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Journal articles on the topic "Plastic Materials - Degradation":
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Chandran, R. Rameshwar, Benjamin Isaac Thomson, A. J. Natishah, Jennita Mary, and Valli Nachiyar. "Nanotechnology in Plastic Degradation." Biosciences Biotechnology Research Asia 20, no. 1 (March 30, 2023): 53–68. http://dx.doi.org/10.13005/bbra/3068.
Plastics pose a huge threat to the environment. Plastic accumulation in the land and the seas is now the world’s most terrorising problem, mainly because of its non-degrading character. Plastic degradation has always been a next to impossible concept in the field of science, but nanotechnology provides a revolutionary and modern way to solve the problem of plastic accumulation in the environment. One of the great advantages of nanoparticles is that we can increase and decrease the rate of biodegradation depending on our needs. Nanoparticles enhance the polythene degradation capacity of the microorganisms by altering their metabolic cycles. Numerous studies showed conclusively that the incorporation of nanotechnology enhances the ability of microorganisms to degrade polythene materials. Even though bio degradable plastics are nowadays produced in large quantities to substitute polythene materials, they fail to match the brittleness of plastics. Biodegradable plastics have poor thermal, mechanical and low gas barrier qualities, which are their main drawbacks. To overcome this, nanoparticles are incorporated into the biopolymers. If an appropriate balance between nanotechnology, microbiology and biotechnology is found, plastic degradation can be done economically and feasibly in all the areas.
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Bartoníček, B., V. Hnát, I. Janovský, and R. Pejša. "Radiation degradation of plastic insulating materials." Radiation Physics and Chemistry 46, no. 4-6 (October 1995): 797–800. http://dx.doi.org/10.1016/0969-806x(95)00264-x.
An, Rongrong, Chengguo Liu, Jun Wang, and Puyou Jia. "Recent Advances in Degradation of Polymer Plastics by Insects Inhabiting Microorganisms." Polymers 15, no. 5 (March 5, 2023): 1307. http://dx.doi.org/10.3390/polym15051307.
Plastic pollution endangers all natural ecosystems and living creatures on earth. Excessive reliance on plastic products and excessive production of plastic packaging are extremely dangerous for humans because plastic waste has polluted almost the entire world, whether it is in the sea or on the land. This review introduces the examination of pollution brought by non-degradable plastics, the classification and application of degradable materials, and the current situation and strategy to address plastic pollution and plastic degradation by insects, which mainly include Galleria mellonella, Zophobas atratus, Tenebrio molitor, and other insects. The efficiency of plastic degradation by insects, biodegradation mechanism of plastic waste, and the structure and composition of degradable products are reviewed. The development direction of degradable plastics in the future and plastic degradation by insects are prospected. This review provides effective ways to solve plastic pollution.
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Geambulat, Aila-Elmaz, Tănase Dobre, and Claudia-Irina Koncsag. "Experimental investigations on polyethylene and polyethylene terephthalate microplastics’ degradation. A review." Ovidius University Annals of Chemistry 33, no. 2 (July 1, 2022): 156–65. http://dx.doi.org/10.2478/auoc-2022-0023.
Abstract A topic of high interest, the plastic degradation in the environment, is approached in this work, to serve for future research. The problem of plastics pollution became critical with the exponential development of plastic materials industry in last decades. Soil and water are primarily polluted, then degradation to microplastics leads to spatial distribution of plastic debris in all ecosystems. Slow natural degradation and pollutants accumulation on the plastic particles are responsible for environment unbalancies. This work follows the new research about the induced degradation methods, abiotic and biotic, pointing out the most notable results. Most research took place in laboratories, but promising results of some biotic methods will hopefully lead to industrial scale-up.
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Gabriel, Djoko Sihono, and Angga Ananditto. "Effect of Repetitive Recycling on the Mechanical Properties of Polypropylene Blends Based on Material Value Conservation Paradigm." Materials Science Forum 1015 (November 2020): 70–75. http://dx.doi.org/10.4028/www.scientific.net/msf.1015.70.
Contaminated plastic waste if undergo a mechanical recycling process will have a low value. This can be overcome by repetitive implementation of Material Value Conservation (MVC) through material purity protection from design stage to the end of the material life cycle. Repetition of recycling up to eight times caused degradation of mechanical properties of plastics by up to 20%. The repetition was done on a laboratory scale with pure polypropylene as raw material. This research was conducted to overcome the degradation of plastic properties by mixing recycled plastic pellets with virgin plastic in the most optimal proportion. Plastic blends with certain compositions were recycled up to 8 times, then its mechanical properties are tested with the American Society for Testing Materials (ASTM) methods. This research revealed the opportunities to utilize the 6th recycled plastic pellets by mixing it with virgin plastic to improve its mechanical properties. Furthermore, this research shows that repetitive recycling of plastic blends with the implementation of material value conservation (MVC) could increase the value of recycled plastic pellets as raw materials and extend the life time of plastic materials.
