Academic literature on the topic 'Biodegradable plastics'

Introduction. Processing agricultural waste into plant biodegradable plastics is a promising way for its recycling. This work featured the main physical-and-mechanical properties of plant plastics without adhesive substances obtained from millet husk and wheat husk and wood plastic obtained from sawdust, as well as their biodegradation potential. Study objects and methods. Objects of the study were plastics without adhesives based on wood sawdust, millet husk, and wheat husk. Results and discussion. We analyzed of the physical-and-mechanical parameters of the plant plastic based on millet husk, wheat husk, as well as wood plastic based on sawdust. The analysis showed that, in general, the strength characteristics of the wood plastics were higher than those of the plastics based on millet husk, especially flexural strength. Thus, the average value of the density of the wood plastic exceeded that of the plant plastic from millet husk by 10%, hardness by 40%, compression elasticity modulus by 50%, and flexural modulus by 3.9 times. It was found that wood and plant plastics obtained from sawdust, millet husk, and wheat husk without adhesives had a high biodegradation potential. Conclusion. The plastics obtained can be used as an insulating, building, and decorative material in the steppe regions experiencing a shortage of wood and wood powder.

The low degradability behaviour of plastics is an important environmental problem. The end-use of plastic creates waste-disposal problems as these plastics do not readily or naturally degrade and gives severe effect when plastic-waste requires more time to break down. However, as the bio-polymer industries have advanced, biodegradable plastic is being presented as a high promising solution to the environmental problem over the conventional non-biodegradable plastics. As one of the great innovation products in bio-polymer industries, biodegradable plastic can potentially lessen the volume of solid waste and reduce the need for waste dumping sites. Whilst, biodegradable plastic also offers the outstanding properties to resist the brittleness and resistance towards heat. This paper review the potential of biodegradable plastics made from petrochemical-polymers blended with starch, including polyethylene (PE), polycaprolactone (PCL), polyvinyl alcohol (PVOH) polypropylene (PP) and polyvinyl chloride (PVC).

In recent years, an increasing trend towards replacement of conventional fossil-based plastics with bio-based plastics was noticed, i.e., production of plastics partly or fully made from biomass is rapidly expanding. Currently, bio-based and biodegradable plastics have a very small market size, approximately only 1% of all plastics produced. However, the forecast of the global bioplastics production capacities predicts an increase from approximately 2.417 million tonnes in 2021 to approximately 7.593 million tonnes in 2026, more than three times the current capacity. Therefore, it is necessary to assess the challenges and identify the barriers for bio-based and biodegradable plastics for waste management and to evaluate the effectiveness of current plastic waste management strategies for the efficient waste management of bio-based and biodegradable plastics. The main barriers and motivators of the biodegradable and biodegradable plastics market that have been identified include macroeconomic factors, regulatory factors, technological factors, and social factors. The bio-based and biodegradable plastics have to be separately collected and treated under mostly controlled, regulated conditions. However, currently, there are no legal provisions providing for the separate collection of bio-based plastics, leading to their disposal with either hazardous waste, conventional plastics, or municipal waste. Since the effective plastic waste management strategy relates to good performance in each step of the waste management process, bio-based and biodegradable plastic waste management could, therefore, be based on an effective strategy for the management of plastic waste. However, there is a need for standardizing waste collection systems and creating a harmonized waste collection infrastructure, which would lead to effective sorting of bio-based plastic waste.

