This paper presents an experimental investigation of nanocomposites composed of three ratios of epoxy/graphene nanoplatelets (GNPs) by weight. The 0.1, 0.2, and 0.3 wt.% specimens were carefully manufactured, and their mechanical and thermal conductivity properties were examined. The tensile strength and modulus of epoxy/GNPs were enhanced by the large surface area of graphene nanoplatelets, causing crack deflection that created new fracture fronts and friction because of the rough fracture surface. However, the compressive strength was gradually reduced as GNP loading percentages increased. This was probably due to severe plastic yielding on the epoxy, leading to catastrophic axial splitting caused by premature fractures. Furthermore, the highest thermal conductivity was 0.1283 W/m-K, representing a 20.92% improvement over neat epoxy (0.1061 W/m-K) when 0.3 wt.% GNPs were added to the epoxy. This was because of efficient heat propagation in the GNPs due to electron movement through percolative paths. The tensile failure mode in epoxy/GNP nanocomposites showed a few deflected and bifurcated rough cracks and brittle, dimple-like fractures. Contrarily, compressive failure mode in GNP-added epoxy showed plastic flexural buckling and brittle large-axial splitting. The epoxy/GNP nanocomposites were considered a damage-tolerant material.

E-glass three dimensional (3D) stitched preform composites have been developed for several industrial applications due to their high mechanical performance and damage tolerance properties. Although some in-plane properties of the stitched E-glass composite structure are slightly lower than in laminated composite, its mode-I delamination failure is improved. This was achieved by using the out-of-plane directional stitched fibers. Recently, some nanoparticles as single-walled nanotubes (SWNT) or multiwalled nanotubes (MWNT) or nanofibers (NF) were added to the glass fabric structure or stitched preform during consolidation process. This further enhances the thermo-mechanical impact properties of the E-glass fiber composites.

Natural fiber–reinforced biocomposites are increasingly used in various industries such as automotive, construction, biomedical, and recreation, thanks to their distinctive advantages over traditional glass fiber–reinforced plastics. Natural fiber composites are sustainable, environmentally friendly, low cost, low density, and easy to process as well as have high mechanical properties. The quality of fiber-matrix interface is of critical importance since it determines the load distribution capability of the material. The interface between natural fibers and polymer resins has always been problematic because of the low compatibility between cellulose-based hydrophilic natural fibers and hydrophobic polymer resins, which leads to poor fiber-matrix adhesion and therefore inefficient load distribution between fibers and matrix. To date, several interfacial modification methods have been implemented to address this issue and improve the properties of the resulting composites. This chapter focuses on the interfacial modification of hemp fiber–based composites. First, hemp fiber structure and the nature of fiber-matrix interface were explained. Mechanisms of fiber/matrix adhesion as well as qualitative and quantitative methods for the determination of interface strength were outlined. Finally, the interface modification methods for hemp fiber–reinforced biocomposites were presented in the light of scientific literature.

Multiaxis three-dimensional (3D) continuous basalt fiber/cementitious concretes were manufactured. The novelty of the study was that the non-interlace preform structures were multiaxially created by placing all continious filamentary bundles in the in-plane direction of the preform via developed flat winding-molding method to improve the fracture toughness of the concrete composite. Principle and off-axis flexural properties of multiaxis three-dimensional (3D) continuous basalt fiber/cementitious concretes were experimentally studied. It was identified that the principle and off-axis flexural load-bearing, flexural strength and the toughness properties of the multiaxis 3D basalt concrete were extraordinarily affected by the continuous basalt filament bundle orientations and placement in the pristine concrete. The principle and off-axis flexural strength and energy absorption performance of the uniaxial (B-1D-(0°)), biaxial ((B-2D-(0°), B-2D-(90°) and B-2D-(+45°)), and multiaxial (B-4D-(0°), B-4D-(+45°) and B-4D-(−45°)) concrete composites were considerably greater compared to those of pristine concrete. Fractured four directional basalt concretes had regional breakages of the brittle cementitious matrix and broom-like damage features on the filaments, fiber-matrix debonding, intrafilament bundle splitting, and minor filament entanglement. Multiaxis 3D basalt concrete, particularly in the B-4D structure, controlled the crack phenomena and it was recognized as a more damage-tolerant material than the neat concrete.

Multiaxis three-dimensional (3D) continuous polymeric carbon fiber/cementitious concretes were introduced. Their angular (off-axis) flexural properties were experimentally studied. It was found that the placement of the continuous carbon fibers and their in-plane angular orientations in the pristine concrete noticeably influenced the angular flexural strength and the energy absorption behavior of the multiaxis 3D concrete composite. The off-axis flexural strength of the uniaxial (C-1D-(0°)), biaxial (C-2D-(0°), and C-2D-(90°)), and multiaxial (C-4D-(0°), C-4D-(+45°) and C-4D-(−45°)) concrete composites were outstandingly higher (from 36.84 to 272.43%) than the neat concrete. Their energy absorption capacities were superior compared to the neat concrete. Fractured four directional polymeric carbon fiber/cementitious matrix concretes limited brittle matrix failure and a broom-like fracture phenomenon on the filament bundles, filament-matrix debonding and splitting, and minor filament entanglement. Multiaxis 3D polymeric carbon fiber concrete, especially the C-4D structure, controlled the crack phenomena and was considered a damage-tolerant material compared to the neat concrete.

The world in which we live is changing at a much faster and more uncontrolled rate. This situation brings with it both negative and positive changes. The textile industry is also part of this rapid change. The growth of the world’s population and the alterations in consumer habits that this change has brought with it also affect the textile industry. In particular, polluting dyehouses and the synthetic dyes used in them are harming the world. This situation is unsustainable. For this reason, the use of natural dyes instead of synthetic dyes in the coloring of textile products is increasing rapidly. In this study, a blend of 80% cotton and 20% wool was dyed with cinnamon, and its fastness and mechanical performance were tested. In addition, the dyeing results were analyzed using a spectral method, FTIR, and SEM. In this study, natural fiber blends with two different chemical structures were dyed with cinnamon in one bath. The fastness values obtained as a result of the dyeing process were very good. The grey scale value of saliva fastness determined through evaluation was 5. The observed strength increase of approximately 24% in the yarn after dyeing was also remarkable. In conclusion, environmentally friendly dyeing was carried out in this study, and a contribution was made to a sustainable world.