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The current study deals with the fabrication of crosslinked epoxy composites reinforced with several loadings of aluminum nanorods (i.e., 5, 10, 15 and 20) wt% by a hand lay-up technique. Both pyromellitic dianhydride and glycerin utilized as cross-linker agents. The thermal, morphological and mechanical properties of the resultant composites were characterized as a function of nanorods content and type of cross-linker using a wide range of analytical and testing techniques. The results showed that using a combination of pyromellitic dianhydride and glycerin provide more adhesion efficiently between the nanorods and epoxy compared to the individual cross-linker. Also, the results demonstrated that both tensile and flexural strengths, and their moduli were increased with adding nanorods content up to 15 wt% followed by the moderate improvement. The maximum value of tensile, flexural strengths, tensile modulus and flexural modulus are ~ (6000, 96, 5000, 10,000) MPa, respectively; for crosslinked epoxy composites, which are higher than of pure epoxy by ~ (20, 37, 56, 53)%. Comparably, thermal degradation temperature (i.e., 300 °C) of the plain epoxy is shifted slightly toward higher temperature after the cross-linking reaction, which is likely due to a good interaction between epoxy molecules leads to an improvement in the thermal stability of the composite materials. In addition, both glass transition and melting temperatures of the crosslinked epoxy samples increased from by 37.6% and 11.7%, respectively. These results correlate with images from scanning electron microscopy, which showed less agglomeration and good distribution of nanorods particles into the crosslinked epoxy matrix. [ABSTRACT FROM AUTHOR]

New 2,6-bis(1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl)pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone (2Tris@PMDA) and its polymeric hybrids with Anderson polyoxometalates (DiTA@PMDA) and with Lindquist polyoxometalates (DiTL@PMDA) have been synthesized and thoroughly characterized. Using dr. Blade's approach, TiO2 based thin films of 2Tris@PMDA, DiTA@PMDA, and DiTL@PMDA have been designed to explore the adsorption study, optical activity, and photocurrent generation. The calculated electrical conductivity values for 2Tris@PMDA, DiTA@PMDA and DiTL@PMDA were 2.8 × 103 S/m−1.90 × 103 S/m, 2.7 × 103 S/m−1.7 × 103 S/m, and 2 × 103 S/m−1.65 ×103 S/m, respectively. Furthermore, computational analysis for 2Tris@PMDA, DiTA@PMDA, and DiTL@PMDA has been studied at B3LYP using 6-31 G (d, p) and LanL2DZ level of density functional theory. It indicates that the conjugation of 2Tris@PMDA with polyoxometalates makes them a suitable candidate for dye sensitized solar cell due to the charge transfer process in DiTA@PMDA and DiTL@PMDA. [ABSTRACT FROM AUTHOR]

The nanocrystalline HZSM‐5 was synthesized by supercritical hydrothermal synthesis for the first time and investigated in catalytic esterification of pyromellitic dianhydride(PMD)and n‐butanol to tetrabutyl pyromellitate(TBPM). The HZSM‐5 prepared by conventional hydrothermal synthesis was also examined for comparison. The catalysts were studied using XRD, N2 adsorption, NH3‐TPD, Pyridine‐adsorption FT‐IR, SEM,[27] Al MAS NMRandCHNS analysis. According to the results of characterization, the supercritical hydrothermal condition was helpful to reduce the size of crystal particles and improve the crystallinity of HZSM‐5, and shorten the crystallization time. The surface area, especially external surface area, and pore volume were increased, and the total acidity was increased. The strong acid sites were transformed into the weak acid sites, and the strength of weak and strong acid was weakened. The amount of framework tetrahedral Al species and Brönsted acid sites were increased. Therefore, the formation of coke was retarded, and thePMD conversion, the TBPM selectivity and the catalytic stability were obviously improved. [ABSTRACT FROM AUTHOR]

