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Nanocomposites of polypyrrole/reduced graphene oxide (PPy/rGO) and polypyrrole/ functionalized reduced graphene oxide with aryl 4-carboxybenzene diazonium salt (PPy/rGO-aryl-COOH) were prepared through covalent bonding by simple one-step chemical oxidative synthesis. The as-prepared nanocomposites were deposited on BOPET substrate by spin coating to test their chemiresistive sensitivity properties on a homemade modular for online detection of (NO 2 ) vapors at ambient temperature. Results showed that PPy/rGO-aryl-COOH forms a homogeneous nanocomposite within the size of 80 nanometers and improvement of the crystalline ordering. The more enhanced NO 2 sensing properties have been shown by PPy/rGO-aryl-COOH in terms of higher sensitivity (1.01%/ppm), the faster response time (129 s), and the detection limit of (2ppm). Reproducibility features were also investigated. Moreover, humidity rates and temperature effects were also tested. Finally, impedance spectroscopy is conducted in the fresh air and in the presence of gas. These results highlight the paramount role of functionalization of reduced graphene oxide (rGO-aryl-COOH).

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This article aims to outline the current progress in the field of energetic copolymer binders for composite solid propellants (CSPs). Propellants, which are a type of energetic material, are used to generate thrust in rockets and missiles, and they are generally less sensitive than explosives. The common formulations of CSPs contain several different chemical compounds that are typically bound together by a polymeric matrix to form a continuous solid. The use of inert polymers, however, does not enhance the overall specific impulse of the propellant. Energetic copolymers have emerged as a compelling category of binders for CSPs in recent years, offering potential advantages over traditional binders such as improved performance, enhanced safety, and increased manufacturing efficiency. The paper reviews the various types of energetic copolymer binders that have been developed, their potential advantages and drawbacks, and the current challenges and opportunities in the field. It suggests directions for future research and development and aims to provide a useful resource for researchers and practitioners interested in the use of energetic copolymer binders toward CSPs.

The performance of thermoplastic polyurethane (TPU) reinforced with natural fibers can be tailored through a suitable choice of the fibers nature or the type of surface treatment applied to them. The present work deals with the improvement of the interfacial properties of natural fibers, namely wood flour (WF) by the introduction of graphene oxide (GO), which may easily disperse on the WF surface to provide hybrid fibers (WF-GO). The latter were then used as reinforcement of a TPU matrix at different ratios of 1, 3 and 5 wt%. The different samples were characterized by FTIR and RAMAN spectroscopies, XRD, SEM and TGA to confirm the structure, morphology and the thermal stability of the prepared hybrid fibers as well as their composites (TPU/WF-GO). SEM micrographs revealed that the surface treatment applied to WF, the distribution of GO sheets on the fiber interface, and the dispersion of (WF-GO) on the polymer matrix were successfully carried out. The thermal stability of the TPU-base composites increased with the increase of WF-GO content from 325 °C for the pure TPU matrix to 343 °C for the composite reinforced by 5% of (WF-GO). In addition, the results confirmed that the incorporation of GO into WF led to a significant improvement in the mechanical properties of the TPU-based composites, with an improvement in strength from 10.9 MPa to 19 MPa.