Introduction to Specialty Polymers
Specialty polymers, also known as high-performance polymers, are a class of polymers that have been designed and engineered to meet the long-term demanding performance needs for specific applications. Specialty polymers often outperform standard plastics and elastomers in characteristics like strength, temperature tolerance, corrosion resistance and customizability. Some common types of specialty polymers include:engineering plastics, conductive polymers, bio-medical polymers, fluoropolymers, liquid crystal polymers and thermoplastic elastomers.
Engineering Plastics
Engineering plastics include nylon, polycarbonate, acrylic, polyacetal, PBT and PEEK. They possess greater mechanical and thermal properties than commodity plastics like polyethylene and polypropylene. Engineering plastics offer benefits like high strength-to-weight ratios, durability, corrosion resistance and precision. Common applications of engineering plastics include gears, bearings, automobile components, machinery parts and electrical components. Nylon for example offers exceptional toughness and is widely used in high-stress applications. Polycarbonate has high impact strength and transparency making it suitable for security glazing and CD/DVD components.
Conductive Polymers
Conductive polymers are a new class of materials that combine the mechanical properties and processing advantages of polymers with the conductive and semiconductive properties of metals. They find applications where traditional polymers or metals cannot be used. Some examples of conductive polymers include polyacetylene, polypyrrole, polyaniline and polythiophene. They are used to make antistatic coatings, electrodes, sensors, transistors and corrosion prevention coatings. Research into conductive polymers continues with the goal of improving conductivity, processability and stability.
Bio-medical Polymers
Bio-medical polymers are specifically engineered for applications within the human body. They must be biocompatible, non-toxic and degrade gradually in the body over time. Some popular bio-medical polymers include PTFE, silicone, polyurethane and polylactic acid. PTFE finds widespread application in vascular grafts due to its non-thrombogenic and durable nature. Silicone is used in breast implants, ostomy bags and catheters due to its flexibility, durability and impermeability. Polyurethanes are used in pacemaker leads, catheters and artificial skin/wound dressings. Polylactic acid is a biodegradable polymer used in sutures, fracture fixation devices and drug delivery systems.
Fluoropolymers
Fluoropolymers contain fluorine atoms, which make the polymer highly resistant to corrosion from solvents, acids and bases. PTFE (Teflon) is the most prominent fluoropolymer valued for its non-stick properties, chemical inertness and thermal stability. Other common fluoropolymers are polyvinylidene fluoride (PVDF) used in lithium-ion batteries, fluoroelastomers for seals, perfluoroalkoxyalkane (PFA) tubing for semiconductor manufacturing and ethylene tetrafluoroethylene (ETFE) roofing films. Fluoropolymers find diverse applications from cookware to waterproof clothing to semiconductor fabrication equipment.
Liquid Crystal Polymers
Liquid crystal polymers (LCPs) possess properties between liquids and solid crystals. They self-orient when force is applied due to molecular structure. As a result, LCPs offer uniquely high strength and rigidity even at elevated temperatures up to 250°C. Their machinability and moldability is also superior to other engineering polymers. Common LCPs are Vectra, Xydar and Zenite. They replace metals in applications requiring high heat resistance like connectors, terminals, spark plugs and connectors. LCPs also enable downgauging and simplify assembly operations compared to metals. Continuous research aims to reduce LCP costs further.
Thermoplastic Elastomers
Thermoplastic elastomers (TPEs) combine the processing benefits of thermoplastics with the mechanical performance of rubber vulcanizates. They can be recycled and bonded like thermoplastics but have elasticity, softness and flexibility like rubber. Major TPE types are styrenic block copolymers (SBC), thermoplastic polyurethanes (TPU), copolyester (COP) and polyolefin blends (TPV). Automotive, consumer goods, wire and cable, sports/recreation, footwear and medical industries utilize TPEs for hoses, gaskets, overmoulding, flexible films and home/healthcare products. TPEs enable complex shapes, textures and colors at high production rates compared to conventional rubbers.
Customization Potential
Specialty polymers offer versatility in customization of properties according to need. Structure and composition can be varied to achieve the desired mechanical, thermal, optical or electrical characteristics. Additives are used to enhance properties like melt strength, crystallinity, tensile strength and flame resistance. Fillers impart reinforcement. Specialty polymer manufacturers work closely with customers to develop made-to-order polymer formulations, process optimizations and test prototypes. Recent advances in polymerization techniques have further expanded the customization potential of specialty polymers. Continual innovations enable them to replace other materials in diversifying applications.
Conclusion
In summary, specialty polymers have been engineered to address the unique needs of applications that cannot be served by commodity plastics or traditional materials. Their superior and customizable properties have led to widespread adoption in industries from automotive and aerospace to electronics, medical and beyond. ___________________________________________________________________________