Benzophenone Tetracarboxylic Acid Research Articles

Two lanthanide coordination polymers: Syntheses, structures and selective detection of Fe3+, Cr2O72−/ CrO42− and antibiotics

Two new lanthanide coordination polymers (CPs) [Tb(bptc)(4,4′-H2bipy)0.5·2H2O]n (1) and [Gd(bptc)(4,4′-H2bipy)0.5·2H2O]n (2) (H4bptc = 3,3′,4,4′-benzophenone tetracarboxylic acid, 4,4′-bipy = 4,4′-bipyridine) have been synthesized under solvothermal conditions. They were characterized by single crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis. CPs 1 and 2 are isomorphous and display a 2D layer structure with the Schlafli symbol of {46·64}{47·63}. CP 1 exhibits excellent fluorescence properties, which can be used for sensitive and selective detection of Fe3+, Cr2O72− / CrO42− and antibiotics (tetracycline (TC), metronidazole (MDZ), and nitrofurazone (NFZ)) simultaneously. The possible luminescence sensing mechanisms were explored in detail. Cyclic experiments demonstrated that the fluorescence intensity of the CP 1 remained basically unchanged even after five cycles.

Lightweight and highly heat-resistant copolymerized polyimide foams for superior thermal insulation and acoustic absorption

The development of lightweight and highly heat-resistant polyimide foams (PIFs) remains a great challenge in areas of aerospace, military ships, transportation, and industries. Herein, a series of lightweight and highly thermal-resistant copolymerized PIFs are successfully fabricated by the “stepwise heating-holding” thermal foaming of the copolymerized polyester ammonium salts (C-PEAS), using 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 2,3,3′,4′-biphenyl tetracarboxylic acid dianhydride (α-BPDA) as codianhydride, and p-phenylenediamine (PDA) as diamine. The introduction of α-BPDA increases the rigidity of PI molecule chains and foamability of C-PEAS, and significantly improves the heat resistance of PIFs. The resultant copolymerized PIFs exhibit ultra-low densities (<10 kg·m-3), excellent heat resistance (Tg ranging from 351.2°C to 405.6°C), and high thermal stability. Moreover, they possess high flame retardancies (LOI>44%) and low thermal conductivities (as low as 0.0463 W·m-1∙K-1 at 20°C and no more than 0.0825 W·m-1∙K-1 at 200°C), demonstrating their excellent thermal insulation properties in a wide temperature range. After the continuous heating at 200°C for 40 min, the upper surface of PIFs present low average temperatures less than 60°C. Additionally, the copolymerized PIFs exhibit remarkable acoustic properties with average acoustic absorption coefficients above 0.6 and noise reduction coefficients (NRC) above 0.3. Therefore, the lightweight and highly heat-resistant copolymerized PIFs show great application potentials in the extreme environments of aerospace, military ships, transportation, and industries.

The effect of a novel MOF containing benzophenone structure on the crystallization and ultraviolet protection capacity of PA5,6

In order to improve the UV protection efficiency of conventional Metal organic Framework (MOF), the introduction of benzophenone in MOF was chosen. In this work, with the assistance of 4,4 ' -bipyridine, 3,3′,4,4′-benzophenonetetracarboxylic acid (BPTC) was added to make benzophenone derivatives as organic ligands to coordinate with Cu2+ to form a new MOF ( [ Cu2 ( BPTC) ( bpy) 2]), which was named as CuBb. Then, CuBb are added into PA5,6 to prepare PA5,6/CuBb composites. It was shown that CuBb can improve the crystallization of PA5,6 by promoting the intramolecular hydrogen bonds of PA5,6 under the action of MOF. Also, PA5,6 has low UV transmittance and possesses good UV resistance (ultraviolet protection factor (UPF) exceeds 30) after the addition of CuBb. CuBb is good nucleating agent and UV-resistance agent for PA5,6.

