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

Diserahkan: 15 Januari 2014/Diterima: 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

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*Pengarang untuk surat-menyurat; email: hazwanisyazaahmad@gmail.com