenuated total reflectance Fourier transform infrared (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were used to evaluate the degree of hydrogenation, glass transition, thermal stability, and rubber crystallinity, respectively. The highest hydrogenation degree was 99%, which resulted in a 57% gel content. Upon hydrogenation, both the glass transition temperature (T_g) and decomposition temperature (T_d) increased. The hydrogenated rubber samples generally showed an amorphous state, except for the 99% hydrogenated sample, which displayed a semi-crystalline state. However, using diimide for direct hydrogenation yields a side reaction from the free radicals in the system, which leads to gel formation. Optimization was accomplished by employing the response surface methodology (RSM), which entailed manipulating parameters such as the total solid content (TSC) of NBR, reaction time, and the mole ratio of H₂O₂ to N₂H₄, to reduce the percentage of gel content. The RSM analysis identified the optimum reaction conditions as a 1:1 mole ratio of H₂O₂: N₂H₄ and 25% TSC, with a reaction time of 8 h, which yielded 32% gel content percentage, where a mole ratio of H₂O₂ to N₂H₄ and reaction time indicated a synergistic effect, whereas TSC denoted an antagonistic effect.

Keywords: Diimide; gel content; hydrogenation; nitrile butadiene rubber; response surface methodology

Abstrak

Penghidrogenan getah nitril butadiena (NBR) telah menunjukkan potensi besar untuk meningkatkan kestabilan fizikal, haba, mekanik dan kimianya. Proses penghidrogenan NBR dalam kajian ini melibatkan penggunaan diimida yang dihasilkan daripada interaksi antara hidrazin hidrat (N₂H₄) dan hidrogen peroksida (H₂O₂), dengan penambahan asid borik sebagai promoter. Spektroskopi jumlah pantulan dilemahkan- inframerah transformasi Fourier (ATR-FTIR), kalorimetri imbasan pembezaan (DSC), analisis termogravimetrik (TGA) dan pembelauan sinar-X (XRD), digunakan untuk menilai darjah penghidrogenan, peralihan kaca, kestabilan terma dan sifat kehabluran getah. Darjah penghidrogenan tertinggi yang dicapai ialah 99%, menghasilkan kandungan gel sebanyak 57%. Selepas penghidrogenan, kedua-dua suhu peralihan kaca (T_g) dan suhu penguraian (T_d) meningkat. Sampel getah terhidrogenasi menunjukkan keadaan amorfus, manakala sampel getah dengan 99% peratusan penghidrogenan, memaparkan keadaan separa kristal. Walau bagaimanapun, diimida menghasilkan tindak balas sampingan daripada radikal bebas dalam sistem, yang membawa kepada pembentukan gel. Pengoptimuman dicapai dengan menggunakan kaedah rangsangan permukaan (RSM), dengan menggunakan parameter yang dimanipulasi, iaitu jumlah kandungan pepejal (TSC) NBR, masa tindak balas dan nisbah mol H₂O₂ kepada N₂H₄, untuk mengurangkan peratusan kandungan gel. Analisis RSM mengenal pasti keadaan tindak balas optimum sebagai nisbah mol 1:1 H₂O₂:N₂H₄ dan 25% TSC, dengan masa tindak balas selama 8 jam yang menghasilkan 32% kandungan gel dengan nisbah molar H₂O₂ kepada N₂H₄ menunjukkan kesan sinergistik, sementara TSC dan masa tindak balas menunjukkan kesan antagonis.

Kata kunci: Diimida; getah nitril butadiena; kandungan gel; kaedah rangsangan permukaan; penghidrogenan

REFERENCES

Ameh, E.S. 2019. A review of basic crystallography and x-ray diffraction applications. The International Journal of Advanced Manufacturing Technology 105(7): 3289-3302.

Aziz, T., Fan, H., Khan, F.U., Haroon, M. & Cheng, L. 2019. Modified silicone oil types, mechanical properties and applications. Polymer Bulletin 76(4): 2129-2145.

De Sarkar, M., De, P.P. & Bhowmick, A.K. 2000. Diimide reduction of carboxylated styrene – butadiene rubber in latex stage. Polymer 41(3): 907-915.

Herlinawati, E., Montoro, P., Ismawanto, S., Syafaah, A., Aji, M., Giner, M., Flori, A., Gohet, E. & Oktavia, F. 2022. Dynamic analysis of tapping panel dryness in Hevea brasiliensis reveals new insights on this physiological syndrome affecting latex production. Heliyon 8(10): 10920.

Li, C.Y. 2020. The rise of semicrystalline polymers and why are they still interesting. Polymer 211: 123150.

Liang, L., Dong, J. & Yue, D. 2019. Branched EHNBR and its properties with enhanced low-temperature performance and oil resistance. RSC Advances 9(55): 32130-32136.