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Schwarz, Weike, Stina Wegener, Gerhard Schertzinger, Helena Pannekens, Peter Schweyen, Georg Dierkes, Kristina Klein, Thomas A. Ternes, Jörg Oehlmann, and Elke Dopp. "Chemical and toxicological assessment of leachates from UV-degraded plastic materials using in-vitro bioassays." PeerJ 11 (April 11, 2023): e15192. http://dx.doi.org/10.7717/peerj.15192.
The broad use of plastics and the persistence of the material results in plastic residues being found practically everywhere in the environment. If plastics remain in the (aquatic) environment, natural weathering leads to degradation processes and compounds may leach from plastic into the environment. To investigate the impact of degradation process on toxicity of leachates, different types of UV irradiation (UV-C, UV-A/B) were used to simulate weathering processes of different plastic material containing virgin as well as recyclate material and biodegradable polymers. The leached substances were investigated toxicologically using in-vitro bioassays. Cytotoxicity was determined by the MTT-assay, genotoxicity by using the p53-CALUX and Umu-assay, and estrogenic effects by the ERα-CALUX. Genotoxic as well as estrogenic effects were detected in different samples depending on the material and the irradiation type. In four leachates of 12 plastic species estrogenic effects were detected above the recommended safety level of 0.4 ng 17β-estradiol equivalents/L for surface water samples. In the p53-CALUX and in the Umu-assay leachates from three and two, respectively, of 12 plastic species were found to be genotoxic. The results of the chemical analysis show that plastic material releases a variety of known and unknown substances especially under UV radiation, leading to a complex mixture with potentially harmful effects. In order to investigate these aspects further and to be able to give recommendations for the use of additives in plastics, further effect-related investigations are advisable.
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Singh, Prashant, Ranjan Singh, Anshul Singh, and Ajad Patel. "Biodegradation of Microplastic: A Sustainable Approach." International Journal of Current Microbiology and Applied Sciences 12, no. 11 (November 10, 2023): 177–93. http://dx.doi.org/10.20546/ijcmas.2023.1211.015.
Annual production of plastic has increased the 390.7 million metric tons in 2021 and plastic’s reprocessing has all but its sustainable solution for disposal of plastic waste has been unsuccessful. Plastic materials (fragments) are continuously accumulating in the environment, like, in sea, soil, air, rivers as well as oceans. Microplastic contamination is becoming a major concern worldwide. Nowadays, scientists are developing sustainable idea for the degradation of plastic waste with the help of microorganisms. In biodegradation of microplastics by microorganisms like fungi and bacteria are playing vital role in breaking-downs of the plastic polymers in simpler form and after that plastics are biologically degraded. Microorganisms (Pseudomonas sp., Rhodococcus sp., Bacillus sp., Zelerionmaritimum, Microalgae) that can degrade the different types of regular used synthetic plastics. The bacterial and fungal species produced Biosurfactants which helps the degradation process rapidly.
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Fesseha, Haben, and Fasil Abebe. "Degradation of Plastic Materials Using Microorganisms: A Review." Public Health – Open Journal 4, no. 2 (December 30, 2019): 57–63. http://dx.doi.org/10.17140/phoj-4-136.
Royer, Sarah-Jeanne, Francesco Greco, Michaela Kogler, and Dimitri D. Deheyn. "Not so biodegradable: Polylactic acid and cellulose/plastic blend textiles lack fast biodegradation in marine waters." PLOS ONE 18, no. 5 (May 24, 2023): e0284681. http://dx.doi.org/10.1371/journal.pone.0284681.
The resistance of plastic textiles to environmental degradation is of major concern as large portions of these materials reach the ocean. There, they persist for undefined amounts of time, possibly causing harm and toxicity to marine ecosystems. As a solution to this problem, many compostable and so-called biodegradable materials have been developed. However, to undergo rapid biodegradation, most compostable plastics require specific conditions that are achieved only in industrial settings. Thus, industrially compostable plastics might persist as pollutants under natural conditions. In this work, we tested the biodegradability in marine waters of textiles made of polylactic acid, a diffused industrially compostable plastic. The test was extended also to cellulose-based and conventional non-biodegradable oil-based plastic textiles. The analyses were complemented by bio-reactor tests for an innovative combined approach. Results show that polylactic acid, a so-called biodegradable plastic, does not degrade in the marine environment for over 428 days. This was also observed for the oil-based polypropylene and polyethylene terephthalate, including their portions in cellulose/oil-based plastic blend textiles. In contrast, natural and regenerated cellulose fibers undergo complete biodegradation within approximately 35 days. Our results indicate that polylactic acid resists marine degradation for at least a year, and suggest that oil-based plastic/cellulose blends are a poor solution to mitigate plastic pollution. The results on polylactic acid further stress that compostability does not imply environmental degradation and that appropriate disposal management is crucial also for compostable plastics. Referring to compostable plastics as biodegradable plastics is misleading as it may convey the perception of a material that degrades in the environment. Conclusively, advances in disposable textiles should consider the environmental impact during their full life cycle, and the existence of environmentally degradable disposal should not represent an alibi for perpetuating destructive throw-away behaviors.
