Continual reduction of landfill space along with rising CO2 levels and environmental pollution, are global issues that will only grow with time if not correctly addressed The lack of proper waste management infrastructure means gloablly commodity plastics are disposed of incorrectly, leading to both an economical loss and environmental destruction The bioaccumulation of plastics and microplastics can already be seen in marine ecosystems causing a negative impact on all organisms that live there, ultimately microplastics will bioaccumulate in humans The opportunity exists to replace the majority of petroleum derived plastics with bioplastics (bio-based, biodegradable or both) This, in conjunction with mechanical and chemical recycling is a renewable and sustainable solution that would help mitigate climate change This review covers the most promising biopolymers PLA, PGA, PHA and bio-versions of conventional petro-plastics bio-PET, bio-PE The most optimal recycling routes after reuse and mechanical recycling are: alcoholysis, biodegradation, biological recycling, glycolysis and pyrolysis respectively

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Recycling of Bioplastics: Routes and Benefits

Nanotechnology is considered a highly valued technology to reduce the current environmental problem that is derived from plastic accumulation. The need to recycle and reuse packaging materials is essential to create a sustainable society towards a circular economy. However, the reprocessing of polymers leads to the deterioration of their characteristic mechanical, optical, thermal, and barrier properties due to the degradation of their polymeric chains. When recycled polymers are reinforced with nanoadditives, aforementioned properties improve and their use in the circular economy is more viable. In this review, different types of nanoadditives and recent advances in the development of recycled polymer nanocomposites reinforced with nanoadditives will be presented. In addition, there is a description of two research topics of current interest, recyclability of nanocomposites and safety for food packaging applications. Recyclability of nanocomposites requires a study that includes the nature of the polymer matrix, the type of polymer and the concentration of nanofiller, the morphology, the presence of additives, and the conditions of the thermal-mechanical cycles. Finally, safety section is dedicated to clarify the migration process in nanoreinforced-recycled polymers in order to assess their safety for food contact applications.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12575

The use of nanoadditives within recycled polymers for food packaging: Properties, recyclability, and safety.

Electrospinning is an advanced technology for the preparation of drug-carrying nanofibers that has demonstrated great advantages in the biomedical field. Electrospun nanofiber membranes are widely used in the field of drug administration due to their advantages such as their large specific surface area and similarity to the extracellular matrix. Different electrospinning technologies can be used to prepare nanofibers of different structures, such as those with a monolithic structure, a core–shell structure, a Janus structure, or a porous structure. It is also possible to prepare nanofibers with different controlled-release functions, such as sustained release, delayed release, biphasic release, and targeted release. This paper elaborates on the preparation of drug-loaded nanofibers using various electrospinning technologies and concludes the mechanisms behind the controlled release of drugs.

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Progress of Electrospun Nanofibrous Carriers for Modifications to Drug Release Profiles

Condensation Polymers: Their Chemical Peculiarities Offer Great Opportunities

The dramatic situation with the environmental impact of plastics waste we observe nowadays is related with their inherent peculiarity as materials – they do not change substantially their properties after converting into waste even into litter. Just this their peculiarity could help for partial solution of the problem – to convert the plastics waste via recycling into valuable materials and thus to reduce the amount of plastics litter. As a possible technology of polymer recycling the concept of microfibrillar composites (MFCs) is discussed when blends of two non-miscible polymers are melt blended, extruded, cold drawn and further compression- or injection molded for manufacturing of polymer-polymer composites. The MFC based on PET from Coca Cola bottle and low-density polyethylene are characterized by superior mechanical properties achieved via cold drawing. It is stressed that the recycling does not solve the problem of the negative impact of plastics on the environment, it only postpones this solution. This is because after the end-of-life of the recycled plastics they are converted again in waste or litter.

A new approach to plastic recycling via the concept of microfibrillar composites

This study investigates the influence of clay nanofiller on morphological, thermal, and mechanical behaviors of post-consumer polypropylene (PCPP)-based nanocomposites. Waste polypropylene was mixe...

