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Topic Review
NIAS in Plastic Food Packaging
Several food contact materials (FCMs) contain non-intentionally added substances (NIAS), and most of the substances that migrate from plastic food packaging are unknown. Food packaging can contain NIAS as a result of the interactions between different substances in the packaging materials, between food content and substances (for example, additives) in FCM, from degradation processes and mainly from the impurities present in the raw materials used for FCM production. (EU) nº 10/2011 defines that “non-intentionally added substance means an impurity in the substances used or a reaction intermediate formed during the production process or a decomposition or reaction product”. Most NIAS are regularly detected when using high sensitivity analytical techniques, although the chemical structure of unknown compounds is often difficult to establish by conventional tools.
  • 3.7K
  • 01 Jul 2021
Topic Review
Polarization Holography
Polarization holography has the unique capacity to record and retrieve the amplitude, phase, and polarization of light simultaneously in a polarization-sensitive recording material and has attracted widespread attention. Polarization holography is a noteworthy technology with potential applications in the fields of high-capacity data storage, polarization-controlled optical elements, and other related fields.
  • 3.6K
  • 23 Jan 2021
Topic Review
Polyethylene Terephthalate
Terephthalate (PET) is one of the most significant modern plastics to be invented. PET is a semi-crystalline polymer, with mechanical properties that depend on crystallinity level. This material is considered to be a thermoplastic polyester material, which is now used globally. 
  • 3.6K
  • 08 Feb 2021
Topic Review
Polylactic Acid and Its Synthesis
Biomaterials are natural or engineered substances that interact with components of living systems that can be exploited for a medical purpose, either as therapeutic or diagnostic agents.  Poly-(lactic Acid) (PLA) is a compostable polymer derived from corn sugar, potato, and sugar cane whose promising physicochemical properties are comparable to those of petroleum-based polymers, such as polyethylene, polypropylene, polystyrene, polycarbonate, and polyethylene terephthalate. PLA is a semicrystalline polymer that hydrolyses in physiological media, yielding lactic acid, a non-toxic component that is eliminated via the Krebs cycle as water and carbon dioxide. The biocompatibility, biodegradability, and resorbability characteristics of PLA have promoted its use in the biomedical field for a wide range of applications (suture threads, bone fixation screws, drug delivery systems, etc.), offering an alternative to conventional biocompatible materials such as metals and ceramics.
  • 3.6K
  • 30 Sep 2022
Topic Review
Polyisoprene Rubber
Rubber materials have been used in a wide range of applications, from automotive parts to special-design engineering pieces, as well as in the pharmaceutical, food, electronics, and military industries, among others. Since the discovery of the vulcanization of natural rubber (NR) in 1838, the continuous demand for this material has intensified the quest for a synthetic substitute with similar properties.
  • 3.5K
  • 25 Oct 2023
Topic Review
Chitosan and Chitosan Modified by Functionalization
The biomedical and therapeutic importance of chitosan and chitosan derivatives is the subject of interdisciplinary research. In this entry, researchers intended to consolidate some of the recent discoveries regarding the potential of chitosan and its derivatives to be used for biomedical and other purposes. Why chitosan? Because chitosan is a natural biopolymer that can be obtained from one of the most abundant polysaccharides in nature, which is chitin. Compared to other biopolymers, chitosan presents some advantages, such as accessibility, biocompatibility, biodegradability, and no toxicity, expressing significant antibacterial potential. In addition, through chemical processes, a high number of chitosan derivatives can be obtained with many possibilities for use. 
  • 3.5K
  • 02 Apr 2022
Topic Review
Aggregation-Induced Emission and Fluorescent Mechanochromism
Mechanochromic fluorescent polymers are defined as materials that are able to detect a mechanical stress through a fluorescence output. This feature has evoked a growing interest in the last decades, thanks to the progress of fluorogenic molecules whose optical characteristics and chemical functionalities allow their effective insertion in many thermoplastic and thermoset matrices. Among the different types of fluorogenic probes able to detect mechanical solicitations, those with aggregation-induced emission (i.e., AIEgens) have attracted tremendous interest since their discovery in 2001. In this contribution, the main principles behind the AIEgens working behavior are introduced along with the current state of knowledge concerning the design and preparation of the derived mechanochromic fluorescent polymers. Examples are provided concerning the most ingenious solution for the preparation of chromogenic materials, starting from dierent types of commodity plastics or synthetic polymers and combined with the latest AIE technology to provide the most sensitive response to mechanical stress.
  • 3.5K
  • 30 Oct 2020
Topic Review
Polyethylene Composites
Polyethylene (PE) is one the most used plastics worldwide for a wide range of applications due to its good mechanical and chemical resistance, low density, cost efficiency, ease of processability, non-reactivity, low toxicity, good electric insulation, and good functionality.
  • 3.5K
  • 10 Feb 2021
Topic Review
Polymeric Surfactants
Polymeric surfactants are surfactant molecules that have a polymeric backbone, which can be made up of various repeating units. These surfactants have both hydrophilic and hydrophobic segments, which allows them to interact with both water and oil. Polymeric surfactants are used in a variety of industrial applications, such as in the production of paints, adhesives, and coatings. They can improve the stability and performance of these products by reducing the surface tension and promoting the dispersion of pigments and fillers. In addition, polymeric surfactants are also used in the formulation of personal care products, such as shampoos, conditioners, and body washes. They can help to improve the texture and feel of these products, as well as enhance their cleaning and conditioning properties. One of the key advantages of polymeric surfactants is their ability to form stable micelles in solution. These micelles are aggregates of surfactant molecules that form a spherical structure with the hydrophobic segments on the inside and the hydrophilic segments on the outside. This allows for efficient emulsification of oil and water, which is important in a variety of industrial processes. Polymeric surfactants are a versatile class of surfactants that offer several unique properties and advantages in various applications. They are commonly used as emulsifiers, stabilizers, and thickening agents, and have potential applications in areas such as agriculture, oil and gas, and papermaking. Polymeric surfactants are a diverse class of surfactants that can be classified based on their composition, molecular weight, and degree of polymerization. They offer a range of unique properties and advantages in various applications, including cosmetics, food and beverage products, pharmaceuticals, and agriculture.
