Sains Malaysiana 44(6)(2015): 835–842

 

ENR-50 Compatibilized Natural Rubber/Recycled Acrylonitrile-Butadiene Rubber Blends

(Penyerasian ENR-50 dalam Adunan Getah Asli/Getah Kitar Semula Akrilonitril Butadiena)

 

HAZWANI SYAZA AHMAD*, HANAFI ISMAIL &AZURA ABD RASHID

 

School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia

14300 Nibong Tebal, Pulau Pinang, Malaysia

 

Received: 15 January 2014/Accepted: 15 November 2014

 

ABSTRACT

Epoxidized natural rubber (ENR-50) has been used as a compatibilizer for natural rubber-recycled acrylonitrile-butadiene rubber (NR/NBRr) blends, vulcanized by sulfur. NBR gloves have excellent resistance to punctures, tear and many types of chemicals, while NR has good physical and mechanical properties. Incorporation of ENR-50 into the rubber blends has improved processability, stiffness, resilience and excellent oil resistance. NR/NBRr blends were prepared by two-roll mill with five different compositions with the ENR-50 content fixed at 10 phr. Cure characteristics, mechanical properties and morphology (SEM) studies were performed to determine the compatibility of NR/NBRr blends in the presence of ENR-50. The cure characteristics showed that NR/NBRr blends with the presence of ENR-50 have lower scorch time (ts2) and cure time (t90) than NR/NBRr blends without ENR-50. However, the NR/NBRr blends with ENR-50 exhibited higher minimum torque (ML) and maximum torque (MH) which indicated difficult processability of the blends after compatibilization. Incorporation of ENR-50 into NR/NBRr blends improved all the tensile properties (tensile strength, tensile modulus and elongation at break) compared with NR/NBRr blends without ENR-50. The improvement in hardness upon compatibilization is due to an increase in crosslink density. Scanning electron microscopy (SEM images) of the fracture surfaces indicates that, with the addition of ENR-50 in NR/NBRr blends, better adhesion between NR and NBRr was obtained, thus improving the compatibility of NR/NBRr blends.

 

Keywords: Curing characteristics; ENR-50; mechanical properties; NBRr; NR; scanning electron microscopy

 

ABSTRAK

Getah asli terepoksida (ENR-50) telah digunakan sebagai agen pembantu pemprosesan untuk adunan getah asli/getah kitar semula akrilonitril butadiena (NR/NBRr), divulkan dengan sulfur. Sarung tangan NBR mempunyai rintangan yang baik terhadap tebuk, koyak dan pelbagai jenis bahan kimia, manakala NR mempunyai sifat fizikal dan mekanik yang baik. Penggabungan ENR-50 di dalam adunan getah telah menambah baik kebolehprosesan, kekakuan, kebingkasan dan kerintangan minyak. Lima komposisi yang berbeza untuk setiap adunan getah NR/NBRr dengan kandungan ENR-50 yang tetap sebanyak 10 phr telah disediakan menggunakan pengisar dua-gulungan. Sifat pematangan, mekanik dan morfologi (SEM) telah dijalankan untuk menentukan keserasian adunan getah NR/NBRr dengan kehadiran ENR-50. Sifat pematangan menunjukkan bahawa adunan getah NR/NBRr dengan kehadiran ENR-50 mempunyai masa skorj (ts2) dan masa pematangan (t90) yang pendek berbanding adunan getah NR/NBRr tanpa kehadiran ENR-50. Walau bagaimanapun, adunan getah NR/NBRr dengan kehadiran ENR-50 mempamerkan tork minimum (ML) dan tork maksimum (MH) yang tinggi, yang menunjukkan bahawa kebolehprosesan adunan getah menjadi semakin sukar. Penggabungan ENR-50 ke dalam adunan getah NR/NBRr telah menambah baik semua sifat tensil (kekuatan tensil, modulus dan pemanjangan takat putus) berbanding adunan getah NR/NBRr tanpa kehadiran ENR-50. Peningkatan kekerasan di dalam adunan getah disebabkan oleh peningkatan ketumpatan sambung silang. Mikrograf SEM ke atas permukaan patah membuktikan bahawa penambahan ENR-50 ke dalam adunan getah NR/NBRr telah menambah baik pelekatan antara-muka NR dan NBRr, seterusnya meningkatkan keserasian adunan getah NR/NBRr.

 

Kata kunci: ENR-50; mikroskop elektron imbasan; NBRr; NR; sifat mekanik; sifat pematangan

REFERENCES

 

El-Nemr, K.F. 2011. Effect of different curing systems on the mechanical and physic-chemical properties of acrylonitrile butadiene rubber vulcanizates. Materials and Design 32: 3361-3369.

Fang, Y., Zhan, M. & Wang, Y. 2001. The status of recycling of waste rubber. Materials and Design 22: 123-127.

