Добірка наукової літератури з теми "Bio-Sourced plastic"

During the last decade, the consumption of plastics has increased highly in parallel with plastic waste. The transition towards a circular economy is the only way to prevent the environment from landfilling and incineration. This review details the recycling techniques with a focus on mechanical recycling of polymers, which is the most known and developed technique in industries. The different steps of mechanical recycling have been highlighted, starting from sorting technologies to the different decontamination processes. This paper covers degradation mechanisms and ways to improve commodity polymers (Polyolefins), engineering polymers (PET, PA6), and bio-sourced polymers (PLA and PHB).

The primary challenge facing the globe today is finding environmentally friendly, ecologically balanced ways to use bio-waste as a source of energy. Typically, the term “biogas” or “renewable energy” refers to a gas created when organic matter breaks down without oxygen. Thus, this study designed and developed a 200L miniature facility capable of transforming bio-waste into renewable energy using locally available materials and tested under the existing weather condition in Awka, Anambra State. The facility developed in this study was utilized to decompose cow manure anaerobically, producing 21.9L of cooking gas overall over the course of a 35-day retention period. Additionally, the water boiling test demonstrated that the purified cooking gas’ high methane gas content development of the digesting chamber using high-density polyethylene plastic (HDPE) allows a reduction in the overall cost of setting up a small-scale plant.

Huge quantity of synthetic polymers is used as packaging materials in different fields of food industries. A significant part of these polymers applied as a primary, direct food contact construction. The scoped application area is the sweet industry. In this field Polystyrol (PS), Polypropylene (PP) and Polyethylene terephthalate (PET) have used but during the last fifteen years the usage of PET has been grown. In one hand the price of this material is efficient, form other hand the PET is the one of the most safe (for food industrial applications) petrol chemical plastic that can be used as primary or secondary food contact packaging material. To maximize the customer safety and minimize the environmental impact of traditional PET, a new bio-sourced and bio-degradable alternative polymer aimed to be used in this special food industrial segment. One of the potential alternatives is the Polylactic acid (PLA) that would be a possible substitute as it is compostable and produced from renewable sources and has good physical and mechanical properties [1].

The energy crisis and environmental concerns have increased interest in natural polymers, and the bio-sourced materials field is experiencing rapid growth. A useful alternative to conventional plastic packaging manufactured from fossil fuels is packaging constructed of biodegradable polymers. Consideration has been given to the instrumental methods for examining modifications to the chemical composition and characteristics of modified chitosan. The molecular weight and the kind of plasticizer present in these materials are the two primary variables influencing their usability and performance. This study set out to physically blend chitosan with two different acids, lauric and maleic, to enhance chitosan cast films' physical and mechanical properties. Different plasticizer ratios appeared to have little effect on the various properties of the chitosan cast films. Examining the obtained films by FTIR implies that chitosan's native structure was unchanged. The films prepared had more flexibility and better solubility than those made with un-plasticized chitosan. It was evident from an analysis of the mechanical properties of the films that both acid plasticizers enhanced the mechanical properties of the chitosan.

Beeswax is a bio-sourced, renewable, and even edible material that stands as a convincing option to provide paper-based food packaging with moisture resistance. Nonetheless, the difficulty of dispersing it in water limits its applicability. This work uses oxidized, negatively charged cellulose nanofibers along with glycerol to stabilize beeswax-in-water emulsions above the melting point of the wax. The synergistic effects of nanocellulose and glycerol granted the stability of the dispersion even when it cooled down, but only if the concentration of nanofibers was high enough. This required concentration (0.6–0.9 wt%) depended on the degree of oxidation of the cellulose nanofibers. Rheological hindrance was essential to prevent the buoyancy of beeswax particles, while the presence of glycerol prevented excessive aggregation. The mixtures had yield stress and showed pseudoplastic behavior at a high enough shear rate, with their apparent viscosity being positively influenced by the surface charge density of the nanofibers. When applied to packaging paper, the nanocellulose-stabilized beeswax suspensions not only enhanced its barrier properties towards liquid water (reaching a contact angle of 96°) and water vapor (<100 g m−2 d−1), but also to grease (Kit rating: 5) and airflow (>1400 Gurley s). While falling short of polyethylene-coated paper, this overall improvement, attained using only one layer of a biobased coating suspension, should be understood as a step towards replacing synthetic waxes and plastic laminates.