The development of high-performance media for protein adsorption in bio-purification is highly desired, particularly in biological pharmaceuticals. In this study, we demonstrate a simple, versatile and mild strategy to construct a nanofibrous aerogel (NFA)-based adsorption media for protein purification. Pyromellitic dianhydride (PMDA) was selected to in-situ graft onto poly(ethylene- co -vinyl alcohol) (PE-co-PVA) nanofibers in aerogels through liquid phase grafting. The obtained PE-co-PVA/PMDA NFAs (PPNAs) possessed superb underwater elasticity, compression fatigue resistance and shape-memory performance. With an open porous network, abundant adsorption ligands, and surface hydrophilicity, the PPNAs exhibited a significant adsorption capacity of 1019.71 mg/g and a short equilibrium time of 3.0 h, surpassing that of commercial and reported nanofiber-based adsorbents. Additionally, the PPNAs demonstrated good dynamic adsorption performance for protein driven solely by gravity. Furthermore, the PPNAs showed reusability, selectivity, acid and alkaline resistance, and practical potential of extracting lysozyme form egg white solution. The successful scale-up of such aerogel-based adsorbents can open up new way for the development and design of next-generation protein adsorption media for bio-purification applications. [Display omitted] [ABSTRACT FROM AUTHOR]

At present, antibiotic resistance is considered a real problem. Therefore, for decades scientists have been looking for novel strategies to treat bacterial infections. Nisin Z, an antimicrobial peptide (AMP), can be considered an option, but its usage is mainly limited by the poor stability and short duration of its antimicrobial activity. In this context, cyclodextrin (CD)-based nanosponges (NSs), synthesized using carbonyldiimidazole (CDI) and pyromellitic dianhydride (PMDA), were chosen for nisin Z loading. To determine the minimum inhibitory of nisin Z loaded on CD-NS formulations, agar well diffusion plates were used. Then, the bactericide concentrations of nisin Z loaded on CD-NS formulations were determined against Gram-positive (Staphylococcus aureus) and -negative (Escherichia coli) bacteria, using microdilution brain heart infusion (BHI) and tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). The minimum and bactericide inhibitory values of the nisin complex with NSs were potentially decreased against both bacteria, compared with the nisin-free sample, while the nisin complex with β-CD showed lower antibacterial activity. The antimicrobial effect was also demonstrated by free NSs. Furthermore, the total viable counts (TVCs) antibacterial experiment indicated that the combination of nisin Z in both PMDA and CDI β-CD-based NSs, especially CDI, can provide a better conservative effect on cooked chicken meat. Generally, the present study outcomes suggest that the cross-linked β-CD-based NSs can present their own antimicrobial potency or serve as promising carriers to deliver and enhance the antibacterial action of nisin Z. [ABSTRACT FROM AUTHOR]

A series of new N,N′-bis[4-oxo-2-(pyridine-2-yl)-1,3-thiazolidin-3-yl]-2,2′-[1,3,5,7-tetraoxo-5,7-dihydropyrrolo[3,4-f]isoindole-2,6(1H,3H)-diyl]diacetamide derivatives were synthesized with acceptable yields starting from pyromellitic dianhydride which was treated with potassium cyanate in DMF under reflux to afford pyromellitic diimide. The latter was further reacted with ethyl chloroacetate in refluxing absolute ethanol to yield diethyl 2,2′-[1,3,5,7-tetraoxo-5,7-dihydropyrrolo[3,4-f]isoindole-2,6(1H,3H)-diyl]diacetate. The subse-quent treatment with excess hydrazine hydrate (80%) gave 2,2′-[1,3,5,7-tetraoxo-5,7-dihydropyrrolo[3,4-f]iso-indole-2,6(1H,3H)-diyl]diacetohydrazide which was condensed with substituted pyridine-2-carbaldehydes in ethanol in the presence of a catalytic amount of glacial acetic acid. The resulting Schiff bases underwent cyclization with thioglycolic acid in the presence of ZnCl2 to produce the corresponding 1,3-thiazolidine derivatives. The product structures were confirmed by FTIR and 1H NMR spectra and elemental analyses. [ABSTRACT FROM AUTHOR]

Pyromellitic dianhydride (PMDA) and 4,4′-diamino-2,2′-stilbenedisulfonic acid (DSD) were polymerized by polycondensation in 1:1 Sulfonated Polyimide (SPI) m-Cresol. The SPI was characterized by spectroscopic analyses (Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), ultraviolet–visible spectroscopy (UV–Vis), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)/ differential thermal analysis (DTA), solubility tests and elemental analysis (EA) techniques. Furrhermore, quantum chemical calculations of the synthesized SPI were analyzed by density-functional theory (DFT) with Becke-3-Parameter-Lee–Yang–Parr (B3LYP)/6–311-G basis set to understand electrical and optic features of SPI. Natural Bond Orbital (NBO) analysis and molecular electrostatic potential (MEP) surfaces were calculated. Quantum theory analysis of atoms in molecules (QTAIM) was made using the AIMAll program to find H-bonding, proton interaction, proton transfer and water uptake script. The second degradation stage was observed at a temperature higher than 450 °C in TGA/DTA curve. The variation of the heat flow in reverse heat flow was based on the Tg of SPI occurring around 353.11 °C. [ABSTRACT FROM AUTHOR]

