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Topic Review
Polyunsaturated Fat
Polyunsaturated fats are fats in which the constituent hydrocarbon chain possesses two or more carbon–carbon double bonds. Polyunsaturated fat can be found mostly in nuts, seeds, fish, seed oils, and oysters. "Unsaturated" refers to the fact that the molecules contain less than the maximum amount of hydrogen (if there were no double bonds). These materials exist as cis or trans isomers depending on the geometry of the double bond. Saturated fats have hydrocarbon chains which can be most readily aligned. The hydrocarbon chains in trans fats align more readily than those in cis fats, but less well than those in saturated fats. In general, this means that the melting points of fats increase from cis to trans unsaturated and then to saturated. See the section about the chemical structure of fats for more information. The position of the carbon-carbon double bonds in carboxylic acid chains in fats is designated by Greek letters. The carbon atom closest to the carboxyl group is the alpha carbon, the next carbon is the beta carbon and so on. In fatty acids the carbon atom of the methyl group at the end of the hydrocarbon chain is called the omega carbon because omega is the last letter of the Greek alphabet. Omega-3 fatty acids have a double bond three carbons away from the methyl carbon, whereas omega-6 fatty acids have a double bond six carbons away from the methyl carbon. The illustration below shows the omega-6 fatty acid, linoleic acid. While it is the nutritional aspects of polyunsaturated fats that are generally of greatest interest, these materials also have non-food applications. Drying oils, which polymerize on exposure to oxygen to form solid films, are polyunsaturated fats. The most common ones are linseed (flax seed) oil, tung oil, poppy seed oil, perilla oil, and walnut oil. These oils are used to make paints and varnishes.
  • 610
  • 24 Oct 2022
Topic Review
Polytetrafluoroethylene-Based Solvent-Free Procedure for Lithium-Ion Batteries Manufacturing
Lithium-ion batteries (LIBs) have become popular for energy storage due to their high energy density, storage capacity, and long-term cycle life. Although binders make up only a small proportion of LIBs, they have become the key to promoting the transformation of the battery preparation process. Along with the development of binders, the battery manufacturing process has evolved from the conventional slurry-casting (SC) process to a more attractive solvent-free (SF) method. Compared with traditional LIBs manufacturing method, the SF method could dramatically reduce and increase the energy density due to the reduced preparation steps and enhanced electrode loading. Polytetrafluoroethylene (PTFE), as a typical binder, has played an important role in fabricating high-performance LIBs, particularly in regards to the SF technique. 
  • 800
  • 15 Dec 2023
Topic Review
Polystyrene vs. Polylactide
Polystyrene (PS) is a thermoplastic polymer made of aromatic hydrocarbon monomer styrene that is derived from fossil-fuels. The synthesis of PS is based on the free radical polymerization of styrene using free-radical initiators. It is mostly used in solid (high impact and general purpose PS), foam and expanded PS forms. The main advantages of PS are low-cost, easy processing ability, and resistance to ethylene oxide, as well as radiation sterilization. Polylactide (PLA)—biodegradable and compostable aliphatic polyester—is one of the key biopolymers with the largest market significance. 
  • 2.5K
  • 28 Dec 2022
Topic Review
Polysiloxane-Based Ionic Polymers
A diverse range of linear polysiloxane-based ionic polymers that are hydrophobic and highly flexible can be obtained by substituting the polymers with varying amounts of ionic centers. The materials can be highly crystalline solids, amorphous soft solids, poly(ionic) liquids or viscous polymer liquids.
  • 1.7K
  • 31 Dec 2020
Topic Review
Polysiloxane-Based Electrolytes
Dye-sensitized solar cells (DSSCs) are a very promising solution as remote sustainable low power sources for portable electronics and Internet of Things (IoT) applications due to their room-temperature and low-cost fabrication, as well as their high efficiency under artificial light. In addition, new achievements in developing semitransparent devices are driving interest in their implementation in the building sector. However, the main obstacle towards the large-scale exploitation of DSSCs mainly concerns their limited long-term stability triggered by the use of liquid electrolytes. 
  • 537
  • 24 Jul 2023
Topic Review
Polysaccharides in Agro-Industrial Biomass Residues
The use of waste biomass to produce biopolymers and nutricosmetic or pharmacological materials is increasing, although still scarcely compared to its great potential, employment, and valorization. Organic waste biomass is a great source of natural polysaccharides such as cellulose, chitin, hyaluronic acid, inulin, and pectin. Biomass from the agricultural sectors is a relevant part of waste generation and commonly comprises leaves, roots, stalks, bark, bagasse, seeds, straw, wood, animal parts, crustacean shells, and others. Polysaccharides are the most abundant biological materials on the planet. This natural abundance contributes to the discovery of their novel applications. Their industrial use is still very modest considering their versatility and great potential, although it has recently seen significant increases.
  • 911
  • 18 Mar 2022
Topic Review
Polysaccharides for Preparation of Adsorbents for Water Treatment
Adsorption processes, due to their technical simplicity and cost-effectiveness, have arisen as one of the most well-known, straightforward solutions to water pollution. In this context, polysaccharides, due to their abundance, biodegradability, and biocompatibility, are appealing raw materials for the design of adsorbents.
  • 136
  • 07 Sep 2023
Topic Review
Polysaccharides Edible Films and Coatings
There has been a significant increase in the development of edible films and coatings in recent times, and this is expected to have a significant impact on the quality of fruit and vegetables in the coming years. Consumers expect fresh fruit and vegetables free from pesticide residues, with high quality, nutritional value and an extended shelf life. The application of coatings and edible films to fruits and vegetables represents an environmentally friendly approach to an innovative solution to this problem. Coatings and edible films can act as ecological and biodegradable packaging. The coating strategy involves a combination of natural biopolymers and appropriate preservation methods. Numerous studies show that natural polysaccharides are well suited for use as packaging material for fresh fruit and vegetables and can often be an important alternative to synthetic compounds. Natural polymer materials are a good barrier to oxygen and carbon dioxide; however, they are characterised by excessive solubility in the water environment, water vapour permeability and low extensibility.
  • 1.5K
  • 05 May 2021
Topic Review
Polysaccharide-ZnO Nanocomposites for Fruits Preservation
Safe coating and film are produced from layer-forming material such as gelling agents. They are favored to be used in food packaging applications as they are made from edible material and can act as gases barrier for prolonging the shelf life of food. Even though both safe coating and film have those similarities, they have differences with respect to their application to food products. The edible film is wrapping materials that are applied to food products separately. Meanwhile, the safe coating is a thin material that is used directly on the food products. Hence, despite both safe coating and film may be produced from the same gelling agent, their characteristics may differ significantly which adjust to the food properties that need to be protected. For applying to fruit, the safe coating becomes one of the prime concerns because of its ability to slow down the ripening process, reduce microbial growth, and maintain the physicochemical properties of fruits.
  • 1.2K
  • 24 Oct 2020
Topic Review
Polysaccharide-Based Hydrogels Drug Delivery in Cancer Therapy
Hydrogels are three-dimensional crosslinked structures with physicochemical properties similar to the extracellular matrix (ECM). By changing the hydrogel’s material type, crosslinking, molecular weight, chemical surface, and functionalization, it is possible to mimic the mechanical properties of native tissues. Hydrogels are currently used in the biomedical and pharmaceutical fields for drug delivery systems, wound dressings, tissue engineering, and contact lenses. Polysaccharide-based hydrogels can be used as drug delivery systems for the efficient release of various types of cancer therapeutics, enhancing the therapeutic efficacy and minimizing potential side effects.
  • 436
  • 01 Feb 2023
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