Goyanes, S., Lopez, C.C., Rubiolo, G.H., Quasso, F. & Marzocca, A.J. 2008. Thermal properties in cured natural rubber/styrene butadiene rubber blends. European Polymer Journal 44: 1525-1534.

Ismail, H. & Ahmad, H.S. 2013. Effect of halloysite nanotubes on curing behavior, mechanical, and microstructural properties of acrylonitrile-butadiene rubber nanocomposites. Journal of Elastomers and Plastics 46: 483-498.

Ismail, H. & Hairunezam, H.M. 2001. The effect of a compatibilizer on curing characteristics, mechanical properties and oil resistance of styrene butadiene rubber/ epoxidized natural rubber blends. European Polymer Journal 37: 39-44.

Ismail, H. & Poh, B.T. 2000. Cure and tear properties of ENR 25/SMR L and ENR 50/SMR L blends. European Polymer Journal 36: 2403-2408.

Ismail, H., Galpaya, D. & Ahmad, Z. 2009. Comparison of properties of polypropylene (PP)/virgin acrylonitrile butadiene rubber (NBRv) and polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr) blends. Polymer- Plastics Technology and Engineering 48: 440-445.

Ismail, H., Galpaya, D. & Ahmad, Z. 2009. The compatibilizing effect of epoxy resin (EP) on polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr) blends. Polymer Testing 28: 363-370.

Ismail, H., Nordin, R. & Noor, A.M. 2003. The effects of recycle rubber powder (RRP) content and various vulcanization systems on curing characteristics and mechanical properties of natural rubber/RRP blends. Iranian Polymer Journal 12(5): 373-380.

Ismail, H., Poh, B.T., Tan, K.S. & Moorthy, M. 2003. Effect of filler loading on cure time and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends. Polymer International 52: 685-691.

Ismail, H., Tan, S. & Poh, B.T. 2001. Curing and mechanical properties of nitrile and natural rubber blends. Journal of Elastomers and Plastics 33: 251-262.

Ismail, H., Ishiaku, U.S., Arinab, A.R. & MohdIshak, Z.A. 1998. Epoxidized natural rubber compounds: Effect of vulcanization systems and fillers. Polymer-Plastics Technology and Engineering 37(4): 469-481.

Jiamjitsiripong, K. & Pattamaprom, C. 2011. Effect of epoxidized natural rubber on gas barrier and mechanical properties of NR/BIIR composites. Journal of Elastomers and Plastics 43: 341-355.

Noriman, N.Z. & Ismail, H. 2011. The effects of electron beam irradiation on the thermal properties, fatigue life and natural weathering of styrene butadiene rubber/recycled acrylonitrile–butadiene rubber blends. Materials and Design 32: 3336-3346.

Noriman, N.Z., Ismail, H. & Rashid, A.A. 2010. Characterization of styrene butadiene rubber/recycled acrylonitrile-butadiene rubber (SBR/NBRr) blends: The effects of epoxidized natural rubber (ENR-50) as a compatibilizer. Polymer Testing 29: 200-208.

Noriman, N.Z., Ismail, H. & Rashid, A. 2008. Curing characteristics and mechanical and morphological properties of styrene butadiene rubber/virgin acrylonitrile-butadiene rubber (SBR/vNBR) and styrene butadiene rubber/recycled acrylonitrile-butadiene rubber (SBR/rNBR) blends. Polymer- Plastics Technology and Engineering 47: 1016-1023.

Perera, M.C.S., Ishiaku, U.S. & Ishak, Z.A.M. 2000. Thermal degradation of PVC/NBR and PVC/ENR50 binary blends and PVC/ENR50/NBR ternary blends studied by DMA and solid state NMR. Polymer Degradation and Stability 68: 393-402.

Rajasekar, R., Pal, K., Heinrich, G., Das, A. & Das, C.K. 2009. Development of nitrile butadiene rubber-nanoclay composites with epoxidized natural rubber as compatibilizer. Materials and Design 30: 3839-3845.

Rattanasom, N., Prasertsri, S. & Ruangritnumchai, T. 2009. Comparison of the mechanical properties at similar hardness level of natural rubber filled with various reinforcing-fillers. Polymer Testing 28: 8-12.

Rattanasom, N., Poonsuk, A. & Makmoon, T. 2005. Effect of curing system on the mechanical properties and heat aging resistance of natural rubber/tire tread reclaimed rubber blends. Polymer Testing 24: 728-732.

Zulkepli, N.N., Ismail, H. & Rashid, A. 2009. Effects of different particle sizes of recycled acrylonitrile-butadiene rubber and its blend ratios on mechanical and morphological properties and curing characteristics of SBR/NBRr blends. Iranian Polymer Journal 18(2): 139-148.

 

 

*Corresponding author; email: hazwanisyazaahmad@gmail.com