Phenolphthalein-based Poly Research Articles

Synthesis, characterization, and thermal pyrolysis mechanism of high temperature resistant phenolphthalein-based poly (arylene ether nitrile)

Phenolphthalein (PP) is usually used as a functional monomer to design novel high performance polymers with adjustable thermal, mechanical, and fluorescent properties. In this study, a soluble, amorphous, high temperature resistant PP-based poly (arylene ether nitrile) (PAEN) was synthesized and its corresponding thermal decomposition mechanism was reported via TGA/DTG, TGA/FTIR and TGA/MS analysis. PP-based PAEN showed a Tg of 250 °C a Tdmax of 503 °C and a char residue of 59.2 % at 800 °C, respectively. According to Kissinger and Flynn–Wall–Ozawa model, the activation energy of thermal pyrolysis was calculated as 225 ± 4 and 284 ± 17 kJ/mol respectively, higher than those of other poly arylene ethers. PP-based PAEN showed a three-stage thermal pyrolysis mechanism. Its initial degradation happened before 400 °C and liberated the inherent moisture. The latter backbone decomposition between 400 and 600 °C involved multiple routes mainly from the CO and CC cleavages of lactone ring, resulting in a Ph2CHPhOPh intermediate by releasing HCHO, HCOOH, CO2, H2O, CH4, C6H6, and C6H5OH. The third carbonization stage over 600 °C included the transformation from biphenyl linkages to aromatic graphite by dehydrogenation. This study not only gives a comprehensive understanding of the thermal pyrolysis behavior of PP-based PAEN, but also provides valuable references for the thermal behaviors of other PP-containing polymers.

Separation performance enhancement of PEEKWC/PEI cross-linked ultrafiltration membranes by poly(ethylene glycol) and polyvinylpyrrolidone as polymeric additives

In order to improve both pure water flux and retention rate of the cross-linked ultrafiltration membranes based on phenolphthalein-based poly(ether ether ketone) (PEEKWC) and polyethyleneimine (PEI), poly(ethylene glycol) (PEG) and polyvinylpyrrolidone (PVP) were used as polymeric additives in non-solvent-induced phase separation process. The characterizations, separation effectiveness, and anti-fouling performance of membranes were investigated. Compared with n-butanol additive, the PEG and PVP could accelerate the phase separation rate and form thinner and denser skin layer, and then that led to an increase in the fluxes of pure water and better dye retention performance. In addition, the impact of variable additive dosage on the pure water flux and retention for dye solutions was investigated, and the pure water flux of membranes could reach 3270.8 L·m−2·h−1 and 2494.5 L·m−2·h−1 at a PEG or PVP concentration of 0.5 wt%, respectively. These membranes also exhibited excellent retention performance for Coomassie brilliant blue and Congo red greater than 98%. The simultaneous improvement of pure water flux and retention performance also could be related to the more efficient water transmission channel forming which was investigated by atomic force microscope phase images. In anti-fouling performance tests, the membranes demonstrated effective anti-fouling properties with a high flux recovery ratio after external cleaning with water only.

Design and synthesis of novel phenolphthalein-based poly (aryl ether) resin containing isopropyl groups

With the rapid development of 5G technology, low dielectric constant materials present a widespread application prospect in microelectronic devices. Poly (aryl ether) resins have been widely used in this field due to their excellent thermal stability, mechanical properties and electrical insulation properties, however, reducing its dielectric constant remains a challenge. In this study, novel phenolphthalein poly (aryl ether ketone) containing isopropyl groups and fluorene groups was successfully synthesized with high molecular weight via SN2 aromatic nucleophilic polycondensation reaction. At lower frequencies ranging from 10 Hz to 1 MHz and higher frequencies from 10 GHz to 42 GHz, the films exhibit the intrinsic dielectric constant in the range of 2.4–2.7. The resin has good thermal stability, mechanical properties and insulation properties. Thus, the functional poly (aryl ether ketone) possesses attractive potential applications in the field of high-performance flexible electronic packaging materials.

