Nanocomposites are a heterogeneous group of materials composed of polymers with inorganic materials at the nanoscale level. These materials are gaining much attention due to their advantages over petroleum-based products. The reinforcement of nanomaterials has led to the improvement of the overall performance of the material. These mainly involve the improvement in mechanical, thermal, chemical resistance, antimicrobial, antioxidant, gas, light, and water barrier properties. Due to these, nanocomposites have applications in several industrial sectors such as food, medical, automotive, and battery applications. Hence, this chapter is concerned with an overview of nanocomposites, their properties, polymer nanocomposites based on chitosan, cellulose, starch, alginate, and lignin, and their application in food packaging.

Researchers have concentrated on innovative approaches to increase the shelf life of perishable food products and monitor their quality during storage and transportation as consumer demand for safe, environmentally friendly, and effective packaging develops. This comprehensive review aims to provide an overview of recent developments in carboxymethyl cellulose (CMC) chemical synthesis and its applications in active and intelligent packaging materials. It explores various methods for modifying cellulose to produce CMC and highlights the unique properties that make it suitable for addressing packaging industry challenges. The integration of CMC into active packaging systems, which helps reduce food waste and enhance food preservation, is discussed in depth. Furthermore, the integration of CMC in smart sensors and indicators for real-time monitoring and quality assurance in intelligent packaging is examined. The chemical synthesis of CMC and strategies to optimise its properties were studied, and the review concluded by examining the challenges and prospects of CMC-based packaging in the industry. This review is intended to serve as a valuable resource for researchers, industry professionals, and policymakers interested in the evolving landscape of CMC and its role in shaping the future of packaging materials.

In recent years, there has been a growing demand for environmentally friendly smart packaging materials. Therefore, in this study, we developed an eco-friendly pH-sensitive indicator film through the solvent casting process, incorporating alginate, polyvinyl alcohol, garlic, and Nelumbo nucifera flower extract. The effect of extract on the chemical and physical properties of the film were extensively studied using various characterization techniques. XRD and FTIR reveal the strong interaction between the polymers and the extract. The incorporation of the extract influenced various parameters such as swelling behavior, water solubility, and moisture content, while also improving the film's thermal stability, biodegradability, as well as its antioxidant and antimicrobial properties. Interestingly, the film exhibited a color change in response to pH change. During shrimp storage, the film showed a visible transition from purple to green, indicating shrimp spoilage. Additionally, the film's ability to detect freshness was confirmed by measuring total volatile basic nitrogen (TVBN). These findings suggest that the PVA/alginate/garlic/Nelumbo nucifera film shows promise as an intelligent packaging material for real-time food monitoring applications.

Freshwater shortage has become a serious issue in today's world due to rapid population expansion. Large amounts of hazardous chemicals were released into waterbodies as a result of the widespread industrial expansion. The removal of impurities from the wastewater, including dyes, heavy metal ions, oil, pharmaceutical products, and other toxins, is crucial in this regard. Due to its large surface area, small pore size, good connection, ease of modification, and fine flexibility, electrospun nanofibers play a superior role in water research. Nanofibers are fibers with dimensions in the range of a few nanometres. They are useful for water purification, energy storage, sensors, tissue engineering, and other applications since they are lightweight and have several distinctive properties. Nanofibers undergo functionalization through different techniques such as electrospinning, phase inversion, track-etching, sintering etc. The electrospinning technique is one of the advanced techniques to develop functionalized nanofiber as compared with other techniques. Functionalized nanofiber shows excellent properties such as surface area, porosity, interconnected structure, easy surface modification etc. Due to its unique features, it is widely used for wastewater treatment. Wastewater removal by functionalized nanofiber is done by separation, filtration, adsorption. In this review, we summarize the challenges and perspectives of functionalized nanofiber for wastewater treatment and purification.

Carbonation of agro-waste into high-value-added products is becoming a promising strategy for producing functional active materials and for reducing landfills. Carbon quantum dots (CQDs) are of great attention due to their non-toxic, antibacterial, antioxidant, fluorescent, and other functional properties. The current study demonstrated the hydrothermal synthesis of dried lemon peel-based carbon quantum dots (LCQDs) and their incorporation in polyvinyl alcohol for developing active films. The developed LCQDs exhibit excellent fluorescence, antioxidant, and antibacterial activities against S. aureus, B. cereus, S. enterica, L. monocytogenes, and E. coli. Interestingly, as confirmed by FE-SEM and FTIR, LCQDs showed excellent compatibility with PVA-based films. The mechanical and water vapor barrier properties were improved by adding 3% LCQDs to the PVA film, which also resulted in improved UVC (99.9%), UVB (99.9%) and UVA (99.1%) blocking effects. Additionally, PVA film containing 3% LCQDs showed 98.9% radical scavenging activity by ABTS method and was 100% effective against S. aureus and S. enterica. Therefore, 3% LCQDs-incorporated PVA films could have excellent potential as active food packaging materials.

