Category: 18959-30-3

Related Products of 18959-30-3, A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 18959-30-3, Name is 4,5-Difluorophthalic Anhydride, molecular formula is C8H2F2O3. In a Article£¬once mentioned of 18959-30-3

Highly soluble phenylethynyl terminated oligoimides derived from 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane, 4,4?-oxydianiline and mixed thioetherdiphthalic anhydride isomers

Novel highly soluble phenylethynyl-endcapped oligoimides derived from mixed thioetherdiphthalic anhydride isomers (m-TDPA) and 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane (DAPI), 4,4?-oxydianiline (4,4?-ODA) with 4-phenylethynylphthalic anhydride (PEPA) as a reactive endcapping agent were synthesized. The calculated molecular weights of all the oligoimides were 2500?g¡¤mol?1.The effect of the mole ratio of DAPI/4,4?-ODA on solubility and melt viscosity of oligoimides as well as the thermal and mechanical properties of cured polyimide films was investigated. Experimental results indicated that DAPI greatly improved the solubility (>30?wt.%) of the oligoimides in low boiling points solvents when the content of DAPI was more than 10?mol% per total diamine. All the oligoimides exhibited very good processability with minimum melt viscosity lower than 60?Pa¡¤s at about 330?C. Tough and brown films were obtained after thermally cured at 370?C for 1?h and dynamic mechanical analysis (DMA) showed that glass transition temperatures of the cured films increased up to 340?C with the increasing content of DAPI. However, the thermal stability and mechanical properties decreased with the increase of DAPI content. The temperature of 5% weight loss was higher than 470?C in both air and N2 atmosphere obtained by thermogravimetric analysis (TGA). And the tensile strengths of the cured films were about 60?MPa.

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Benzofuran – Wikipedia,
Benzofuran | C8H2946O – PubChem

Reference of 18959-30-3, A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 18959-30-3, Name is 4,5-Difluorophthalic Anhydride, molecular formula is C8H2F2O3. In a Article£¬once mentioned of 18959-30-3

Olive cake and leaf extracts as valuable sources of antioxidant and antimicrobial compounds: a comparative study

Purpose: Aiming to exploit the remediation of olive cake and leaves, a comparative study between these extracts from the same trees has been carried out to explore them as a source of bioactive compounds with added value. Methods: Olive cake (OCE) and leaf (OLE) methanolic extracts were chemically characterized by UPLC-QTOF-MS, and tested for their in vitro antimicrobial activity using a broth microdilution method. The antioxidant activity was evaluated using the DPPH scavenging, ferric reducing-antioxidant power and iron chelation assays. Results: Our results demonstrated that Gram-positive bacteria were more sensitive to the extracts tested than Gram-negative bacteria, with the exception of Yersinia enterocolitica and Campylobacter jejuni. OLE have higher amounts of ash, carbohydrates, total phenolic content and flavonoids than OCE. UPLC-ESI-TOF-MS allowed the putative identification of 48 and 45 compounds in OLE and OCE, respectively, with three newly identified compounds in OLE. OLE had the highest antioxidant activity based on DPPH, ferrozin and FRP. Conclusion: This study provides novel information on the presence of bioactive compounds, antioxidant and antibacterial capacity of Olea europaea L. leaf and cake extracts, which can lead to the use of these by-products as sources of natural-based bioactive compounds suitable for numerous applications. Graphic Abstract: [Figure not available: see fulltext.]

Balanced chemical reaction does not necessarily reveal either the individual elementary reactions by which a reaction occurs or its rate law.Reference of 18959-30-3. In my other articles, you can also check out more blogs about 18959-30-3

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Benzofuran – Wikipedia,
Benzofuran | C8H2956O – PubChem

In heterogeneous catalysis, the catalyst is in a different phase from the reactants. HPLC of Formula: C8H2F2O3, At least one of the reactants interacts with the solid surface in a physical process called adsorption in such a way. 18959-30-3, name is 4,5-Difluorophthalic Anhydride. In an article£¬Which mentioned a new discovery about 18959-30-3

Effective reduction of volumetric thermal expansion of aromatic polyimide films by incorporating interchain crosslinking

To develop a facile method for reducing the coefficient of volumetric thermal expansion (CVE) of polymer films, the thermal expansion behaviors of thermally cross-linkable polyimide (PI) films with isomeric diamine structures were investigated via thermal mechanical analyses and optical interferometry measurements. The degree of crosslinking of the PI films containing the diphenylethynylene (Ph-C?C-Ph) structure in the main chain was characterized by far-infrared (far-IR) spectra and density functional theory (DFT) calculations, and variations in the CVE induced by thermal crosslinking were quantitatively estimated. The crosslinking reactions effectively reduced the CVEs of the PI films by suppressing intermolecular free volume expansion and local molecular motions promoted at elevated temperatures. The lowest CVE value observed for a crosslinked PI cured at 400 C (+98 ppm/K at 80-280 C) was one of the smallest values reported to date in polymers. Incorporating interchain crosslinking into the main chain is an effective method for reducing the CVE of aromatic polymers.