The world today seems unimaginable without plastics or synthetic organic polymer, however their large-scale production and use only dates back to 1950 (1). The resulting rapid growth in plastics production is remarkable, surpassing most other man-made materials. The study presents the utilization of banana peel as biodegradable plastic to substitute the existing non-biodegradable plastic. The objectives of this research are to aims to develop and produce biodegradable plastic that will substitute the existing non-biodegradable plastic to help in saving the environment as well as to compare the properties of biodegradable plastic based on banana peel with the commercial biodegradable plastic. The use of waste banana peel in this study is mainly to replace the synthetic materials used in the conventional biodegradable plastic. Furthermore, the environmental pollutions can be reduced due to the usage of waste banana peels to produce a new value-added biodegradable plastic. Keywords : Banana peel, biodegradable plastic, pollution, environment

Since their inception and invention, plastic materials have taken on an essential role in numerous applications within the lives of human beings for years now. Each year, the global figure for production of plastic is estimated to be more than 100 million tons. The major reason for the existence of such an enormous amount is due to plastics’ supremacy over other materials with their exceptionally useful properties. According to Hong Kong’s Environmental Protection Department, 13,458 tons of waste was disposed in Hong Kong’s landfills per day during 2011. Such an amount is very large in quantity, and it is predicted that the three strategic landfills of Hong Kong will be fully saturated in 2015-16 if the waste generation rate remains similar as present time and business as usual. Plastics made up approximately 19% of the overall composition of Hong Kong’s disposed municipal solid waste in 2011. Plastic material does not degrade efficiently, and since it has only been in production during the most current century, plastic specialists have not been able to conclude the final life span of the material before it completely degrades. Estimates for different plastic polymers range from 20 years to 400 years and above. To solve these increasingly serious environmental issues, the society has raised its demands and directed many researches into biodegradable polymers (i.e., plastics). They have now become more seriously considered as alternative solutions for conventional, non-biodegradable plastics. However, the creation of such biodegradable materials, the efficiency and cost of that creation and the true biodegradability of those materials is under much scrutiny and debate. The purpose of this study was multi-faceted. It primarily focused on (1) the status and production of biodegradable products in Hong Kong and (2) assessment of the general public’s receptiveness towards using such products. This study aimed to evaluate the above two aspects via literature review and interviews of representatives from biodegradable plastics companies in Hong Kong as well as students and general working-class citizens. This element inquired whether the general public would be willing to pay extra money to use biodegradable plastic products, and whether they thought that these products had beneficial effects towards environmental conservation and protection. Also, the general public would be asked their opinion on a duty for biodegradable products and whether they would be adverse to a policy implementation involving such a duty. A large portion of this project’s critically significant data was generated from random, systematic sampling of different people, asking them about the aforementioned monetary scenarios. Results were insightful and informative giving evident trends that represented the public’s attitude towards biodegradable plastics. Overall, the public was positively supportive of biodegradable technology, which is relatively new. Concurrently, extensive literature review was conducted to assess foreign practices and policies regarding biodegradable plastics, as well as the life-cycle of a primary biopolymer called polylactic acid. A concluding recommendation was constructed to envision the future waste management infrastructure in Hong Kong. That infrastructure could build off of the special region’s budding development of incinerators, composting facilities, waste-to-energy facilities, and sorting technologies. Then, to supplement biodegradable polymer production and post-use handling facilities, the Hong Kong SAR Government could implement strong waste management policies to motivate its society to aim for a more sustainable way of life.
published_or_final_version
Environmental Management
Master
Master of Science in Environmental Management

Packaging waste forms a big a part of municipal solid waste and has caused increasing environmental considerations, leading to a strengthening of varied rules aimed toward reducing the amounts generated. Among different materials, a good vary of oil-based polymers is presently employed in packaging applications. These are nearly all non-biodegradable, and a few are troubled to recycle or apply because of being advanced composites having variable levels of contamination. Recently, important progress has been created within the development of biodegradable plastics, for the most part from renewable natural resources, to provide biodegradable materials with similar practicality thereto of oil-based polymers. The enlargement within these bio-based materials has many potential advantages for greenhouse gas balances and different environmental impacts over whole life cycles and in the use of renewable, instead of finite resources. it's supposed that use of biodegradable materials can contribute to sustainability and reduction within the environmental impact related to disposal of oil-based polymers. The diversity of biodegradable materials and their variable properties makes it trouble to create straightforward, generic assessments like biodegradable product are all ‘good’ or petrochemical-based product are all ‘bad’. during this analysis I'm aiming to discuss the benefits of bioplastics and their substitution potential with respect to petroleum-based materials, the production of bioplastics using scratch and environmental impacts of its composting.

