Titanate nanotubes and nanosheets as a mechanical reinforcement of water-soluble polyamic acid: Experimental and theoretical studies

Abstract

Titanate nanosheets (TiNS), titanate nanotubes (TiNT), and scrolled titanate nanosheets (STiNS) were used to synthesise polymer nanocomposites by solution processing. The hardness was found to increase by 90% on addition of 2% TiNS while the modulus (Er) increased by 103% compared to the pure polymer. Small angle X-ray scattering (SAXS) measurements of composite films were used to study alignment of nanostructures within the polymer. The obtained data on mechanical properties of composites have been tested against theoretical values and it was established that both nanostructures alignment as well as their mechanical properties affect the hardness and modulus of the polymer composites. At a low content of TiNS, the reinforcement behaviour matched well with Halpin-Tsai theory which assumes the filler has unidirectional orientation. After addition of 2 wt% TiNT, the hardness and modulus of the polyamic acid salt composites increased by 91% and 165%, respectively, and were higher than theoretical predictions, indicating that both TiNT and STiNS, prepared by hydrothermal synthesis, may have higher mechanical properties than bulk TiO 2. At a high filler loading (>2 wt%), the mechanical properties of composites do not fit established theories due to agglomeration of titanate nanostructures.

Voltammetric characterisation of diferrocenylborinic acid in organic solution and in aqueous media when immobilised into a titanate nanosheet film

“…Ferrocene was purchased from Fluka, t-BuLi, tetrabutylammonium hexafluorophosphate (TBAH), sodium sulphate, and sodium fluoride from Sigma Aldrich, ferroceneboronic acid from TCI Europe, and all solvents were purchased from VWR International or Sigma Aldrich. Titanate nanosheet material was synthesized as a colloidal solution (2.56 g dm −3 ) as described previously by Sasaki 26 and by Harito et al 23 Solutions were prepared under ambient condition in volumetric flasks with ultrapure water from ELGA Purelab Classic system (resistivity of 18.2 MΩ cm at 22°C).…”

“…22 In previous studies, it has been shown that such titanate nanosheets can be beneficial as an additive to polymer composite materials to improve their mechanical properties. 23 A report on potential applications of multi-layer titanate nanosheet film deposits in electroanalysis has also appeared. 24 One of the first studies with modified electrodes based on titanate nanosheets with an embedded electrochemical probe (ferroceneboronic acid) was reported recently.…”

Inhibition of Polyimide Photodegradation by Incorporation of Titanate Nanotubes into a Composite

“…7 at 0 h) probably due to the low concentration of TiNT (1 wt%) in composite. We have previously shown that improvement of mechanical properties of the TiNT/PI composites is more evident at higher filler loadings [38].…”

Incorporation of titanate nanosheets to enhance mechanical properties of water-soluble polyamic acid

“…Adding TiNS to polyethylene naphthalate (PEN) film significantly decrease helium gas permeability [7]. However, systematic study about mechanical reinforcement effects of titanate nanosheets on the polymer nanocomposite is still limited [8].…”