مقاله انگلیسی رایگان در مورد بازیافت کامپوزیت پلی پروپیلن تقویت شده با فیبر باگاس – الزویر ۲۰۱۸

Recycling is a key component of modern waste reduction technique and a third component in the “Reduce, Reuse and Recycle” waste hierarchy. Generally, recyclability and degradability are considered as opposite terms as degradable materials are unrecyclable due to the deterioration in the properties over a period of time. The opportunities for recycling offer sound economic benefits due to the high cost of the virgin materials. In common industrial practice, 20% of the process waste (after shredding) is mixed with 80% of the virgin thermoplastic polymer to produce the part, which also helps in reducing the polymeric waste. When material arrives in the waste stream, recycling is the process of using the recovered material to fabricate a new product [1]. In plastics, the waste generated during the fabrication of part in form of gate, flash and defective parts etc. are termed as “process waste”, while the wastage after serving the designed life of a product is termed as “aged waste”. The recyclability of plastic waste depends mainly on the aging time, as after a prolonged time, plastic losses its inherent properties i.e. mechanical properties, appearance, surface finish, flowability etc. Mechanical properties of pure polypropylene decrease with the number of cycles as when PP is exposed to high temperatures and shear, then due to oxygenation and other impurities i.e. peroxides and catalyst residues, resulting in a decrease in viscosity and a considerable decline in mechanical properties, which makes it more brittle and also exhibits staining [2]. Composites can be used in a wide variety of applications as a replacement of pure plastic in various engineering products, but they have not been properly recycled, due to their intrinsic nature of heterogeneity [3]. Glitches associated with recycling thermoplastics and their composites are much less compared with the reprocessing of thermosets. Therefore, the prevalent practice of thermoplastic composites in various applications is projected to have a more advantageous environmental impact. Present environmental concerns have generated awareness in the recycling of composite materials and plastics in particular. Until now, landfilling and burning have been the most common end-routes for FRP products and waste plastic material. However, with the environmental consciousness as well as government laws and legislation on waste management, the above-mentioned end-routes will be gradually unavailable. The use of natural fibers is often seen as the panacea for these glitches, such as environmental issues, end-oflife (ELV) vehicles, waste minimization etc. [4]. Much less energy (60e80%) is required in growing and harvesting of natural fibers as compared to the production of synthetic fibers (Glass fibers: 31.7 MJ/kg; Flax fibers: 6.65 MJ/kg, China reed fibers: 3.64 MJ/kg, Kenaf fibers: 15 MJ/kg) [5e7], but later, it also depends on the processing route followed to get them in their usable form. Due to growing environmental consciousness, natural fiber reinforced polymer composites are fetching dominance in usage in various engineering applications. Some other benefits of using natural fibers in composites are relatively lower cost, density, comparable specific properties, biodegradability and recyclable properties. These materials are durable, reliable, light-weight and are expressively better than traditional materials, therefore, empowering the demand for natural fiber reinforced composites in various industries [8,9]. As the largest application segment, use of natural fiber reinforced composite materials in the automotive industry is growing very swiftly (fabrication of body parts and interiors).