Fabrication of multifunctional polyimide foams with co-polymerized benzimidazole moieties for excellent thermal insulation and flame retardancy applications

In this study, heterocyclic diamine 2-(4-aminophenyl)-5-aminobenzimidazole (APBIA) was employed as a co-polymerization component to improve the properties of polyimide foams (PIFs) which were synthesized from 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 4,4′-diaminodiphenyl ether (ODA). The rheological behavior of polyester ammonium salt (PEAS) precursors was regulated by introducing APBIA moieties to the chain backbones, which affected the foaming behavior of PEAS and the microstructure of corresponding PIFs. Anisotropic porous structure was constructed with the help of microwave-assisted foaming strategy due to the directional growth of foam pores, which led to anisotropic mechanical and thermal insulation performance of resultant PIFs. PIFs demonstrated robust mechanical performance in the vertical direction (i.e., parallel to pore growth direction) and mechanical flexibility (compression response rate of 97.1–99.0 %) in the horizontal direction (i.e., perpendicular to the pore growth direction). The co-polymerized PIFs also presented excellent thermal insulation performance, with thermal conductivity ranging from 0.0266 to 0.0517 W/(m·K) within a temperature range of 25∼300 °C. In addition, PIFs exhibited exceptional thermal stability and flame retardancy performance, which demonstrate a great potential for high-temperature thermal protection applications. To summarize, multifunctional PIFs with excellent mechanical, thermal insulation and flame retardancy were successfully prepared by adopting co-polymerization strategy and microwave-assisted foaming technique, which have promising applications in high-end engineering sectors.

Fabrication of thermally resistant and mechanically flexible polyimide foams with anisotropic pore structures for thermal insulation and irradiation tolerance applications

Flexible polyimide foams (PIFs) demonstrate a great potential for applications in the fields of thermal insulation, flame retardancy and irradiation tolerance. In this work, mechanically flexible PIFs with anisotropic pore structure were prepared by adopting the copolymerization strategy and microwave-assisted foaming process. The copolymerization reaction was conducted to synthesize polyester ammonium salt (PEAS) precursors using 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) as dianhydride, 4,4′-diaminodiphenyl ether (ODA) and 4,4′-diaminodiphenyl sulfone (DDS) as the copolymerized diamines; afterwards, PEAS powders with particle sizes ranging from 100 to 300 μm were obtained by drying, crushing and sieving treatments, which were used as the feedstock for “bottom-up” microwave-assisted foaming and thermal imidization process, thereby leading to the formation of PIFs with regular three-dimensional near-spherical pores in vertical direction (parallel to the pore growth direction) and the aligned ellipsoidal strip-like pore structure in horizontal direction. The directional growth of foam pores resulted in anisotropic mechanical flexibility and thermal insulation performance. Moreover, PIFs possessed excellent thermal stability and flame retardancy with the initial thermal degradation temperature higher than 545 °C and limited oxygen index up to 58.8%. The PIFs exhibited exceptional thermal insulation performance with thermal conductivity values ranging from 0.0276 to 0.0517 W/(m·K) between 25 and 300 °C. Additionally, the PIFs demonstrated excellent irradiation tolerance, with the mechanical and thermal stability retention rate being above 96% after the irradiation experiment (radiation dosage: 1.15 × 105 Gy) using 60Co source. Thus, lightweight PIFs with superior high temperature thermal insulation performance, flame retardancy and irradiation tolerance were successfully prepared, which showed potential applications in aerospace, medical and nuclear power sectors.

Lightweight thermo- and heat-resistant composite materials based on polyimide foam

A prepolymer foaming composition based on 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride methyl ester and diamines: 4,4'-diaminodiphenylmethane and m-phenylenediamine for the production of high-temperature polyimide foam (PIF) is proposed. The p ossibility o f u sing P IF a s a b inder f or c omposite materials (foam composites) reinforced with carbon or organic fibers with low density (0.4–1.1 g/cm3) a s a result of foaming of the binder during the formation of the foam composite is shown. The density and mechanical properties of the foam composite can vary within a relatively wide range depending on the volume content of the fiber and air pores. The high glass transition temperature of 260°C, combined with the high thermal stability of carbon or polyimide fibers, contributes to the retention of the mechanical properties of such composites at elevated temperatures. The temperature of the start of mass loss of the foam composite must be at least 550°C, and it depends on the type of fibrous material. The combination of the excellent thermal and mechanical properties of lightweight PIF composites, together with the exceptional fire resistance of polyimide materials, may provide new applications in advanced aircraft and shipbuilding technologies.

