فصلنامه بسپارش
سال سیزدهم شماره 1 (پیاپی 46، بهار 1402)

Today the appearance of food packaging is very important because it has an advertising aspect and helps to sell the product better. In many cases, instead of relying on creating a beautiful color to give the appearance of a polymer package, the consumer wants the packaged product to be clearly visible in order to ensure its health and quality. Some polymers are highly transparent, however, when water molecules condense on the surface, small water droplets form. In transparent films and structures, water droplets act as a scatterer for incident light on the surface. This phenomenon, which is called fogging, makes the film appear opaque. Droplets are formed when the surface tension of the polymer is lower than the surface tension of water, and as a result, the water remains in the droplet form instead of forming a continuous layer. By increasing the critical surface tension of the polymer surface, anti-fog additives allow water molecules to spread on the surface and form a continuous layer of water that does not scatter light. Therefore, it does not interfere with the transparency of the film surface. In this article, the phenomenon of fogging, the production of polyethylene films with anti-fog capability, the types of anti-fog additives and the methods of mixing these materials with polymer have been reviewed, among others. Also, the methods of evaluating the anti-fog properties of polyethylene films were introduced.

Oil-based products have led to a brilliant and magnificent civilization for the development of human society, but these materials have also caused serious damage to the environment and human health. Food coating with biodegradable polymers and nanomaterials can increase the preservation of nutritional value and shelf-life, improve the quality, and increase food safety, and can be a natural and suitable alternative to common plastic materials used in packaging industry. Ensuring the protection of the quality and taste of food products, increasing the durability, and reducing the packaging wastes is the priority of researchers. Synthetic plastics are widely used, especially in food packaging industry, and cause problems in disposal and recycling. These issues have caused increasing concerns about environmental pollution and destruction. Therefore, it is possible to address these challenges by developing of biodegradable polymers and nanomaterials. In addition, consumers demand sustainable (durable) packaging materials that reduce the environmental problems associated with plastic wastes. In this article, the applications of nanomaterials and biodegradable polymers in the packaging of food products are reviewed. In these composite materials, effective nanoparticles (i.e., gold, copper, copper oxide, and silver nanoparticles) have combined with biodegradable and eco-friendly polymers (i.e., gelatin and cellulose obtained from natural resources).

In recent decades, biomass resources have received a lot of attention due to the increasing population growth, oil crisis, limitations and disadvantages of using oil derivatives in all industries, including medicine and pharmaceuticals. A large amount of lignocellulosic waste are generated annually, and currently most of these compounds are either left in the environment or used for low-value applications. Lignocellulosic biomass materials as a renewable, economical, and abundant alternative to fossil resources are promising for the production of diverse value‐added products. In recent years, many researchers have focused on biorefinery concept as a green and safety approach. Biorefinery is aimed to efficient conversion of biomass waste into high value-added bio-based products. As the main component of lignocellulosic waste, hemicelluloses are the second most abundant polysaccharide in nature. These heteropolysaccharides are used directly in food, pharmaceutical, papermaking, etc. Also, they are used as precursor polymers for the production and processing of chemicals such as xylitol, ethanol, furfural, etc. Also, they are used as precursor polymers for the production and processing of chemicals such as xylitol, ethanol, furfural, etc. In this article, the use of hemicelluloses in various industries and also the valuable products based on hemi-cellulose have been reviewed.

Organogels are one of the main components of a group of gels that are noncrystalline and viscoelastic in nature and show three-dimensional and cross-linked networks in the organic liquid phase. Applications of organogels include their use in chemistry, pharmaceutical and cosmetic industries, biotechnology and food technology. Unfortunately, in recent years, the use of organogels as drug delivery systems has faced problems due to the toxicity of selective organic solvents. But recently, the synthesis of biocompatible organogels has led to the development of several biomedical and pharmaceutical applications. In this article, hydrogels are briefly reviewed, followed by a more in-depth review of gels that have been investigated for drug delivery. Over the past two decades, organogels have made significant advances as drug delivery matrices. The favorable and impressive performance of organogels is due to their ease of preparation, cost-effectiveness and their ability to have hydrophilic and lipophilic compounds. The ability of organogels to incorporate hydrophilic and hydrophobic compounds into their structure has expanded the use of organogels in various drug delivery systems. Organogels are used as drug delivery platforms to administer the active agent through various routes such as dermal, oral and injectable.

Wound healing is a complex process, and in some cases, it is accompanied by persistent inflammation, cell dysfunction, and angiogenesis limitations, which leads to long-term medical care, high cost, and poor quality of treatment. The use of antibiotics, dressings, and skin alternatives are current methods of wound healing treatments. However, the existing wound dressings are not yet capable of fully restoring all the structural and functional characteristics of the skin. Therefore, the development of asymmetric membranes with the ability to mimic the structure and function of the human skin multilayers has been considered as more efficient structures in facilitating wound healing as well as skin tissue engineering. Wet or dry/wet phase inversion, supercritical carbon dioxide (scCO2) phase inversion, and electrospinning of polymer solutions are the common methods for the fabrication of multilayer structures. Among these, the electrospinning technique, due to its ease and versatility, the possibility of using different polymers, and the possibility of tailoring dressings in terms of specific structures of skin layers is promising. Another generation of emerging therapies is based on loading cells with the potential of wound healing acceleration. In the first part of this review, the last achievements obtained polymers used in asymmetric structures are discussed and then the electrospun structures containing special cells are reviewed.

The further development of environmentally friendly materials requires the knowledge of environmental stimuli, new materials, as well as the assessment of environmental impacts, and the conventional materials in construction. According to the definitions of sustainable development and materials, it is necessary to use materials that have low energy consumption and properties such as sufficient durability, appropriate physical and chemical properties, and at the same time reduce environmental pollution. Geopolymer materials can be a suitable answer for this problem. Geopolymers are ceramic-like mineral polymers that expand with poly-compact structures in three dimensions. Geopolymers are formed by the chemical activation of solid materials containing aluminum and silica at relatively low temperature. In recent years, geopolymer has emerged as a sustainable, environmentally friendly material and an alternative to Portland cement. Geopolymers are ceramic-like materials with three-dimensional polycompact structures that are formed by the chemical activation of solids containing aluminum and silica at relatively low temperatures.  In recent years, geopolymers have been proposed as a sustainable, environmentally friendly material and an alternative to concretes made of Portland cement. For the production of geopolymer concrete and use in buildings, waste or by-products from industries can be used. In this article, the synthesis method and properties of geopolymers for use in construction as sustainable materials and as a suitable alternative to Portland cement, in order to reduce the emission of environmental pollutants with the approach of life cycle assessment, based on the studies, are briefly reviewed. Findings and results show that geopolymer concretes have much better mechanical properties and chemical performance than hardened concretes with Portland cement and show significant environmental benefits.

Introduction of polymeric companies, new published books and theses