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Gabriel, Djoko Sihono, and Husen Nasrullah. "Optical Properties Improvement of Recycled Polypropylene with Material Value Conservation Schemes Using Virgin Plastic Blends." Materials Science Forum 1020 (February 2021): 199–205. http://dx.doi.org/10.4028/www.scientific.net/msf.1020.199.
Repetitive implementation of material value conservation (MVC) in plastic packaging may lead to good quality plastic waste and high acceptance for secondary recycling. This makes the obtained recycled plastic pellets has good quality and can be used as an alternative raw material for new products. However, treatments and processing in the recycling processes can lead to the degradation of material properties and disrupt the recycled plastics life cycle to be used for new products with high specifications. Recycled plastics are certainly cheaper than virgin plastics, but they have low properties, contaminated, and are only used for low-value products. Therefore, a solution is needed for this problem. This study proposed mixing recycled and virgin plastic pellets to improve recycled plastics whose optical properties have been subjected to quality degradation. A series of tests were carried out on specimens and tested according to the American Society for Testing and Materials (ASTM) method. The optical properties tested were transparency, gloss, and colour. This study revealed that optical properties had an increasing trend along with the large number of virgin plastic pellets added to the blends. The optimal composition was found in the 50:50 composition of virgin-recycled plastic pellets to the 70:30 composition of virgin-recycled plastic pellets. These findings can be useful in improving the optical properties of recycled plastics. In addition, the widespread implementation of MVC can improve the quality of plastic waste and strengthen its acceptance for secondary recycling.
Dissertations / Theses on the topic "Plastic Materials - Degradation":
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Gregory, P. W. "Finite elastic-plastic deformations of highly anisotropic materials." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282601.
Plastics glazing materials have properties which allow their widespread use in construction, for example as rootlights. However, they are more susceptible than is glass to degradation by weathering, notably the combined effects of ultraviolet light, heat and moisture. Examples of unacceptable durability have been seen in practice, particularly when high operating temperatures occur in sunlight. Artificial weathering tests are used to assess plastics glazing materials in a reasonably short time, two main types being utilised in this study. The applicability of ultra-fast methods of accelerated degradation has been shown to depend on the extent to which the mechanisms of degradation simulate practical weathering, since different procedures were found to promote different mechanisms in the materials tested. Misleading information was obtained when the full spectrum of solar UV and much of the visible was not adequately reproduced in the accelerated tests. In particular an established grade of PVC-U performed unexpectedly poorly under fluorescent lamps. Procedures based on xenon arc sources were found to be the most generally applicable because they better reproduce the full solar spectrum range and, hence, the typical effects observed in plastics materials in practice. Several analytical techniques were used to characterise the virgin polymers and to assess the weathered materials. Two commercial grades of each polymer type (poly[vinylchloride], polycarbonate and poly[methylmethacrylate]) were studied, and measured changes explained in terms of initial polymer properties. Profiling of chemical (e.g. carbonyl index measured by photo-acoustic fourier transform infrared), physical (e.g. molecular weight, surface gloss/roughness), optical (e.g. colour, light transmission) and mechanical properties (e.g. impact resistance) as a function of exposure period and environmental conditions enabled degradation rates and mechanisms to be established for each material. In conducting these tests particular attention was given to the control and effects of sample temperature during weathering, and to the wavelength range of the light source used. Poly(vinylchloride) was affected much more by weathering at higher temperatures, and by exposure to short wavelength radiation, than was polycarbonate, with acrylic being the most durable overall. Practical applications of this work are through Standards committees primarily. in particular with plastics rootlights (B/542/8 and CEN/TCI28/SC9).
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Li, Junhong. "Elastic - plastic interfacial crack problems." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297517.
Davenport, James Charles William. "Mixed mode elastic-plastic fracture." Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357788.
Viesca, Lobaton Gabriel D. "Fatigue crack propagation in plastic fields." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301842.
Stelmashenko, Nadia. "Microstructural studies of plastic indentations at low loads." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390178.
Lim, Chwee-Teck. "Effects of compliance and friction on elastic-plastic impact." Thesis, University of Cambridge, 1996. https://www.repository.cam.ac.uk/handle/1810/273133.
Wahl, Aurélie. "Distribution et comportement de débris plastiques dans un sol agricole amendé en compost de déchets ménagers." Electronic Thesis or Diss., Rennes 1, 2022. http://www.theses.fr/2022REN1B031.
