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Processing of Biodegradable Composites
Published in Arbind Prasad, Ashwani Kumar, Kishor Kumar, Biodegradable Composites for Packaging Applications, 2023
Gourhari Chakraborty, Arbind Prasad, Ashwani Kumar
Thermoplastics which may be processed by the thermoforming method are as follows:Polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), low-density polyethylene (LDPE), high-density polyethylene (HDPE), cellulose acetate, poly(methyl methacrylate) (PMMA) and acrylonitrile butadiene styrene (ABS).In the food packaging sector, thermoforming is commonly used to make ice cream and margarine tubs, meat trays, microwave containers, snack tubs, sandwich packs, among other things. Thermoforming is also used to make small tools, fasteners, toys, boat hulls, blister and skin packs, and pharmaceutical and electrical items.
Conventional Processing of Polymer Matrix Composites
Published in Sanjay Mavinkere Rangappa, Jyotishkumar Parameswaranpillai, Suchart Siengchin, Lothar Kroll, Lightweight Polymer Composite Structures, 2020
M.K. Singh, N. Verma, S. Zafar
Thermoforming is a process in which plastic sheets are formed with the application of heat and pressure. The thermoplastic sheet is placed horizontally over the surface of the mold and clamped using a holding device as shown in Figure 2.5. The sheet is heated up to glass transition temperature using a heater. The thermostat sets the heater temperature. The cooled air is provided when the temperature becomes high in the mold. The thermoplastic sheet softens with the effect of heat and is pressed into the mold surface by air pressure or by any other suitable means. The softened sheet deforms into the mold shape and removed after gradual cooling of mold. The mold cavity is opened and the thermoformed part is released. Some plastics require air cooling to become rigid quickly because the thermal conductivity of some plastics is low. The excess material is removed by secondary operations. Excess material can mix again with unused plastic, and can be again deformed into plastic sheets. Thin and thick sheets can be deformed easily. The different types of thermoplastic materials which can be processed using thermoforming process are polypropylene, acrylonitrile butadiene styrene (ABS), acrylic (PMMA), HDPE, polystyrene (PS), LDPE, cellulose acetate, and PVC.
Plastics and Plastic Processing
Published in Leo Alting, Geoffrey Boothroyd, Manufacturing Engineering Processes, 2020
Leo Alting, Geoffrey Boothroyd
Description: Thermoforming is a forming process in which a sheet of ther- moplastic material is heated to its softening point by infrared radiation and then pressed against the contours of a mold by a plug or pressurized air. A vacuum is applied to pull the plastic tightly against the contours of the mold where it is allowed to cool. An excess of material is needed for proper holding, forming, and sealing of the sheet to the mold. This excess is trimmed off in a secondary operation.
Bonding strength calculation in multicomponent plastic processing technologies
Published in Materials and Manufacturing Processes, 2022
A. Szuchács, T. Ageyeva, R. Boros, J. G. Kovács
Although thermoforming and injection molding are usually considered mature technologies with short cycle times (in the range of seconds), the parts produced are limited in geometry and mechanical performance. Therefore, a decade ago, the scientific and industrial community started to develop “hybrid” or “integrated” processes, which are a combination of two TCM technologies (Fig. 1).[7–10] In these hybrid methods, a rigid thermoplastic substrate is produced in the first step, and additional structural elements are built on the surface of the substrate in the second step. The name of the second step depends on the technology used, for example, “overmolding” or “overprinting.” The resulting TCM structures may include stiffness ribs, undercuts, inserts, and other sophisticated features, which improve the performance of the part. At the same time, structures produced via hybrid TCM processing methods can be 20–30% lighter compared to alternatives manufactured by conventional technologies.[7,8] Consequently, hybrid TCM methods are suitable for the production of semi-structural and even structural automotive parts (e.g. floors, door panels, crossbeams, airbag modules, and others).
Effects of substrates on the performance of optoelectronic devices: A review
Published in Cogent Engineering, 2020
Joseph Asare, Benjamin Agyei-Tuffour, Evangeline A. Amonoo, David Dodoo-Arhin, Emmanuel Nyankson, Bismark Mensah, Oluwaseun O. Oyewole, Abu Yaya, Boateng Onwona-Agyeman
In terms of application, polydimethylsiloxane (PDMS) is the most utilized organic polymer substrate in the organic electronics industry. It is known for its extraordinary flow properties, non-flammability, high optical transmittance, inertness, and non-toxic nature. (Wypych, 2016) This viscoelastic silicon-based polymer is applied in various capacities from contact lenses and medical devices to elastomers; it is also present in shampoos, food, caulk, lubricants and heat-resistant tiles. (Barth-Wehrenalp & Block, 1963; Duffy et al., 1998; McDonald & Whitesides, 2002).Polyethylene-terephthalate (PET) is another generally useful flexible substrate applied in devices that require chemical and thermal resistant features as well as transparency (Hwang et al., 2009). PET stands out as the most familiar thermoplastic polymer resin of the polyester family and is often used in fibers for clothing, solid and liquid food containers, thermoforming for manufacturing, and composites with glass fiber for engineering resins. Most PET production is directed towards artificial/synthetic fibres with bottle production accounting for about 30% of the demand. It is also applied in textiles and packaging materials. (Aleksandrova et al., 2015; Cho et al., 2008; Hwang et al., 2009; Kuwabara et al., 2012; Li et al., 2017; Li et al., 2005; Moro et al., 2012; Part et al., 2014; Sun et al., 2010; Yu et al., 2016).Polyimide is a polymer of imide monomers. Registering high heat-resistances, polyimides afford diverse applications in parts that require unrefined organic materials such as high-temperature fuel cells, displays, and many military roles. (Ding et al., 2011; Li et al., 2017)