Excellent mechanical, thermal, and electrical properties of carbon nanotubes (CNTs) and nanofibers (CNFs) have motivated the development of advanced nanocomposites with outstanding and multifunctional properties. After achieving a considerable success in utilizing these unique materials in various polymeric matrices, recently tremendous interest is also being noticed on developing CNT and CNF reinforced cement‐based composites. However, the problems related to nanomaterial dispersion also exist in case of cementitious composites, impairing successful transfer of nanomaterials′ properties into the composites. Performance of cementitious composites also depends on their microstructure which is again strongly influenced by the presence of nanomaterials. In this context, the present paper reports a critical review of recent literature on the various strategies for dispersing CNTs and CNFs within cementitious matrices and the microstructure and mechanical properties of resulting nanocomposites.

In recent years there have been several attempts to replace synthetic fibers with natural fibers in fiber reinforced composites, due to increasing environmental awareness and depletion of oil resources. The fact that natural fibers are available cheaply and in abundance, being biodegradable and low density, has motivated many researchers throughout the world to explore their application potential in various industrial sectors. However, natural fibres also have some limitations such as high moisture absorption and subsequent swelling and degradation, poor chemical and fire resistance, high dispersion of mechanical properties, poor interfacial interactions with polymeric or cementitious matrices, etc. Therefore, there is a huge concern to modify the surface of natural fibers through various techniques, in order to overcome their inherent drawbacks and to successfully utilize these materials in various applications. This paper presents a review of existing research studies focused on the surface treatment of natural fibers and the use of nanocelulose, a natural nanofiber, for their application in composite materials

The article throws light on the physical methods to modify natural fibers to be used in composites. Physical methods in natural fiber processing are used to separate natural fiber bundles into individual filaments and to modify the surface structure of the fibers so as to improve the use of natural fibers in composites. Steam explosion and thermomechanical processes fall in the first category while plasma, dielectric barrier techniques and corona fall in the second. The physical treatments have also been used to modify the thermoplastic polymeric films like polyethylene and polypropylene in a bid to impart reactivity. Reviewing such developments, the areas for further research are suggested.

Multiple environmental concerns such as garbage generation, accumulation in disposal systems and recyclability are powerful drivers for the use of many biodegradable materials. Due to the new uses and requests of plastic users, the consumption of biopolymers is increasing day by day. Polylactic Acid (PLA) being one of the most promising biopolymers and researched extensively, it is emerging as a substitute for petroleum-based polymers. Similarly, owing to both environmental and economic benefits, as well as to their technical features, natural fibers are arising as likely replacements to synthetic fibers to reinforce composites for numerous products. This work reviews the current state of the art of PLA compounds reinforced with two of the high strength natural fibers for this application: flax and jute. Flax fibers are the most valuable bast-type fibers and jute is a widely available plant at an economic price across the entire Asian continent. The physical and chemical treatments of the fibers and the production processing of the green composites are exposed before reporting the main achievements of these materials for structural applications. Detailed information is summarized to understand the advances throughout the last decade and to settle the basis of the next generation of flax/jute reinforced PLA composites (200 Maximum).