This work proposes for the first time to develop a nanocomposite from polymethyl methacrylate (PMMA) based microfibers and reduced graphene oxide (rGO), synthesized using the Solution Blow-Spinning (SBS) technique [1]. This technique allows the production of fibers with a small diameter using a thermoplastic polymer, being capable of producing microfibers on a large scale. The interest is related to the reduction of the diameter when compared to conventional fibers, as the diameter size of these materials directly affects their properties, which tend to improve as the contact surface increases, thereby improving wettability [2][3]. The use of graphene and graphene oxide as reinforcing materials in composites has attracted attention, as they tend to provide greater rigidity, strength and conductivity to the material [4]. Graphene oxide is obtained by functionalizing graphene through exfoliation, creating regions with sp2 and sp3 hybridized carbons [5], in addition to hydroxyl and epoxy functional groups. This structure improves the interaction with the polymer matrix, increasing the rigidity of the composite and making it conductive, with the advantage of reducing costs when using reduced graphene oxide (rGO). The results obtained from experimental tests of concentration and morphology through Scanning Electron Microscopy (SEM) during the development of the nanocomposite will indicate the feasibility of producing a pure PMMA nanocomposite (matrix) reinforced with rGO in powder form (filler) for applications such as conductive polymer composites via Solution Blow Spinning.

Natural lignocellulosic fibers (NLFs) have been widely studied as sustainable alternatives to synthetic fibers, standing out for being renewable, biodegradable, economically viable and for presenting good specific mechanical properties [1-3]. In this context, the present study aimed to evaluate the flexural strength of polyester matrix composites reinforced with short jute and piassava fibers. The fibers were used in their natural form, without surface treatment, cut to a length of 15 mm, and incorporated into the matrix by manual molding (hand lay-up) using silicone molds, without the application of pressure. The specimens were produced with randomly distributed discontinuous fibers, with mass fractions adjusted to the mold volume. The bending tests indicated that the pure polyester composite presented a bending stress of 112.12 ± 17.58 MPa, while the composites reinforced with jute and piassava fibers reached 59.16 ± 8.37 MPa and 62.48 ± 5.89 MPa, respectively, representing reductions of approximately 47% and 44% in relation to the pure matrix. Fractographic analysis of the rupture surfaces revealed that the failure of the composites was predominantly governed by fiber pull-out and low interfacial adhesion between fiber and matrix, also associated with the presence of internal voids resulting from the manual molding process. These factors contributed to the reduction of the mechanical efficiency of the composites, highlighting the need for surface treatments of the fibers and improvements in processing to optimize structural performance.

This study aims to develop a nanocomposite based on recycled polycarbonate (PC) with reduced graphene oxide (rGO), intended for applications in electromagnetic radiation absorbing materials (ERAM), with emphasis on stealth technologies applied to vessels [1]. The nanofibers were produced using the Solution Blow Spinning (SBS) process, aiming to maximize efficiency in electromagnetic radiation absorption [2-4]. The methodology involved the characterization of the individual components (PC and rGO) and the resulting nanocomposite through thermal analyses (DSC and TGA), gel permeation chromatography (GPC) to determine the molar mass of PC, and complementary techniques such as Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and electromagnetic radiation absorption analysis using a vector network analyzer. The results demonstrated that incorporating different proportions of rGO into the PC significantly enhanced radiation absorption in the X-band, indicating the formation of a promising functional system for electromagnetic shielding applications. The combined analyses revealed a homogeneous morphological structure and suitable thermal and structural properties, confirming the potential of the developed nanocomposite as an efficient alternative for use in defense and security systems [5-6].