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Polymeric biomaterials such as polylactic acid (PLA) play a prominent role in the advancement of biomedical additive manufacturing (AM). PLA offers indeed a very advantageous combination of thermo-mechanical properties and functional attributes, as it is biobased, biodegradable, biocompatible and easy to print. However, PLA can be damaged by common sterilization methods and is sensitive to most chemical disinfectants, and this may impair its widespread usage. One of the most promising ways to overcome this shortcoming is to provide PLA with embedded antibacterial activity by the addition of appropriate fillers such as ZnO nanoparticles. After a detailed introduction to the basic properties of PLA and ZnO nanoparticles, the present review analyzes the main variables that govern the antibacterial activity of PLA-ZnO nanocomposites. Current applications and related manufacturing processes are also presented to showcase the importance of having embedded antibacterial functions in demanding fields such as food packaging and wound dressing. Emphasis is then placed on the emerging literature of the AM of PLA-ZnO nanocomposites, with a focus on fused filament fabrication (also known as fused deposition modeling). Existing gaps and hurdles related to the development and 3D printing of such composites are critically discussed. It is envisioned that a deeper understanding of the processability, thermo-mechanical behavior, biocompatibility and anti-bacterial efficacy of additively manufactured PLA-ZnO nanocomposites will foster their adoption in the biomedical field and, ultimately, in all circumstances where it is crucial to limit infection transmission.

Nowadays, non-degradable plastic packaging materials have created significant disposal and pollution issues threatening human health and development. The utilization of biodegradable packaging materials can help address the issue. Cellulose is abundant and renewable, and cellulose-based materials have been regarded as an alternative to petroleum-based plastic food packaging. With the development of cellulose solvents, various regenerated cellulose films and hydrogels have been fabricated for different applications. In this review, we summarize the recent progress in the preparation of regenerated cellulose films and hydrogels, and highlight their potential applications as biodegradable packaging, active packaging, and intelligent packaging. Finally, the biodegradability and safety of cellulose-based materials are stated, and future opportunities and challenges in this active research area are described.

Organic Phase Change Materials (oPCMs) are practical and efficient materials in regulating temperature changes, with broad applications including building material, textiles, and food packaging. However, their flammability poses the main challenge to their widespread applications. This review summarizes various approaches to reduce the flammability of oPCMs including incorporation of flame retardants in shape stabilized PCMs and microencapsulated PCMs, chemical transformations and surface coating, paying particular attentions to the flammability parameters such as limiting oxygen index (LOI), total heat released (THR), peak heat release rate (pHRR) as well as the mechanisms of fire retardancy. Flame-retardant oPCM for practical applications such as plasterboards and fabrics will be highlighted. Further strategies to enhance flame retardant properties of oPCM, such as, incorporation of synergistic flame retardants, chemical modification of PCM (e.g. intrinsically flame-retardant oPCM), have been proposed and commented in the conclusion of this paper.

Dry powder products are highly sensitive to oxygen and water vapour and must have a long shelf life. Currently, they are vacuum-packaged in sachets whose walls are made of a composite film that stops oxygen and water vapour from entering the package. Most of these composites are not biodegradable, a situation that the most agricultural company now wants to change to gain in sustainability. According to National Geography (2019), every year, about 8 million tons of plastic waste escapes into the oceans from coastal nations, with some estimates ranging to at least 400 years to break down. Over the years, there is huge interest in the development and use of biobased packaging materials, however, most of these materials are brittle and have low mechanical properties. Thus, in order to overcome these drawbacks, blended polymers with the reinforcement of nanocellulose are recommended. The aim of this paper is to review packaging films with oxygen barrier properties similar to those of the conventional films but also having biodegradable properties. From the literature, the oxygen permeability coefficient improved with the high strength, modulus, and ductility, as the nanocellulose was reinforcing with biopolymer. This might be due to nanocellulose that contributes to the higher stretchability of the composite biofilms. A fine dispersion of nanocellulose throughout the polymer host promoted several improved properties of the composite biofilms. In addition, nanocellulose had greatly enhanced oxygen and water vapour barrier properties. It would indeed push the usability of biopolymers forward, and certainly, prompt wider application of biodegradable polymers in the fields of environmental protection such as biodegradable food packaging.