High-performance carbon molecular sieve membrane for C2H4/C2H6 separation: Molecular insight into the structure-property relationships

Carbon molecular sieve (CMS) membranes show attractive potential for energy-efficient separation of C2H4/C2H6 due to their unique slit-like pore structure. In this work, a novel precursor polymer of phenolphthalein-based poly(arylene ether ketone) (PEK-C) was introduced to prepare high-performance CMS membranes for C2H4/C2H6 separation. Molecular insight into the effect of the sp3/sp2 hybridized carbon ratio on the packing morphology of carbon layers, pore size and configuration, and C2H4/C2H6 diffusion and separation properties of CMS membranes was investigated via using in-depth characterization techniques combined with molecular simulations. Results show that the carbon layers with more sp3 hybridized carbons lead to forming a loose and disordered carbon structure and pore structure with large pore volume and micropore size (steric voids), resulting in low C2H4/C2H6 permselectivity of CMS membrane. With the reduction of the sp3/sp2 hybridized carbon ratio, a compact and graphite-like carbon structure with the two-dimensional slit-like ultramicropore structure is formed, and the C2H4/C2H6 permselectivity is obviously enhanced. The CMS membranes derived from the novel precursor of PEK-C exhibit high C2H4 permeability with superior C2H4/C2H6 selectivity, which have surpassed the trade-off bounds of both polymeric membrane and CMS membrane, and reveal a great potential in the industrial applications of C2H4/C2H6 separation.

MOF-derived nanocomposites functionalized carbon molecular sieve membrane for enhanced ethylene/ethane separation

Fine tailoring the pore structure and sorption capability of carbon molecular sieve (CMS) membrane is highly desirable for efficient separation of C2H4/C2H6 gas pair. In this work, a facile approach was proposed to enrich the ultramicroporosity of CMS membrane and enhance the affinity adsorption capacity for C2H4, in which ZIF-8 nanoparticles were incorporated into a novel precursor polymer of phenolphthalein-based poly (arylene ether ketone) (PEK-C) followed by carbonization to prepare mixed matrix CMS membranes to achieve simultaneously high C2H4 permeability and high C2H4/C2H6 selectivity. The ZIF-8-derived nanocomposites partially maintain the pore structure of ZIF-8 precursor, and have good compatibility with the carbon matrix. The BET surface areas, micropore volume and the number of ultramicropore with molecular sieving ability of CMS membrane are greatly improved due to the introduction of ZIF-8-derived microporous carbons, resulting in a significant increase in the C2H4 permeability and C2H4/C2H6 diffusion selectivity. The C2H4/C2H6 sorption selectivity of CMS membrane is also enhanced owing to the selective adsorption affinity of the ZIF-8-derived Zn2+ metal oxides for C2H4. The C2H4 permeability of mixed matrix CMS membrane with 10 wt% ZIF-8 loading is increased by 42% compared to that of neat CMS membrane, and the C2H4/C2H6 selectivity is increased by 102%.

Synthesis and properties of low dielectric constant phenolphthalein-based poly (aryl ether) resin containing isopropyl groups

In this study, a novel phenolphthalein poly (ether nitrile) containing isopropyl groups (iPrPENC) was successfully synthesized via SN2 aromatic nucleophilic polycondensation. The flexible and tough iPrPENC films exhibited an intrinsic low dielectric constant value of 2.86 at the frequency of 1 MHz. The resin has good thermal stability and mechanical property. In addition, it can be dissolved in common organic solvents. Thus, the functional poly (aryl ether nitrile) possessed attractive potential applications in the field of high-performance flexible electronic packaging materials.

Thermal crosslinking membrane with enhanced CO2 separation performance derived from nitrile-containing phenolphthalein-based poly(arylene ether ketone)

Enhancing gas permeabilities of thermal crosslinking membranes while retaining adequate selectivity is of great significance for industrial applications. In this work, a novel and commercial polymer of nitrile-containing phenolphthalein-based poly (arylene ether ketone) (PEK-C(CN)) was introduced to prepare thermal crosslinking membranes via pretreatment in air and subsequent thermal crosslinking treatment in N2, and the high permselectivity for CO2/CH4 and CO2/N2 gas pairs was achieved. The ATR-FTIR and XPS results demonstrated that the nitrile groups might undergo thermal cyclotrimerization reaction with the formation of stable triazine rings across molecular chains during the pretreatment, which is conducive to the preparation of defect-free and highly permeable thermal crosslinking membranes. During thermal crosslinking treatment, the Cardo moieties decomposed and induced crosslinking with forming bulky biphenyl linkages between polymeric chains, accompanied with pyrolysis of some nitrile groups, which resulted in an increase in interchain distance and microvoid size. The CO2 permeability of the resulting thermal crosslinking membrane was increased to around 3 times without sacrificing CO2/CH4 and CO2/N2 selectivities due to the incorporation of nitrile groups, compared to the thermal crosslinking membrane derived from nitrile-free PEK-C. For equimolar binary mixture gases, the fully crosslinked membranes present the CO2 permeability of around 1300 Barrer with CO2/CH4 and CO2/N2 separation factors of 32.6 and 35.8, respectively, which offer a promising alternative in CO2 capture and separation.

