List of Articles بندی

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  Zohre Taherkhani
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• Open Access Article
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  2 - A Review of Mechanical Recycling of Polylactic Acid: Challenges and Recent Achievements
  Farzane Tabatabaee
  The growing use of polylactic acid (PLA) encourages technologists to conduct extensive research into valorization of PLA waste with best quality. In general, mechanical recycling of PLA is one of the most cost-effective recycling methods. However, recycled materials are More

  The growing use of polylactic acid (PLA) encourages technologists to conduct extensive research into valorization of PLA waste with best quality. In general, mechanical recycling of PLA is one of the most cost-effective recycling methods. However, recycled materials are commonly used for minor applications due to the inherent thermo-mechanical degradation of the polymer during recycling, which mainly results in chain scissions and intramolecular and intermolecular transesterification reactions. Therefore, it has a negative effect on the molar mass distribution and consequently on the mechanical, thermal and rheological properties of recycled PLA. In this article, a review of recent research on the effects of mechanical recycling on the properties of PLA including structural, morphological, mechanical, rheological and thermal changes was done. Furthermore, a review of three main ways of valorization of recycled PLA including thermal modification, chemical modifications in the presence of stabilizers, chain extenders, branching agents and finally mixing with nanoadditives or with other polymers was done in order to improve the properties of recycled PLA. Moreover, due to the widespread use of natural fibers to improve the performance of PLA, the recyclability of natural fiber-reinforced PLA biocomposites was investigated. Finally, two important applications of recycled PLA in the food packaging and the 3D printing industries were discussed. Manuscript profile
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  3 - Mini-Review of Self-Healing Mechanism and Formulation Optimization of Polyurea Coating
  Moein Behzadpour Mahdi Hemmatian Damghani
  Self-healing polymers are categorized as smart materials that are capable of surface protection and prevention of structural failure. Polyurethane/polyurea, as one of the representative coatings, has also attracted attention for industrial applications. Compared with po More

  Self-healing polymers are categorized as smart materials that are capable of surface protection and prevention of structural failure. Polyurethane/polyurea, as one of the representative coatings, has also attracted attention for industrial applications. Compared with polyurethane, polyurea coating, with a similar formation process, provides higher tensile strength and requires shorter curing time. The working principle of polyurea self-healing mechanisms is to fill cracks by introducing more healing components, which can polymerize and seal damage in the material. Alternatively, it can also be addressed by encouraging continuous chemical reactions, which can form bonds to close gaps between the separated faces of material due to the damage. In this paper, extrinsic and intrinsic mechanisms are reviewed to address the efficiency of the self-healing process. Furthermore, the extrinsic and intrinsic mechanisms have been compared to attain a better understanding of the advantages and limitations of each mechanism. Moreover, formulation optimization and strategic improvement to ensure self-healing within a shorter period of time with acceptable recovery of mechanical strength are also discussed. The choice and ratio of diisocyanates, as well as the choice of chain extender, are believed to have a crucial effect on the acceleration of the self-healing process and enhance self-healing efficiency during the preparation of polyurea coatings. Manuscript profile
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  4 - Application of Bio-nanocomposites in Food Packaging
  Fatemeh Savojbolaghi Mahshid Maroufkhani
  20.1001.1.25383345.1402.8.1.2.4
  The need for food packaging to maintain quality and shelf life is increasing day by day. Nanostructured materials are preferred over microstructures due to their unique physical and chemical properties and improved performance. Advanced packaging based on nanotechnology More

  The need for food packaging to maintain quality and shelf life is increasing day by day. Nanostructured materials are preferred over microstructures due to their unique physical and chemical properties and improved performance. Advanced packaging based on nanotechnology has made it possible to preserve and transport food safely without changing the taste and quality. In addition, it prevents contamination and preserves the mechanical, physiological, physical and chemical properties of food. Various nanomaterials have been used in food packaging to prepare improved, active, smart and bio-based packaging. Smart packaging ensures food safety by detecting contamination, gases, humidity, temperature and other food parameters using sensors. With the increasing demand for the production of new, environmentally friendly and high-performance packaging, "bio-nanocomposites" have attracted a lot of attention in recent years. Bio-nanocomposites are bio-based polymers that consist of two main components, one acting as a matrix called biopolymer (continuous phase) and the second as a reinforcing agent (dispersed phase) with dimensions ranging from 1 to 100 nm. . Bio-based packaging is a new and new generation packaging that replaces natural polymers with synthetic plastics. In this article, recent research in the field of bio-nanocomposites has been reviewed based on the application for different needs and the possible risk of nanoparticle migration. Manuscript profile