Lin, X. 2005. Hydrogenation of unsaturated polymers in latex form. Ph.D. Thesis, University of Waterloo, Ontario, Canada (Unpublished).

Liu, X., Fu, Y., Zhou, D., Chen, H., Li, Y., Song, J., Zhang, S. & Wang, H. 2022. Hydrogenation of carboxyl nitrile butadiene rubber latex using a ruthenium-based catalyst. Catalysts 12(1): 97.

Liu, J., Sun, J., Zhang, Z., Yang, H. & Nie, X. 2020. One-step synthesis of end-functionalized hydrogenated nitrile-butadiene rubber by combining the functional metathesis with hydrogenation. ChemistryOpen 9(3): 374-380.

Luo, Z.H., Feng, M., Lu, H., Kong, X.X. & Cao, G.P. 2019. Nitrile butadiene rubber hydrogenation over a monolithic Pd/CNTs@Nickel foam catalysts: Tunable CNTs morphology effect on catalytic performance. Industrial and Engineering Chemistry Research 58(5): 1812-1822.

Mandlekar, N., Joshi, M. & Butola, B.S. 2022. A review on specialty elastomers based potential inflatable structures and applications. Advanced Industrial and Engineering Polymer Research 5(1): 33-45.

Mutia Anissa Marsya, Bismo Dwi Putranto, Santi Puspitasari, Adi Cifriadi & Mochamad Chalid 2019. Catalyst screening on diimide transfer hydrogenation of natural rubber latex catalyst screening on diimide transfer hydrogenation of natural rubber latex. IOP Conference Series: Materials Science and Engineering 509: 012078.

Ngudsuntear, K., Limtrakul, S. & Arayapranee, W. 2022. Synthesis of hydrogenated natural rubber having epoxide groups using diimide. ACS Omega 7(25): 21483-21491.

Nguyen Duy, H., Rimdusit, N., Tran Quang, T., Phan Minh, Q., Vu Trung, N., Nguyen, T.N., Nguyen, T.H., Rimdusit, S., Ougizawa, T. & Tran Thi, T. 2021. Improvement of thermal properties of Vietnam deproteinized natural rubber via graft copolymerization with styrene/acrylonitrile and diimide transfer hydrogenation. Polymers for Advanced Technologies 32(2): 736-747.

Petrukhina, N.N., Golubeva, M.A. & Maksimov, A.L. 2019. Synthesis and use of hydrogenated polymers. Russian Journal of Applied Chemistry 92(6): 715-733.

Puspitasari, S., Falaah, A.F. & Zanki, A.N. 2019. Selection of stabilizer and coagulant for natural rubber latex colloidal system during diimide catalytic hydrogenation at semi pilot scale reaction Selection of stabilizer and coagulant for natural rubber latex colloidal system during diimide catalytic hy. IOP Conference Series: Materials Science and Engineering 509: 012128.

Shahrul Fizree Idris, M., Hanis Adila Azhar, N., Firdaus, F., Efliza Ashari, S. & Fairus Mohd Yusoff, S. 2019. Effect of temperature, time and diimide/rubber ratio on the hydrogenation of liquid natural rubber by response surface methodology. Indonesian Journal of Chemistry 19(4): 882-891.

Wang, X., Sun, J., Xia, L., Wang, C., Kim, J.K. & Zong, C. 2020. Kinetics of hydrogenation of acrylonitrile butadiene rubber: A latex-based in situ and low-temperature approach. Colloid and Polymer Science 298(11): 1501-1513.

Wong, J.L.O., Munusamy, Y. & Ong, K.S. 2019. Effect of total solids content of nitrile rubber latex on coating performance of phase change material. AIP Conference Proceedings 2157: 020046.

Yew, G.Y., Tham, T.C., Show, P.L., Ho, Y.C., Ong, S.K., Law, C.L., Song, C. & Chang, J.S. 2020. Unlocking the secret of bio-additive components in rubber compounding in processing quality nitrile glove. Applied Biochemistry and Biotechnology 191: 1-28.

Yusof, M.J.M., Tahir, N.A.M., Firdaus, F. & Yusoff, S.F.M. 2018. Diimide reduction of liquid natural rubber in hydrazine hydrate/hydrogen peroxide system: A side reaction study. Malaysian Journal of Analytical Sciences 22(6): 1023-1030.

Zhang, J., Wang, C., Zao, W., Feng, H., Hou, Y. & Huo, A. 2020. High-performance nitrile butadiene rubber composites with good mechanical properties, tunable elasticity, and robust shape memory behaviors. Industrial and Engineering Chemistry Research 59(36): 15936-15947.

Zhou, S., Bai, H. & Wang, J. 2004. Hydrogenation of acrylonitrile - butadiene rubber latexes. Journal of Applied Polymer Science 91(4): 2072-2078.

*Corresponding author; email: sitifairus@ukm.edu.my