Curcumin and Fenugreek essential oil (FEO) were blended into the PLA matrix by solution casting technique to improve the functional properties of the composite film. Both fillers (curcumin and FEO) were properly combined and uniformly distributed in the polymer matrix to create a PLA-compatible composite evidenced by Scanning electron microscope (SEM) and Fourier Transform Infrared (FT-IR) results. The addition of FEO and curcumin to the composite film improved UV-blocking, surface color, tensile strength, flexibility, thickness, and Water contact angle (WCA). However, the inclusion of curcumin and FEO slightly diminish the Water vapor permeability (WVP) while maintaining its thermal stability. The PLA-based composite film exhibited good antibacterial and anti-oxidant properties. In addition, a food quality test was performed on strawberry, and the results were compared to the commercial (polyethylene) film.

In the field of food packaging, the addition of exfoliated layered silicates in polymers has been established to improve the polymers&rsquo, gas barrier properties. Using these polymers as coatings to protect smart textiles from oxidation and corrosion while maintaining their textile properties should significantly extend their lifetime and promote their market penetration. The aim of this study was to print new polymer dispersions containing layered silicates to protect screen-printed conductive structures, and to test the resulting samples. For this, appropriate printing parameters were determined by statistical design of experiments. According to these results, conductive structures were printed and protected with the selected coating. The abrasion resistance and the continuity of the protective layer of the printed samples were then measured. A continuous protective coating of approximately 70&ndash, 80 &micro, m thickness was applied on a conductive structure. The printed samples showed a very high resistance to abrasion (unchanged by 85,000 abrasion cycles) while remaining flexible and presenting a lower water vapor permeability (&lt, 2.5 g/m&sup2, d) than the coatings commonly used in the textile field.

High oxygen and moisture barrier metal oxide (MO)-coated multilayer polymer packaging can retain the shelf life of in-package sterilized food products. However, presence of cracks and pinholes in the coating layer of these films can increase their oxygen and moisture permeabilities. The defects have microscopic dimensions and can be present at random locations in the films��� coatings, making it difficult to find and characterize them using traditional microscopes. To solve these challenges, this research focused on three objectives: (i) to develop an oxygen indicator that can locate the defects in the metal-oxide coated films and validate its functionality; (ii) to assess the performance of newly developed MO-coated films with multiple coated-PET layers; (iii) to accelerate the detection process of the indicator to make it more industry oriented. In the first study, a methylene blue and agar gel-based color changing oxygen indicator was developed that could visually identify the defects in MO-coated films. Microscopic characterization confirmed the presence of defects at the locations indicated by the indicator, hence validating its effectivity. The indicator worked efficiently at 23 ��� to detect the defects but was not successful when tested under accelerated conditions at 40���., The second study assessed the efficacy of two newly developed MO-coated films with multiple coated-PET layers by exposing them to retort and microwave assisted thermal sterilization (MATS) processes. Films with three coated PET layers showed no oxygen permeation after retort and MATS processing. The three-layer coated-PET films had limited moisture absorption and least number of defects, as demonstrated by the oxygen indicator, SEM and CLSM., The third study explored the possibility of accelerating the detection process by formulating the indicator using three different gelling agents: Agar, Gellan_ NaCl, Gellan_ CaCl2 and testing them at 23 ��� and 40 ��� with two MO-coated films. Gellan_ NaCl was faster than the other two gel-based indicators. Additionally, Gellan_ NaCl could detect the defects in 20 days at 40 ���. This reduced the detection period from 180 days at 23 ���, as seen in the first study. Overall, the method could expeditiously detect the defects and thus, could reduce the cycle time needed for developing newer MO-coated films.

Nanotechnology has proven as progressive technology that enables to contribute, develop several effective and sustainable changes in food products. Incorporating nanomaterials like TiO2, SiO2, Halloysite nano clay, Copper sulfide, Bentonite nano clay, in carrageenan to develop innovative packaging materials with augmented mechanical and antimicrobial properties along with moisture and gas barrier properties that can produce safe and healthy foods. Intervention of carrageenan-based bio-nanocomposites as food packaging constituents has shown promising results in increasing the shelf stability and food quality by arresting the microbial growth. Nanomaterials can be incorporated within the carrageenan for developing active packaging systems for continuous protection of food products under different storage environments from farm to the fork to ensure quality and safety of foods. Carrageenan based bio nanocomposite packaging materials can be helpful to reduce the environmental concerns due to their high biodegradability index. This review gives insight about the current trends in the applications of carrageenan-based bio nanocomposites for different food packaging applications.

