List of Articles Recycling

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  1 - 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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  2 - Recycling of Waste Tires
  Zahra Khoubi-Arani
  Waste tires are the main source of waste rubbers. Their recycling raises environmental concerns due to the high volume of production as well as a very crosslinked and non-biodegradable structure. This leads to finding easy, low-cost, and energy-efficient methods for rec More

  Waste tires are the main source of waste rubbers. Their recycling raises environmental concerns due to the high volume of production as well as a very crosslinked and non-biodegradable structure. This leads to finding easy, low-cost, and energy-efficient methods for recycling waste tires. To now, many studies have been devoted to the improvement of conventional recycling methods and the introduction of new ones for the management of waste tires. Methods for recycling waste tires include retreading, incineration, pyrolysis, and grinding. The lifetime of a tire can be extended using the retreading process, in which the old tread is removed and a new one is inserted. The produced energy from the incineration of the waste tire can be used as a fuel source for steam, electrical energy, paper paste, paper, lime, and steel production. In the pyrolysis process, oil, gas, and char are produced through thermal decomposition. The main method of waste tire recycling is grinding for the incorporation of produced particles in the polymer matrices. The ambient and cryogenic grinding are the most conventional methods for grinding waste tires. The size reduction results in a higher specific area and better distribution of rubber particles in the matrix. The produced particles can be used as fillers in asphalt, concrete and glassy polymers. Manuscript profile
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  3 - The effect of additives and masterbatch to improve the properties of recycled polyolefins
  Hamidreza Haydari marziyeh hosseini
  Although the recycling of polymer products is beneficial for the environment and economy, the main goal is to achieve the efficiency of raw (intact) polymers in recycled polymers. The best type of recycling to have maximum energy efficiency and minimum environmental con More

  Although the recycling of polymer products is beneficial for the environment and economy, the main goal is to achieve the efficiency of raw (intact) polymers in recycled polymers. The best type of recycling to have maximum energy efficiency and minimum environmental consequences is mechanical recycling. However, there are a number of differences between virgin and recycled polymers. Due to the structural changes and the presence of impurities in the polymer, it is difficult to achieve a quality recycling. Whether the recycled polymer is suitable for obtaining new applications or not is measured by mechanical tests (such as tensile test, impact test), physical tests (such as hydraulic stability, surface roughness) and operational tests (extrusion and molding) under standard conditions. When these tests are performed, most recycled polymers do not meet the requirements required for various applications, unless we use additives that improve their properties. These additives may include coupling agents, impact improvers, metal deactivators, melt flow regulators, antioxidants, masterbatches, etc., and each is used in some way to improve specific properties of the polymers. Although the recycling of polymer products is beneficial for the environment and economy, the main goal is to achieve the efficiency of raw (intact) polymers in recycled polymers. Manuscript profile