Sequencing batch reactor (SBR) systems were used for the development of a system and operating procedures for the high production of polyhydroxyalkanoates (PHAs) by wastewater treatment (activated sludge) bacterial cultures. It was found that unbalanced growth conditions stimulated massive PHA production in activated sludge biomass. Operating conditions had a significant effect on PHA production and the composition of the accumulated copolymer when either laboratory prepared mixtures of organics or a high acetic acid industrial wastewater were used as the organic substrate mixture. Fully aerobic (AE) conditions with nitrogen (N) and phosphorus (P) limitations were the optimum conditions for PHA production when the laboratory prepared mixtures of orgnics were used, while fully AE with the combinations of N, P, and potassium (K) limitations were better for PHA production using a high acetic acid industrial wastewater as the substrate. One nutrient limitation or partial limitation of either N or P as used for commercial production using pure cultures did not promote massive PHA production in activated sludge biomass compared to the combination of nutrient limitations. A maximum cellular PHA accumulation of 70%TSS was obtained under fully AE conditions with multiple alternating periods of growth and N&P limitations. Microaerophilic/aerobic (MAA/AE) or anaerobic/aerobic (AN/AE) cycling promoted less PHA production compared to fully AE conditions. The relative amounts of the PHA copolymers formed, i.e., polyhydroxybutyrate (PHB) and polyhydroxyvalerate (PHV) were different under different operating conditions, even though the types and amounts of volatile fatty acids (VFAs) in the feed were the same. It was determined that high total phosphorus (TP) content inside the bacterial cells had a significant detrimental impact on PHA production by activated sludge biomass. A two-stage bioprocess was a better approach for obtaining activated sludge PHA accumulation because a growth phase was necessary to grow the bacterial population that contains minimal TP before starting the subsequent PHA accumulation phase. Seeding sludge obtained from a conventional fully aerobic wastewater treatment system was more suitable than seed obtained from a biological phosphorus removal (BPR) system because bacterial populations from BPR systems tended to convert organic substrates to intracellular carbohydrate content rather than PHA under nutrient limitation conditions. The molecular weights and melting point temperatures of PHAs produced by the mixed culture of activated sludge biomass were comparable to those obtained from pure cultures and have the potential to be used for commercial applications. The results of this study indicate that activated sludge biomass has considerable potential for PHA production for commercial purposes, and likely could do so utilizing wastewater sources of organics. In particular organic rich, nutrient limited wastewaters have potential for efficient PHA production.
Ph. D.

Els encoixinats plàstics agrícoles són una peça fonamental del sistema agrícola, contribuint a fer front a la demanda d'alimentació de la creixent població mundial. El seu ús incrementa la producció, precocitat i qualitat de les collites, redueix el consum d'aigua i l'aplicació de pesticides i prevé el desenvolupament de males herbes. Els encoixinats són majoritàriament de polietilè (PE), no biodegradables, i encara que s'han de retirar després de la collita, molts fragments romanen en el camp i es van acumulant, disminuint la qualitat del sòl i de les collites. Els encoixinats de plàstic biodegradable (BDM) s'han presentat com una alternativa sostenible que evita aquesta acumulació; després de la collita seran biodegradats pels microorganismes del sòl en el qual s'integren. Tanmateix, això implica l'aportació al sòl dels diversos compostos (polímers i additius) presents en els fragments, dels que a penes s'han estudiat els seus efectes en les plantes conreades i en els organismes del sòl. L'objectiu d'aquesta tesi és avaluar l'efecte que tenen vuit BDM de diferent formulació i els seus components en el microbioma del sòl agrícola i en plantes conreades. Per a això es van triar dues espècies comunament conreades amb encoixinats que estan entre els principals productes hortícoles a nivell mundial, l’enciam (Lactuca sativa L.) i el