Enhanced ionic conductivity of anion exchange membranes by grafting flexible ionic strings on multiblock copolymers

A new strategy to prepare high-conductivity anion exchange membranes (AEMs) is presented here. A series of phenolphthalein-based poly(arylene ether sulfone nitrile) multiblock AEMs has been synthesized by selectively grafting flexible ionic strings on hydrophilic segments to form ionic regions. Moreover, the phenolphthalein groups are introduced to force chains apart and create additional interchain spacing. In addition, the nitrile groups suspended on main chains are aimed at enhancing the anti-swelling behavior of as-prepared AEMs. Along these processes, well-defined phase separation has been attained, forming excellent ion-transport channels. The effective phase separation has been confirmed by atomic force microscopy. Finally, as-prepared AEMs exhibit a high hydroxide conductivity, ranging from 40.1 to 121.6 mS cm−1 in the temperature range of 30–80 °C, and superior ionic conductivity to IEC ratio at 80 °C. Furthermore, excellent thermal stability and desirable mechanical strength have been rendered by as-prepared AEMs. However, the alkaline stability of as-prepared AEMs requires further optimization.

Imidazolium-functionalized poly (arylene ether ketone) cross-linked anion exchange membranes

A series of phenolphthalein-based poly (arylene ether ketone) (PEK) copolymer are synthesized to prepare anion exchange membranes (AEMs). The ion group 1-vinyl imidazole is introduced on the unit of phenolphthalein-based as a hydrophilic segment and cross-linking agent. The structure of resulting membranes was investigated by 1H NMR and FT-IR. The well-defined microphase-separated structures were verified by TEM and SAXS profiles. The cross-linked membrane of ImPEK-0.4 exhibits high hydroxide conductivity (0.0836 S/cm, at 80 °C), excellent mechanical performance (69.6 MPa) and the maximum swelling ratio is only 7.95% at 80 °C. Furthermore, the excellent alkaline stability is demonstrated by immersing the prepared membrane in 1 M NaOH at 40 °C for 400 h. The ionic conductivity is still high to 0.0381 S/cm for ImPEK-0.4. These results indicate that combining phase separation architecture and crosslinking may possess potential applications for alkaline fuel cells (AFCs).

Perforative silica microsphere-modified phenolphthalein-based poly(arylene ether sulfone) composites: tensile and thermal properties

Perforative silica microspheres (PSMs) were prepared by an emulsion method coupled with sol–gel technology and phase separation. Next, phenolphthalein-based poly(arylene ether sulfone)/PSM composites (PES-C/PSM) were fabricated. PSM was characterized by scanning electron microscopy (SEM) and the Brunauer–Emmett–Teller (BET) method. The as-synthesized PSM exhibited a spherical shape with an external diameter of 2–10 µm, surface area of 166.5 m2/g and pore volume of 1.35 cm3/g. SEM and energy-dispersive spectroscopy (energy-dispersive spectroscopy) were used to characterize the morphology and the composition of the composite, respectively. Both SEM and energy-dispersive spectroscopy results revealed that the PES-C polymer chains penetrated into the PSM pores. In addition, the effect of PSM weight content on the mechanical properties and thermal stability of the composites was characterized by tensile tests and thermal analysis, respectively. A 19% increase in tensile strength and a 29% increase in breaking elongation of PES-C were achieved by the addition of 0.50 wt% PSM. Moreover, the thermal oxidative stability of PES-C was remarkably improved with the incorporation of PSM. Compared with pristine PES-C, the final degradation temperature was enhanced by 42 °C at 1.0 wt% PSM loading. Our studies have indicated that PSM is a kind of promising reinforcement for improvement of tensile and thermal properties of engineering plastics.

Comb-shaped phenolphthalein-based poly(ether sulfone)s as anion exchange membranes for alkaline fuel cells

A series of novel comb-shaped phenolphthalein-based poly(ether sulfone)s was synthesized for preparing anion exchange membranes (AEMs).

