Selectively Etched Halloysite Nanotubes as Performance Booster of Epoxidized Natural Rubber Composites

Abstract

Halloysite Nanotubes (HNT) are chemically similar to clay, which makes them incompatible with non-polar rubbers such as natural rubber (NR). Modification of NR into a polar rubber is of interest. In this work, Epoxidized Natural Rubber (ENR) was prepared in order to obtain a composite that could assure filler–matrix compatibility. However, the performance of this composite was still not satisfactory, so an alternative to the basic HNT filler was pursued. The surface area of HNT was further increased by etching with acid; the specific surface increased with treatment time. The FTIR spectra confirmed selective etching on the Al–OH surface of HNT with reduction in peak intensity in the regions 3750–3600 cm−1 and 825–725 cm−1, indicating decrease in Al–OH structures. The use of acid-treated HNT improved modulus, tensile strength, and tear strength of the filled composites. This was attributed to the filler–matrix interactions of acid-treated HNT with ENR. Further evidence was found from the Payne effect being reduced to 44.2% through acid treatment of the filler. As for the strain-induced crystallization (SIC) in the composites, the stress–strain curves correlated well with the degree of crystallinity observed from synchrotron wide-angle X-ray scattering.

Improved cure characteristics and mechanical properties of an epoxidized natural rubber filled with cerium oxide nanoparticles: Influence of epoxide levels and filler loading

“…42 The Payne effect and dispersion of CeO 2 nanoparticles in the ENR matrix were elevated by the difference between the storage shear modulus (G 0 ) at low strain (0.5%) and higher strain (90%). 43…”

Synergies in antimicrobial treatment by a levofloxacin-loaded halloysite and gold nanoparticles with a conjugation to a cell-penetrating peptide

“…3600 cm À1 ) to a double keen peak corroborates successful activation of the HNTs, especially the interior layers (alumina). 73 Again, aer surface-modifying of the tubes by MPTMS, the separated peaks of AlO-H have been converted to a broad peak, conrming the good coating of the surfaces (spectrum c). As is observed, the intensity of the peak that appeared at ca.…”

Insight into Mechanical Properties and Strain-induced Crystallisation of Epoxidized Natural Rubber Filled with Various Silanized Halloysite Nanotubes

“…NR was first modified into an epoxidized natural rubber (ENR) and further applied as a matrix to ensure HNT-rubber compatibility. Although the performance of this solution is well reported 4,6 , it was still unsatisfactory as HNT characteristics could themselves be to blame; particularly the interfacial filler-matrix adhesion. This includes the use of silane coupling agents 7 , modifying the compounding methods 8 , and using compatibilizers 9 .…”