Effect of Citric Acid and Benzophenone Tetracarboxyclic Acid Treatments on Stability, Durability, and Surface Characteristic of Short Rotation Teak

Short rotation teak (SRT) has a diameter of around 30 cm at the age of 15 years; however, the wood still has low quality, especially in dimensional stability and biological durability. The objective of this study was to improve dimensional stability and biological durability of SRT through modification treatment using non-biocide chemicals, citric acid (CA) and benzophenone tetracarboxylic acid (BPTCA). SRT sapwood was impregnated by 20% and 40% of CA or BPTCA followed by heating in the oven at 150 °C for 2 h. Dimensional stability, strength, surface characteristics and durability against termite attacks of the modified woods were evaluated. Results show that dimensional stability as anti-swelling efficiency (ASE) increased by an average of 46% (CA) and 50% (BPTCA) after treatments. Durability against termites showed that the modified woods were categorized to be class 1 (very durable). Fourier Transform Infrared (FTIR) and X-ray Diffraction observations indicated a possible chemical reaction between the wood components with CA and BPTCA. The water-based acrylic and oil-based alkyd contact angle values of the modified woods were lower than 90°, indicating their high wetting ability against the varnish liquids. The treatment can be applied to improve the quality of SRT for high-quality wood product utilization.

Tuning antibacterial properties of poly(vinyl alcohol)/TiO2 composite films by chemically grafting with 3,3′,4,4′-biphenyltetracarboxylic acid

Polyvinyl alcohol (PVA)/titanium dioxide nanoparticles (TiO2 NPs)/3,3′,4,4′-Benzophenone tetracarboxylic acid (BPTA) antibacterial films were prepared by solvent casting and chemical grafting using PVA as the base material and TiO2 NPs and BPTA as antibacterial materials. Scanning electron microscopy results showed that the distribution of TiO2 NPs inside the polymer matrix was substantially uniform. X-ray diffraction (XRD) and FTIR-ATR spectroscopy were used to demonstrate the successful embedding of NPs and the formation of ester bonds in the grafting process, respectively. In the antibacterial experiment, the PVA/1%TiO2 NPs/BPTA film exhibited higher antibacterial activity than other films. Compared with the control group, the surviving population of S. aureus and E. coli decreased by 99.62 ± 0.38% and 98.27 ± 1.47%, respectively. The mechanism of reactive oxygen species (ROS) production was discussed, and the amount of ROS produced by the composite films under light and dark conditions was quantitatively measured. A cycling experiment after quenching ROS showed that the PVA/1%TiO2 NPs/BPTA composite film retained 81.01% and 66.12% of the original charging capacity of the OH• radical and H2O2 after seven cycles. In terms of biodegradability, the degradation performance of the PVA/TiO2 NPs/BPTA composite film was stronger than that of the pure PVA film. Thus, the PVA/TiO2 NPs/BPTA film is considered a promising antibacterial material with superior characteristics of structural stability, reusability, and functionality under both light and dark conditions.

The effects of long and bulky aromatic pendent groups with flexible linkages on the thermal, mechanical and electrical properties of the polyimides and their nanocomposites with functionalized silica.

