Gas Transport Properties of Polybenzimidazole and Poly(Phenylene Oxide) Mixed Matrix Membranes Incorporated with PDA-Functionalised Titanate Nanotubes

Abstract

Functionalised titanate nanotubes (TiNTs) were incorporated to poly(5,5-bisbenzimidazole-2,2-diyl-1,3-phenylene) (PBI) or poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) for improving the interfacial compatibility between the polymer matrix and inorganic material and for altering the gas separation performance of the neat polymer membranes. Functionalisation consisted in oxidative polymerisation of dopamine-hydrochloride on the surface of non-functionalised TiNTs. Transmission electron microscopy (TEM) confirmed that a thin polydopamine (PDA) layer was created on the surface of TiNTs. 1.5, 3, 6, and 9 wt.% of PDA-functionalised TiNTs (PDA-TiNTs) were dispersed to each type of polymer matrix to create so-called mixed matrix membranes (MMMs). Infrared spectroscopy confirmed that –OH and –NH groups exist on the surface of PDA-TiNTs and that the nanotubes interact via H-bonding with PBI but not with PPO. The distribution of PDA-TiNTs in the MMMs was to some extent uniform as scanning electron microscope (SEM) studies showed. Beyond, PDA-TiNTs exhibit positive effect on gas transport properties, resulting in increased selectivities of MMMs. The addition of nanotubes caused a decrease in permeabilities but an increase in selectivities. It is shown that 9 wt.% of PDA-TiNTs in PBI gave a rise to CO2/N2 and CO2/CH4 selectivities of 112 and 63 %, respectively. In case of PPO-PDA-TiNT MMMs, CO2/N2 and CO2/CH4 selectivity increased about 25 and 17 %, respectively. Sorption measurement showed that the presence of PDA-TiNTs in PBI caused an increase in CO2 sorption, whereas the influence on other gases is less noticeable.

A Multiscale Approach for Estimating Permeability Properties of Polymers with Complex Aromatic Backbones: A Case Study on Diffusivity of Small Gas Molecules in Polyphenylene Ether

“…A comparison of the calculated diffusion coefficients, given in Table 6, with experimental data from Giel et al [10] and with molecular simulations performed by Fried et al [11] using the condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) molecular mechanics force field is shown in Figure 11. Figure 11 proofs a proper prediction of diffusion coefficients of gas molecules in PPE using MD simulations.…”

“…[3][4][5][6] In order to overcome the inherent limitations in its processability, [7] PPE is widely employed in the form of miscible or immiscible blends with a variety of other polymers. [7][8][9][10] When developing barrier or selective permeability solutions with PPE, it then becomes critical to screen the permeability properties of a multitude of formulations with PPE so as to balance permeability with processability. Computational chemistry can be leveraged very effectively in such scenarios to carry out an initial screening of the formulations before planning experimental formulation trials.…”

“…In this report, we implement a multiscale approach implemented in commercially available software chemistry unified language interface (CULGI) [12] to arrive at the estimates of diffusivity of five different gases (H 2 , CO 2 , N 2 , O 2 , and CH 4 ) through PPE; these estimates are validated against experimental measurements. [10] In Section 1.2, a synopsis of multiscale computational chemistry approaches for polymeric materials is provided, followed by a brief description of the specific approach followed in this study in Section 1.3. Section 2 details the steps followed in the approach and the parameterization of the multiscale modeling steps.…”

Nanotubes Reinforcement of Degradable Polymers for Orthopedic Applications

“…Moreover, TiNTs compositions and structures may be practically unlimited and, by functionalization, their adhesion to polymer matrices can be improved. 38 A few studies have been performed for the use of TiNTs in reinforcement of polymer matrices. Reinforcement of a polymer composite film PEO/CS with 25 wt% content of TiNTs was found to be 2.6 times harder than the neat polymer blend and 3.4 times stiffer.…”

“…functionalization with poly dopamine (PDA) improves the interfacial compatibility between the polymer matrix and inorganic material. 38 Silicon(Si) doped into the titanium dioxide nanotubes on Ti surface, using plasma immersion ion implantation, significantly enhanced the expression of genes related to osteogenic differentiation and improved bone-Ti integration. 78 Ion exchange of one-dimensional titanate nanotubes (TiONTs) can alter their biological activities.…”