METAL-ORGANIC FRAMEWORK: A SMART REPLACEMENT FOR CONVENTIONAL NANOFILLERS FOR THE ENHANCEMENT OF MECHANICAL PROPERTIES AND THERMAL STABILITY OF SBR NANOCOMPOSITE

Jessy Joseph; T. K. Sreethu; Subhra Mohanty; Virendra Kumar Gupta; Anil K. Bhowmick

doi:10.5254/rct.21.79903

Article Contents

ABSTRACT
INTRODUCTION
EXPERIMENTAL
RESULTS AND DISCUSSION
COMPARISON OF REINFORCING PROPERTIES OF MOF WITH CONVENTIONAL INORGANIC FILLERS
CONCLUSIONS
REFERENCES

Editorial Type:

Article Category: Research Article

Online Publication Date: 04 Jun 2021

METAL-ORGANIC FRAMEWORK: A SMART REPLACEMENT FOR CONVENTIONAL NANOFILLERS FOR THE ENHANCEMENT OF MECHANICAL PROPERTIES AND THERMAL STABILITY OF SBR NANOCOMPOSITE

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Page Range: 515 – 532

DOI: 10.5254/rct.21.79903

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ABSTRACT

To the best of our knowledge, for the first time, metal-organic framework (MOF), a porous reticular structure, has been tried as a reinforcing filler for rubber. A MOF synthesized by solvothermal reaction between 2-aminoterephthalic acid and aluminum chloride hexahydrate was characterized and incorporated as reinforcing filler in SBR. A comparative investigation on the properties of the well-dispersed, thermally stable nano-MOF composite (SBR-MOF) was carried out with reference to SBR–nano alumina composite (SBR-nAl). The SBR-MOF was mechanically more robust than SBR-nAl. The SBR-MOF showed 130% improvement in tensile strength over the pristine SBR composite and 50% better elongation at break than SBR-nAl at 10 phr loading. The thermal and dynamic mechanical properties of SBR-MOF are superior to SBR-nAl composite. The highly porous organic framework was favorable for the enhanced entanglement of polymer chains at the interface. The effectiveness of the organic framework on the dispersion and compatibility was evaluated by scanning electron microscopy. The dispersion studies substantially supported the overall property enhancement. To substantiate the superiority of MOF in the rubber matrix, the tensile properties of SBR-MOF were compared with SBR composites filled with nano silica, nano titania, as well as nano silica and nano alumina with a compatibilizer, thereby documenting a promising nanofiller for introduction into the rubber industry.

Fig. 1. —

(a) Schematic representation of the synthesis of NH₂-MIL-53(Al); (b) reaction and structure of NH₂-MIL-53(Al). Color code: violet, carbon; blue, aluminum; red, oxygen; white, nitrogen; green, hydrogen; sky blue, AlO₆ polyhedra.

Fig. 2. —

Structure of nano alumina.

Fig. 3. —

Schematic representation of the preparation of SBR nanocomposites.

Fig. 4. —

FTIR spectra of (a) NH₂-MIL-53(Al) and (b) nano alumina.

Fig. 5. —

XRD diffractogram of (a) NH₂-MIL-53(Al) and (b) nano alumina.

Fig. 6. —

TEM image of (a) NH₂-MIL-53(Al), (b) a single NH₂-MIL-53(Al) particle, and (c) nano alumina.

Fig. 7. —

Stress–strain curves of SBR, SBR-nAl, and SBR-MOF.

Fig. 8. —

Mechanical properties of SBR, SBR-nAl, and SBR-MOF composites.

Fig. 9. —

Maximum elongation attained by SBR, SBR-nAl, and SBR-MOF.

Fig. 10. —

Cross-link density of SBR, SBR-nAl, and SBR-MOF.

Fig. 11. —

SEM image showing the dispersion of filler in (a) SBR-nAl, (b) SBR-MOF at 10 μm scale, and (c) SBR-MOF micrograph at 200 nm scale.

Fig. 12. —

Schematic representation of interaction between porous NH₂-MIL-53(Al) and SBR. Color code: violet, carbon; blue, aluminum; red, oxygen; white, nitrogen; green, hydrogen; sky blue, AlO₆ polyhedra.