tomàquet (Lycopersicon esculetum Mill.). Com a control es va incloure un encoixinat de PE. En primer lloc, es va avaluar si els BDM poden alliberar compostos per contacte amb un mitjà aquós abans d'iniciar la seva biodegradació, i si els compostos alliberats poden afectar el desenvolupament de les plantes. Es va trobar que tots els BDM assajats van alliberar una diversitat de compostos, que en diversos casos (Bioplast SP4 i SP6, Mirel i Biofilm) van afectar negativament la germinació, la morfologia de les arrels o el desenvolupament i fisiologia de totes dues espècies, mentre que els altres BDM van causar efectes menors (Ecovio, Mater-Bi) o no significatius (Bioflex). A continuació, es van identificar els compostos alliberats, que van resultar ser diversos, tant components de la seva estructura polimèrica (1,4-butanediol, àcid làctic, àcid tereftàlic, etc.) com a additius (àcids grassos, glicerol, etc.). D'entre els identificats es va quantificar principalment els que anteriorment havien mostrat afectar el desenvolupament de plantes de tomàquet i d'enciam (1,4-butanediol, àcid làctic i àcid adípic). Les concentracions en què es van trobar van resultar ser substancialment menors que les responsables de causar efectes en les plantes, la qual cosa no permet establir una relació directa entre el seu alliberament dels BDM i els efectes que puguin tenir en les plantes. En tercer lloc, es va estudiar l'efecte de l’acumulació de fragments de BDM en el sòl sobre la germinació i desenvolupament de plantes de tomàquet i d'enciam. La presència de fragments de la majoria dels BDM no va afectar la germinació però si va reduir el creixement i el nivell de clorofil•la en tomàquet i especialment en enciam. En general, els efectes identificats van ser consistents amb els dels compostos alliberats dels BDM trobats anteriorment, i els fragments de PE no van causar efectes. En conjunt, els resultats suggereixen que la composició química del BDM té un paper rellevant en la seva interacció amb el sistema radical de les plantes, i que les conseqüències de la presència de fragments de BDM en el sòl es relaciona amb aquesta composició, probablement pel fet que alliberen components, més que a la seva presència física. Finalment, es va estudiar l'impacte de l'acumuació en el sòl de fragments de BDM en l'estructura i funcions de les comunitats microbianes del sòl agrícola. Després de tres mesos d'incubació, aquesta acumulació va tenir un baix impacte en la diversitat i estructura de les comunitats microbianes del sòl. No obstant això, alguns materials van provocar canvis significatius en l'abundància i diversitat de determinats grups bacterians (Mater-Bi), fúngics (paper MIMGreen) i protistes (Ecovio). Encara que l'activitat microbiana total no es va veure alterada, l'activitat quitinasa, implicada en el cicle del nitrogen, va disminuir significativament per la presència tant de BDM com de PE. Els resultats obtinguts en aquesta tesi doctoral aporten nous coneixements sobre els BDM i els seus potencials efectes. Principalment evidencien que els BDM (1) poden alliberar amb facilitat diversos compostos molt abans que s'iniciï la seva biodegradació, (2) que la solució que conté els compostos alliberats, en funció de la seva composició, pot tenir efectes sobre les plantes i (3) que l’acumulació de fragments de BDM en el sòl presenta capacitat d'afectar el desenvolupament de les plantes i de modificar l'abundància i diversitat del microbioma del sòl en funció de la composició del BDM. Tot això, resulta rellevant per al disseny i desenvolupament d'encoixinats plàstics biodegradables que tinguin sota impacte sobre plantes conreades i sobre el medi ambient.
Los acolchados plásticos agrícolas son una pieza fundamental del sistema agrícola, contribuyendo a hacer frente a la demanda de alimentación de la creciente población mundial. Su uso incrementa la producción, precocidad y calidad de las cosechas, reduce el consumo de agua y la aplicación de pesticidas y previene el desarrollo de malas hierbas. Los acolchados son mayoritariamente de polietileno (PE), no biodegradables, y aunque se deben retirar tras la cosecha, muchos fragmentos permanecen en el campo y se van acumulando, disminuyendo la calidad del suelo y de las cosechas. Los acolchados de plástico biodegradable (BDM) se han presentado como una alternativa sostenible que evita este acúmulo; tras