The photocatalytic oxidation ability of polyimide is weak because of the relatively low valence band (VB). The valence band potential of the PMDA/PDA linear polyimide is +2.45 eV, showing that it has strong oxidizing property and strong oxidative degradation ability without constructing heterojunction.In order to prepare a kind of polyimide with high visible-light photocatalytic activity,linear polyimide (PI) with strong oxidizability is prepared by two-step method using pyromellitic dianhydride（PMDA） and p-phenylenediamine （PDA） as raw materials and ethanol as co-solvent. The chemical composition, microstructure and photoelectrochemical properties of PI are investigated by scanning electron microscopy (SEM), fourier infrared spectroscopy (FTIR),UV-vis diffuse reflectometer (UV-vis DRS), fluorescence spectrometer (PL) and X-ray photoelectron spectroscopy (XPS). The band gap width, Homo potential and lowest unoccupied molecular orbital (LUMO) potential of PI are measured.The results show that the main photocatalytic active center of the obtained polyimide is found to be photogenerated holes through a series of experiments. The photocatalytic activity of polyimide is evaluated by photodegradation of Rhodamine B, and the degradation efficiency of the as-prepared polyimide is three times as that of the commonly used photocatalyst g-C3N4. Therefore, PMDA/PDA linear polyimide is a kind of polyimide with high visible-light photocatalytic activity and high photocatalytic stability.

In this work, four types of nanosponges were prepared from pyromellitic dianhydride (PMDA) and D-glucose (GLU) with different molar ratios (1.5:1, 2:1, 2.5:1 and 3:1). The obtained PMDA/GLU nanosponges were then pyrolyzed at 800 °C for 30 min under N2 gas flow. The prepared polymeric nanosponges were investigated by FTIR spectroscopy, elemental and thermogravimetric analyses to unravel the role played by the different molar ratio of the precursors in the formation of the polymer. The pyrolyzed nanosponges were investigated by means of porosity measurements, X-ray diffraction analysis, Raman spectroscopy and high-resolution transmission electron microscopy. Notably, no significant correlation of the amounts of used precursors with the porous texture and structure was evidenced. The results corroborate that PMDA and GLU can be easily combined to prepare nanosponges and that the carbon materials produced by their pyrolysis can be associated with glassy carbons with a microporous texture and relatively high surface area. Such hard carbons can be easily obtained and shrewdly used to segregate relatively small molecules and organic contaminants; in this study methylene blue adsorption was investigated. [ABSTRACT FROM AUTHOR]

Copyright of China Surfactant Detergent & Cosmetics (1001-1803) is the property of China Surfactant Detergent & Cosmetics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A procedure was developed for preparing resorcinolpyromellitein [3,3,7,7-tetrakis(4-hydroxy-2,2ʹ-oxydiphenyl)pyromellitide] by acylation of resorcinol with pyromellitic dianhydride using tin tetrachloride as a catalyst (120–210°С, 30 h, reactant ratio pyromellitic dianhydride : SnCl4 : resorcinol = 1.0 : 2.5 : 5.0). The structure of the target product was proved by elemental analysis, thin-layer chromatography, UV and IR spectroscopy, 1H NMR spectroscopy, differential scanning calorimetry, and high-performance liquid chromatography with mass-spectrometric detection. The synthesized product exhibits increased hydrophilicity and imparts fluorescence properties to aqueous solutions when dissolved in a small amount (5 × 10–4 wt %), which allows it to be recommended as a chemical marker in tracer exploration of oil strata at oil fields. [ABSTRACT FROM AUTHOR]