Les déchets plastiques s’accumulent dans tous les compartiments environnementaux, et cette présence suscite un vif intérêt de la part de la communauté scientifique. Pourtant, leur étude dans les sols n’est que très récente par rapport aux rivières et océans. Ce travail de doctorat s’est donc concentré sur le comportement des micro- et nanoplastiques et des contaminants associés issus de l’amendement en compost de déchets ménagers, enrichi en débris plastiques dans un sol agricole. Les microplastiques collectés dans le sol ont un degré d’altération avancé qui favorise la libération de petites particules plastiques telles que les nanoplastiques. Afin de les identifier, une méthode d’extraction /identification a été développée et a prouvé pour la première fois la présence de nanoplastiques composés des trois polymères les plus courants dans la couche de surface du sol. Il a ensuite été démontré que ces nanoplastiques étaient présents dans les couches minérales en profondeur alors que les microplastiques n’étaient présents que dans la profondeur de labour. Les nanoplastiques sont donc mobiles dans les sols et ont la capacité d’atteindre les nappes d’eau souterraines sous-jacentes. Enfin, le rôle de déchets plastiques dans la contamination concomitante en métaux relevée dans le sol a été étudié. Les plus fortes concentrations correspondent aux métaux utilisés comme additifs dans la formulation des plastiques mais les plastiques n’ont pu être mis en cause avec certitude dans la contamination du sol. Les métaux et leur signature isotopique représentent cependant de bons candidats pour le traçage des nanoplastiques dans les matrices naturelles complexes Plastic waste is accumulating in all environmental compartments, and its presence is of great interest to the scientific community. However, plastic waste study in soils is only very recent compared to rivers and oceans. This PhD work therefore focused on the behaviour of micro- and nanoplastics and associated contaminants from the composting of household waste enriched with plastic debris in agricultural soil. The microplastics collected in soil have an advanced degree of weathering that favours the release of small plastic particles such as nanoplastics. In order to identify them, an extraction/identification method was developed and highlighted for the first time, the presence of nanoplastics containing the three most common polymers in the uppermost soil surface layer. It was then demonstrated that these nanoplastics were present in the mineral layers at depth, whereas the microplastics were only present at ploughing depth. Nanoplastics are therefore mobile in soils and can reach the underlying groundwaters. Finally, the role of plastic waste in the concomitant metal contamination found in soil was investigated. The highest concentrations correspond to metals used as additives in the formulation of plastics, but the plastic role could not be implicated with certainty in soil contamination. However, metals and their isotopic signatures are good candidates for tracing nanoplastics in complex natural matrices
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Goldthorpe, Martin Richard. "An elastic-plastic finite element program with applications to cracked bodies." Thesis, University of Sheffield, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315414.
Books on the topic "Plastic Materials - Degradation":
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Rosa, Maria I. De. Oxidative thermal degradation of PVC-derived fiberglass, cotton, and jute brattices and other mine materials: A comparison of toxic gas and liquid concentrations and smoke-particle characterization. Pittsburgh, Pa. (Cochrans Mill Rd., P.O. Box 18070, Pittsburgh 15236): U.S. Dept. of the Interior, Bureau of Mines, 1986.
E, Kamvouris John, and United States. National Aeronautics and Space Administration., eds. Penetration of carbon-fabric-reinforced composites by edge cracks during thermal aging. [Washington, DC]: National Aeronautics and Space Administration, 1994.
E, Kamvouris John, and United States. National Aeronautics and Space Administration., eds. Penetration of carbon-fabric-reinforced composites by edge cracks during thermal aging. [Washington, DC]: National Aeronautics and Space Administration, 1994.
Volume 11B serves as a reference and guide to help engineers determine the causes of failure in plastic components and make corrective adjustments through design and manufacturing modifications. It contains seven major divisions, covering polymer science and processing, material selection and design, chemical, thermal, and physical analysis, mechanical behavior and testing, degradation mechanisms, systematic failure analysis, and life assessment and optimization. It examines a wide range of factors that contribute to the properties and behaviors of engineering plastics and the effect of thermal and mechanical stresses, impact loading, fatigue, wear, weathering, moisture and chemical exposure, photochemical aging, microbial degradation, and elevated temperatures. It addresses issues such as flammability, environmental stress cracking, crazing, and stress whitening and describes the unique characteristics of polymer fracture and how to assess and predict service life using fracture mechanics. It also presents and analyzes numerous examples of failure, including design and manufacturing related failures, wear failures of reinforced plastics, and failures due to creep and yielding.
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Hummel, Dieter O. Atlas of Polymer and Plastics Analysis: Plastics Fibres, Rubbers, Resins ; Starting and Auxiliary Materials, Degradation Products. VCH Publishing, 1989.
