فصلنامه بسپارش
سال چهاردهم شماره 2 (پیاپی 51، تابستان 1403)

Hydroxyl-terminated polybutadiene resin is used as binder prepolymer in the preparation of composite solid propellant in the military industry. Today, the unique properties of this resin and its derivatives have significantly extended their commercial and civilian applications. In this article, various commercial applications of hydroxyl terminated polybutadiene are reviewed. According to previous studies, incorporation of small amounts of hydroxyl terminated polybutadiene can significantly improve the mechanical properties, especially the impact resistance, of various composites and thermosetting resins. We have also addressed the use of this resin in the preparation of adhesives and sealants, as well as the preparation of waterproof membranes with unique capabilities and various applications, such as oil industry. Moreover, this resin can be used as an additive to increase the dielectric strength, especially in the automotive industry. Thereafter, the use of hydroxyl-terminated polybutadiene in drug delivery systems, lubricating oil production and bitumen modification is discussed. Despite the high price of this resin, its use as a raw material for the preparation and design of new materials is expected to grow in the near future.

For high-voltage transmission lines near industrial plants and in areas with coastal weather conditions, insulation contamination strongly affects the reliability of the transmission network. Due to the great importance of insulation in power transmission, it is necessary to increase the reliability of these equipment through various methods. Common methods include regular washing and lubrication and use of room temperature vulcanized (RTV) silicone rubber polymer coatings. In the meantime, application of polymer coatings perform have been proposed as an efficient method worldwide, due to their very good performance in polluted environmental, resistant to weathering and suspended particles, as well as prolonging the life and reducing the cost of repairing and replacing insulators. In recent years, several reports have been published on the use of nanotechnology to improve the properties of insulators. Today, the use of RTV-based nanocoatings is common in many countries and has brought good results. Therefore, it seems necessary to assess the feasibility, optimization and selection of the appropriate coating to be applied on the insulators installed in different regions of the country are appropriate according to the weather conditions specific to that region. In this article, the solution of adding nanomaterials to solve the problems of silicone rubber polymer coatings applied on high-pressure insulators in the electrical industry is reviewed. The most common nanoparticles used to improve the properties of the coatings, the role of this filler in improving the properties of the coating, and the existing challenges in the uniform distribution of nanoparticles in the polymer matrix are also explained.

Carbon quantum dots (CQDs) are a special subset of carbon nanoparticles with average dimensions about 10 nm. Their unique properties include low toxicity, chemical inertness, excellent biocompatibility, and tunable luminescence behavior by surface modification. There are several sources for synthesis of CQDs in nature, each of which has different effects on the properties of these particles. So far, several methods have been used to synthesize CQDs including laser ablation, microwave radiation, hydrothermal reaction, electrochemical oxidation, reflux method and ultrasonication. Due to the small particle size, CQDs have strong tunable fluorescent properties. The usage of these particles has been examined in various fields such as photocatalysis, ion sensor, biological imaging, heavy metal detection, adsorption treatment, supercapacitor, membrane fabrication, and water pollution treatment. Research works on the field of using CQDs in polymer materials, especially CQDs-reinforced composite materials have received attention in recent years. This is due to unique properties of carbon quantum dots such as renewability, stability, high mechanical properties, low weight, and comparatively low cost. This review article is aimed to discuss the physical, chemical and stability properties of CQDs, raw materials and synthesis methods as well as their potential applications in various fields, especially in the rubber industry. Finally, recent developments in the field of using carbon quantum dots in rubber products and their effects on the improvement of mechanical and dynamic properties are reviewed.

Pearlescent pigments are a special kind of natural or synthetic materials that are divided into two categories without a substrate (bismuth oxychloride, iron mica oxide, and titanium dioxide sheets) and a coated substrate (natural mica coated with metal oxides such as titanium dioxide, iron oxide, and aluminum oxide). Pearlescent pigments due to their special properties such as creating different colors by changing the angle of view, high heat resistance, high resistance to penetration, and brilliance are used in the form of pearlescent masterbatches in various industries such as plastic and packaging, cosmetics, automotive, textile, etc. Today, the use of masterbatches is increasing due to various reasons such as improving the dispersion and distribution of particles, excellent product quality, reducing the production costs, the health issues of employees, etc. Masterbatches are concentrated compounds that are added to polymers to make and improve color properties, as well as reduce the production cost. Masterbatch consists of three components: polymer, pigment or filler, and compatibilizing agent. Among the various methods of making masterbatches, the most common method is use of twin screw extruders (generally twin screw extruders). In general, 3 methods of pre-mixing, divided feeding, and color matching are used to make masterbatch with an extruder. The aim of this article is to investigate pearl pigments, general methods of making plastic and pearl masterbatches, and their applications in various industries.

Today, people are exposed to radiation in their living and working environment. Electronic equipment and devices are widely used in various fields with the development of electronic science and technology. An excessive use of electronic devices leads to unwanted and undesirable byproduct, which is a novel kind of pollution called electromagnetic interference (EMI).  Although traditional metals and their alloys can serve as good electromagnetic shielding materials, their heavy weight, high cost as well as poor corrosion resistance limit their application in this field. Therefore, electromagnetic shielding materials with lightweight are gradually attracting more and more attention to meet the trend of lightweight and highly integrated electronic equipment. Polymer material and their composites have been used as EMI shielding materials due to their characteristics like lightweight, good corrosion resistance, and superior electrical, thermal, mechanical and magnetic properties. These lightweight materials with good EMI shielding performance will find more potential applications in communications, electronics, aerospace, military, etc. In this article, the phenomenon of electromagnetic interference and its type of shielding by polymer materials and its composites and their shielding effectiveness have been reviewed.

Metal-organic frameworks (MOFs) can be defined as porous crystalline materials that formed from the network synthesis of metal ions and clusters as nodes, and organic molecules as ligands. The flexibility of the components has led to the report of more than 20,000 different MOFs. MOF-5 can be mentioned as one of the most famous MOFs. These materials are divided into four categories of first, second, third, and fourth generation frameworks. There are various methods for the synthesis of MOFs, but the most common one is the solvothermal method. Metal-organic frameworks sometimes perform better than other porous materials, such as activated carbon or zeolites. These materials have exceptional properties such as high surface area (6000 m2/g), porosity and high pore volume. The existence of these features along with high adjustability and flexibility have led to wide applications in various fields. Applications like gas storage and separation, catalytic applications, biomedical applications such as drug release, sensors, membranes, and water purification can be mentioned. In this article, in addition to introducing metal-organic frameworks, their structural features and synthesis methods and a number of common applications of these materials have been reviewed.