Side-chain-type phenolphthalein-based poly(arylene ether sulfone nitrile)s anion exchange membrane for fuel cells

A series of phenolphthalein-based poly(arylene ether sulfone nitrile)s containing imidazolium groups on the side chains was synthesized to prepare anion exchange membranes (AEMs) for alkaline fuel cells. Strong polar nitrile groups were introduced into the polymer backbone with the intention of improving the dimensional stability of the AEMs. The content of nitrile groups was varied to study the effect of nitrile groups on the morphology and properties of the AEMs. With imidazolium groups locating on the cardo side chains, all the AEMs exhibited well-defined microphase-separated structures. Furthermore, the imidazolium groups tend to aggregate with increasing the nitrile group content resulting in the formation of larger and more interconnected ionic domains in the AEMs. The ionic conductivity in the range of 2.21–8.14×10−2Scm−1 increased with increasing the nitrile group content and temperature. The AEMs showed superb ratios of conductivity to IEC or swelling ratio at 60°C, good mechanical properties, and thermal and alkaline stability. A single H2/O2 fuel cell using the as-prepared AEMs showed an open circuit voltage of 0.95V and a peak power density of 50.6mWcm−2 at 60°C.

Phenolphthalein-based Poly(arylene ether sulfone nitrile)s Multiblock Copolymers As Anion Exchange Membranes for Alkaline Fuel Cells.

A series of phenolphthalein-based poly(arylene ether sulfone nitrile)s (PESN) multiblock copolymers containing 1-methylimidazole groups (ImPESN) were synthesized to prepare anion exchange membranes (AEMs) for alkaline fuel cells. The ion groups were introduced selectively and densely on the unit of phenolphthalein as the hydrophilic segments, allowing for the formation of ion clusters. Strong polar nitrile groups were introduced into the hydrophobic segments with the intention of improving the dimensional stability of the AEMs. A well-controlled multiblock structure was responsible for the well-defined hydrophobic/hydrophilic phase separation and interconnected ion-transport channels, as confirmed by atomic force microscopy and small angle X-ray scattering. The ImPESN membranes with low swelling showed a relatively high water uptake, high hydroxide ion conductivity together with good mechanical, thermal and alkaline stability. The ionic conductivity of the membranes was in the range of 3.85-14.67×10(-2) S·cm(-1) from 30 to 80 °C. Moreover, a single H2/O2 fuel cell with the ImPESN membrane showed an open circuit voltage of 0.92 V and a maximum power density of 66.4 mW cm(-2) at 60 °C.

Synthesis and Characterization of Phenolphthalein-based Poly(arylene ether sulfone) Hydrophilic−Hydrophobic Multiblock Copolymers for Proton Exchange Membranes

Hydrophilic−hydrophobic alternating multiblock poly(arylene ether sulfone) copolymers containing 4,4′-biphenol (BP) or phenolphthalein (PPH) were synthesized via a coupling reaction between phenoxi...

Amorphous phenolphthalein-based poly(arylene ether)- modified cyanate ester networks: Effect of thermal cure cycle on morphology and toughenability

Reactive functional thermoplastic poly(arylene ether) toughness modifiers were demonstrated to enhance toughness of brittle thermosetting cyanate ester networks and also allowed retention of a highly desirable stability to solvent stress cracking and a moderately high modulus. Careful control of the heterophase morphological structure was necessary to achieve significant toughening. In contrast to the well-defined morphologies of the reactive thermoplastic-modified networks, the use of nonreactive simple physical blend modifiers of the same molecular weight and backbone chemistry produced a macrophase separation and no apparent control over the sizes of the phase-separated domains. Macrophase-separated morphologies are inherently process-sensitive and less desirable from the point of performance control and prediction. Generation of controlled microphase-separated morphologies can be achieved by systematically varying thermal cure cycles in the case of the reactive thermoplastic-modified systems. Such a cure cycle dependence of the morphology was particularly demonstrated for the case of the 25 wt % 15,000 (Mn) (15K) phenolphthalein-based hydroxy-functionalized poly(arylene ether sulfone) (PPH-PSF-OH)-modified networks. Morphologies that exhibit finer textures of the phase separated domains usually result in lower fracture toughness values. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 167–178, 1997

Amorphous phenolphthalein-based poly(arylene ether)- modified cyanate ester networks: Microwave processing

Amorphous phenolphthalein-based poly(arylene ether)- modified cyanate ester networks: Microwave processing