Book chapters on the topic "Plastic Materials - Degradation":
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Real, Luís Eduardo Pimentel. "Degradation and Stabilization of Polymers." In Weathering of Polymers and Plastic Materials, 1–33. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-33285-2_1.
Parangi, Tarun, and Manish Kumar Mishra. "Photocatalytic Degradation of Plastic Polymer: A Review." In Re-Use and Recycling of Materials, 225–50. New York: River Publishers, 2022. http://dx.doi.org/10.1201/9781003339304-15.
Manos, George. "Catalytic Degradation of Plastic Waste to Fuel over Microporous Materials." In Feedstock Recycling and Pyrolysis of Waste Plastics, 193–207. Chichester, UK: John Wiley & Sons, Ltd, 2006. http://dx.doi.org/10.1002/0470021543.ch7.
Gaur, Nisha, Ravish Chowdhary, Dilip Brunwal, Rekha Singh, and S. S. Maitra. "Degradation of Plastic in Environment and Its Implications with Special Reference to Aromatic Polyesters." In Handbook of Environmental Materials Management, 1–26. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-319-58538-3_176-1.
Saukkonen, Tapio, Miikka Aalto, Iikka Virkkunen, Ulla Ehrnstén, and Hannu Hänninen. "Plastic Strain and Residual Stress Distributions in an AISI 304 Stainless Steel BWR Pipe Weld." In 15th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors, 2351–67. Hoboken, New Jersey, Canada: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118456835.ch244.
Manfredi, M., E. Barberis, and E. Marengo. "Prediction and classification of the degradation state of plastic materials used in modern and contemporary art." In inArt 2016, 391–401. Berlin, Heidelberg: Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-55417-3_38.
Saukkonen, Tapio, Miikka Aalto, Iikka Virkkunen, Ulla Ehrnstén, and Hannu Hänninen. "Plastic strain and residual stress distributions in an AISI 304 stainless steel BWR pipe weld." In Proceedings of the 15th International Conference on Environmental Degradation of Materials in Nuclear Power Systems — Water Reactors, 2351–67. Cham: Springer International Publishing, 2011. http://dx.doi.org/10.1007/978-3-319-48760-1_142.
Dylingowski, P. J., and R. G. Hamel. "Microbial degradation of plastics." In Directory of Microbicides for the Protection of Materials, 325–42. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/1-4020-2818-0_19.
Müller, A., Volker Trappe, S. Hickmann, and H. P. Ortwein. "Investigation of the infinite life of fibre-reinforced plastics using X-ray refraction topography for the in-situ, non-destructive evaluation of micro-structural degradation processes during cyclic fatigue loading." In Fatigue of Materials at Very High Numbers of Loading Cycles, 417–39. Wiesbaden: Springer Fachmedien Wiesbaden, 2018. http://dx.doi.org/10.1007/978-3-658-24531-3_19.
Patil, P. D. "Biodegradable Plastics from Renewable Raw Materials." In Degradation of Plastics, 37–80. m, 2021. http://dx.doi.org/10.21741/9781644901335-2.
Fossil oil prices are soaring steeply due to the depleting petroleum raw materials. Extensive research has been carried out around the globe to develop efficient processes that can replace oil-derived polymers (conventional plastic) with bio-based polymers that originate from renewable resources. Fossil-oil based plastic products take decades to degrade, leading to the unwanted accumulation of plastic waste that can be seen all around. Further, greenhouse gases emission occurs during the production and destruction of synthetic plastic. Therefore, plastic waste has become a massive threat to the biosphere and needs to be addressed immediately. To overcome this issue, a new type of plastic can be produced from bio-resources that can fulfill even the energy demand in today's world. This new form of plastic must be accommodated fast in daily life, considering the range of applications of plastics. Biodegradable plastics made from renewable raw materials can retain all the benefits of petroleum-based plastic without having any negative impacts on the environment. Bioplastics are not toxic in nature and can easily decay back into carbon dioxide via degradation. The products made from bioplastics may be commercialized, considering their superior properties over conventional plastic. The discovery and implementation of plastic made from renewable raw material resources could be a giant leap into the sustainable future.
Conference papers on the topic "Plastic Materials - Degradation":
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Hussein, Amal A., Mohammed Alzuhairi, and Noor H. Aljanabi. "Degradation and depolymerization of plastic waste by local bacterial isolates and bubble column reactor." In TECHNOLOGIES AND MATERIALS FOR RENEWABLE ENERGY, ENVIRONMENT AND SUSTAINABILITY: TMREES18. Author(s), 2018. http://dx.doi.org/10.1063/1.5039268.