Impact of Tunisian clay nanofillers on structure and properties of post-consumer polypropylene-based nanocomposites:

Modified (or unmodified) Tunisian clay nanoparticles were incorporated as nanofillers in post-consumer polypropylene (PCPP) polymer matrix in order to improve its inherent properties. PCPP loaded with Na-clay or organoclay nanocomposites were elaborated by melt intercalation method. Morphological, thermal and rheological properties of prepared nanocomposites were then evaluated. SEM observations showed better nanoparticles dispersion when PCPP was filled with organoclay compared to Na-clay. According to FTIR analysis, the increase of PCPP band intensity is much higher when using organoclay, suggesting that the nanocomposites might have more intercalation of organoclay aggregates than in the case of filled with Na-clay. Thermal gravimetric and thermal degradation analyses results confirmed that the addition of modified clay allows better thermal stability than PCPP filled with unmodified clay. This result was confirmed by DSC analysis. We deduced from the rheological analysis that PCPP storage modulus G′ and loss modulus G″ increased with the addition of clay nanoparticles. This increase was higher when the organo-modified clay was dispersed into the PCPP matrix, demonstrating the reinforcing effect of the latter on PCPP polymer. Storage modulus of pure PCPP and PCPP/clay nanocomposites.

Valorization of Post-consumer PP by (Un)modified Tunisian Clay Nanoparticles Incorporation

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/adv.22159

Rheological and thermal behavior of Tunisian clay reinforced recycled polypropylene composites

Over the last two decades, bio-polymer fibers have attracted attention for their uses in gene therapy, tissue engineering, wound-healing, and controlled drug delivery. The most commonly used bio-polymers are bio-sourced synthetic polymers such as poly (glycolic acid), poly (lactic acid), poly (e-caprolactone), copolymers of polyglycolide and poly (3-hydroxybutyrate), and natural polymers such as chitosan, soy protein, and alginate. Among all of the bio-polymer fibers, alginate is endowed with its ease of sol–gel transformation, remarkable ion exchange properties, and acid stability. Blending alginate fibers with a wide range of other materials has certainly opened many new opportunities for applications. This paper presents an overview on the modification of alginate fibers with nano-particles, adhesive peptides, and natural or synthetic polymers, in order to enhance their properties. The application of alginate fibers in several areas such as cosmetics, sensors, drug delivery, tissue engineering, and water treatment are investigated. The first section is a brief theoretical background regarding the definition, the source, and the structure of alginate. The second part deals with the physico-chemical, structural, and biological properties of alginate bio-polymers. The third part presents the spinning techniques and the effects of the process and solution parameters on the thermo-mechanical and physico-chemical properties of alginate fibers. Then, the fourth part presents the additives used as fillers in order to improve the properties of alginate fibers. Finally, the last section covers the practical applications of alginate composite fibers.

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Alginate-Based Bio-Composites and Their Potential Applications

Chitosan is a biopolymer obtained from deacetylation of the abundant natural chitin polymer. It has found its use in many applications due to its unique solubility as well as chemical and biological properties. In addition to its biodegradability and biocompatibility, it has many reactive amino side groups that offer the possibilities of chemical modification and formation of a large variety of beneficial derivatives. Numerous researchers have published works outlining the physical and chemical properties of chitosan, as well as its use in several industries, such as medical, environmental and food. Due to its excellent absorption and biological properties, chitosan present a myriad of opportunities in eco-friendly textile processes. Chitosan is able to confer antimicrobial, antiviral, anti-odor and other biological activities to textile fibers and fabrics. In this review, the first part is dedicated to developing the physio-chemical and biological characteristics of chitosan. Then, we present chitosan applications in the textile industry over the past decade. Literature works on chitosan usage along with different textile production steps (fiber formation, functional treatments, dyeing and effluent treatment) are extensively discussed.

Khmais Zdiri

Papers

Impact of Tunisian clay nanofillers on structure and properties of post-consumer polypropylene-based nanocomposites:

Valorization of Post-consumer PP by (Un)modified Tunisian Clay Nanoparticles Incorporation

Rheological and thermal behavior of Tunisian clay reinforced recycled polypropylene composites

Alginate-Based Bio-Composites and Their Potential Applications

Chitosan: A biopolymer for textile processes and products