مجله پژوهش و توسعه فناوری پلیمر ایران
سال هشتم شماره 1 (پیاپی 29، بهار 1402)

Over the years, conventional wastewater treatment processes have achieved to some extent in treating effluents for discharge pints. Development in wastewater treatment processes is essential to make treated wastewater reusable for industrial, agricultural, and domestic purposes. Membrane technology has emerged as an ideal technology for treating wastewater from different wastewater streams. Membrane technology is one of the most up‐to‐date advancements discovered to be successful in fundamentally lessening impurities to desired levels. In spite of having certain impediments, membrane bioreactors (MBRs) for biological wastewater treatment provide many advantages over conventional treatment. This review article covers all the aspects of membrane technology that are widely used in wastewater treatment process such as the principle of membrane technology, the classification of membrane technology processes in accordance to pressure, concentration, electrical and thermal‐driven processes, its application in different industries, advantages, disadvantages and the future prospective. Over the years, conventional wastewater treatment processes have achieved to some extent in treating effluents for discharge pints. Development in wastewater treatment processes is essential to make treated wastewater reusable for industrial, agricultural, and domestic purposes. Membrane technology has emerged as an ideal technology for treating wastewater from different wastewater streams. Membrane technology is one of the most up‐to‐date advancements discovered to be successful in fundamentally lessening impurities to desired levels. In spite of having certain impediments, membrane bioreactors (MBRs) for biological wastewater treatment provide many advantages over conventional treatment.

The need for food packaging to maintain quality and shelf life is increasing day by day. Nanostructured materials are preferred over microstructures due to their unique physical and chemical properties and improved performance. Advanced packaging based on nanotechnology has made it possible to preserve and transport food safely without changing the taste and quality. In addition, it prevents contamination and preserves the mechanical, physiological, physical and chemical properties of food. Various nanomaterials have been used in food packaging to prepare improved, active, smart and bio-based packaging. Smart packaging ensures food safety by detecting contamination, gases, humidity, temperature and other food parameters using sensors. With the increasing demand for the production of new, environmentally friendly and high-performance packaging, "bio-nanocomposites" have attracted a lot of attention in recent years. Bio-nanocomposites are bio-based polymers that consist of two main components, one acting as a matrix called biopolymer (continuous phase) and the second as a reinforcing agent (dispersed phase) with dimensions ranging from 1 to 100 nm. . Bio-based packaging is a new and new generation packaging that replaces natural polymers with synthetic plastics. In this article, recent research in the field of bio-nanocomposites has been reviewed based on the application for different needs and the possible risk of nanoparticle migration.

Hydrogels are three-dimensional networks of hydrophilic polymers capable of absorbing and retaining significant amounts of fluids, which are also widely applied in wound healing, cartilage tissue engineering, bone tissue engineering, release of proteins, growth factors, and antibiotics. In the past decades, a lot of research has been done to accelerate wound healing. Hydrogel-based scaffolds have been a recurring solution in both cases, although their mechanical stability remains a challenge, some of which have already reached the market. To overcome this limitation, the reinforcement of hydrogels with fibers has been investigated. The structural similarity of hydrogel fiber composites to natural tissues has been a driving force for the optimization and exploration of these systems in biomedicine. Indeed, the combination of hydrogel formation techniques and fiber spinning methods has been very important in the development of scaffold systems with improved mechanical strength and medicinal properties. Hydrogel has the ability to absorb secretions and maintain moisture balance in the wound. In turn, the fibers follow the structure of the extracellular matrix (ECM). The combination of these two structures (fiber and hydrogel ) in a scaffold is expected to facilitate healing by creating a suitable environment by identifying and connecting cells with the moist and breathing space required for healthy tissue formation. Modifying the surface of fibers by physical and chemical methods improves the performance of hydrogel composites containing

Lithium-ion batteries, as one of the most advanced and suitable rechargeable batteries, have received considerable attention in recent years. Polymer electrolytes are considered as one of the main components of the battery and good substitute for liquid electrolytes in the next generations of batteries. The polymer electrolytes used in the battery may be damaged or lose performance due to the alternating movement of ions or physical damage. To avoid the damages caused by this phenomenon, the use of self-healing polymer electrolytes is suggested as a appropriate solution. The ability of self-healing in the polymer electrolytes makes them start to repair themselves as soon as a craze or crack occurs on their surface, without the need for any stimulus, and even after repair, they are able to recover all their properties. This ability comes from the microstructure and type of chemical bonds of self-healing polymers. In general, the self-healing polymer electrolytes used in batteries are divided into two main categories: polymer electrolytes based on reversible covalent bonds, and polymer electrolytes based on non-covalent supramolecular bond type. Considering the importance of this issue, in this research, a review of self-healing polymer electrolytes in the next generation of lithium batteries will be done.

Basically, gears are an evolved form of friction wheels that have teeth added to them to prevent slippage and ensure relative motion uniformity. The use of polymer gears is increasing due to advantages such as corrosion resistance, injection molding capability, operation without lubricants and low noise. However, the mechanical strength, thermal resistance and durability of polymer gears are lower than metal gears. The locking mechanism in metal gears is different from polymer gears. Among the important damages that lead to failure of polymer gears is thermal deformation, which does not exist in metal gears. In polymer gears, due to the viscoelastic and plastic nature of polymers, a lot of heat is generated during gear engagement and the temperature increases. An increase in temperature causes the ribs to soften and, as a result, change their shape. Pitting, fatigue and wear are other factors that lead to failure of polymer gears. The contact stress resulting from the torque applied to the gear plays the most important role in the intensity of each of the mentioned delays. Investigating the contact stress in polymer gears, including the challenges of industrialists and researchers, will provide a better understanding for the better design of these types of gears, as well as life expectancy. This research is a review of various methods for determining and checking contact stress, including Hertz numerical model, standard method and finite element method.

Petrochemical industry is a branch of chemical industry that uses raw materials in the form of oil and gas to produce industrial products. Various chemical or physical processes are used to produce optimal products. Among the key and strategic products in the petrochemical industry, we can mention propylene and polypropylene. Propane dehydrogenation (PDH-Propane dehydrogenation) is a highly efficient catalytic technology that is used to convert propane into propylene and finally polypropylene, and it has received wide attention today. Propylene is one of the intermediate products used in many petrochemical applications, such as the production of polypropylene resins, acrylic acids, propylene glycol, acrylonitrile, cumene/phenol and other industrial products. Usually, propylene is obtained by cracking naphtha derived from oil and is a byproduct of ethylene production, but currently, in order to produce propylene more widely, propane dehydrogenation process is used. With the increase in global demand for propylene in the automotive sector, the production of bottle caps, fabrics, packaging materials and the production of chemicals, the petrochemical industry is inevitably moving towards the targeted production of propylene. This goal will be achieved mainly through propane dehydrogenation, where propane is selectively hydrogenated (removal of hydrogen from the propane stream). The results of this research, in addition to identifying the most suitable method of producing propylene from propane (Oleflex or Catofin), indicate that the implementation of PDH projects in the country, in addition to meeting the needs of domestic industries, completing the chains It will also bring value to the country's petrochemical industry.