A novel diamine bis(4-aminophenyl)bis{3,4[(4-(8-quinolyloxymethyl carbonyl)]}methane, containing two long/bulky aromatic pendent chains was synthesized by incorporating aromatic and hetero aromatic groups with flexible linkages. Flexible, stretchable, thermally stable and processable polyimides were prepared by reacting this newly synthesized diamine with commercial tetracarboxylic acid dianhydrides like 3,3′,4,4′-benzophenone tetra carboxylic acid dianhydride (BTDA) and 4,4′-(4,4′-isopropylidenediphenoxy)diphthalic Anhydride (BPADA). Nanocomposites of polyimides were prepared using aromatic amine functionalized silica as a filler by solution casting method. The current work investigates the effects of incorporating long/bulky aromatic side chains and flexible linkages on the thermal, mechanical, electrical and optical properties of the polyimides and nanocomposites. The polyimides showed good thermal stability (T10% = 364 & 388), high flame resistance, low glass transition temperatures (Tg = 130 °C & 156 °C), very low dielectric constants (2.5 & 2.8 at 1 MHz) and good optical transparency. The neat polyimides displayed good elongation at break (133–155%) but possessed low tensile strength. The chemically imidized polyimides showed good solubility in low and high boiling solvents. Nanocomposites of polyimides based on aromatic amine functionalized silica exhibited enhanced properties with T10% values varying between 409–482 °C, Tg between 165–280 °C and higher dielectric constants (3–5.7 at 1 MHz).

Electrospun antibacterial poly(vinyl alcohol)/Ag nanoparticles membrane grafted with 3,3′,4,4′-benzophenone tetracarboxylic acid for efficient air filtration

In this study, poly(vinyl alcohol) (PVA) membranes containing Ag nanoparticles (AgNPs) were prepared by electrospinning and grafted copolymerization with 3,3′,4,4′-benzophenone tetracarboxylic acid (BPTA) to provide better mechanical properties, lower water vapor transmittance, and higher antibacterial activity (against Staphylococcus aureus and Escherichia coli) than the PVA/AgNPs membrane. The PVA/AgNPs/BPTA membrane showed higher antibacterial activity than the other membranes, and it produced inhibition zones with diameters of 18.12 ± 0.08 and 16.41 ± 0.05 mm against S. aureus and E. coli, respectively. The PVA/AgNPs/BPTA membrane was found to be capable of promoting reactive oxygen species (ROS) formation under both light and dark conditions. Cycling experiments performed following ROS quenching showed that the best-performing composite membrane retained >70% of its original OH⋅ radical and H2O2 charging capacity after seven cycles. In the filtration test, the electrospun nanofibrous membranes showed high filtration efficiencies of 99.98% for sodium chloride (NaCl). In addition, these membranes maintained a relatively low pressure drop of 168 Pa with a basis weight of 2.1 g m−2. Thus, the PVA/AgNPs/BPTA membrane was concluded to be a promising medical protective material offering the benefits of structural stability and reusability.

An investigation on curing rheokinetics of a nadic end-capped MDA-BTDA-ODA copolyimide resin by dynamic mechanical analysis

Abstract The curing behavior of a nadic end capped MDA-BTDA-ODA copolyimide resin was investigated using dynamic mechanical analysis in the shear mode. The studied copolyimide consists of 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride (BTDA) with a 50:50 M combination of 4,4′-diaminodiphenylmethane (MDA) and 3,4′-oxydianiline (ODA) monomers. The effects of curing temperature and time on the rheological properties of the resin were examined. At the beginning of the network formation process, an increase in the storage modulus, loss modulus and complex viscosity was observed. The gelation temperature, Tgel, was determined from the intersection points of the temperature-dependent storage and loss moduli curves. It was found that the rate of gelation of the resin was increased with increasing temperature. In terms of mechanical curing condition, the kinetics of isothermal network formation process at different isothermal curing temperatures were monitored by using Kamal-Sourour model. The model fitted well with experimental data. Therefore, mechanical conversion at different temperatures can be well predicted by the kinetics data.

Phase state diagram of a poly(amic acid)–solvent–nonsolvent system

Phase behavior and structure formation was studied using optical interferometry, nephelometry, and refractometry in the polymer–solvent–nonsolvent system for DMF solutions of two poly(amic acids): based on 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride and meta-phenylenediamine (PAA-1) and pyromellitic acid dianhydride and 4,4′-oxydianiline (PAA-2). Distilled water and its mixtures with DMF were used as a nonsolvent. According to the results of the study, isothermal cross sections of the phase state diagram in the threecomponent system were plotted, the position of the critical point, the spinodal, and the conodes were determined, the movement of the figurative points in the system was traced depending on the nonsolvent composition.