Rahmayanti, Handika, Desvi Setiadi, Julia Ginting, Akmal Zulfi, Septia Ardiani, Nurul Akmalia, and Tipri Kartika. "The Simple Degradation Test for Nata de coco-based Film as Alternative Biodegradable Plastic Materials." In Proceedings of the First Jakarta International Conference on Multidisciplinary Studies Towards Creative Industries, JICOMS 2022, 16 November 2022, Jakarta, Indonesia. EAI, 2022. http://dx.doi.org/10.4108/eai.16-11-2022.2326141.
de Castro, Paulo Bastos, Thiago André Carniel, Jan-Michel Colombo Farias, and Eduardo Alberto Fancello. "A variational constitutive model for elastic-viscoplastic materials subjected to plastic damage and hydrolytic degradation." In XXXVI Iberian Latin American Congress on Computational Methods in Engineering. Rio de Janeiro, Brazil: ABMEC Brazilian Association of Computational Methods in Engineering, 2015. http://dx.doi.org/10.20906/cps/cilamce2015-0879.
Ladani, Leila J., and A. Dasgupta. "Partitioned Cyclic Fatigue Damage Evolution Model for PB-Free Solder Materials." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/creep2007-26306.
This study presents an approach to predict the degree of material degradation and the resulting changes in constitutive properties during cyclic loading in viscoplastic materials in micro-scale applications. The objective in the modeling approach is to address the initiation and growth of distributed micro-damage, in the form of micro-cracks and micro-voids, as a result of cyclic, plastic and creep deformations of material. This study extends an existing micromechanics-based approach, developed for unified viscoplastic models [Wen, et al, 2001], which uses dislocation mechanics to predict damage due to distributed micro-scale fatigue crack initiation [Mura and Nakasone, 1990]. In the present study, the approach is extended to a partitioned viscoplastic framework, because the micro-scale mechanisms of deformation and damage are different for plastic and creep deformation. In this approach, the model constants for estimating cyclic damage evolution are allowed to be different for creep and plastic deformations. A partitioned viscoplastic constitutive model is coupled with an energy partitioning (E-P) damage model [Oyan and Dasgupta, 1992] to assess fatigue damage evolution due to cyclic elastic, plastic and creep deformations. Wen’s damage evolution model is extended to include damage evolution due to both plastic and creep deformations. The resulting progressive degradation of elastic, plastic and creep constitutive properties are continuously assessed and updated. The approach is implemented on a viscoplastic Pb-free solder. Dominant deformation modes in this material are dislocation slip for plasticity and diffusion-assisted dislocation climb/glide for creep. The material’s behavior shows a good correlation with the proposed damage evolution model. Damage evolution constants for plastic and creep deformation were obtained for this Pb-free solder from load drop data collected from the mechanical cycling experiments at different temperatures. The amount of cyclic damage is evaluated and compared with experiment.
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Fayomi, O. S. I., P. A. L. Anawe, A. O. Inegbenebor, and N. E. Udoye. "Comparative assessment of the microhardness and plastic degradation mechanism of deposited modulated coatings on mild steel." In TECHNOLOGIES AND MATERIALS FOR RENEWABLE ENERGY, ENVIRONMENT AND SUSTAINABILITY: TMREES18. Author(s), 2018. http://dx.doi.org/10.1063/1.5039244.
Xiao, Bing, Toshihiko Hojo, Hiroyuki Hamada, and Yuqiu Yang. "Fatigue Properties of Cellulosic-Fiber Mat Reinforced Thermosetting Plastic Composites." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-37802.
Natural fiber composite materials are expected as capable materials which may replace the conventional and synthetic materials for the practical applications where manufacture requires less weight and energy conservation. In this study, three kinds of cellulosic-fiber mats including kenaf, bamboo and jute mats were used to fabricate composites by hand lay-up and compression molding methods. As the basic investigation, low cycle fatigue tests were carried out to analyze the material’s fatigue properties by using different bending or tensile loads. Moreover, the scanning electron microscope observation (SEM) on the fracture surfaces has been carried out respectively to investigate the degradation under cycle loads and discuss the possibility of kenaf/bamboo/jute composites achieving hypothetical outstanding mechanical properties in engineering uses.
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Lee, Wen-Hao, D. S. Liang, W. P. Wang, and C. S. Hsiao. "Thermal Degradation and Mass Transport of Underfill Material." In ASME 2007 InterPACK Conference collocated with the ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ipack2007-33057.
In order to enhance the reliability of flip chip packages, the initiation and propagation of various interfacial failures and robust interfacial bonds between the underfill and the other components are highly desired. The water molecules inside the plastic material were chemically bonded with polymers by hydrogen bonds in the microholes formed by the polymer molecule chains. The bonding of water molecules and polymers reduced the adhesion strength at the interface between epoxy material and die. In this study, the interfacial bond strengths of commercial underfills with silicon nitride passivation are measured using bottom shear test. The thermal degradation of epoxy-based underfill material has been studied by thermogravimetric analysis (TGA). The results show that adhesion strength is correlated with TGA weight loss curve. Besides, epoxy is sensitive to moisture at high temperature storage. Moisture diffusion characterization at high temperatures in polymeric packaging materials is important since moisture absorption of polymeric packaging materials plays a determining role in “popcorn cracking” of IC packages during the solder reflow process especially for lead-free solder reflow profile. The moisture absorption was measured by using mass transport and diffusion theory.
