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In the present work, novel and effective quinoline-based polybenzoxazines coatings were prepared on cotton fabrics and mild steels to improve the hydrophobic properties and corrosion resistance, respectively. For this purpose, four quinoline containing mono-oxazine-based benzoxazines were synthesized using 8-hydroxyquinoline (Q), and various monoamines, such as: butylamine (ba), hexylamine (ha), octylamine (oa) and aniline (a). The molecular structure of the benzoxazine monomers was verified by 1H-NMR and FTIR spectroscopy. The effect of the aliphatic and aromatic functional groups of the benzoxazines on oxazine ring-opening curing was investigated, and the influence of their corresponding materials on thermal and morphological properties was also elucidated. These quinoline-based monomers have been successfully coated onto the surface: i) cotton fabrics to be used as a water – oil separation method; and ii) mild steel as inhibitor of the corrosion. In this sense, cotton fabric coatings exhibited highly hydrophobic properties (contact angle from 124° to 139°), and subsequently the water oil-separation efficiency was measured to the material that presented the highest contact angle (Poly Q-oa), obtaining a 91% separation efficiency. For benzoxazines coatings on mild steel, impedance tests have indicated that these polymers are corrosion inhibitor effectives. Finally, the antibacterial properties of the quinoline based benzoxazines was also analysed, indicating good antibacterial resistance owing to the existence of long alkyl chains in their respective molecular structure. According to the results obtained from numerous analyses, the quinolone-based polybenzoxazines can be considered as successful materials for applications such as corrosion resistance, oil-water separation, marine coating and microelectronics insulation. [ABSTRACT FROM AUTHOR]

In the first article of this sequel (J. Appl. Polym. Sci., 2018, 135, 45747), an experimental and theoretical investigation was developed on the two‐steps synthesis of linear segmented thermoplastic polyurethanes. The reactions were carried out at 60°C, with methylene diphenyl diisocyanate (MDI), two poly(tetramethylene oxide) macrodiols, and 1,4‐butanediol (BD) as chain extender. In our second article (J. Appl. Polym. Sci., 2019, 136, 46946), a mathematical model for the prepolymerization was developed, that involved integrating a differential equation for each generated polymer species. The present article extends such model, and predicts the molecular structure along the finishing stage. In each stage, the new model first solves the molar balances at polymer topologies level (i.e.,: Disregarding the molar mass distribution [MMD] of the reacted macrodiol chains), and then calculates the MMD of the evolving polymer and its main subsets through an algebraic convolution procedure. The model reproduces the prepolymerization predictions of our previous article, but is three orders of magnitude faster. In the finishing stage, up to 156,000 polymer topologies and 4.53 × 108 polymer species were calculated; and the rate constant was readjusted to (k2 = 0.00129 L mol−1 s−1), in order to fit the measured MMDs. [ABSTRACT FROM AUTHOR]

This work investigates the two-step polymerization between methylene diphenyl diisocyanate (MDI), two different poly(tetramethylene oxide) macrodiols, and 1,4-butanediol (BD) as chain extender. At the end of the prepolymerization, the reaction mixture contains MDI in excess and a prepolymer with isocyanate end group. Then, BD and a solvent (tetrahydrofuran) were added to start the finishing stage under nominal stoichiometric equilibrium. The reaction was analyzed by Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance (1H-NMR), and size exclusion chromatography. 1H-NMR was employed to follow global concentrations of unreacted isocyanate end groups and internal urethane groups. This information enabled to estimate the following "effective" rate constants: k1 =1.07 x 10-3 L mol-1 s-1 for the prepolymerization; and k2=1.94 x 10-4 L mol-1 s-1 for the finishing stage. These values are subject to errors caused by biases introduced in the recipe, in the measurements, in the reaction conditions, in the quality of reagents, and in the reaction mechanism assumptions. Such errors also explain the dispersion of the published rate constants values. The ¹H-NMR measurements also enabled to estimate the evolution (with extent of reaction) of the numberaverage number of structural units along the prepolymerization and finishing stages; and such estimates reasonably verify Flory's classical expressions. [ABSTRACT FROM AUTHOR]

