Jute fiber-reinforced composites have become a promising alternative to synthetic fiber composites because of their favorable environmental characteristics, cost efficiency, and good mechanical properties. The present review provides a comprehensive examination of the manufacturing processes and mechanical properties of polymer composites reinforced with jute fibers. This study investigates the influence of several fabrication methods, such as hand lay-up, compression molding, injection molding, pultrusion, etc., on the mechanical properties of the composites. It also provides SWOT analyses of various manufacturing processes of jute fiber-reinforced composites. Important aspects, including fiber orientation, fiber/matrix adhesion, and the effects of different surface treatments on improving mechanical characteristics, such as tensile strength, flexural strength, and impact resistance, are discussed. The difficulties associated with moisture absorption, degradation, and the lack of uniformity in jute fibers, as well as approaches to alleviate these problems, are presented. The goal of this study is to establish a basis for future investigation and advancement in enhancing the mechanical properties of jute fiber-reinforced composites.

Natural fibres have recently become an attractive alternative to synthetic fibres in the implementation of polymer composite structures. Inherent flaws within natural fibres in terms of their constituent contents (hemicellulose, cellulose, and lignin) reduce the compatibility of these fibres with polymer matrices. In this study, the effects of chemical treatments on hemp fibres and the resulted polyester matrix composite are investigated. The fibres were treated with alkali (0–10% NaOH), acetyl, and silane chemicals. Long unidirectional fibre composites were prepared by vacuum‐assisted resin transfer moulding (VARTM) process. Thermal properties of the fibres were tested using differential scanning calorimetry (DSC) analyses. The mechanical properties of the composite samples were tested using compression and bending tests. Failure analysis of tested composites was undertaken through Optical Microscope (OM) and Scanning Electron Microscope (SEM). The results showed that the treatments of the 4% NaOH reduced interfacial bonding strength and decreased composite properties compared to untreated samples. At higher concentrations (6–10% NaOH), the mechanical properties of the composites increased as a result of greater interfacial bonding. Different trends were observed in the case of alkalised fibres that were further treated with acetyl and silane treatments. It was observed that the treated fibres effectively improved the bonding properties of composites and was in agreement with the micrographs.

Prepregs are resin-impregnated, expensive composites mainly limited to high-end applications within the aeronautical, defense, automotive, and energy sectors. Prepreg technology is mainly protected by trade secrets, resulting in limited studies on prepreg resin matrix development and recent advancements. Three key parameters for epoxy resin matrix development including B-staging, viscosity, and tackiness, and their control strategies are discussed in detail. The B-stage is defined as the partially cured stage of epoxy prepregs and is extremely important for prepreg layup, pot life, and final performances. The three key parameters are interrelated and accurately controlled, and, hence, resin development plays a huge role in the prepreg development process. This review also discusses the measuring techniques of the parameters in detail. Based on the resin impregnation techniques and B-stage control, two approaches are proposed to develop the prepreg resin formulations: conventional resin impregnation and viscosity-controlled resin impregnation. The approaches would be extremely useful, especially for advancing beyond the existing prepreg applications and developing smart materials and functional composites through advanced resin modification strategies.

The global production of macadamia nuts has witnessed a significant increase, resulting in the accumulation of large quantities of discarded nutshells. These nutshells possess the properties of remarkable hardness and toughness, which are comparable to those of aluminum. Incorporating natural fillers to enhance the properties of composite materials for various applications, including light duty, structural, and semi-structural purposes, is a common practice. Given their inherent hardness and toughness, macadamia nutshells present an intriguing choice as fillers, provided that the manufacturing conditions are economically viable. With the urgent need to shift toward natural fillers and reduce reliance on synthetics, exploring macadamia nutshells as components of natural fiber composites becomes imperative. This review aims to comprehensively examine the existing body of knowledge on macadamia nutshells and their bio-synthetic polymer composites, highlighting key research findings, achievements, and identifying knowledge gaps. Furthermore, the article will outline prospective areas of focus for future research endeavors in this domain, aligning with the universal goal of minimizing synthetic materials.

Shape memory polymers (SMPs) and their composites (SMPCs) can hold a programmed temporary shape and recover to their original shape once exposed to a particular external stimulus. The stimulus light has the advantage of being both an excitation energy source and a control signal carrier for remote actuation of SMP materials. Here we present the capability of D-shaped optical fibres to send near infrared (NIR) light into a light activated shape memory polymer composite (LASMPC) which generates the adequate photothermal effect necessary for the shape recovery process of relatively large samples. A D-shaped optical fibre enables dispersion of light through the polished area around the fibre than the dispersion of light through the tip of the fibre. Embedment of a D-shaped optical fibre in a LASMPC creates a single unit smart actuator, which can be remotely activated by light. Remotely controllable smart actuators can be located at any difficult to reach positions and controlled safely with light energy. It would be a breakthrough technology for biomedical, aerospace and many other engineering applications.

Fiber-reinforced composites are a well-recognized option for repair and rehabilitation of the pipelines for the oil and gas industry. Infilled composite sleeve system provides an effective rehabilitation solution, where the sleeve acts as prime reinforcement without any direct contact with steel. However, the long-term performance of the repair is dependent, in part, on the effect of hygrothermal ageing of the composites. In this publication, glass transition temperature and mechanical properties are compared for glass-fiber reinforced vinyl ester composite, both as-manufactured and after hot-wet conditioning at 80℃. The tensile and shear strength reduced substantially during conditioning, whilst the elastic modulus was relatively stable. The average glass transition temperature of the composite dropped from the as-manufactured value of 110℃ to 97℃ and 101℃, after 1000 and 3000 h of conditioning, respectively, indicating that it is stable and that the composite is suitable for use as a pipeline repair material operating at 80℃. The results indicate that a 1000 h conditioning period, specified as a minimum period in ISO/TS 24817 is suitable for representing long-term properties for stiffness-based designs for the composite material and conditioning temperature investigated.