Plastics have become ubiquitous in modern society, finding applications in virtually every industry from construction to transportation to healthcare. While commodity plastics like polyethylene, polypropylene and PVC dominate traditional consumer applications, a class of advanced plastics known as engineering plastics have increasingly gained importance in industrial and engineering applications due to their superior mechanical and thermal properties compared to traditional plastics. In this article, we discuss the key types of engineering plastics, their properties and applications.
Thermoplastic vs Thermosetting Plastics
Plastics can generally be categorized into two classes based on their molecular structure – thermoplastics and thermosets. Thermoplastics, including most engineering plastics, soften when heated and harden when cooled. They can be repeatedly melted and reshaped. Thermosetting plastics on the other hand undergo an irreversible chemical reaction when heated called curing and set into a rigid shape that cannot be remolded.
Some major thermoplastic Engineering Plastics include polyamides (nylons), polyacetals (POM), fluoropolymers (PTFE, FEP), polycarbonates (PC), polyphenylene oxide (PPO), polysulfones (PSU, PES), liquid crystal polymers (LCP) and acrylonitrile butadiene styrene (ABS). Thermosetting engineering plastics include epoxies, phenolics, polyesters, melamines, silicones and polyurethanes.
Properties and Applications of Key Engineering Plastics
Nylons or polyamides are among the most widely used engineering thermoplastics due to their strength, rigidity and dimensional stability. Nylon 6 and nylon 6,6 are the most common types. They exhibit good fatigue resistance, oil and chemical resistance as well as self-lubrication. Nylons find applications in gears, bushings, pulleys, fasteners, connectors, low friction bearings etc. in automotive, electronics and industrial equipment industries.
Polycarbonate exhibits high strength, toughness and optical clarity along with self-extinguishing properties. It has the highest impact strength of amorphous engineering thermoplastics. This makes it popular for applications requiring impact resistance like helmets, bullet-proof windows, riot shields, light covers and lenses. PC is also used in CDs/DVDs, medical devices, electrical switch gear and connectors.
Polyethylene Terephthalate (PET)
PET is a polyester with excellent mechanical strength, stiffness, creep resistance, chemical and dimensional stability. It is transparent and an excellent barrier to water, gases and essential oils. PET finds applications in beverage bottles, food packaging, engineering components, clothing fibers and films. It is also used as an engineering plastic for electrical insulators and switch gears.
PEEK is a semi-crystalline thermoplastic with exceptional heat resistance (up to 250°C), chemical resistance, impact strength and dimensional stability. It is an ideal engineering plastic for high temperature applications in automotive, aerospace, petrochemical equipment and medical devices. PEEK finds use in engine parts, fasteners, bearings, pumps, valves and precision mechanical components.
Fluoropolymers like polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP) and perfluoroalkoxy alkanes (PFA) exhibit high thermal stability, chemical resistance and low coefficient of friction. They are used in non-stick cookware, plumber tapes, tubings, seals, bushings, bearings and gaskets for applications involving corrosive fluids at high temperatures in industries like chemical, oil & gas, aerospace and healthcare.
With their superior mechanical and thermal properties compared to traditional plastics, engineering plastics have become preferredmaterials for applications involving durability, strength, heat resistance and chemical tolerance. As new engineering plastic grades with new proprietary property combinations are continuously developed, the use of these advanced thermoplastics and thermosets will undoubtedly increase in industrial and engineering components across diversified markets from transportation to electronics to medical devices. Engineering plastics truly represent a new class of versatile materials for modern technological applications.
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it