Contamination caused by the accumulation of petrochemical-based plastics has reached worrying magnitudes and led to the development of biopolymers as an option to mitigate the problem. This work thus presents a bibliometric analysis of all that concerns the development of such bionanocomposite materials, using ScientoPy and SciMAT software to establish associations between the number of published documents, countries, institutions and most relevant topics. The bionanocomposites topic was found to throw up the biggest number of documents associated (2008) with the different types of raw materials and methods used to obtain nanoparticles and their combination with biopolymeric materials, the result known as a “bionancomposite*”. Analysis of the documents related to the application for development of packaging materials from biological molecules, carbohydrate polymers, compounds, conjugates, gels, glucans, hydrogels, membranes, mucilage (source unspecified), mucoadhesives, paper, polymers, polysaccharide, saccharides etc, is also presented, emphasizing mechanical, thermal and barrier properties, which, due to the inclusion of nanoparticles mainly from natural sources of cellulose, show increases of up to 30%. The inclusion of nanoparticles, especially those derived from cellulose sources, generally seeks to increase the properties of bionanocomposite materials. Regarding an increase in mechanical properties, specifically tensile strength, inclusions at percentages not exceeding 10 wt% can register increases that exceed 30% were reported.

With the increasingly serious plastic pollution, people's demand for the multi-functional biodegradable plastics is becoming more and more urgent. Inspired by the crosslinked shape memory polymers, the crosslinked starch films were synthesized by inducing the decomposition of benzophenone into free radical and depriving hydrogen on starch macromolecules under UV irradiation, in order to gain a high shape memory performance. The results showed that a three-dimensional crosslinking network between starch macromolecule chains was formed. Compared with the uncrosslinked starch films, the photo-crosslinked films not only had higher mechanical property (tensile strength increased by 154%), but also had better water resistance (water contact angle from 60° to 87°) due to the reduction of free hydroxyl groups. In addition, the stable covalent bonds serving as netpoints endow photo-crosslinked films with great improvement in shape memory property, with nearly 180° bending recovery. More importantly, the maximum shape memory fixity ratio (Rf) and shape memory recovery ratio (Rr) under stretch deformation were 96.5% and 99.8%, respectively. And the Rf and Rr could reach 94.6% and 79.8% even at higher strain. In all, the excellent shape memory performance and good degradability crosslinked starch films, which have great potential application in disposable heat-shrinkable packaging materials.

The main purpose of this study was to increase shelf life of banana using active hydrogel. For this purpose, carboxymethylcellulose/nanofiber cellulose/potassium permanganate (CMC/NFC/KMnO4) hydrogel film was prepared. The morphology and physicochemical properties of CMC hydrogels was investigated. The prepared films were used as humidity/ethylene absorbent in banana packaging for 30 days at 0 and 25 °C. The physical, mechanical and sensory properties of bananas were studied during storage. SEM images confirmed the presence of nanofibers in the hydrogel structure. NFC and KMnO4 increased the tensile strength of the film and decreased its elongation. On the 15th day of storage, bananas packaged with optimal active hydrogel (CMC/NFC/KMnO4) at 25 °C had a flavor of 3 and a general acceptance of 3.5, while control bananas had a flavor of 0.5 and a general acceptance of less than 1. On the 30th day of storage, bananas packaged with optimal active hydrogel at 25 °C had a toughness of 4 (N·s) and a firmness of 20 (N), while control bananas had a toughness of about 1 (N·s) and a firmness of about 8 (N). On the 30th day of storage, the humidity inside the package of bananas packed with the optimum active hydrogel at 25 °C was 59.5%, while the humidity in the control packages was 85%, indicating that the hydrogel was able to absorb the moisture inside the package. Totally it can be said that CMC/NFC/KmnO4 hydrogel can increase shelf life of a banana by simultaneously controlling ethylene and humidity in food packaging.