la cosecha serán biodegradados por los microorganismos del suelo en el que se integran. Sin embargo, ello implica el aporte al suelo de los diversos compuestos (polímeros y aditivos) presentes en los fragmentos, pero apenas se han estudiado sus efectos en las plantas cultivadas y en los organismos del suelo. El objetivo de esta tesis es evaluar el efecto que tienen ocho BDM de diferente formulación y sus componentes en el microbioma del suelo agrícola y en plantas cultivadas. Para ello se eligieron dos especies comúnmente cultivadas con acolchados que están entre los principales productos hortícolas a nivel mundial, lechuga (Lactuca sativa L.) y tomate (Lycopersicon esculetum Mill.). Como control se incluyó un acolchado de PE. En primer lugar, se evaluó si los BDM pueden liberar compuestos por contacto con un medio acuoso antes de iniciar su biodegradación, y si los compuestos liberados pueden afectar al desarrollo de las plantas. Se encontró que todos los BDM ensayados liberaron una diversidad de compuestos, que en varios casos (Bioplast SP4 y SP6, Mirel y Biofilm) afectaron negativamente a la germinación, la morfología de las raíces o el desarrollo y fisiología de ambas especies, mientras que los de otros BDM causaron efectos menores (Ecovio, Mater-Bi) o no significativos (Bioflex). A continuación, se identificaron los compuestos liberados, que resultaron ser diversos, tanto componentes de su estructura polimérica (1,4-butanediol, ácido láctico, ácido tereftálico, etc.) como aditivos (ácidos grasos, glicerol, etc.). De entre los identificados se cuantificó principalmente los que anteriormente habían mostrado afectar al desarrollo de plantas de tomate y de lechuga (1,4-butanediol, ácido láctico y ácido adípico). Las concentraciones en que se encontraron resultaron ser sustancialmente menores que las responsables de causar efectos en las plantas, lo que no permite establecer una relación directa entre su liberación de los BDM y los efectos que puedan tener en las plantas. En tercer lugar, se estudió el efecto del acúmulo de fragmentos de BDM en el suelo sobre la germinación y desarrollo de plantas de tomate y de lechuga. La presencia de fragmentos de la mayoría de los BDM no afectó a la germinación pero si redujo el crecimiento y el nivel de clorofila en tomate y especialmente en lechuga. En general, los efectos identificados fueron consistentes con los de los compuestos liberados de los BDM encontrados anteriormente, y los fragmentos de PE no causaron efectos. En conjunto, los resultados sugieren que la composición química del BDM tiene un papel relevante en su interacción con el sistema radical de las plantas, y que las consecuencias de la presencia de fragmentos de BDM en el suelo se relaciona con esta composición, probablemente debido a que liberan componentes, más que a su presencia física. Finalmente, se estudió el impacto del acumulo en el suelo de fragmentos de BDM en la estructura y funciones de las comunidades microbianas del suelo agrícola. Tras tres meses de incubación, este acúmulo tuvo un bajo impacto en la diversidad y estructura de las comunidades microbianas del suelo. Sin embargo, algunos materiales provocaron cambios significativos en la abundancia y diversidad de determinados grupos bacterianos (Mater-Bi), fúngicos (papel MIMGreen) y protistas (Ecovio). Aunque la actividad microbiana total no se vio alterada, la actividad quitinasa, implicada en el ciclo del nitrógeno, disminuyó significativamente por la presencia tanto de BDM como de PE. Los resultados obtenidos en esta tesis doctoral aportan nuevo conocimiento sobre los potenciales efectos de los BDM en las plantas cultivadas y los microorganismos del suelo. Principalmente evidencian que los BDM (1) liberan con facilidad diversos compuestos mucho antes de que se inicie su biodegradación, tras el contacto con el agua, (2) la solución que contiene los compuestos liberados, en función de su composición, puede tener efectos sobre las plantas, (3) que el acúmulo de fragmentos de BDM en el suelo presenta capacidad de afectar al desarrollo de las plantas y de modificar la abundancia y diversidad de los microorganismos del suelo en función de la composición del BDM. Todo ello resulta relevante para el diseño y desarrollo de acolchados plásticos biodegradables que tengan un bajo impacto sobre las plantas cultivadas y sobre el medio ambiente.
