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Plastic Packaging for Parenteral Drug Delivery
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Lloyd Waxman, Frances L. DeGrazio, Vinod D. Vilivalam
Injection molding is a process used to convert resin from a melt into a molded shape using a mold pattern to form the part. Injection-molded products are replacing materials such as glass, metals, and paper in many areas of parenteral drug packaging. The development of newer plastic resins, combined with improvements in the injection molding process, is setting the stage for these changes. For example, materials such as CZ resin have been used to develop larger size containers, such as the 1-L bottle, and small conical vials by injection molding. Many of these newer resins are used for drug delivery systems that can replace products traditionally made from glass. In this process, plastic resin is melted using the extrusion process and is injected into a mold where the resin is cooled sufficiently to be removed in a solid state. Similar to the other plastic processes, heat, pressure, and time are controlled in each of the steps to produce a molded product. Injection-molded items are finding many uses in parenteral drug packaging. The injection molding process is also used to produce components such as IV spikes and IV administration sets.
Ceramic Biomaterials
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Injection molding is a common technique used to form plastic parts for many commercial applications such as automobile parts. Briey, the process involves forcing a heated material into a die and then ejecting the formed piece from the die. Injection molding allows for making complex shapes. Cihlar and Trunec (1996) found that by calcining (1273 K, 3 h) and milling the HA prior to mixing with a binder, an ethylene vinyl acetate copolymer (EVA)/HA mixture of 63% HA, they achieved 98% relative density with only 16% shrinkage using injection molding. e maximum exural strength was 60 MPa for HA products sintered at 1473 K. However, this is still not strong enough for load-bearing applications. ey also observed that HA decomposed to α-TCP at temperatures greater than 1573 K (Cihlar and Trunec, 1996).
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Published in Splinter Robert, Illustrated Encyclopedia of Applied and Engineering Physics, 2017
[chemical, fluid dynamics, mechanics] Elastic polymer with high yield-strain value (i.e., resilient) and generally in solid form has a low elastic modulus (Young’s modulus). Elastomers have mechanical properties that are similar to rubber, and are formed by either vulcanization (thermal setting: thermoset) providing thermal cross-linking (forming irreversible chemical bonds) or by means of thermal blending, where the material is moldable—semi-liquid state—above a certain temperature (the “glass temperature”) while it sets to a solid state when the material cools down (thermoplastic elastomer; reversible; which makes them ideal for mold forming). Thermoplastic elastomers are frequently used in injection molding (see Figure E.29).
Analysis on effect of injection residual stress on impact resistance of composite wheel made of long glass fiber reinforced thermoplastic
Published in International Journal of Crashworthiness, 2021
Daijun Hu, Yingchun Shan, Tian He, Xiandong Liu
The composite wheel is shown in Figure 6. Since the internal fibers are unevenly distributed at different positions and aligned along irregular orientations during the injection molding process, that is, there exists an anisotropic property in the wheel. This property can have a great influence on the wheel’s mechanical performance, so it is necessary to take it into account in the simulation. In the previous paper [12], authors proved that the introduction of anisotropic property in the simulation of 13° impact test of composite wheel could reduce the simulation error to some extent. Here the Moldflow software is used to simulate the injection molding process. The injection molding parameters are set according to the actual situation (listed in Table 3). The process includes three steps: filling, packing and cooling. Due to the complexity of the wheel structure, it is meshed by 3D solid elements as shown in Figure 7, and the injection gate locates at each vent of the wheel.
Robust asynchronous switching predictive control for multi-phase batch processes with time-varying tracking trajectory and delay
Published in International Journal of Control, 2023
Bo Peng, Huiyuan Shi, Chengli Su, Xin Wen, Ping Li
With the popularity of plastic products, injection moulding technology is increasingly used in industrial production. First, the molten plastic is injected into the cavity through a screw. Second, maintaining the pressure in the cavity allows the plastic to maintain the shape of the cavity. Finally, a moulded product is obtained by cooling and solidifying the material of the cavity. The advantages of the injection moulding are that the operation can be automated, the product size is accurate, the product is easy to update and the parts with complex shape can be formed. Reciprocating screw injection moulding machine is shown in Figure 1.
Recycling strategies for vitrimers
Published in International Journal of Smart and Nano Materials, 2022
Haochuan Zhang, Jingjing Cui, Guang Hu, Biao Zhang
Injection molding is the process of melting plastic to ‘flow’ and injecting it into the mold at a certain speed. The mold is cooled by the watercourse and the plastic is solidified to give the same shape as the designed mold cavity. Extrusion molding is a method of processing where the material is thermal-treated by the action of the extruder barrel and screw. Then, the fluidic material is pushed forward by the screw and continuously passes through the head to make various cross-sectional products or semi-products. According to the general rule, materials are suitable for injection molding when the melt flow index (MFI) is greater than 10 g (10 min)−1 at the processing temperature (measured by the ASTM D-1238 standard) [57]. Leibler and coworkers [19] demonstrated that epoxy/anhydride polymer networks containing a large number of hydroxyl/ester groups can be reprocessed in the presence of a suitable catalyst. Despite being permanently cross-linked past the gel point, the broken or ground samples can still be reprocessed by injection molding (Figure 5(a)). Shrinkage-free molding can be achieved by adjusting the molding temperature and dwell time. Zhou [64] et al. proposed a method to prepare polybutylene terephthalate (PBT) vitreous based on an ester exchange reaction. By adjusting the molding temperature and dwell time, the relatively long relaxation time and high viscosity of PBT vitreous can be overcome, and a high production rate of the finished product by injection molding can be maintained. Inspired by Zhou’s work [64], Qiu et al. [65] introduced 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol (BIS-TRIS) with more reactive groups into the poly(ethylene terephthalate) (PET) chains. During the extrusion process, a commonly used double epoxy resin is also introduced to cross-link the activated PET chains through the reaction between hydroxyl and epoxy groups. The extra hydroxyl and tertiary amine structure accelerates the dynamic ester exchange reaction of the vitreous network and thus maintains the post-processing capability like a thermoplastic. The improved PET vitrimer retains its pre-processing properties after extrusion and injection molding (Figure 5(b)).