Synthesis and characterization of novel high temperature structural adhesives based on nadic end capped MDA-BTDA-ODA copolyimide

A series of novel copolyimide structural adhesives were synthesized using 4,4′-diaminodiphenylmethane (MDA), 3,4′-oxydianiline (ODA) and 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride (BTDA) as co-monomers, and nadic anhydride as an end cap reagent. The adhesives with different MDA and ODA contents were examined in terms of their structure, thermal stability, mechanical properties, and adhesive performance. They have glass transition temperatures (Tg) about 400 °C, with thermal stability up to 500 °C. The effect of diamine monomer compositions on adhesion performance and processability of the copolyimides were studied. The copolyimides exhibited adhesion strength up to 16.3 MPa at room temperature. Nadic end capped MDA-BTDA-ODA copolyimide resins gained adjustable and controllable processability with the addition of ether bridged aromatic segments. The copolyimide adhesive with equimolar composition of MDA:ODA is distinguished form the both commercial PMR-15 and LARC RP-46 polyimides in terms of its better processability and mechanical performance.

Light-induced antibacterial and UV-protective properties of polyamide 56 biomaterial modified with anthraquinone and benzophenone derivatives

The bio-based material polyamide 56 (PA 56) is a new kind of biopolymer. Reactive Blue P-3R, which is a derivative of anthraquinone, can react directly with the amino groups on PA 56. 3,3′,4,4′-Benzophenone tetracarboxylic acid (BPTCA), which is a photoactive derivative of benzophenone, can also react directly with the amino groups on PA 56 to form amide bonds. The modified bio-based PA 56 fabrics not only exhibited excellent ultraviolet (UV) protective property, but also exhibited important photochemical properties, such as producing reactive oxygen species, including hydroxyl radicals (HO) under UV light exposure. The hydroxyl radical-generating abilities of these materials were measured, and their photochemical reactive mechanisms were discussed. The modified PA 56 fabrics demonstrated good antimicrobial activities against both E. coli and S. aureus. Reactive Blue P-3R and BPTCA exhibited good synergistic properties. These modified biomaterials could therefore be used in medical textiles and biological materials.

A novel 3D self-penetrating metal–organic framework with unprecedented 7-connectivity and entangled pattern

A novel (4,4,7)-connected 3D self-penetrating network with unprecedented 7-connectivity, has been constructed using 1,4-bis(2-methylbenzimidazol-1-ylmethyl) benzene and 3,3′,4,4′-Benzophenonetetracarboxylic acid as co-ligands. It represents an unusual self-penetrating pattern with the entanglements of nonequivalent 4- and 6-membered shortest rings.

Chemically induced dynamic nuclear polarization study of the reduction of histidine radical in the reactions with aromatic amino acids

In order to model the involvement of histidine radicals in the electron transfer reactions in proteins, we investigated the kinetics of the reduction of hisitidine radicals in the reactions with aromatic amino acid residues by means of chemically induced dynamic nuclear polarization with microsecond time resolution. Histidine radicals were generated in photochemical reaction with triplet-excited 3,3’,4,4’-benzophenone tetracarboxylic acid. The intermolecular electron transfer from N-acetyl derivatives of tyrosine and tryptophan to the radical of N-acetyl histidine was studied in neutral and basic aqueous solutions. It was found that the rate constant of reduction of short-lived histidine radical in the reactions with tyrosine anion is k r = (1.9±0.5)•108 L mol–1 s–1, which is more than two orders of magnitude higher than that of reduction of histidine radical with neutral tyrosine (k r = (1.2±0.4)•106 L mol–1 s–1). In the reduction of histidine radical with N-acetyl tryptophan, the protonated states of reagents do not change, when pH of aqueous solution varies from neutral to basic and the reaction rate coefficient remains constant being k r = (1.3±0.4)•106 L mol–1 s–1.