  • 3.5K
  • 24 Mar 2023
Topic Review
Antifoaming Agent for Lubricating Oil
In the process of using lubricating oil, it is inevitable that bubbles will be produced, which can not only accelerate the oil’s oxidation and shorten the oil change cycle but also reduce its fluidity and lubricity, aggravate the wear of mechanical parts and produce an air lock that interrupts the oil pump supply and causes an oil shortage accident.
  • 3.5K
  • 18 Apr 2023
Topic Review
Available Sampling Methods for Plastic Waste
Given the rapid development of plastics recycling in recent years, the need for guidelines for sampling and material characterization is steadily emerging. However, there still exists a considerable scarcity of methods that enable proper material data acquisition. It was found that neither the literature nor the standards provide a comprehensive practice that considers the distinctive characteristics of plastic waste and applies it to different situations along the value chain. Two variants of the proposed plan were evaluated based on the flake size distribution and the apparent density of four different pretreated polyolefin (PO) waste materials. Combining stratified random sampling with composite sampling yields a good sampling technique for rigid PO waste. Moreover, the analysis of a composite sample adequately conveys the true material properties of a sublot or lot.
  • 3.4K
  • 31 Aug 2022
Topic Review
Lignin
Lignin is an extremely abundant substance that has a chemical functionality that endows it with the necessary properties to be an attractive platform material for the new millennium. We must continue to explore and exploit its potentiality as a stand-alone material, raw feedstock for refining to chemicals, polymeric filler, and co-composite material. This review highlights hardwood-derived lignin, a little explored form of lignin, as a promising platform material.
  • 3.4K
  • 13 Aug 2020
Topic Review
Biological Degradation of Polymers
Biodegradable plastics can make an important contribution to the struggle against increasing environmental pollution through plastics. This entry provides an overview of the main environmental conditions in which biodegradation takes place and then presents the degradability of numerous polymers. 
  • 3.4K
  • 23 Nov 2020
Topic Review
PET-RAFT
Photoinduced Electron/Energy Transfer Reversible Addition-Fragmentation Chain-Transfer (PET-RAFT) polymerization, proposed for the first time in 2014, is based on an alternative activation of the thiocarbonylthio compounds through photoredox catalysts (PCs). This last presents significant advantages compared to other photochemical techniques in terms of applicability, cost, and sustainability. 
  • 3.3K
  • 26 May 2021
Topic Review
Fundamental Concepts of Hydrogels
Hydrogels are three-dimensional crosslinked porous networks and can be synthesized from natural polymers, synthetic polymers, polymerizable synthetic monomers, and combination of natural and synthetic polymers. Synthesis of hydrogels involves physical, chemical and hybrid bonding. The bonding is formed via different routes such as solution casting, solution mixing, bulk polymerization, free radical mechanism, radiation method, and interpenetrating network formation. The synthesized hydrogels have significant properties such as mechanical strength, flexibility, biocompatibility, biodegradability, swellability, and stimuli sensitivity. Furthermore, owing to the smart and aqueous medium, robust mechanical strength, adhesiveness, stretchability, strain sensitivity, and self-healability, hydrogels can be potentially used in biomedical, electrochemical, sensors, contact lens, and soft robotic applications.
  • 3.3K
  • 03 Dec 2020
Topic Review
Fluorescent Polymers Conspectus
The development of luminescent materials is critical to humankind. The Nobel Prizes awarded in 2008 and 2010 for research on the development of green fluorescent proteins and super-resolved fluorescence imaging are proof of this (2014). Fluorescent probes, smart polymer machines, fluorescent chemosensors, fluorescence molecular thermometers, fluorescent imaging, drug delivery carriers, and other applications make fluorescent polymers (FPs) exciting materials. 
  • 3.3K
  • 22 Mar 2022
Topic Review
Synthesis and Characteristics of PEDOT:PSS and PEDOT:Carrageenan
Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been mostly used as a counter electrode to give a high performance of dye-sensitized solar cell (DSSC). PEDOT doped by carrageenan, namely PEDOT:Carrageenan, was introduced as a new material to be applied on DSSC as an electrolyte. PEDOT:Carrageenan has a similar synthesis process as PEDOT:PSS, owing to their similar ester sulphate (-SO3H) groups in both PSS and carrageenan. 
  • 3.3K
  • 17 Jul 2023
Topic Review
Terpenes and Terpenoids for Bioplastics
This entry describes the most common types of bioplastics and biopolymers, and focuses specifically on the polymerization of terpenes and terpenoids, which represent a source of promising monomers to create bio-based polymers and copolymers.
  • 3.3K
  • 25 Aug 2021
Topic Review
Functional Polymer Materials for Energy Applications
This entry provides insight into the recent energy applications of polymers.
  • 3.2K
  • 15 Dec 2021
Topic Review
Poly(Ethylene Terephthalate) Microplastics
The high PET production volume and the waste mismanagement of PET litter make it one of the most polluting plastic material. Its diffusion in marine litter is widely assessed according to public opinion and documented in the literature. The major sources of PET microplastics in the marine environment are bottles and fibers. The role of PET micro/nanoplastics of vector of toxic chemicals, their fate and the negative effects on the environment and human health is still under discussion.
  • 3.2K
  • 27 Apr 2021
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