Efficient polymerization catalyses transform bio-sourced monomers into thermoplastics with high elasticity and strength, which can be degraded to allow for chemical recycling. The plastics utilize carbon dioxide, limonene oxide and ε-decalactone.

High separations costs reduce the practicality of polymers sourced from renewable bio-oils, motivating economical multicomponent bio-oil polymerizations. Thus, this paper investigates polymerization behavior of model bio-oil components and their mixtures.

La pollution plastique, résultant de la production massive et de l'utilisation de plastiques depuis le 20e siècle, est omniprésente dans la biosphère. Les plastiques, conçus pour leur durabilité, perdurent des décennies, voire des siècles, et se fragmentent en microplastiques, répandus partout, des fonds marins aux montagnes. Dans le milieu aquatique, les plastiques favorisent la formation de communautés microbiennes, appelées "plastisphère", similaires aux biofilms aquatiques naturels. Les écosystèmes marins ont été largement étudiés pour quantifier la présence de plastiques, en particulier de microplastiques, et leur impact sur les communautés microbiennes. Cependant, les écosystèmes d'eau douce ont été moins explorés que les écosystèmes marins, tant sur la présence de plastiques que sur l'impact de ces derniers sur les communautés microbiennes naturelles du benthos de la rivière. De plus, la fraction de taille la plus étudié correspond aux microplastiques par rapport aux macroplastiques.La première partie de cette thèse a comparé la colonisation microbienne entre deux types de plastiques (non biodégradable et biodégradable) et des substrats naturels (sédiments, rochers et feuilles) sur deux sites de rivières, avec des niveaux de pollution plastique distincts. Cette comparaison a été faite avec l'analyse des descripteurs structuraux et fonctionnels des communautés microbiennes. De façon globale, les densités microbiennes et les activités de décomposition du carbone, azote et phosphore organique étaient plus élevées au niveau des substrats naturels (sédiments, rochers et feuilles) qu'au niveau des substrats plastiques. Ceci peut être dû à une plus grande disponibilité en carbone organique et en nutriments dans les substrats naturels. Les microorganismes de rivière ont montré des différences de colonisation, avec une densité bactérienne et des activités enzymatiques plus élevées sur le plastique biodégradable dans le site en aval. En conséquence, la présence de macroplastiques biodégradables augmenterait davantage l'hétérotrophie de l'écosystème fluvial que la présence de macroplastiques non biodégradables.La deuxième partie a évalué l'impact structurel et fonctionnel des deux types de plastiques sur les communautés microbiennes des sédiments et rochers en microcosmes de rivière. Les résultats ont montré des effets contrastés en fonction de l'échelle d'étude. Au niveau du substrat, l'ajout de plastique non biodégradable a augmenté l'activité enzymatique β-glucosidase et l'ajout de plastique biodégradable a réduit la densité fongique sur les communautés microbiennes des rochers. Cependant, à l'échelle du microcosme, la présence des deux plastiques a réduit les activités N-acetyl-glucosaminidase et phosphatase ainsi que les biomasses fongique et algale présents dans l'ensemble du microcosme. Tant à l'échelle du substrat qu'à l'échelle du microcosme, l'ajout de litières de feuilles tend à réduire l'impact des plastiques sur les communautés microbiennes naturelles.L'impact des plastiques sur les communautés microbiennes benthiques dépend de divers facteurs, notamment le type de plastique, les conditions physico-chimiques de la rivière, la présence de substrats organiques (ex. feuilles) et de l'échelle de l'étude. Cette recherche met en évidence l'impact des macroplastiques sur la structure et la fonction des communautés microbiennes des rochers et appel à un équilibre dans la recherche sur la pollution plastique, au-delà des microplastiques
Plastic pollution, resulting from massive production and use of plastic polymers since the 20th century, is now ubiquitous in the biosphere. Plastics durability makes them able to persist for decades to centuries, fragmenting into microplastics, that can accumulate everywhere from the deep ocean to the top of the mountains. In aquatic environments, plastics promote the formation of microbial communities similar to natural aquatic biofilms known as the 'plastisphere'. While the presence and impact of plastics on microbial communities has been extensively characterized for the marine ecosystems, freshwater ecosystems have been less explored. Furthermore, most of the studies focus on the effect of the microplastics size fraction rather than on macroplastics.The first part of this thesis compared the microbial colonization between two plastic types (non-biodegradable and biodegradable) and natural substrata (sediments, rocks, and leaves) in two sites of the same watershed with contrasting plastic-pollution levels. This comparison included an analysis of the structural and functional descriptors of microbial communities during substrata colonization. Overall, microbial densities and enzymatic activities involved in organic carbon, nitrogen, and phosphorous decomposition were higher on natural substrata (sediments, rocks, and leaves) than on plastics substrata. This could be due to the greater availability of organic carbon and nutrients in natural substrata. River microorganisms exhibited colonization differences between plastic types at the downstream site, with higher bacterial density and enzymatic activities values measured on the biodegradable compared to the non-biodegradable plastic. Consequently, the presence of biodegradable macroplastics would increase heterotrophy to the river ecosystem more than the presence of non-biodegradable macroplastics.The second part assessed the structural and functional impact of the same plastic types on sediment and rock microbial communities in a river microcosm experiment. Main findings revealed contrasting plastic effects depending on the approach used. At the substratum scale, the addition of non-biodegradable plastic increased β-glucosidase activity and the addition of biodegradable plastic reduced the fungal density in microbial communities from rocks. However, at the microcosm scale, the presence of both plastics reduced N-acetyl-glucosaminidase and phosphatase activities, as well as fungal and algal biomasses in the entire microcosm. At both substratum and microcosm scales, the addition of leaf litter tended to mitigate the plastic impact on microbial communities, especially those from rocks.The impact of plastics on benthic microbial communities depends on several factors, including the plastic type, water physicochemical characteristics, the presence of organic substrata (e.g. leaves), and the scale of the study. This research highlights the impact of macroplastics on the structure and function of rock microbial communities, and calls for a more balanced research between the study of microplastics and plastics form other size fractions