Cyclodextrin-based nanosponges (CD-NS) are a novel class of polymers cross-linked with a three-dimensional network and can be obtained from cyclodextrins (CD) and pyromellitic dianhydride. Their properties, such as their ability to form an inclusion complex with drugs, can be used in biomedical science, as nanosponges influence stability, toxicity, selectivity, and controlled release. Most pharmaceutical research use CD-NS for the delivery of drugs in cancer treatment. Application of molecular targeting techniques result in increased selectivity of CD-NS; for example, the addition of disulfide bridges to the polymer structure makes the nanosponge sensitive to the presence of glutathione, as it can reduce such disulfide bonds to thiol moieties. Other delivery applications include dermal transport of pain killers or photosensitizers and delivery of oxygen to heart cells. This gives rise to the opportunity to transition to medical scaffolds, but more, in modern times, to create an ultrasensitive biosensor, which employs the techniques of surface-modified nanoparticles and molecularly imprinted polymers (MIP). The following review focuses on the biomedical research of cyclodextrin polymers cross-linked via dianhydrides of carboxylic acids. [ABSTRACT FROM AUTHOR]

In this work, four types of nanosponges were prepared from pyromellitic dianhydride (PMDA) and D-glucose (GLU) with different molar ratios (1.5:1, 2:1, 2.5:1 and 3:1). The obtained PMDA/GLU nanosponges were then pyrolyzed at 800 °C for 30 min under N2 gas flow. The prepared polymeric nanosponges were investigated by FTIR spectroscopy, elemental and thermogravimetric analyses to unravel the role played by the different molar ratio of the precursors in the formation of the polymer. The pyrolyzed nanosponges were investigated by means of porosity measurements, X-ray diffraction analysis, Raman spectroscopy and high-resolution transmission electron microscopy. Notably, no significant correlation of the amounts of used precursors with the porous texture and structure was evidenced. The results corroborate that PMDA and GLU can be easily combined to prepare nanosponges and that the carbon materials produced by their pyrolysis can be associated with glassy carbons with a microporous texture and relatively high surface area. Such hard carbons can be easily obtained and shrewdly used to segregate relatively small molecules and organic contaminants; in this study methylene blue adsorption was investigated.

The acylation of o-cresol with pyromellitic dianhydride (PMDA) has been experimentally studied. The optimum conditions of the acylation reaction of o-cresol with PMDA have been determined. The synthesis has been performed in o-cresol melt at 120°C for 30 h at a reactant molar ratio of PMDA : o-cresol : SnCl4 = 1.0 : 4.1 : 2.0. The yield of 3,3,7,7-tetrakis(3-methyl-4-oxyphenyl)pyromellitide is 62.0% of the theoretical value. The structure of the target synthesis product has been proven by instrumental methods, namely, elemental analysis; thin layer chromatography (TLC); UV, IR, and 1H NMR spectroscopy; DSC; and high-performance liquid chromatography coupled with mass spectrometry (HPLC/MS). The revealed properties of 3,3,7,7-tetrakis(3-methyl-4-oxyphenyl)pyromellitide allow it to be recommended as a tracer for oil reservoir evaluation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hebei University of Science & Technology is the property of Hebei University of Science & Technology, Journal of Hebei University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A series of boron nitride-pyromellitic dianhydride composites have been successfully synthesized by calcinating the mixtures of boron nitride (BN) and pyromellitic dianhydride (PA) at 350 °C, in which the composite (BNPA2) has the largest adsorption quantity (65.1 mg/g) for rhodamine B (RhB) and the best photo-removal efficiency for RhB under visible light irradiation. 1H NMR characterizations for BN, PA and BNPA2 suggest that this composite is formed via the reaction between the OH groups in BN and PA. BNPA2 can also adsorb neutral red (NR), methyl orange (MO), tetracycline (TC) and atrazine (AT). NR and MO can be photo-removed by BNPA2 under visible light irradiation. Colorless TC and AT can also be degraded by BNPA2 under visible light irradiation, suggesting that BNPA2 is visible light responsible photocatalyst. BNPA2 has the highest photo-removal efficiency for the cationic RhB and NR, followed by the anionic MO. This is from that BNPA2 has negative surface. When anionic MO mixes with cationic RhB (or NR) together, BNPA2 prefers to remove cationic RhB (or NR) from the mixture solution under visible light irradiation and the removal efficiency of anionic MO by BNPA2 is also increased. Thus, electrostatic interactions between dyes and BNPA2 as well as between dyes play significant role in the removal process. •O2− makes a main contribution for this photo-removal of these aromatic pollutants (dyes, TC and AT) by BNPA2 under visible light irradiation. Furthermore, the removal performance of BNPA2 for RhB, TC and AT can be effectively regenerated by visible light irradiation. • Boron Nitride-Pyromellitic Dianhydride composite (BNPA2) is first time synthesized with BN and PA as precursors. • BNPA2 can remove organic pollutants (dyes and atrazine) via adsorption and photodegradation. • BNPA2 is visible light responsive photocatalyst and the photocatalytic performance of BN is from sensitization. • Electrostatic attraction between dyes and BNPA2 play significant role during the removal process of dyes. • Visible light irradiation can regenerate the removal performance of BNPA2 for dyes. [ABSTRACT FROM AUTHOR]