Background Owing to increasing environmental concerns and growing demands for food quality maintenance, biodegradable active packaging is emerging on the market to overcome the challenges faced by traditional plastic packaging. Pectin, with characteristics of low price, non-toxic and good polymerization, is an ideal material for active food packaging. Scope and approach This review offers the current state of studies on pectin-based active packaging. Three different film formation methods were critically summarized. Physical properties of pectin-based packaging were systemically characterized regarding various pectin structural conformation. Furthermore, preservation behaviors and related mechanisms were fully illustrated to exhibit the outstanding advantages of pectin-based active packaging in food preservation. Key findings and conclusions Pectin-based active packaging can be developed in either wet or dry processes. Wet process contains casting method leading to compact surface morphology and spraying method requiring specialized equipment, while dry process mainly refers to extrusion method with higher efficiency and meets the needs at commercial production. Physical properties of packaging including mechanical, hydrophobic and thermal characteristics are enhanced by modification of pectin conformation or incorporation with bio-polymers, overcoming the weaknesses of pure pectin packaging, such as thermal instability and strong hydrophilicity. After being functionalized with active compounds, pectin-based packaging with great antimicrobial, antioxidant and barrier properties is quite suitable for food preservation. Pectin-based packaging has great advantages to extend shelf-life of food by retarding lipid oxidation, inhibiting microbial growth, controlling water movement, etc. As a result, pectin-based active packaging with great physical and functional properties, has promising prospects in food preservation.

The aim of this research was to investigate the potential of tomato seed mucilage (TSM) as a new source for preparation of biodegradable films. After extraction and chemical analysis of TSM, the glycerol-plasticized and cellulose nanofiber (CNF)–reinforced bionanocomposite TSM films were successfully prepared and the effect of glycerol (5 and 10%) and CNF (0, 5, and 10%) on physical, structural, morphological, thermal, barrier, antioxidant, and antimicrobial properties of films was determined. Formation of new bonds between TSM and CNF was approved by ATR-FTIR spectroscopy. According to FE-SEM images, when both CNF and glycerol were simultaneously increased to 10%, the aggregation of CNF was observed. The film containing 5% glycerol and 10% CNF had the highest thermal stability in TGA. Water barrier properties decreased by glycerol addition and improved by CNF. Oxygen permeability improved by incorporation of CNF at lower amounts of glycerol. All the films had low opacity but they exhibited strong UV-blocking behavior. The best improving effect of CNF on mechanical properties was observed in lower concentration of glycerol. Interestingly, the TSM film had naturally good antioxidant potential and antimicrobial activity against Listeria monocytogenes. The 5% glycerol and 10% CNF were proposed to fabricate ideal TSM films. This study suggests TSM as a new naturally active edible film with interesting characteristics that can potentially be used for food packaging applications.

Polymer temperature sensors are important for applications in food packaging, air conditioning, wearable devices, and biomedicine. However, the sensing range of these sensors is narrow, and the mod...

Global food packaging is a billion-dollar market that is projected to reach USD 464 billion by 2027. Various regulations, bans, and standards paved the way for utilizing environmentally acceptable and biodegradable materials including cellulose and its derivatives as food packaging materials. Considering end-user application requirements, a high priority has been afforded to the enhancement of the performance of nanocellulose-based sustainable materials. The swelling behavior of cellulosic materials, low resistance to wettability, and inherent sensitivity to liquid water and moisture are those characteristics of cellulosic surfaces that have made their utilization in the packaging industry more challenging. To make cellulose a more mainstream raw material for the sustainable packaging industry, surface hydrophobic modification of cellulose can be a prior choice. Hydrophobic modification strategies provide a barrier to wettability and offer low permeability to moisture for cellulose to improve the water barrier property and mechanical stability of those packaging materials that utilize cellulose as host matrix, reinforcement agent, and binder in thin films or as a coating for paper-based matrices. Moreover, superhydrophobic coatings can be applied to the inner surface of food packaging to reduce and even eliminate the adhesion of liquid foods on the inside of food packaging leading to waste reduction. This work aimed to comprehensively review the state-of-knowledge studies about hydrophobic cellulose-based packaging materials and elucidate the key indicators of each method.

The applications of edible coatings stemmed exclusively from alginate in food packaging are restricted due to their inherent deficient antimicrobial, barrier, and UV-barrier properties. In this work, we aimed to design smart alginate-based coatings for active food packaging through the addition of both aloe vera (AV) and garlic oil (GO). The interactions between the film components were verified by FTIR and XRD. Thermal and mechanical properties were improved by the presence of AV and GO. The presence of AV and GO did not significantly influence the transparency of alginate films. The films exhibited a significant UV-shielding to all UV regions. Water vapor permeability was significantly (p 0.05) reduced either through the incorporation of AV or GO. The antimicrobial properties of the prepared films were considerably improved by the presence of AV and GO. The shelf-life of tomatoes (Solanum lycopersicum L.) was extended when coated with the alginate film incorporated with AV and GO. Owing to the outstanding UV-shielding, mechanical, thermal, and antimicrobial properties, the alginate/AV/GO active coatings could potentially be implemented in the food packaging industry.