Characterization of styrene butadiene rubber/recycled acrylonitrile-butadiene rubber (SBR/NBRr) blends: The effects of epoxidized natural rubber (ENR-50) as a compatibilizer

• Published in: Polymer testing Vol. 29; no. 2; pp. 200 - 208
• Main Authors: Noriman, N.Z., Ismail, H., Rashid, A.A.
• Format: Journal Article
• Language: English
• Published: Kindlington Elsevier Ltd 01.04.2010; Elsevier
• Subjects: Acrylonitrile butadiene resins; Applied sciences; Blends; Butadiene; Compatibility; Cures; DSC; Exact sciences and technology; FTIR; Mechanical properties; NBRr; Polymer blends; Polymer industry, paints, wood; Rubber; SBR; Scanning electron microscopy; Styrenes; Technology of polymers; Waste treatment; NBRr; Mechanical properties; Scanning electron microscopy; SBR; DSC; FTIR; Scrap rubber; Property composition relationship; Molecular structure; Crosslink density; Nitrile rubber; Hardness; Experimental study; Compatibilizer; Heterogeneous mixture; Structure composition relationship; Tensile strength; Thermal properties; Vulcanization; Morphology; Epoxidized natural rubber; Recycled material
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2009.11.002

The effects of epoxidized natural rubber (ENR-50) as a compatibilizer on the properties of styrene butadiene rubber/recycled acrylonitrile-butadiene rubber (SBR/NBRr) blends were studied. Styrene butadiene rubber/recycled acrylonitrile-butadiene rubber (SBR/NBRr) blends were prepared by two-roll mill with five different compositions (i.e., 85/5/10, 75/15/10, 65/25/10, 55/35/10 and 40/50/10), with the ENR-50 content fixed at 10 phr. Cure characteristics, mechanical properties, FTIR analysis, differential scanning calorimetry (DSC) and morphology (SEM) studies were performed to determine the compatibility of SBR/NBRr blends in the presence of ENR-50. The cure characteristics showed that SBR/NBRr blends with the presence of ENR-50 have lower scorch time t 2 and cure time t 90 than SBR/NBRr blends without ENR-50. The SBR/NBRr blends with ENR-50 exhibited lower minimum torque ( M L) compared with SBR/NBRr blends without ENR-50, which indicates better processability of the blends after compatibilization. However, SBR/NBRr blends with ENR-50 exhibited a higher value of maximum torque ( M H) than SBR/NBRr blends without ENR-50. The incorporation of ENR-50 improved the tensile strength and tensile modulus (M100, stress at 100% elongation) of SBR/NBRr blends with ENR-50 compared with SBR/NBRr blends without ENR-50 at all blend ratios. Nevertheless, the addition of ENR-50 reduced the elongation at break ( E b) and rebound resilience of compatibilized SBR/NBRr blends compared with SBR/NBRr without ENR-50. The improvement in hardness upon compatibilization is due to an increase in crosslink density. FTIR analysis showed that ENR-50 is compatible with NBRr through the oxirane group and with SBR through the isoprene group. Differential scanning calorimetry results show an improvement in the compatibility of SBR/NBRr blends with the presence of ENR-50. Scanning electron microscopy (SEM) of the fracture surfaces indicates that, with the addition of ENR-50 in SBR/NBRr blends, better adhesion between SBR and NBRr was obtained, thus improving the compatibility of SBR/NBRr blends.