Cyclodextrin-based nanosponges (CD-NS) are a novel class of polymers cross-linked with a three-dimensional network and can be obtained from cyclodextrins (CD) and pyromellitic dianhydride. Their properties, such as their ability to form an inclusion complex with drugs, can be used in biomedical science, as nanosponges influence stability, toxicity, selectivity, and controlled release. Most pharmaceutical research use CD-NS for the delivery of drugs in cancer treatment. Application of molecular targeting techniques result in increased selectivity of CD-NS; for example, the addition of disulfide bridges to the polymer structure makes the nanosponge sensitive to the presence of glutathione, as it can reduce such disulfide bonds to thiol moieties. Other delivery applications include dermal transport of pain killers or photosensitizers and delivery of oxygen to heart cells. This gives rise to the opportunity to transition to medical scaffolds, but more, in modern times, to create an ultrasensitive biosensor, which employs the techniques of surface-modified nanoparticles and molecularly imprinted polymers (MIP). The following review focuses on the biomedical research of cyclodextrin polymers cross-linked via dianhydrides of carboxylic acids.

Abstract Smart hydrogels with pH and enzyme triggered release suitable for colon specific drug delivery were prepared by crosslinking inulin with pyromellitic dianhydride (PMDA) in a simple one pot synthesis. Back titration, Fourier transform infrared spectroscopy (FTIR) and ultraviolet spectrophotometry (UV) demonstrated that the hydrogel crosslinking reaction resulted in ester linkages and carboxylic acid groups and that the amount of the crosslinker in the hydrogel increased with increasing PMDA concentration in the crosslinking reaction. Thermal analysis and scanning electron microscopy (SEM) confirmed the chemical change by illustrating the hydrogels changed thermal properties and appearance compared to inulin. This hydrogel showed excellent swelling in water and the degree of swelling was inversely proportional to the cross-linking density, as determined using Flory-Rehner theory. Due to the presence of the carboxylic acid groups in the structure, the swelling was pH dependent, with significantly reduced swelling as acidity decreased from pH 7.4 to pH 1.2. Highlights • Novel hydrogel was obtained by esterification reaction between inulin and PMDA • The synthesized hydrogel were characterized using different analytical techniques and swelling experiment • By varying the ratio of PMDA, hydrogels with different crosslink density can be obtained • Hydrogels demonstrated pH dependent swelling [ABSTRACT FROM AUTHOR]

The purpose of the study was to explore the effect of different type of crosslinked cyclodextrins for the delivery of poorly soluble, photosensitive drug, resveratrol. Crosslinkers, diphenyl carbonate and pyromellitic dianhydride were used to prepare carbonyl (NS-I) and carboxylate (NS-II) crosslinked cyclodextrin respectively. The solubility and in silico molecular interaction of resveratrol with these NS at different crosslinker ratio were studied. The results showed enhanced solubility and better interaction of resveratrol with nanosponges prepared with 1:4 Cyclodextrin: crosslinker ratio. The drug-loaded nanosponges (RES-NS-I and II) prepared using 1:4 crosslinked NS-I and II were characterized using DSC, PXRD, SEM, FTIR and evaluated for particle size, zeta potential, photodegradation, in vitro drug release, in vitro cytotoxicity and in vivo oral bioavailability in rats. Physical characterization confirmed the molecular inclusion of drug with NS. The release of the drug was increased to 2.5-3 folds in the dissolution medium, with initial drug release faster with RES-NS-II. Photostability was enhanced to 2.3 fold with RES-NS-II. The cytotoxicity test exhibited 1.5 fold reduction in IC50 with drug-loaded NS. RES-NS-II exhibited 2.5 fold increase in Cmax and fourfold decrease in Tmax. Carboxylate crosslinked Cyclodextrin using pyromellitic dianhydride proves to be an effective nanocarrier for resveratrol. [ABSTRACT FROM AUTHOR]

