Polycarbonates are a group of thermoplastics polymers with Bisphenol (A) parts and carbonate groups in their chemical structure. Polycarbonates are strong, rigid, transparent, and have reasonably high heat resistance, making them optimal materials for industrial and medical trades alike.
In industrial applications, manufacturers use different blends of polycarbonates to enhance the desired properties of the product they are constructing. For example, they can be used to increase the ductility and strength of a given material at varying temperatures. Polycarbonates are also crucial in medical applications such as surgical instruments, connectors, and needle-free injections.
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Polycarbonates are ideal materials and thus widely used in various medical applications and other industrial applications. They have gained popularity due it their versatile characteristics, recyclability, and eco-friendly processing. Some of the remarkable properties of polycarbonates include:
There are about 2.7 million tons of polycarbonates produced annually across the world. The standard manufacturing process involves reacting bisphenol A and phosgene in an interfacial polymerization process. Essentially, the disodium salt of bisphenol A reacts with phosgene that is dissolved in a chlorinated organic solvent like methylene chloride to produce polycarbonates. The reaction can be carried out in one or two stages, in a batch or continuous operation.
Some of the standard methods to produce polycarbonate medical device parts include injection molding, extrusion, blow molding, and thermoforming. Typically, polycarbonates are melted and forced into a mold with high pressure to achieve the desired shape. Before processing, it is recommended that the material is dried at temperatures of 120°C. The ideal target moisture should not go past 0.02 percent.
Medical device manufacturers often use polycarbonates when creating materials due to their exceptional properties like clarity, heat resistance, toughness, and dimensional stability. It is a material of choice because manufacturers can sterilize polycarbonate using FDA-approved methods such as ETO, irradiation, and limited autoclave cycles. Some of the typical medical applications of polycarbonates include:
Renal dialysis involves the process of removing and screening blood so that toxins are removed. This process depends on passing the blood through a semi-permeable membrane cartridge, and polycarbonates can form a transparent and sturdy material to house the membrane. Polycarbonates are also resistant to chipping, shattering, and withstand several types of sterilization, and thus can be reused without compromise on performance.
In cardiac procedures, polycarbonates are used in blood oxygenators, blood filters, and reservoirs. Because they feature high transparency, polycarbonate allows doctors to monitor blood easily. Polycarbonates are also the ideal choice for intravenous connectors owing to sterilization flexibility. And because of the clarity, doctors and patients can easily track the administration of fluids. Its structural stability also enables it to fit securely with other devices.
In surgical applications, polycarbonates are replacing metal in procedures that use trocars and tube-like instruments to insert into the body. Polycarbonates prevent trocars from bending and enable doctors to track and monitor the performance of these tools efficiently.
In the medical field, sterilization is an essential factor in making devices that have direct contact with patients. One critical attribute of polycarbonates is that they can be sterilized using all the available options, including steam autoclaving, irradiation (both gamma and electron-beam), and ethylene oxide (ETO). It can also be disinfected through common clinical disinfectants like isopropyl alcohol. However, the most effective method and its suitability depend on polycarbonate material's specific properties. It is important to note that polycarbonates are not ideal for devices that require repeated autoclaving.