Barbara Gerard CEO Craftech Industries, Inc.
materials
What type of plastic is ideal for high-performance fasteners? Polyoxymethylene (POM) is supplied in a granulated form and, with heat and pressure, can be molded into the desired shape. It offers strength and hardness, making POM plastic an ideal choice for many fastener applications.
Metal has long been the material of choice for mechanical fasteners. However, it’s no longer the go-to option for all design engineers. Depending on the application, the use of plastic is gaining popularity and offers several material advantages including strength, longevity, and cost-effectiveness. Plastic fasteners are now more frequently used in high-pressure and critical environments. Much like with metals, plastics offer different properties and options — such as nylon, polyvinyl chloride (PVC), polyoxymethylene (POM), and others. The choice should be based on the demands of the application and its environment. For example, nylon is a popular choice and works fine for everyday
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wear and tear. PVC is often ideal when corrosion and weather-resistance are required. For high-performance, however, you’ll want to consider POM. Precision parts Polyoxymethylene is an engineering material used in parts that require precision. Applications for POM include high-performance components, such as fasteners (screws, nuts, washers, etc.). The material is ideal for parts that require high strength, stability, durability, and low friction. It’s also used in a variety of other applications, such as for zippers, ski bindings, insulin pens, coffee spigots, and even as a solvent for perfumes and as a synthetic flavoring ingredient. www.fastenerengineering.com
POM is a thermoplastic material also known as acetal. It’s a molecule containing the functional group of carbon bonded to two –OR groups and was first discovered by a German chemist, Hermann Staudinger, who won the 1953 Nobel Prize in Chemistry. Staudinger had studied this material in the 1920s but found it to be thermally unstable. This thermal instability meant the material was not useful, at least not commercially. Eventually, however, a heat-stable POM homopolymer was discovered by the chemist, Dal Nagore. He realized that by reacting the hemiacetal ends with acetic anhydride, he could readily depolymerize hemiacetal into a thermally stable and melt-processable thermoplastic. Soon after, the chemical company DuPont synthesized a version and filed for patent protection of the homopolymer. In 1960, it built a manufacturing plant to produce Delrin — its version of the POM homopolymer, which is still offered today. Around the same time, the chemical company Celanese completed its study of the copolymer and started production of Celcon. Other manufacturers soon followed with their versions of this material. The process It’s important to note that different manufacturing processes are used to produce the homopolymer and the copolymer versions of POM. To make the homopolymer, first anhydrous formaldehyde is necessary. The formaldehyde is then polymerized by anionic catalysis and the resulting polymer is stabilized by the reaction to acetic anhydride. DESIGN WORLD
