Fabrication and characterization of novel highly transparent and organo-soluble poly(ether imide)s thin film for gas separation

Abstract

A novel diamine with ether and phenyl linkages was prepared in two steps by the nucleophilic substitution reaction of 2-(2-hydroxy-5-methylphenylsulfinyl)-4-methylphenol and 1-chloro-4-nitrobenzene in N,N 0dimethylacetamide, followed by reduction with hydrazine monohydrate and Pd/C in ethanol. Four series of solution-processable aromatic poly(ether imide)s (PEI)s were prepared from the newly synthesized diamine and various dianhydrides via one-step high-temperature solution polymerization. The diamine monomer and PEIs were characterized by elemental analyses, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The inherent viscosities of the obtained poly(amic acid) (PAA) ranged from 1.09 to 1.93 dL g À1 at a concentration of 0.5 g dL À1 in N,N 0 -dimethylacetamide at 30 1C. All the obtained polymers were readily soluble in polar solvents and showed useful levels of thermal stability associated with high glass-transition temperatures (T g , 279-303 1C) and high char yields (higher than 62% at 800 1C in nitrogen).Flexible and transparent films were obtained easily by solution casting. The cast films exhibited high optical transparency and almost no color with a UV-Vis absorption edge of 368-382 nm. These films also showed excellent mechanical properties with tensile strengths of 118-154 MPa and elongations at breakage of 11-15%. The combination of excellent solubility, film quality, and thermal stability makes these PEIs potential candidates for high-performance gas separation membrane applications by solution-casting processes. Permeability measurements were made for O 2 , H 2 , CO 2 and CH 4 at 35 1C.

Synthesis of highly transparent and heat‐resistant polyimides containing bulky pendant moieties

“…Different approaches have been reported in order to improve the transmittance and solubility of PI films, including the incorporation of flexible linkages, fluorinated structures, unsymmetrical or noncoplanar structures, alicyclic structures in the backbone and the introduction of bulky pendant substituents to the polymer chains . On the other hand, the solubility and transparency of PI films could be improved by the incorporation of flexible lineages like –O– or –S–.…”

Multi-functional polydopamine coating: simultaneous enhancement of interfacial adhesion and CO2 separation performance of mixed matrix membranes

“…Membrane separation is one of the potential methods to remove CO 2 from flue gas. [1][2][3] Compared with traditional separation techniques such as cryogenic distillation or absorption, membrane-separation technology has advantages of low energy consumption, mechanical simplicity, ease to scale up and a smaller footprint. 4 Polymeric membranes suffer from a trade-off between permeability and selectivity, i.e., polymers with high gas permeability generally have low gas selectivity and vice versa.…”

In situ thermal synthesis of novel polyimide nanocomposite films containing organo-modified layered double hydroxide: morphological, thermal and mechanical properties

“…31 Of thermally stable organic polymers, the excellent properties of aromatic PIs such as outstanding thermooxidative stability and higher chemical resistance led to the use of PIs in different areas, such as insulating materials for electronics, semipermeable membranes for gas separation, and high-temperature adhesives and coatings. 32,33 In spite of their excellent properties, aromatic PIs have a few problems in which inefficient processability is the most obvious one originating from their very high glass-transition temperature and lack of efficient solubility in common organic solvents. 34 Therefore, extensive efforts such as introducing bulky pendant groups, flexible linkage, noncoplanar structures and copolymerizing from different diamines or dianhydrides have been made to improve their processability.…”

“…3,[20][21][22] Organically modified LDH have been dispersed in various polymers, such as polypropylene, 23 polystyrene, 24 poly (methyl methacrylate), 25 polylactide, 26 polyimide (PI), 27 poly(amide-imide) 28 and poly(ethylene glycol diacrylate). 32,33 In spite of their excellent properties, aromatic PIs have a few problems in which inefficient processability is most obvious one originating from their very high glass-transition temperature and lack of efficient solubility in common organic solvents. 30 Thermally stable organic polymers have been the subject of various studies to enlarge the application of organic materials in harsh environment.…”