The increasing global environmental concerns and awareness of renewable green resources is continuously expanding the demand for eco-friendly, sustainable and biodegradable natural fibre reinforced composites (NFRCs). Natural fibres already occupy an important place in the composite industry due to their excellent physicochemical and mechanical properties. Natural fibres are biodegradable, biocompatible, eco-friendly and created from renewable resources. Therefore, they are extensively used in place of expensive and non-renewable synthetic fibres, such as glass fibre, carbon fibre and aramid fibre, in many applications. Additionally, the NFRCs are used in automobile, aerospace, personal protective clothing, sports and medical industries as alternatives to the petroleum-based materials. To that end, in the last few decades numerous studies have been carried out on the natural fibre reinforced composites to address the problems associated with the reinforcement fibres, polymer matrix materials and composite fabrication techniques in particular. There are still some drawbacks to the natural fibre reinforced composites (NFRCs)—for example, poor interfacial adhesion between the fibre and the polymer matrix, and poor mechanical properties of the NFRCs due to the hydrophilic nature of the natural fibres. An up-to-date holistic review facilitates a clear understanding of the behaviour of the composites along with the constituent materials. This article intends to review the research carried out on the natural fibre reinforced composites over the last few decades. Furthermore, up-to-date encyclopaedic information about the properties of the NFRCs, major challenges and potential measures to overcome those challenges along with their prospective applications have been exclusively illustrated in this review work. Natural fibres are created from plant, animal and mineral-based sources. The plant-based cellulosic natural fibres are more economical than those of the animal-based fibres. Besides, these pose no health issues, unlike mineral-based fibres. Hence, in this review, the NFRCs fabricated with the plant-based cellulosic fibres are the main focus.

The aim of this study is to review three-dimensional (3D) braided fabrics and, in particular, to provide a critical review of the development of 3D braided preform structures and techniques. 3D braided preforms are classified based on various parameters depending on the yarn sets, yarn orientation and intertwining, micro-meso unit cells and macro geometry. Biaxial and triaxial two-dimensional (2D) braided fabrics have been widely used as simple- and complex-shaped structural composite parts in various technical areas. However, 2D braided fabric has size and thickness limitations. 3D braided fabrics have multiple layers and no delamination due to intertwine-type out-of-plane interlacement. However, the 3D braided fabrics have low transverse properties and they also have size and thickness limitations. On the other hand, various unit cell base models on 3D braiding were developed to analyze the properties of 3D braided structures. Most of the unit cell base models include micromechanics and numerical techniques. Multiaxis 3D braided fabrics have multiple layers and no delamination. The in-plane properties of multiaxis 3D braided fabrics may be enhanced due to the ±bias yarn layers. However, the multiaxis 3D braiding technique is at an early stage of development and needs to be fully automated.

The aim of this study is to review three-dimensional (3D) fabrics and a critical review is especially provided on the development of multiaxis 3D woven preform structures and techniques. 3D preforms are classified based on various parameters depending on the fiber sets, fiber orientation and interlacements, and micro–meso unit cells and macro geometry. Biaxial and triaxial two-dimensional (2D) fabrics have been widely used as structural composite parts in various technical areas. However, they suffer delamination between their layers due to the lack of fibers. 3D woven fabrics have multiple layers and no delamination due to the presence of Z-fibers. However, the 3D woven fabrics have low in-plane properties. Multiaxis 3D knitted fabrics have no delamination and their in-plane properties are enhanced due to the ±bias yarn layers. However, they have limitations regarding multiple layering and layer sequences. Multiaxis 3D woven fabrics have multiple layers and no delamination due to Z-fibers and in-plane properties enhanced due to the ±bias yarn layers. Also, the layer sequence can be arranged based on end-use requirements. However, the multiaxis 3D weaving technique is at an early stage of development and needs to be fully automated. This will be a future technological challenge in the area of multiaxis 3D weaving.

In this study, the impact resistance of two-dimensional (2D) fabrics and three-dimensional (3D) preforms is explained. These fabrics and preforms include 2D and 3D woven and knitted flat and circular fabrics. Various types of soft/layered structures as well as rigid composite are outlined with some design examples for ballistic and stab threats. The recent developments in nanotubes/nanofibers and shear-thickening fluids (STF) for ballistic fabrics are reviewed. The ballistic properties of single- and multi-layered fabrics are discussed. Their impact mechanism is explained for both soft vest and rigid armor applications. Analytical modeling and computational techniques for the estimation of ballistic properties are outlined. It is concluded that the ballistic/stab properties of fiber-reinforced soft and rigid composites can be enhanced by using high-strength fibers and tough matrices as well as specialized nanomaterials. Ballistic/stab resistance properties were also improved by the development of special fabric architectures. All these design factors are of primary importance for achieving flexible and lightweight ballistic structures with a high ballistic limit.

Graphene-based materials in the form of fibres, fabrics, films, and composite materials are the most widely investigated research domains because of their remarkable physicochemical and thermomechanical properties. In this era of scientific advancement, graphene has built the foundation of a new horizon of possibilities and received tremendous research focus in several application areas such as aerospace, energy, transportation, healthcare, agriculture, wastewater management, and wearable technology. Although graphene has been found to provide exceptional results in every application field, a massive proportion of research is still underway to configure required parameters to ensure the best possible outcomes from graphene-based materials. Until now, several review articles have been published to summarise the excellence of graphene and its derivatives, which focused mainly on a single application area of graphene. However, no single review is found to comprehensively study most used fabrication processes of graphene-based materials including their diversified and potential application areas. To address this genuine gap and ensure wider support for the upcoming research and investigations of this excellent material, this review aims to provide a snapshot of most used fabrication methods of graphene-based materials in the form of pure and composite fibres, graphene-based composite materials conjugated with polymers, and fibres. This study also provides a clear perspective of large-scale production feasibility and application areas of graphene-based materials in all forms.