Agricultural plastic mulches are an essential part of the agricultural system, contributing to face the food demand for the growing world population. Its use increases crop production, earliness and quality, reduces water consumption and pesticide delivery and prevents weed development. Mulches are mostly made of polyethylene (PE), non-biodegradable. Although they must be removed after harvesting, many fragments remain and accumulate in the field, reducing soil and crop quality. Biodegradable plastic mulches (BDM) have been fostered as a sustainable alternative preventing this accumulation. After harvest they will be biodegraded by the soil microorganisms in which they are integrated. However, this entails the various compounds (polymers and additives) present in the fragments are supplied to the soil, but their effects on cultivated plants and on soil organisms have hardly been studied. The objective of this PhD thesis is to evaluate the effect of eight BDM of different formulation, and their components, on the agricultural soil microbiome and on plants. For this purpose two plant species commonly cultivated with mulches which are among the main horticultural products were targeted, lettuce (Lactuca sativa L.) and tomato (Lycopersicon esculetum Mill.). One PE mulch was included as control mulch. Firstly, it was evaluated whether BDM can release compounds by contact with an aqueous environment before the onset of their biodegradation, and whether the released compounds can affect plant development. It was found that all the BDM tested released a diversity of compounds, which in several cases (Bioplast SP4 and SP6, Mirel and Biofilm) inhibited germination, root morphology or the development and physiology of both plant species, while those from other BDM caused minor (Ecovio, Mater-Bi) or non-significant (Bioflex) effects. Next, the released compounds were identified, which were eventually diverse, both components of its polymeric structure (1,4-butanediol, lactic acid, terephthalic acid, etc.) and additives (fatty acids, glycerol, etc.). Among those identified, the ones having previously shown to affect tomato and lettuce plant development (1,4-butanediol, lactic acid and adipic acid) were quantified. They were found to be in substantially lower concentrations than the ones responsible for causing effects on plants, which does not allow establishing a direct relationship between their release from BDM and the effects they may have on plants. Thirdly, the effect of the accumulation of BDM fragments in the soil on tomato and lettuce germination and plant development was studied. For most BDM, the presence of their fragments did not affect germination but it reduced plant growth and chlorophyll content in tomato and especially in lettuce. In general, the identified effects were consistent with those of compounds released from BDM previously found, and PE fragments caused no effects. Altogether, results suggest that the BDM chemical composition plays a relevant role in its interaction with the plant root system, and that the consequences of the presence of BDM fragments in the soil is related to this composition, likely due to the release of components, rather than to their physical presence. Finally, the impact of the BDM fragments’ accumulation in the soil on the structure and functions of the agricultural soil microbial communities was studied. After incubation for three months, this accumulation had a low impact on the soil microbial communities’ diversity and structure. However, some materials caused significant changes in the abundance and diversity of selected bacterial (Mater-Bi), fungi (MIMGreen paper) and protists (Ecovio) groups. Although the total microbial activity was not altered, the chitinase activity, involved in the nitrogen cycle, was significantly decreased by both BDM and PE presence. The results obtained in this doctoral thesis provide new knowledge on the potential effects of BDMs on cultivated plants and soil microorganisms. They mainly show that BDM (1) easily release several compounds soon before their biodegradation starts, after contact with water, (2) the solution containing the released compounds, depending on its composition, may have effects on plants and (3) the accumulation of BDM fragments in the soil has the capacity to affect plant development and to modify the abundance and diversity of soil microorganisms depending on the composition of the BDM. The results will contribute to the design and development of biodegradable plastic mulches that have a low impact on cultivated plants and the environment.

Recently, the rapid and almost uncontrollable growth in the consumption of synthetic plastics in many sectors of the economy, especially in the field of packaging, has been a serious concern. Plastic containers are used for packaging food products, medicines, electronic devices, liquids, including those with a higher hazard class, etc. [1]. According to the German Nova-Institute, the global plastic production in 2020 has reached almost 400 Mill. Tons. At the same time, the volume of biodegradable plastics obtained from renewable resources amounted to only 3.5 million tons, i.e., about 1% of the total volume production [2]. Considering that only 25% of plastic waste is recycled, the growing consumption of polymer products is forcing manufacturers to develop biodegradable polymer compositions [3]. The problem has economic and environmental aspects since it is interconnected with the growing need to protect the environment and reduce the cost of raw materials for the production of various products.