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Kronenwett, Felix, Pia Klingenberg, Georg Maier, Thomas Längle, Elke Metzsch-Zilligen, and Jürgen Beyerer. "Regression-based Age Prediction of Plastic Waste using Hyperspectral Imaging." In OCM 2023 - 6th International Conference on Optical Characterization of Materials, March 22nd – 23rd, 2023, Karlsruhe, Germany : Conference Proceedings. KIT Scientific Publishing, 2023. http://dx.doi.org/10.58895/ksp/1000155014-5.
In order to enable high quality recycling of polypropylene (PP) plastic, additional classification and separation into the degree of degradation is necessary. In this study, different PP plastic samples were produced and degraded by multiple extrusion and thermal treatment. Using near infrared spectroscopy, the samples were examined and regression models were trained to predict the degree of aging. The models of the multiple extruded samples showed high accuracy, despite only minor spectral changes. The accuracy of the models of the thermally aged samples varied with the design of the training set due to the non-linear aging process, but showed sufficient accuracy in prediction.
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Trindade, Elizabeth Cristine Adam, Camille Ruest, Jean-Sébastien Deschênes, and Jean Brousseau. "Food Contact Materials: An Analysis of Water Absorption in Nylon 12 3D Printed Parts Using SLS After VaporFuse Surface Treatment." In 2022 International Additive Manufacturing Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/iam2022-93944.
Abstract Selective laser sintering (SLS) is a typical method of 3D printing in an industrial environment. It is often used to print different materials, such as metals, ceramics, and plastics. Nylon 12 is the most common plastic and material processed by SLS technology. In the present paper, the water absorption and wettability of Nylon 12 in additive manufacturing (AM) products are explored. The research for obtaining inert, non-absorbent and non-corrosive surfaces, and globally more effective materials to reduce the proliferation of microorganisms is becoming a necessity for the development of novel food contact materials. Surface treatments aim at improving the porosity and general roughness of the material and are expected to improve its hydrophobicity. The wetting state between Nylon 12 and water was studied by measuring the contact angles as primary data. The measurement of absorbed water (ASTM 570) is thus used as an indicator of material quality to prevent bacterial growth and degradation of the material mechanical properties. Therefore, water absorption tests were performed with SLS printed plates with and without surface treatment. Plates with surface treatment showed a mass increase of 0.35 ± 0.04% while those without surface treatment showed a mass increase of 0.76 ± 0.08%.
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Prakash, Raghu V. "A Decade of Experience With Small Specimen Testing to Evaluate Mechanical Properties of Materials." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-37356.
Small specimen testing has become popular in the recent times, due to the need for material property evaluation using limited volume samples available from processing techniques, scoop extraction of materials. There are several methods of direct and in-direct mechanical property evaluation such as: automated ball indentation, miniature tensile testing, small punch testing, shear punch testing and miniature specimen impact testing. Most of these techniques provide a correlation with standard specimen test data through empirical relationships. This paper summarizes work done at the author’s Institution during the last decade on small specimen testing, with specific reference to spherical ball indentation (both static as well as cyclic indentation), shear punch and small punch testing on a number of metallic materials. Specific examples of how the material degradation due to prior damage (plastic deformation, fatigue, creep) are discussed.
Reports on the topic "Plastic Materials - Degradation":
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Whisler, Daniel, Rafael Gomez Consarnau, and Ryan Coy. Novel Eco-Friendly, Recycled Composites for Improved CA Road Surfaces. Mineta Transportation Institute, July 2021. http://dx.doi.org/10.31979/mti.2021.2046.
The continued use of structural plastics in consumer products, industry, and transportation represents a potential source for durable, long lasting, and recyclable roadways. Costs to dispose of reinforced plastics can be similar to procuring new asphalt with mechanical performance exceeding that of the traditional road surface. This project examines improved material development times by leveraging advanced computational material models based on validated experimental data. By testing traditional asphalt and select carbon and glass reinforced composites, both new and recycled, it is possible to develop a finite element simulation that can predict the material characteristics under a number of loads virtually, and with less lead time compared to experimental testing. From the tested specimens, composites show minimal strength degradation when recycled and used within the asphalt design envelopes considered, with an average of 49% less wear, two orders of magnitude higher compressive strength, and three orders for tensile strength. Predictive computational analysis using the validated material models developed for this investigation confirms the long-term durability.