In the modern world, there is increasing demand for naturally based polymer for active food packaging due to its eco-friendliness, biodegradability, non-toxicity, abundance, and renewability. The naturally bio-based nanocomposite films have some drawbacks, such as hydrophilic nature, low mechanical properties, water resistance properties, etc. In order to improve the overall properties of naturally based nanocomposite coupled with inorganic fillers, matrix filler interaction and different formulations to fabricate the biofilms have potential application in food packaging. Nanoparticles can be incorporated in bio-nanocomposite films to improves their antibacterial, thermal, mechanical, and water barrier properties. Nanoparticles produce such exceptional properties due to their larger surface area and aspect ratio. This chapter deals with the incorporation of fillers/nanomaterials, and how they influence the physical and chemical properties of nanocomposite films.

Strawberries spoil rapidly after harvest due to factors such as the ripening process, weight loss, and, most importantly, microbial contamination. Traditionally, several methods are used to preserve strawberries after harvest and extend their shelf life, including thermal, plasma, radiation, chemical, and biological treatments. Although these methods are effective, they are a concern from the perspective of safety and consumer acceptance of the treated food. To address these issues, more advanced environment-friendly technologies have been developed over the past decades, including modified and controlled atmosphere packaging, active biopolymer-based packaging, or edible coating formulations. This method can not only significantly extend the shelf life of fruit but also solve safety concerns. Some studies have shown that combining two or more of these technologies can significantly extend the shelf life of strawberries, which could significantly contribute to expanding the global supply chain for delicious fruit. Despite the large number of studies underway in this field of research, no systematic review has been published discussing these advances. This review aims to cover important information about postharvest physiology, decay factors, and preservation methods of strawberry fruits. It is a pioneering work that integrates, relates, and discusses all information on the postharvest fate and handling of strawberries in one place. Additionally, commercially used techniques were discussed to provide insight into current developments in strawberry preservation and suggest future research directions in this field of study. This review aims to enrich the knowledge of academic and industrial researchers, scientists, and students on trends and developments in postharvest preservation and packaging of strawberry fruits.

The hydrothermal synthetic approach was used to synthesize unique nanoplatelets of manganese(IV) nickel(II) oxide (NMN) and successively implanted into reduced graphene oxide to develop Ni–Mn oxide implanted reduced graphene oxide (NMNG). The Raman study, X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, surface porosity study, etc., were used to explore its structure–property correlation. The humidity sensing performance of NMNG was assessed, and its sensing mechanism was explored. The higher concentration of H+ or H3O+ on the surface of NMNG showed higher conductivity and generated higher responses. Notably, RGO introduction can enhance sensor performance up to 100 times. The sensitivity of NMNG was greatly improved surpassing the most efficient humidity sensors. NMNG displayed excellent sensitivity and a fast recovery (5 s). Additionally, NMNG can proficiently sense humidity at a wide range of 8–81 relative humidity (RH)

From the environmental perspective, it is essential to develop cheap, eco-friendly, and highly efficient materials for water and wastewater treatment. In this regard, hydrogels and hydrogel-based composites have been widely employed to mitigate global water pollution as this methodology is simple and free from harmful by-products. Notably, alginate and cellulose, which are natural carbohydrate polymers, have gained great attention for their availability, price competitiveness, excellent biodegradability, biocompatibility, hydrophilicity, and superior physicochemical performance in water treatment. This review outlined the recent progress in developing and applying alginate- and cellulose-based hydrogels to remove various pollutants such as dyes, heavy metals, oils, pharmaceutical contaminants, and pesticides from wastewater streams. This review also highlighted the effects of various physical or chemical methods, such as crosslinking, grafting, the addition of fillers, nanoparticle incorporation, and polymer blending, on the physiochemical and adsorption properties of hydrogels. In addition, this review covered the alginate- and cellulose-based hydrogels' current limitations such as low mechanical performance and poor stability, while presenting strategies to improve the drawbacks of the hydrogels. Lastly, we discussed the prospects and future directions of alginate- and cellulose-based hydrogels. We hope this review provides valuable insights into the efficient preparations and applications of hydrogels.

With growing concerns about the environmental impact of petroleum-based products, researchers are exploring new materials for food packaging. One promising avenue is the use of nanotechnology and natural materials. In this study, active and intelligent composite films were developed by solvent casting method using polyvinyl alcohol (P), chitosan (C), zinc oxide nanoparticles (Z), and sweet purple potato extract (S). The results demonstrated that C and Z did not affect the pH-based structural transformation of pigment (S)-containing PVA solutions. SEM microstructural observation revealed a uniform distribution of zinc oxide nanoparticles in the polymeric matrix. The addition of C and Z to the composite film improved its thermal, water barrier, and antibacterial and antioxidant properties. The tensile strength of the neat film (P) was 13.0 MPa and increased to 30.8 MPa for PCZS composite film because of the good interaction between PVA and the additives. The strong antimicrobial activity of PCZS composite films against environmental pathogens was validated by antimicrobial barrier analysis. Additionally, the functional composite film (PCZS) efficiently detected chicken freshness as a function of pH change. These findings suggest that the PCZS film has great potential as a smart and active food packaging material or as an antimicrobial wrap.