Bio-plastics are characterized by the highest rate of growth in the plastics industry. In connection with the recycling chain they constitute the so-called “oxo-biodegradation” and drop-in problems. The present study tries to clarify possibilities of automatic recognition and sorting of conventional fossil-based plastics against similar “oxo-biodegradable” plastics and drop-ins by means of NIR-SWIR-Hyperspectral-Imaging (HIS). The spectral structures of the most important plastics (conventional fossil-based plastics and bio-plastics) have been incorporated in a database as references for different plastic types to be subject to identification by NIR-SWIR-HSI. In addition to widespread chemometrical methods (PLS-DA), artificial neural networks (ANN) and support vector machines (SVM) are estimated for classification. For “oxo-biodegradable” plastics it turns out that a decision tree is the most reliable procedure for identification. Different decision trees are passed to an industrial NIRSWIR- Hyperspectral-Imager for generating chemical images of different plastic mixtures. The mixtures consist of conventional fossil-based plastics and bio-plastics. The aim of the tests was to find bounds for sorting throughput and purity. Results of an industrial sorting trial are finally described.

Plastic pollution has become one of the major concerns in the world. Plastic waste is not biodegradable, which makes it difficult to manage waste plastic pollution. Recycling and reusing waste plastic is an effective way to manage plastic pollution. Because of the huge quantity of waste plastic released into the world, industries requiring a large amount of material, like the pavement industry, can reuse some of this mammoth volume of waste plastics. Similarly, the use of reclaimed asphalt pavement (RAP) has also become common practice to ensure sustainability. The use of recycled waste plastics and RAP in HMA mix can save material costs and conserve many pavement industries’ resources. To successfully modify HMA with RAP and waste plastic, the modified HMA should exhibit similar or better performance compared to conventional HMA. In this study, recycled waste plastic, linear low-density polyethylene (LLDPE), and RAP were added to conventional HMA, separately and together. The mechanical properties of conventional and modified HMA were examined and compared. The fatigue cracking resistance was measured with the IDEAL Cracking (IDEAL CT) test, and the Hamburg Wheel Tracking (HWT) test was conducted to investigate the rutting resistance of compacted HMA samples. The IDEAL CT test results showed that the cracking resistance was similar across plastic modified HMA and conventional HMA containing virgin aggregates. However, when 20% RAP aggregates were used in the HMA mix, the fatigue cracking resistance was found to be significantly lower in plastic modified HMA compared to conventional HMA. The rutting resistance from the HWT test at 20,000 passes was found to be similar in all conventional and modified HMA.

This rapid evidence assessment undertaken by RSM UK Consulting LLP (RSM) and Dr Samuel Short (University of Cambridge) aimed to develop an understanding of the alternatives to single-use plastics in food packaging and production in terms of their risks and opportunities, as well as potential future developments. Literature from within and beyond the UK was gathered from academic databases and reports published by government and non-governmental organisations such as environmental charities. Evidence from the literature was supplemented by findings from a workshop with experts in the field from a variety of industries such as academia, manufacturing, and government. Two broad groups of alternatives were established: material/product alternatives (traditional materials, natural fibres, biopolymers synthesised from biomass, biopolymers synthesised from bioderived monomers, biopolymers produced by microorganisms) and, and system/process alternatives (reducing, reusing, and recycling food packaging and, active and intelligent packaging). These alternatives and systems vary considerably in terms of their properties, such as effectiveness as a barrier to moisture or contamination, convenience for consumers, production costs, and potential for commercialisation. Our review also highlighted gaps in the current knowledge, for example in terms of consumer acceptance and carbon footprint at each stage of their life cycle. The capacity to produce bioplastics (i.e. biopolymers that look and feel similar to conventional plastics but are made from natural materials rather than fossil fuels and are biodegradable or compostable) is anticipated to increase globally from 2.1 million tonnes in 2019 to 6.3 million tonnes by 2027. This growth appears to be enabled by increased consumer awareness of environmental issues and existing regulation and legislation encouraging the development and establishment of a circular economy. However, there are barriers that may challenge this growth. These include already established industry regimes, high production cost of novel materials and a lack of waste management guidance. Overall, fossil-based conventional plastics are a very cheap, versatile material compared to the alternatives currently being developed and tested. Because of this, they might remain the preferred industry choice for certain applications, while alternatives continue to be optimised and commercially scaled. To add to this, the reviewed evidence suggests that there is unlikely to be one single solution to the single-use plastics problem. The solution will likely draw on a range of materials and systems depending on food type and context.