Initially, the carboxylated-acryl amido propane sulfonic acid (C-AMPSA) was synthesized through the thiol-ene reaction using 2-acrylamido-2-methylpropane sulfonic acid and 3-mercapto propane sulfonic acid monomers. The C-AMPSA was cross-linked with polyvinyl alcohol to create a non-perfluorinated membranes were of these acid group-containing monomers. Using a cross-linking technique, a poly vinyl alcohol cross-linked C-AMPSA (PVA-C-AMPSA) polymer was prepared. Following that, the MoS2 nanosheets (NSs) were synthesized through the one-pot hydrothermal method, and their phase purity, functionality, and morphology were evaluated by p-XRD, FT-IR, and FE-SEM analyses. These nanosheets were then incorporated into PVA-C-AMPSA polymer nanocomposite membranes at various concentrations (0%, 1%, 2%, 3%, and 5% by weight). In addition, the physicochemical properties of bare and MoS2 nanosheets incorporated PVA-C-AMPSA polymer nanocomposite membranes were assessed, including water uptake, swelling ratio, and ion-exchange capacity. Remarkably, the membrane with 5% of MoS2 NSs in PVA-C-AMPSA displayed an ion-exchange capacity of 1.13 mmol g−1 and a proton conduction of 1.8 × 10−3 S cm−1 at 110°C. The Arrhenius plot indicated that the proton transport was involved in both Grotthuss and vehicular mechanisms. In the fuel cell testing, the PVA-C-AMPSA polymer nanocomposite membrane containing MoS2 NSs demonstrated superior performance, achieving a peak power density (PD) exceeding 0.7 W cm−2 and an open-circuit voltage (OCV) surpassing 0.93 V at 110°C. In contrast, the pure PVA-C-AMPSA membrane exhibited a peak PD of over 0.4 W cm−2 and an OCV of around 0.6 V at the same temperature. Additionally, the 5% of MoS2 NSs incorporated PVA-C-AMPSA polymer nanocomposite membrane exhibited outstanding oxidative stability with 87.7% of degradation when exhibited to a Fenton reagent at 80°C for 8 h. [ABSTRACT FROM AUTHOR]

In this work, a straightforward and scalable method was used to generate nitrogen-rich porous carbon (NRPC), which was then incorporated with a graphitic carbon nitride and magnetite (g-C 3 N 4 /Fe 3 O 4 ) nanocomposite, fabricated with Fe 3 O 4 nanoparticles as an eco-friendly and economically viable component. The fabricated NRPC/g-C 3 N 4 /Fe 3 O 4 nanocomposite was applied as an electrode in supercapacitor applications. The synthesized NRPC/g-C 3 N 4 /Fe 3 O 4 nanocomposite, NRPC, g-C 3 N 4 , and Fe 3 O 4 were characterized by analytical and morphological analyses. The spherically shaped Fe 3 O 4 nanoparticles were analyzed by field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). The specific surface area of NRPC/g-C 3 N 4 /Fe 3 O 4 was determined to be 479 m 2 g -1 . All the crosslinked composites showed exceptional electrochemical performance and exhibited a pseudo-capacitance behaviour. In comparison to the Fe 3 O 4 and g-C 3 N 4 /Fe 3 O 4 electrodes, the NRPC/g-C 3 N 4 /Fe 3 O 4 electrode showed a lower charge-transfer resistance and higher capacitance. The prepared NRPC/g-C 3 N 4 /Fe 3 O 4 electrode exhibited the highest specific capacitance of 385 F g -1 at 1 A g -1 compared to Fe 3 O 4 (112 F g -1 ) and g-C 3 N 4 /Fe 3 O 4 (150 F g -1 ). Furthermore, the cycling efficiency of NRPC/g-C 3 N 4 /Fe 3 O 4 remained at 94.3% even after 2000 cycles. The introduction of NRPC to g-C 3 N 4 /Fe 3 O 4 improved its suitability for application in high-performance supercapacitors.