Afin de répondre à l'intérêt grandissant autour de l'écologie, le développement de matériaux éco-responsables est devenu prépondérant dans des domaines tels que les transports et la mobilité. Le remplacement des fibres synthétiques par des fibres naturelles et des polymères vierges par des recyclés sont des solutions potentiellement intéressantes. En effet, ces matériaux présentent des propriétés mécaniques spécifiques similaires et une empreinte environnementale plus faible. Néanmoins, les fibres naturelles présentent une forte hydrophilie, ce qui peut poser problème lors d'une utilisation à long terme en extérieur. Les polymères quant à eux subissent des modifications lors de leur recyclage qui peuvent affecter leur compatibilité avec les fibres. L'objectif de cette thèse est d'étudier comment l'utilisation d'une matrice recyclée influe sur les propriétés d'usage de composites polypropylène/lin et sur leur comportement lors de vieillissements hydrothermiques et cycliques. Dans un premier temps, l'influence des paramètres de mise en œuvre (pourcentage d'agent compatibilisant, temps, température et pression de consolidation, vitesse de refroidissement et température de sortie du moule) sur les propriétés mécaniques des composites à matrice vierge a été étudiée afin d'obtenir un matériau de référence. Ensuite, l'impact de l'utilisation de matrices recyclées sur les propriétés du composite a été étudiée. Enfin, des vieillissements hydrothermiques et cycliques (immersion, gel, séchage) ont été appliqués aux différents composites (matrices vierges et recyclées). Une analyse multi-échelle conjuguant caractérisations physico-chimiques, structurales et mécaniques a été réalisée au cours du vieillissement afin de mieux comprendre l'effet de matrices recyclées sur le comportement dans le temps des composites
To respond to the growing interest in ecology, the development of eco-responsible materials has become preponderant in areas such as transportation and mobility. One potential solution is to replace synthetic fibers by natural ones and virgin polymers by recycled ones. Indeed, these materials present similar specific properties and a lesser environmental footprint. However, natural fibers are very hydrophilic, which can be a problem in long-term outdoor use. As for the polymers, they undergo modifications during recycling that can affect their compatibility with fibers. This thesis' aim is to investigate how the use of a recycled matrix affects the properties of polypropylene/flax composites and their behavior under hydrothermal and cyclic ageing. First, the influence of processing parameters (compatibilizing agent's percentage, consolidation time, temperature and pressure, cooling rate and exit temperature) on the mechanical properties of virgin matrix composites was studied in order to obtain a reference material. Then, the impact of the use of recycled matrices on the properties of the composite was studied. Finally, hydrothermal and cyclic ageing (immersion, freezing and drying) were applied to all composites (with virgin and recycled matrices). A multiscale analysis combining physicochemical, structural and mechanical characterizations was carried out during ageing to better understand the influence of the matrix on the behavior of the composites over time