Summary: In this paper, pyromellitic dianhydride (PMDA) was firstly used as fire safety agent for thermoplastic polyurethane (TPU). And, the fire safety improvement of PMDA in TPU was intensively investigated by limiting oxygen index (LOI), smoke density test (SDT), cone calorimeter test, and thermogravimetric/infrared spectroscopy, respectively. It has been found that PMDA could significantly improve the ignition level, and the LOI value increase to 28.5% when 8.0 wt% PMDA was incorporated into TPU; PMDA also could effectively suppress the smoke production and heat release during the combustion process. The peak heat release rate and total smoke release of the sample with 8.0 wt% PMDA were decreased by 68% and 22% compared with pure TPU in cone calorimeter test. The thermogravimetric/infrared spectroscopy results showed that PMDA could improve the thermal stability of TPU composites at high temperature and increased the release of CO2, H2O, and so on. All results confirmed that PMDA would have a good prospect in reducing the fire hazard of TPU. [ABSTRACT FROM AUTHOR]

A carboxy modified long-chain diol (CMLCD) was synthesized for the first time through esterification of pyromellitic dianhydride (PMDA) and polytetramethylene glycol 1000 (PTMG1000). Waterborne polyurethane (WPU) was prepared based on an organic solvent-free and self-catalytic process, using synthesized CMLCD as a hydrophilic diol. The CMLCD has self-catalytic ability to the reaction of hydroxyl and isocyanate during the prepolymerization, which can greatly shorten the preparation period and avoid the utilization of highly toxic catalyst such as dibutyltin dilaurate. Importantly, the prepared WPU has narrow particle size distribution with the average particle size of 137 nm, which leads to good stability even centrifugated at 3000 rpm. Mechanical test results show that the WPU film possesses good mechanical performance with the tensile strength of 59.3 MPa and elongation at break of 819.2%. Additionally, the prepared WPU film has high water resistance. This study is attractive for future green WPU in industrial production and application. [ABSTRACT FROM AUTHOR]

The compound TPP-PMDI-TPP, synthesized through a porphyrin-based anhydride approach, was thoroughly characterized using various analytical techniques. Computational studies were conducted to further investigate its properties. Specifically, the compound's MEP and global reactivity parameters were studied, providing valuable insights into its electronic behavior and reactivity. photovoltaic measurements were carried out to evaluate the compound's potential for solar energy conversion. [Display omitted] A new covalently linked porphyrin-based anhydride(C 108 H 86 N 10 O 4 Zn 2) named TPP-PMDI-TPP has been successfully synthesized through a simple thermal imidization reaction of electron-donating Zn(5-(4-aminopheny)-10,15,20-triphenylporphyrin(Zn-ATPP) and electron-accepting pyromellitic dianhydride(PMDA) moieties and tested in the of photovoltaic application. TPP-PMDI-TPP was subjected to comprehensive characterization using various analytical techniques, including FT-IR, 1H NMR, UV–visible, PXRD, cyclic voltammetry, and molecular simulation. Fluorescence studies were also employed to characterize TPP-PMDI-TPP. Excellent fluorescence quenching of 95 % was observed in TPP-PMDI-TPP, indicating remarkable electron transfer from porphyrin to pyromellitic dianhydride within TPP-PMDI-TPP. The cyclic voltammetric analysis provided the HOMO and LUMO values of TPP-PMDI-TPP as −6.172 eV and −4.185 eV, respectively. The investigation of the charge-transfer phenomenon in the entitled compound was assessed using FMOs. Results obtained from cyclic voltammetry and computational calculations for HOMO, LUMO, and band gap (E g) of porphyrin-based anhydride (TPP-PMDI-TPP) are in well concordance, indicating the practicality of the utilized experimental approach. Global reactivity parameters were obtained by using HOMO–LUMO energies of compounds. The photovoltaic measurements of ITO-coated TPP-PMDI-TPP film was performed to check different photovoltaic parameters (V OC , I SC , FF, and η), showing values of about 0.858 V, 8.1794 mA/cm2, 0.561 and 3.9 % respectively, calculated from current-voltage (I–V) graph. The lower photocurrent and power conversion efficiency in the TPP-PMDI-TPP film is due to the electron withdrawal caused by the dianhydride group, transferring electrons from porphyrin to PMDA. This electron-withdrawing effect leads to imbalanced charge transport, with higher hole mobilities than electron mobilities, resulting in lower efficiency for TPP-PMDI-TPP-based photovoltaic cells. [ABSTRACT FROM AUTHOR]

