Synthesis of silane functionalized sodium titanate nanotubes and their influence on thermal and mechanical properties of epoxy nanocomposite

Abstract

Sodium titanate nanotubes (NaTiNTs) were prepared by hydrothermal method and functionalized with three different silane coupling agents. The existence of the chemical bond between silane molecules and nanoparticles was confirmed by scanning electron microscopy (SEM) equipped with electron dispersive X-ray spectroscopy (EDS) mapping, Fourier transform infrared (FTIR) spectroscopy, and simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TGA). NaTiNTs before and after functionalization were characterized by X-ray diffraction (XRD) technique. Functionalized NaTiNTs were used to prepare epoxy-based nanocomposites with three different wt.% of nanofillers (1, 2, and 3 wt.% per epoxy). The thermal and mechanical properties of prepared nanocomposites were studied by DSC, DSC-TGA, and dynamic mechanical analysis (DMA). The obtained results were compared to the epoxy. The results showed that the glass transition temperature increased from 72 to 79 8C. Storage modulus increased by 10.4% at 3 wt.% nanotubes. From all results appropriate functionalized NaTiNTs were chosen and nanocomposites for determination of combustion properties by cone calorimeter were prepared (1, 3, and 5 wt.% of nanofiller per epoxy). Significant reduction of the heat release rate (HRR) depending on the inorganic particles loading was observed. The peak value for HRR was reduced by about 40% compared to the epoxy, while ignition time and total heat release (THR) are not significantly affected by the presence of the inorganic particles.

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

“…by the controlled hydrolysis of trialkoxysilanes (e.g. Si(EtO) 3 R) in anhydrous solvents to link any organic group via a strong Ti-O-Si-C bond [76] or by esterification with carboxylic acids in anhydrous alcohol [77]. The linked organic groups may then serve as a template for subsequent chemical reactions, e.g.…”

Layered titanate nanostructures: perspectives for industrial exploitation

“…Covalent functionalization is beneficial when anisotropic layered titanates are used as polymer fillers. Brnardic et al reported 7 °C higher glass transition temperature and 10.4% higher storage modulus in epoxy composites loaded with 3 wt% silanized titanate nanotubes [143].…”

“…This anchors the R chain onto the titanate by a strong Ti-O-Si-C bond. The primary use of this reaction is covalent hydrophobization, however, if the R group is reactive enough then it can also serve as a bridgehead for further organic functionalization steps and subsequent polymer grafting for nanocomposite applications [142][143][144]. The surface -OH groups can enter an esterification reaction with carboxylic acids in anhydrous alcohol [145].…”

Composites of Inorganic Nanotubes and Polymers

“…The composite material obtained was tested in light-emitting devices realizing a new class of device with promising improved mechanical and thermal properties without affecting the optoelectronic performance of the device [4]. Brnardić and co-workers report the synthesis, by a hydrothermal method, and functionalization of sodium titanate nanotubes (NaTi-NTs) [5]. Addition of low concentrations of NaTi-NTs to an epoxy resin resulted in an increase in the glass transition temperature (T g ) and storage modulus (E′) of the epoxy, and interestingly, the combustion properties, specifi cally the heat release rate (HRR) of the [6].…”