Antiwrinkle Finishing of Cotton Fabrics with 5-(Carbonyloxy succinic)-benzene-1,2,4-tricarboxylic Acid: Comparison with Other Acids

5-(Carbonyloxy succinic)-benzene-1,2,4-tricarboxylic acid (BSTA) was synthesized and applied as an effective cross-linking agent for cotton fabrics. In this study, BSTA was analyzed and compared with two other extensively investigated poly(carboxylic acid)s, 1,2,3,4-butanetetracarboxylic acid (BTCA) and 3,3′4,4′- benzophenone tetracarboxylic acid (BPTCA), in cross-linking cellulose. Possessing both aromatic and aliphatic carboxylic acid groups and respective properties, BSTA can cross-link cellulose as efficiently as BTCA without causing significant loss of tensile strength of the products. In addition, BSTA exhibits better hydrophilicity and higher affinity to cellulose than the aromatic acid. BSTA is able to produce anhydride under high temperature but it is not a rate-determining step in the esterification process. The kinetic data of BTCA, BPTCA, and BSTA with cellulose were calculated by measuring the concentrations of the carboxylic acids on the fabric, showing an order of BPTCA< BSTA< BTCA in react...

UV Light-Induced Generation of Reactive Oxygen Species and Antimicrobial Properties of Cellulose Fabric Modified by 3,3',4,4'-Benzophenone Tetracarboxylic Acid.

3,3',4,4'-Benzophenone tetracarboxylic acid (BPTCA) could directly react with hydroxyl groups on cellulose to form ester bonds. The modified cotton fabrics not only provided good wrinkle-free and ultraviolet (UV) protective functions, but also exhibited important photochemical properties such as producing reactive oxygen species (ROS) including hydroxyl radicals (HO(•)) and hydrogen peroxide (H2O2) under UV light exposure. The amounts of the produced hydroxyl radical and hydrogen peroxide were measured, and photochemical reactive mechanism of the BPTCA treated cellulose was discussed. The results reveal that the fabrics possess good washing durability in generation of hydroxyl radicals and hydrogen peroxide. The cotton fabrics modified with different concentrations of BPTCA and cured at an elevated temperature demonstrated excellent antimicrobial activities, which provided 99.99% antibacterial activities against both E. coli and S. aureus. The advanced materials have potential applications in medical textiles and biological material fields.

Catalytic Actions of Sodium Salts in Direct Esterification of 3,3′4,4′-Benzophenone Tetracarboxylic Acid with Cellulose

Aromatic polycarboxylic acids can directly react with cellulose to form ester cross-linking structures and provide wrinkle resistance functions to cotton fabrics, different from aliphatic polycarboxylic acids, which will form anhydrides as intermediates. Sodium hypophosphite is a catalyst proven effective in the reactions of both acids. In order to find alternative catalysts, the mechanism of the direct esterification and the role of the catalyst in the reaction were investigated in this study. Several sodium salts of phosphorous acid and dichloroacetic acid with varied pKa values were employed in the treatment of cotton fabric with 3,3′,4,4′-benzophenone tetracarboxylic acid (BPTCA). The results confirmed that the overall reaction follows the Fischer esterification mechanism, an acid catalyzed reaction. The acid anions also play an important role in the reaction. Results of wrinkle recovery angles, FTIR band ratios of ester bonds, and thermogravimetric analyses of the treated fabrics consistently support...

Synthesis and Characterization of a Novel High-Temperature Structural Adhesive Based on MDA-BAPP-BTDA Co-Polyimide

A series of polyimide(PI) adhesives were synthesized from 2,2'-Bis [4-(4-aminophenoxy)phenyl] propane(BAPP), 4,4'-Diaminodiphenylmethane (MDA) and 3,3',4,4'-Benzophenonetetracarboxylic acid dianhydride (BTDA) via a two-step process. PI adhesives with different BAPP content were characterized in regard to their structure, thermal stability, mechanical properties and adhesive performance. Results showed that these PIs had excellent thermal stability, whose glass transition temperature (Tg) were around 300°C. While, superior dynamic mechanical behavior was observed, and the maximum loss factor declined with the increase of BAPP content. Single-lap shear strength of over 15.58 MPa at room temperature was obtained, and it remained high even at the temperature of 350°C. Factors that could affect bonding strength of these PI adhesives such as molar ratio of the diamine monomers, surface roughness of adherends and curing processes were investigated.