Cyclodextrins play an important role in supramolecular chemistry acting as building blocks than can be cross-linked by various linker molecules forming nano-porous structures called nanosponges (NS). NS have the ability to enhance the stability, solubility and bioavailability of various actives. This work aimed at elaborating rosuvastatin (ROS) loaded NS to improve its oral bioavailability. Carboxylate-linked NS were synthesized by reacting β-CD with pyromellitic dianhydride (PDA) at different molar ratios under specific conditions. ROS-loaded NS were prepared by lyophilisation technique and characterized for particle size, zeta potential, entrapment efficiency and drug release. Occurrence of cross-linking and ROS incorporation within the NS were assessed by DSC, FT-IR and SEM micrographs. NS prepared at a molar ratio of 1:6 of β-CD: PDA demonstrated the highest entrapment efficiency (88.76%), an optimum particle size of 275 nm, a narrow size distribution (PDI of 0.392), and zeta potential of − 61.9 indicating good colloidal stability. In vivo oral pharmacokinetics study in male Sprague Dawley rats showed that ROS-NS provided an outstanding enhancement in oral bioavailability compared to drug suspension and marketed tablets besides their physicochemical stability for 3 month. Accordingly, ROS-NS represent a superior alternative to the conventional marketed formulation for effective ROS delivery. [ABSTRACT FROM AUTHOR]

A series of poly (1, 4-cyclohexylenedimethylene terephthalate) (PCT) with controllable molecular weight was prepared by direct esterification,subsequent polycondensation and molten chain-extending reaction using 1, 4-cyclohexanedimethanol (CHDM), terephthalic acid (PTA), pyromellitic dianhydride (PMDA) and triglycidyl isocyanurate (TGIC) as materials. The molecular structure, thermal and mechanical properties of polymers were characterized by Fourier Transform Infrared Spectrum (FT-IR), Gel Permeation Chromatograph (GPC), Differential Scanning Calorimetry (DSC), Thermal Gravity (TG) analysis, Wide Angle X-ray Diffraction (WAXD) and electronic universal testing machine. Results showed that when n(CHDM): n(PTA) was 1.2, and combined catalysts including tetrabutyl titanate (TBT), germanium dioxide (GeO2), antimony trioxide (Sb2O3) (0.1 mg/g) and cobalt acetate (Co(Ac)2) (0.05 mg/g), reaction 3 h at 290 ℃, the intrinsic viscosity of PCT was 0.560 dL/g. Then the product was used to react with combination chain-extend agent of PMDA-TGIC, which had the intrinsic viscosity 0.680 dL/g. The films of PCT and chain-extend PCT had excellent mechanical property. [ABSTRACT FROM AUTHOR]

β-Cyclodextrin polymer, namely nanosponges (NSs), were synthesized using two cross-linkers: 1,1′-carbonyldiimidazole (CDI) and pyromellitic dianhydride (PMDA). The synthesized NSs were complexed with N,N-diethyl-meta-toluamide (DEET) and, after complex characterization, the NSs cross-linked with CDI were found more effective than those cross-linked with PMDA in terms of encapsulation efficiency and loading capacity. The CDI-NSs were dispersed in a polyacrylic resin, which was thermally polymerized on a polyester fabric surface. The fabric functionalization was evaluated through quantification of DEET extracted from the polyester fabrics, before and after three washing cycles. The results showed that encapsulation into NSs prolongs the persistence of DEET on polyester fabrics. [ABSTRACT FROM AUTHOR]

We present an alternative polymer modification of poly (propylene carbonate) (PPC). A conventional practice for PPC melt processing is the melt – modification with maleic anhydride (MAH) – a di-carboxylic anhydride –. In our work, PPC is melt-modified with pyromellitic di-anhydride (PDAH) – a tetra-carboxylic dianhydride –. Using MAH modified PPC as reference, the polymer degradation and the thermal and viscoelastic properties of the materials are studied. Both anhydrides after their melt compounding have similar efficiency in the conservation of the molecular weight. Strikingly, the use of PDAH is advantageous over MAH considering the improvement of the thermal stability, the decrease of the complex melt viscosity and higher storage modulus (stiffness) of the modified PPC. It is speculated that the changes in the material performance arise from the occurrence of long chain branching and non-covalent interactions from the PDAH modifier.