Foodborne illnesses and food intoxications caused by bacterial and viral pathogens are severe global issues that require novel attempts to manage and consider food safety without deranging consumer preferences. Metal oxide nanoparticles (MONPs) have recently attracted attention as excellent antibacterial and antiviral biocides for active food packaging. Many studies have reported several MONPs with antibiotic activity. Incorporating MONPs with antibacterial and antiviral abilities into a polymer matrix creates a multi-germicidal packaging material for the control of infectious food pathogens. MONPs eliminate bacterial pathogens through multiple mechanisms, including interaction and damage to cell membranes, the release of cations, damage to biomolecules, and the production of reactive oxygen species (ROS). Similarly, they also exert intracellular and extracellular strategies to interfere with viral pathogens. To develop functional packaging materials with multi-germicidal activities, a clear understanding of the properties of materials, the factors influencing the manufacturing of the antibacterial ability of MONPs, and antibacterial mechanisms is required. This review provides a deeper understanding of mechanistic insights into how specific MONPs interact to control foodborne pathogens. Discussing the affinity of MONPs for bacterial and viral cellular components may lead to the discovery of new metal oxide combinations with improved bactericidal efficiency. Therefore, understanding these mechanisms will help develop new functional packaging materials with targeted antibacterial or antiviral activities.

Technological advancements and innovations in lightweight materials can have significant promises in day-to-day life. Many lightweight materials like aluminum, magnesium, titanium, beryllium, carbon-based composites, and glass fiber–based composites are highly demandable due to their protruding features over petroleum-based products. Lightweight materials are characterized to have low-density materials having higher strength, excellent flexibility, thermal resistance, and improved performances. Due to this, these materials have profound applications in automobile, construction, packaging, biomedical, aerospace, and acoustic applications. Moreover, these functional materials can be developed using several host matrices and reinforcing materials. Hence, this chapter will give a brief introduction to lightweight materials, biocomposites as lightweight materials, different lightweight materials like carbon-based composites, glass fiber–based composites, foams as lightweight materials, wood fiber–based composites, hybrid composites, and bionanocomposites. In addition to this, the global impact of lightweight materials in various industries and the impact of COVID-19, challenges and future outlooks are also discussed.

The death caused by multidrug-resistant pathogens is increasing day by day, and it needs special attention due to the challenges faced by the world health care systems. Hence, there is an urgent need to develop novel materials for antimicrobial and drug delivery applications due to the emergence of multidrug-resistant microbial pathogens. The innovations in polymer nanotechnology have paved the way to explore their applications in biomedical and other industrial sectors. Two-dimensional (2D) materials are ultrathin nanomaterials that receive great attention due to the degree of anisotropy, a higher surface area, antimicrobial activity, and a drug-carrying capacity. These easily tunable materials can be functionalized with any material of interest that makes them superior to others. The polymer nanocomposites based on 2D materials can have significant potential in drug delivery and antimicrobial applications. Hence, this review will give an overview of different types of 2D nanomaterials, their properties, their interaction with biological systems, their antimicrobial mechanisms, antiviral properties, 2D material-based viral detection, their interaction with surfaces, immunomodulating effect, biocompatibility, 2D materials and inflammation, polymer composites based on 2D materials, and their antimicrobial as well as biomedical applications.

Fabrication of food packing material is an interesting area of research and has received great attention in industrial sectors. Both synthetic and natural polymers have been employed to engineer effective food packing materials. However, recently, due to the nonbiodegradability and toxic nature of packaging materials, there is an increase in replacement of nondegradable petroleum-based materials with biomaterial to develop active food packaging materials. Biomaterials are abundant, low-cost, nontoxic, eco-friendly, and biodegradable in nature. In this chapter, recent trends in biobased materials for active packaging, thermomechanical, optical, rheological morphological, and antibacterial properties of the biomaterials are discussed. The role of nanomaterials in improving the properties of nanocomposite is also described in detail.

Over the last few decades, there has been an increase in the usage of natural fibers-based products in our day-to-day life. Natural fibers are generally derived from plants and animals. The attractive features of nature fibers are low cost, abundance, non-toxicity, renewability and high modulus. The incorporation of natural fibers into polymer matrix caused an enhancement in physical and mechanical properties. The present chapter focuses and discusses the significant findings of recent research works that has been carried out on natural fiber-reinforced epoxy composites. The influence of fiber content, surface treatment, fiber size and coupling agent on thermomechanical behavior of natural fiber-reinforced polymer composites is also presented here.