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Oliynyk, Kateryna, and Matteo Ciantia. Application of a finite deformation multiplicative plasticity model with non-local hardening to the simulation of CPTu tests in a structured soil. University of Dundee, December 2021. http://dx.doi.org/10.20933/100001230.
In this paper an isotropic hardening elastoplastic constitutive model for structured soils is applied to the simulation of a standard CPTu test in a saturated soft structured clay. To allow for the extreme deformations experienced by the soil during the penetration process, the model is formulated in a fully geometric non-linear setting, based on: i) the multiplicative decomposition of the deformation gradient into an elastic and a plastic part; and, ii) on the existence of a free energy function to define the elastic behaviour of the soil. The model is equipped with two bonding-related internal variables which provide a macroscopic description of the effects of clay structure. Suitable hardening laws are employed to describe the structure degradation associated to plastic deformations. The strain-softening associated to bond degradation usually leads to strain localization and consequent formation of shear bands, whose thickness is dependent on the characteristics of the microstructure (e.g, the average grain size). Standard local constitutive models are incapable of correctly capturing this phenomenon due to the lack of an internal length scale. To overcome this limitation, the model is framed using a non-local approach by adopting volume averaged values for the internal state variables. The size of the neighbourhood over which the averaging is performed (characteristic length) is a material constant related to the microstructure which controls the shear band thickness. This extension of the model has proven effective in regularizing the pathological mesh dependence of classical finite element solutions in the post-localization regime. The results of numerical simulations, conducted for different soil permeabilities and bond strengths, show that the model captures the development of plastic deformations induced by the advancement of the cone tip; the destructuration of the clay associated with such plastic deformations; the space and time evolution of pore water pressure as the cone tip advances. The possibility of modelling the CPTu tests in a rational and computationally efficient way opens a promising new perspective for their interpretation in geotechnical site investigations.
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Friedman, Haya, Chris Watkins, Susan Lurie, and Susheng Gan. Dark-induced Reactive Oxygen Species Accumulation and Inhibition by Gibberellins: Towards Inhibition of Postharvest Senescence. United States Department of Agriculture, December 2009. http://dx.doi.org/10.32747/2009.7613883.bard.
Dark-induced senescence could pose a major problem in export of various crops including cuttings. The assumption of this work was that ROS which is increased at a specific organelle can serve as a signal for activation of cell senescence program. Hormones which reduce senescence in several crops like gibberellic acid (GA) and possibly cytokinin (CK) may reduce senescence by inhibiting this signal. In this study we worked on Pelargonium cuttings as well as Arabidopsis rosette. In Pelargonium the increase in ROS occurred concomitantly with increase in two SAGs, and the increase persisted in isolated chloroplasts. In Arabidopsis we used two recentlydeveloped technologies to examine these hypotheses; one is a transcriptome approach which, on one hand, enabled to monitor expression of genes within the antioxidants network, and on the other hand, determine organelle-specific ROS-related transcriptome footprint. This last approach was further developed to an assay (so called ROSmeter) for determination of the ROS-footprint resulting from defined ROS stresses. The second approach involved the monitoring of changes in the redox poise in different organelles by measuring fluorescence ratio of redox-sensitive GFP (roGFP) directed to plastids, mitochondria, peroxisome and cytoplasm. By using the roGFP we determined that the mitochondria environment is oxidized as early as the first day under darkness, and this is followed by oxidation of the peroxisome on the second day and the cytoplast on the third day. The plastids became less oxidized at the first day of darkness and this was followed by a gradual increase in oxidation. The results with the ROS-related transcriptome footprint showed early changes in ROS-related transcriptome footprint emanating from mitochondria and peroxisomes. Taken together these results suggest that the first ROS-related change occurred in mitochondria and peroxisomes. The analysis of antioxidative gene’s network did not yield any clear results about the changes occurring in antioxidative status during extended darkness. Nevertheless, there is a reduction in expression of many of the plastids antioxidative related genes. This may explain a later increase in the oxidation poise of the plastids, occurring concomitantly with increase in cell death. Gibberellic acid (GA) prevented senescence in Pelargonium leaves; however, in Arabidopsis it did not prevent chlorophyll degradation, but prevented upregulation of SAGs (Apendix Fig. 1). Gibberellic acid prevented in Pelargonium the increase in ROS in chloroplast, and we suggested that this prevents the destruction of the chloroplasts and hence, the tissue remains green. In Arabidopsis, reduction in endogenous GA and BA are probably not causing dark-induced senescence, nevertheless, these materials have some effect at preventing senescence. Neither GA nor CK had any effect on transcriptome footprint related to ROS in the various organelles, however while GA reduced expression of few general ROS-related genes, BA mainly prevented the decrease in chloroplasts genes. Taken together, GA and BA act by different pathways to inhibit senescence and GA might act via ROS reduction. Therefore, application of both hormones may act synergistically to prevent darkinduced senescence of various crops.