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Benzofuran – Wikipedia,
Benzofuran | C8H2920O – PubChem

In homogeneous catalysis, the catalyst is in the same phase as the reactant. The number of collisions between reactants and catalyst is at a maximum.In a patent, 18959-30-3, name is 4,5-Difluorophthalic Anhydride, introducing its new discovery. Recommanded Product: 18959-30-3

Meltable phenylethynyl-capped oligoimide resins derived from 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene and 3,4?-oxydianiline

A series of meltable oligoimide resins with controlled molecular weights by reactive phenylethynyl endcapping groups have been prepared by the thermal polycondensation of 3,3?,4,4?-biphenyltetracarboxylic dianhydride (s-BPDA) with the aromatic diamine mixtures consisting of different mole ratios of 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (1,4,4-6FAPB) and 3,4?-oxydianiline (3,4?-ODA) in the presence of 4-phenylethynylphthalic anhydride (PEPA) as molecular weight-controlling and reactive endcapping reagent. Experimental results indicated that the molecular weight-controlled oligoimide resins were mixtures containing a series of biphenylethynyl-endcapped oligoimides with different chemical structures and different molecular weights. The typical oligoimide resins could be melted at temperatures of 300 C to yield stable molten fluid with melt viscosity of 13.4 Pa s, which was suitable for melt processing. The molten oligoimide resins could be further polymer chain extended and crosslinked by thermal curing of the reactive phenylethynyl groups to give strong and tough thermosetted polyimides. Thus, the oligoimide resin with calculated molecular weight of 2500 exhibited not only good meltability with low melt viscosity, but also high melt stability and fluidability at temperatures of <300 C. After thermal curing, the obtained thermosetted polyimide showed high glass transition temperature (>316 C, DMA), excellent thermal stability with initial thermal decomposition temperature of 588 C and good mechanical properties with flexural strength of 159.1 MPa, flexural moduli of 3.3 GPa, tensile strength of 94.7 MPa and elongation at breakage of 9.0%.

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Benzofuran – Wikipedia,
Benzofuran | C8H2990O – PubChem

In heterogeneous catalysis, the catalyst is in a different phase from the reactants. Safety of 4,5-Difluorophthalic Anhydride, At least one of the reactants interacts with the solid surface in a physical process called adsorption in such a way. 18959-30-3, name is 4,5-Difluorophthalic Anhydride. In an article£¬Which mentioned a new discovery about 18959-30-3

Synthesis, properties and gas separation performance of poly(arylene ether sulfone) containing imide pendant groups

The precursor poly(arylene ether sulfone) containing amino-groups was synthesized by a nucleophilic polymerization route, and then modified using three commercially available anhydrides. The anhydride modified polymers had fractional free volume (FFV) values in the range of 0.128-0.162, and good mechanical, thermal and gas transport properties, which were correlated with the polymer chain structure. They showed higher glass transition temperatures in the range 207-227 C compared with the precursor polymers due to the introduction of imide pendant groups, and better thermal stability with 5% weight loss above 512 C. The incorporation of imide pendant groups into poly(arylene ether sulfone)s improved the gas transport performance evidently due to the higher fractional free volume. The anhydride modified polymer Br-PAES-20 possesses higher permeability and permselectivity simultaneously. The most permeable membrane PEP-PAES-60 showed permeability coefficients of 8.66 barrers to O2, 0.64 barrers to N2 and 13.56 barrers to CO2, with an ideal selectivity factor of 13.53 for the O2/N2 pair.

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Benzofuran – Wikipedia,
Benzofuran | C8H2982O – PubChem

One of the major reasons for studying chemical kinetics is to use measurements of the macroscopic properties of a system, category: benzofuran, such as the rate of change in the concentration of reactants or products with time.In a article, mentioned the application of 18959-30-3, Name is 4,5-Difluorophthalic Anhydride, molecular formula is C8H2F2O3

Phenylethynyl terminated oligoimides derived from 3,3?,4,4?-diphenylsulfonetetracarboxylic dianhydride and their adhesive properties

A series of phenylethynyl terminated oligoimides based on 3,3?,4,4?-diphenylsulfonetetracarboxylic dianhydride (DSDA), m-phenylene diamine (m-PDA) or/and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (6FAPB) with calculated molecular weight of 5000 g mol-1 were synthesized. The effect of molecular structure on solubility and melt viscosity of oligoimides as well as the thermal properties of cured polyimide resins was investigated. Experimental results indicated that the oligoimides have good solubility in strong polar solvents to afford homogeneous solutions with the solid content as high as 50 wt%. The oligoimides exhibited better solubility and lower minimum melt viscosity at relatively lower temperature with the incorporation of flexible 6FAPB. These oligoimides could be thermally cured at 320-380 C to give thermosetted resins. The cured resins have good thermal stability with the glass transition temperatures of 278-329 C and the onset decomposition temperatures higher than 500 C. Adhesive properties of polyimides adhered to stainless steel at various conditions were evaluated by lap shear strength test. It was found that the LSS at room temperature increased with the molar ratio of 6FAPB increasing. The polyimides with combination of rigid and flexible structures exhibited good adhesive properties. With the increasing of curing temperature, the lap shear strength of polyimides at elevated temperature maintained at a high level due to the formation of strong bond.

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Benzofuran – Wikipedia,
Benzofuran | C8H2965O – PubChem