Methanotrophic bacteria can use methane as their only energy and carbon source, and they can be deployed to manufacture a broad range of value-added materials, from single cell protein (SCP) for feed and food applications over biopolymers such as polyhydroxybutyrate (PHB) to value-added building blocks and chemicals. SCP can replace fish meal and soy for fish (aquacultures), chicken and other feed applications, and also become a replacement of meat after suitable treatment, as a sustainable alternative protein. Polyhydroxyalkanoates (PHA) like PHB are a possible alternative to fossil-based thermoplastics. With ongoing and increasing pressure towards decarbonization in many industries, one can assume that natural gas consumption for combustion will decline. Methanotrophic upgrading of natural gas to valuable products is poised to become a very attractive option for owners of natural gas resources, regardless of whether they are connected to the gas grids. If all required protein, (bio)plastics and chemicals were made from natural gas, only 7, 12, 16–32%, and in total only 35–51%, respectively, of the annual production volume would be required. Also, that volume of methane could be sourced from renewable resources. Scalability will be the decisive factor in the circular and biobased economy transition, and it is methanotrophic fermentation that can close that gap.

The increasing global awareness of environmental issues has led to a growing demand for sustainable practices in various industries. One crucial aspect is the development and utilization of eco-friendly materials, which are designed to minimize the environmental impact of production, consumption, and disposal. This abstract provides an overview of the concept of eco-materials, highlighting their significance, characteristics, and potential applications. Eco-materials, also known as environmentally friendly materials or green materials, are those that are sourced, processed, and used in a way that has minimal negative effects on the environment. These materials aim to reduce resource depletion, energy consumption, and waste generation throughout their life cycle. Key characteristics of eco-materials include recyclability, biodegradability, low carbon footprint, and the use of renewable resources. The development of eco-materials involves a multidisciplinary approach, combining principles from materials science, chemistry, engineering, and environmental science. Researchers and industries are actively exploring innovative ways to replace conventional materials with eco-friendly alternatives in various applications such as construction, packaging, textiles, and electronics. Several types of eco-materials have emerged, including bio-based polymers, recycled materials, sustainable composites, and materials designed for disassembly. Bio-based polymers, derived from renewable resources like plants and bacteria, offer a biodegradable alternative to traditional petroleum-based plastics. Recycled materials, such as recycled metals, paper, and glass, contribute to reducing the demand for virgin resources. Sustainable composites combine materials like natural fibers with recycled polymers to create durable and environmentally friendly alternatives. In conclusion, the development and utilization of eco-materials represent a crucial step towards achieving a more sustainable and environmentally conscious future. As research continues to advance in this field, the integration of eco-friendly materials into mainstream industries will contribute to a more circular and regenerative economy, fostering a harmonious relationship between human activities and the natural environment.

Birch tree barks are regarded as waste in the pulp and papermaking industry and used as fuel. However, this material presents a source that contains many bio-based chemicals suitable for applications ranging from pharmaceuticals, plastics and composites, coatings, and antifeedants. Among the mixture of bio-derived chemicals in birch barks, triterpenoids, such as betulin, betulinic acid, and lupeol, can be present up to 30% weight of dry bark mass. They are highly valued for their anti-tumor, HIV, and inflammatory responses. In our presented work, triterpenoid mixtures were extracted through a Soxhlet extractor using the barks from locally sourced river birch trees (Betula nigra) with an average yield of 10.6% (dry bark mass). The extracted materials were characterized using the Nuclear Magnetic Resonance (NMR), Advanced Polymer Chromatography (APC), High-Performance Liquid Chromatography (HPLC), and hydroxyl number titration to assess the identity, average molecular weight, triterpenoid content, and the number of reactive sites, respectively. The extracts have been used to synthesize bio-based polymers with promising thermal and mechanical properties using minimal processing steps. Birch bark extract naturally contains many potential reactive sites and thus making it advantageous for synthesizing polymers without requiring multiple purification steps. We demonstrate the potentials for increasing the utility of birch bark, contributing to sustainability challenges in materials science and engineering.