In recent times, demand for light weight and high strength materials fabricated from natural fibres has increased tremendously. The use of natural fibres has rapidly increased due to their high availability, low density, and renewable capability over synthetic fibre. Natural leaf fibres are easy to extract from the plant (retting process is easy), which offers high stiffness, less energy consumption, less health risk, environment friendly, and better insulation property than the synthetic fibre-based composite. Natural leaf fibre composites have low machining wear with low cost and excellent performance in engineering applications, and hence established as superior reinforcing materials compared to other plant fibres. In this review, the physical and mechanical properties of different natural leaf fibre-based composites are addressed. The influences of fibre loading and fibre length on mechanical properties are discussed for different matrices-based composite materials. The surface modifications of natural fibre also play a crucial role in improving physical and mechanical properties regarding composite materials due to improved fibre/matrix adhesion. Additionally, the present review also deals with the effect of silane-treated leaf fibre-reinforced thermoset composite, which play an important role in enhancing the mechanical and physical properties of the composites.

The present investigation addresses the influence of fly ash filler material on physico-mechanical properties (water absorption, tensile, flexural, impact, and hardness) and abrasive wear on alkali-treated (2% NaOH) chopped Himalayan agave fiber randomly oriented compound with polyester resin. The physico-mechanical properties such as void fraction, water resistance capability, tensile, flexural, impact, hardness, and dry abrasive wear characteristics of Himalayan agave fiber/polyester composites was determined. The maximum tensile strength (30.09 MPa), flexural strength (54.51 MPa), impact strength (30.24 J/m²), and hardness (42.5 H_V) were observed at 15 wt.% of Himalayan agave fiber and fly ash. The abrasive specific wear rate of the composite was studied at four different factors, i.e., fiber loading (5–15 wt.%), normal load (10–30 N), fly-ash content (5–15 wt.%), and speed (50–150 rpm) using Taguchi’s method L₉ orthogonal array. The study determined that the control parameters of fiber loading (15 wt.%), normal load (10 N), fly-ash content (15 wt.%), and speed (100 rpm) exhibited the least specific abrasive wear rate. The SEM analysis of worn abrasive surfaces revealed the micro-cuts, fiber breakage, micro-plowing, cracks, and wear debris as the dominant wear mechanism.

Remarkable progress has been established in the field of nanoenergetic materials (mixture of nanoscale fuel and oxidizer) since the advent of nanotechnology. Combustion of nanoenergetic materials depends on many key factors like synthesis route, equivalence ratio, morphology of constituents, and arrangements and handling of materials. For tailoring and tuning of the combustion properties of nanoenergetics, sound knowledge of the reaction mechanism is needed; in this review article a schematic study on the reaction mechanism is presented. By employing various routes and strategies in synthesizing and nanoengineering of the fuel or/and oxidizer to realize a significant evolution from normal physical mixing of nanopowders to the formulation of core/shell nanostructures, the nanoenergetic materials achieved the best ever combustion properties in terms of combustion reactivity, ignition sensitivity, energy density, etc. Overall, in this article, a critical state-of-the-art review of the existing literatures has been conducted to feature the main developments in the molecular combustion modeling of melting, oxidation, and core–shell reaction/diffusion of nanoaluminum and the molecular modeling of combustion reactivity and ignition sensitivity of nanoenergetic materials.