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Plastic Waste in the Aquatic Environment
Published in Leo M. L. Nollet, Khwaja Salahuddin Siddiqi, Analysis of Nanoplastics and Microplastics in Food, 2020
Isangedighi Asuquo Isangedighi, Gift Samuel David, Ofonmbuk Ime Obot
The degradation of negatively buoyant plastics depends on very slow thermal oxidation, or hydrolysis, as a result of most wavelengths being readily absorbed by water. Hence, plastics residing in marine environments degrade at a significantly slower rate than they do on land. Polymer degradation can be categorized as any physical or chemical changes resulting from environmental factors, including light, heat, moisture, chemical conditions and biological activity [19]. It is not clear just how long plastic items remain in their original form. However, some plastic items appear to be broken up into smaller and smaller fragments over time [21]. At sea, this process is thought to occur because of wave action, oxidation and ultraviolet light. On the shore, plastic may break up into smaller pieces owing to grinding from rocks and sand [22]. The resulting plastic fragments may be mistaken for prey and ingested by marine organisms. Plastic debris in the oceans may eventually be broken up so much that it becomes microscopic in size like grains of sand, hence the term microplastics. These tiny fragments (about 20 μm in diameter) have been identified in marine sediments and in ocean waters [23].
Polymer Specifications for Photovoltaic (PV) Packaging and Balance of System (BOS) Components
Published in Michelle Poliskie, Solar Module Packaging, 2016
Polymer degradation is a behavior-modifying chemical mechanism that can be inhibited by stabilizers. Degradation can be catalyzed by light, heat, oxygen, metal, and biological molecules. The polymer can be introduced to these catalysts during processing or service. Both organic and inorganic molecules can be used as stabilizers to deactivate these catalysts or halt degradation. Flame retardants, ultraviolet (UV) stabilizers, antioxidants, metal deactivators, and antimicrobial agents are the most relevant stabilizers for PV packaging.
Natural fibre filament for Fused Deposition Modelling (FDM): a review
Published in International Journal of Sustainable Engineering, 2021
H. J. Aida, R. Nadlene, M.T. Mastura, L. Yusriah, D. Sivakumar, R. A. Ilyas
A thermoset polymer is in a three-dimensional (3D) linkage and known as a permanent structure that does not allow the reshaping or reprocessing of their structure, unlike thermoplastics. The permanent linkage shape occurrs when the thermoset polymer is already ‘cured’ and hard to recycle, but some findings have discovered that some thermosets can be recycled (Peças et al. 2018; Sreenivasan et al. 2013). Certain industries prefer to use thermosets rather than thermoplastic because thermosets resist water better than thermoplastics, and have good thermal behaviour. However, thermosets cannot be reprocessed or recycled, unlike thermoplastics (Furtado et al. 2012). Table 8 extract the mechanical properties of thermoset and thermoplastic. Polymer degradation is found to be a disadvantage and limits the value of demands in industries (Mohamed et al. 2018).
Thermal behaviour of polystyrene/silica composites
Published in Philosophical Magazine Letters, 2018
Olga V. Alekseeva, Andrew V. Noskov, Sabir S. Guseynov, Alexander V. Agafonov
Thermal resistance is one of the most significant properties of polymer materials, as it ultimately governs their mechanical properties, durability and shelf life. Once degradation begins, the above-mentioned properties will gradually deteriorate and so the thermophysical properties of composites are important for designing advanced structures. Therefore, the synthesis of polymer systems with enhanced thermal properties is an important issue for both materials science and various application fields. A better understanding of polymer degradation gives valuable data on the applicability time of the material. It has been shown that the thermal behaviour of polymer composites depends on the filler type and content [23].
UV weathering and performance of a novel corrosion protective coating on steel made from recycled polyethylene terephthalate (PET)
Published in Corrosion Engineering, Science and Technology, 2021
Mônica M. Ferreira, Elisângela A. da Silva, Fernando Cotting, Vanessa de F. C. Lins
Polymeric degradation reactions are always initiated by the rupture of a covalent chemical bond, which causes the formation of reactive species responsible for the propagation of the mechanism. The polymer degradation process is commonly initiated by thermal interference (thermal degradation), high energy radiation, mechanical stress, light (photodegradation), chemical or biological attack, among others [13,14].