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Life Cycle Assessment (LCA) of Recycled Polymer Composites
Published in R.A. Ilyas, S.M. Sapuan, Emin Bayraktar, Recycling of Plastics, Metals, and Their Composites, 2021
H.N. Salwa, S.M. Sapuan, M.T. Mastura, M.Y.M. Zuhri, R.A. Ilyas
Mechanical recycling is the physical conversion of flakes into fiber or other products by melt-extrusion. Currently, there are two ways to produce recycled fiber from mechanical recycling: (1) directly extrude flakes into fiber; or the more common method, (2) first transform flakes into pellets or chips (pelletizing) and then melt-extrude pellets or chips into fiber (Tshifularo & Patnaik, 2020). Mechanical grinding is considered a mature technology for recovery of raw materials (Cousins et al., 2019). Polymer composites can be combusted on an industrial scale to supply energy for cement kilns, and the recovered fibers can be used for other applications such as mixed with cement for building construction. On the other hand, thermal degradation-pyrolysis allows the recovery of fiber from either thermoset or thermoplastic polymer composites.
Packaging and Assembly of Microelectronic Devices and Systems
Published in Anwar Sohail, Raja M Yasin Anwar Akhtar, Raja Qazi Salahuddin, Ilyas Mohammad, Nanotechnology for Telecommunications, 2017
The fillers used in conductive adhesives are metal particles that are made of gold (Au), silver (Ag), nickel (Ni), indium (In), copper (Cu), chromium (Cr), or lead-free alloy (Sb-Bi). The filler particles are available as spheres, flakes, fibers, and granules but the optimum geometry is that which provides both the best contact with neighboring filler particles and adhesion to the polymer. Flakes, due to their high aspect ratio, provide more particle-to-particle contact, greater conductivity, and consistency of product performance. Silver is the widely used filler material due to its excellent electrical conductivity and low contact resistance between particles. Copper oxidizes fast and turns nonconductive. Although nickel oxidizes slowly, it is less malleable and hence cannot be formed into particles of a desired size and shape. Gold and indium are expensive. Nanoconductive particles are being embedded into the ECAs to enhance the conductivity of the ECA joints.
Melt Pelletization and Size Reduction
Published in Isaac Ghebre-Sellassie, Charles Martin, Feng Zhang, James DiNunzio, Pharmaceutical Extrusion Technology, 2018
Christopher C. Case, Albrecht Huber, Kathrin Nickel
The result is a product shape called “flakes.” Depending on desired flake size, different pin breaker types are available, which include a pin crusher and a teeth crusher. If smaller fragments are desired, a teeth crusher is useful; otherwise a pin crusher is used. Depending on the end product requirements, the flakes can be further processed through, for example, milling and tableting. Therefore, an integration of a mill is possible so that the flakes can be milled in-line (Figure 9.17). Different mills are available that are used for different particle sizes. A conical sieve mill can be integrated for sizes up to 150 μm, while a hammer mill can be used for smaller sizes, down to 50 μm.
Ultrathick Boron Carbide Coatings for Nuclear Fusion Targets
Published in Fusion Science and Technology, 2023
Swanee J. Shin, Leonardus B. Bayu Aji, Alison M. Engwall, John H. Bae, Gregory V. Taylor, Paul B. Mirkarimi, Chantel Aracne-Ruddle, Jack Nguyen, Casey W. N. Kong, Sergei O. Kucheyev
A somewhat extreme case of particulate formation is illustrated in Fig. 5, which shows photographs of the substrates (Fig. 5a) and the target (Fig. 5b) after the deposition in DCMS run D (Table I). It is seen from Fig. 5a that large (millimeter scale) flakes decorate the substrates. These flakes fell on substrates from the sputter source and the shutter (positioned directly above the substrates in the sputter-down deposition configuration described here) during the cooldown period after the deposition. Such flakes could be readily removed from the film surface after the deposition by blowing with dry N2 or by wiping.
Effects of drawing process on crimp formation-ability of side-by-side bicomponent filament yarns produced from recycled, fiber-grade and bottle-grade PET
Published in The Journal of The Textile Institute, 2019
Polymers are used in a wide range of applications. One of the most family types of plastic packaging found in the American household is made from a plastic is poly(ethylene terephthalate) (PET) (Fann, Huange, & Lee, 1997). Currently, a wide range of things, such as mineral water, soft drinks, and other foods, are being kept in PET dishes, and many more are being added to the list every day (Gurudatt, De, Rakshit, & Bardhan, 2003). However, the increased use of PET has resulted in post-consumer waste in the garbage. It is necessary to increase an eco-friendly industry and to recycle waste for environmental conservation. The accumulation of this non-biodegradable polymer waste has led to serious ecology difficulties (Gurudatt et al., 2003; Shen, Worrell, & Patel, 2010; Welle, 2011). As the mechanical recycling is well established, chemical recycling is highly dependent on the manner in which the de-polymerization is accomplished (Venkatachalam et al., 2012). Global consumption of PET bottles grows to almost 19.1 million tons by 2017 (Smithers Pira Market Intelligence, 2012). Bottle-grade PET is one of the most commonly used packaging materials for water and beverages. In competition with other polymer material waste, PET can be easily collected, and recycled into useful end products (Gurudatt et al., 2003; Shen et al., 2010). They are sorted by type (PET, HDPE, LDPE, etc.) and color. Their labels and caps removed off and washed to take any adhesives and other possible contaminants. Next, they are crushed and chopped into flakes. The small flakes are then fed into an extruder (Shah, 2013; Shukla, Harad, & Jawale, 2009). R-PET fibers have lower price by 20% compared to other fibers for the same physical characters. It is clear that cost advantage and being eco-friendly of the fiber is the intention for increasing R-PET fiber usage (Sarioglu, 2017; Telli & Özdil, 2015).