Mechanochemical and Mechanobiological Recycling of Postconsumer Polyethylene terephthalate (PET) Plastics under Microwave irradiation: A comparative study (original) (raw)

How advances in biodegradable polymers increase advancement in waste management

Review paper , 2022

Over the years, the use and improper disposal of plastic has increased waste in the environment. This waste accumulation leads to the buildup of litter, which is fouling the environment, harming wildlife, and wasting valuable resources. Interest in the use of biodegradable materials in many applications such as packaging, biomedical and agricultural fields have increased recently to solve this issue. Production of biodegradable polymers can be via physical decomposition either by hydrolysis or photodegradation reactions and the second process is by aerobic and anaerobic reactions known as biological processes.This study explains how the advancement of biodegradable polymers helps to improve plastic waste management better than other methods such as landfilling, regeneration, incineration and recycling.

Polymer Degradation and Stability

2021

This paper presents a new recognition in reactive toughening of poly(ethylene terephthalate) (PET), namely the major effect of the molecular weight of PET on the evolution of the compatibilization and crosslinking reactions with ethylene-butyl acrylate-glycidyl methacrylate (EBA-GMA) type reactive terpolymer, and thus indirectly on its toughening efficiency. It was found that the use of highly degraded recycled PET (rPET) grades, due to the available larger number of reactive functional end groups and increased mobility of the decreased-molecular-weight chains, multiplies the impact strength of the product compared to that of original PET (oPET) with identical EBA-GMA contents. The evinced noticeable difference between the toughening behaviour of rPET and oPET is explained by morphological and interfacial factors and connected to differences in rheological behaviour as well. The reactive oligomeric rPET macromolecules form a Toughening Enhancer Interphase (TEI) around the dispersed particles. Based on systematic analyses, conclusions were drawn regarding the quality, i.e. optimal intrinsic viscosity (IV) range, and quantity of rPET to be used to obtain high-impact-strength PET blends (notched Izod impact strength higher than 40 kJ/m 2) with optimised mechanical properties, being suitable even for injection moulding applications, at significantly lower terpolymer contents (10.0-12.5 wt%) than expected. Besides, the proposed new way of utilisation of PET recyclates, especially the unmarketable highly degraded fractions, is believed to give a new driving force in PET recycling.

Degradable plastics and their potential for affecting solid waste systems

WIT Transactions on Ecology and the Environment, 2014

Plastic waste forms a substantial part of municipal solid waste and has caused environmental concerns, particularly due to the chemical contamination of the environment and effects from persistent litter. Plastics also complicate waste management processes, such as by having poor recovery rates through recycling and causing contamination in composting operations. One potential means of addressing some of these challenges is through degradable plastics, which unlike conventional plastics, are designed to decompose at an accelerated rate in specific environments. Degradable plastics aim to address the end-of-life of plastic products and are intended to reduce the environmental impacts associated with their use and management. The first generation of degradable plastics did not meet marketing claims; some of the more recent formulations, partly as a consequence of third party certifications, are more compliant. However, many plastics that are labelled as degradable do not decompose very readily, and it is not clear that litter will be diminished to any great degree through their use. In addition, user confusion regarding degradable definitions is common. Multiple formulations mean that not all degradable plastics address compost contamination and most degradable plastics do not address other problems associated with plastics waste management. Therefore it is not clear that degradable plastics constitute a major technological advance. In fact, they may be more harmful than helpful to waste management systems at this time. Here we discuss how these materials perform in different aspects of solid waste programs: recycling, composting, WTE incineration and landfills, as well as the potential for these plastics to reduce litter problems, both on land and at sea.

Mechanistic implications of plastic degradation

Polymer Degradation and Stability, 2008

Plastics have become an indispensable ingredient of human life. Their enormous use is a matter of great environmental and economic concern, which has motivated the researchers and the technologists to induce different degrees of degradations in the plastic. These degradations can be induced in a better way if their mechanistic implications are properly understood. A better understanding of the mechanism for these degradations is also advocated in order to facilitate the proper use of the alternative waste disposal strategies. In view of the facts concerning the plastic degradation, in this review article, we have discussed various types of polymeric degradations along with their mechanisms, which include photo-oxidative degradation, thermal degradation, ozone-induced degradation, mechanochemical degradation, catalytic degradation and biodegradation. This article also discusses the different methods used to study these degradations and the factors that affect these degradations.

Sustainability performance of polyethylene terephthalate, clarifying challenges and opportunities

Journal of Polymer Science, 2021

Publications on polyethylene terephthalate (PET) continue to increase including the number of publications on recycling. PET is a versatile material with the ability to be remade from its polymer state through mechanical recycling and even back to its original monomer through advanced recycling. The scale of PET's use affords continued research and applications in improved recycling. Publications on new uses of discarded PET and the ability to clean and convert it into many forms including alternative materials are expanding with an attempt to complete circular use or improve the end of life. As indicated in life cycle assessment studies, increases in recycling lower the energy required to manufacture products. The future for PET will reduce energy demands further with the largest breakthroughs in recycling technologies and bio‐sourced resins trending toward zero energy and carbon negative solutions. Opportunities remain for improvement in the use of PET with light weighting. Th...

Degradable Plastics and Solid Waste Management Systems

2013

Plastics, which are woven into the fabric of modern life, have consequential impacts on the environment. Many of these are associated with end-of-lifetime processes, and include chemical contamination of the environment and effects from litter. Plastics also complicate waste management processes, causing contamination in composting operations, and having poor recovery rates through recycling. Plastics that are not as biologically recalcitrant, that decompose when use is done, have been perceived as solutions to at least some of these problems. The first generation of degradable plastics did not meet marketing claims; some of the more recent formulations, partly as a consequence of third party certifications, are more compliant. However, many plastics that are labeled as "degradable" do not decompose very readily, and it is not clear that litter will be diminished to any great degree through their use. In addition, because not all plastics are or will be degradable, user confusion is and will be common. Multiple formulations mean not all degradable plastics address compost contamination, and most degradable plastics do not address other problems associated with plastics waste management. Therefore it is not clear that degradable plastics constitute a major technological advance; in fact, overall they may be more harmful than helpful.

Introduction, Past and Present Scenarios of Plastic Degradation

2021

The fascinating properties of plastic make its use widely possible in every field for the ease of human life. On the other hand, these properties make plastic non-biodegradable in nature. Hence the increasing accumulation of plastic in the environment is the arising concern for environmentalists and human society. This growing concern has motivated researchers and technologist to promote research activity for finding new degradation methods for plastics, synthesis of new plastic with biodegradable nature or find alternatives to plastics. Considering these facts, this book chapter briefly discusses the management of post-consumer plastic products and all the possible methods for plastic degradation such as photo and thermo-oxidative, catalytic, mechano-chemical and chemical along with the factors affecting these degradation methods.