Thermoplastics and thermoplastic materials soften when heated and harden when cooled. They can withstand many heating and cooling cycles and are often suitable for recycling. Most thermoplastics consist of polymers, long chains of molecules that contain smaller, repeating units called monomers. Typically, monomers are held together by covalent bonds within or between polymer chains. Addition polymers are thermoplastic materials in which a rearrangement of bonds joins monomers together without the loss of atoms or molecules. Condensation polymers are formed by a reaction in which a molecule, usually water, is lost during bond formation. Some thermoplastic and thermoplastic materials contain filler materials such as powders or fibers to provide improved strength and/or stiffness. Fibers can be either chopped or wound, and commonly include glass, fiberglass, or cloth. Some products contain solid lubricant fillers such as graphite or molybdenum disulfide. Others contain aramid fibers, metal powders, or inorganic fillers with ceramics and silicates.
There are many material grades and types of thermoplastics and thermoplastic materials. Examples include monomers, intermediates, binders, base polymers, elastomers, and rubber materials. Composite materials consist of a matrix and a dispersed, fibrous or continuous second phase. Semi-finished or shaped stock forms include bars, sheets, film, profiles, and hollow or angled materials. Spheres, shims, and rectangular or hexagonal products are also available. Fabricated or finished shapes or parts are formed through a variety of molding, casting, extrusion, pultrusion, machining, welding, and grinding processes. Resins, liquids, gels, and powders are common raw materials. Electrical, electronic and optical-grade materials are also available.
Thermoplastics and thermoplastic materials soften when heated and harden when cooled. They can withstand many heating and cooling cycles and are often suitable for recycling. Most thermoplastics consist of polymers, long chains of molecules that contain smaller, repeating units called monomers. Typically, monomers are held together by covalent bonds within or between polymer chains. Addition polymers are thermoplastic materials in which a rearrangement of bonds joins monomers together without the loss of atoms or molecules. Condensation polymers are formed by a reaction in which a molecule, usually water, is lost during bond formation. Some thermoplastic and thermoplastic materials contain filler materials such as powders or fibers to provide improved strength and/or stiffness. Fibers can be either chopped or wound, and commonly include glass, fiberglass, or cloth. Some products contain solid lubricant fillers such as graphite or molybdenum disulfide. Others contain aramid fibers, metal powders, or inorganic fillers with ceramics and silicates.
There are many material grades and types of thermoplastics and thermoplastic materials. Examples include monomers, intermediates, binders, base polymers, elastomers, and rubber materials. Composite materials consist of a matrix and a dispersed, fibrous or continuous second phase. Semi-finished or shaped stock forms include bars, sheets, film, profiles, and hollow or angled materials. Spheres, shims, and rectangular or hexagonal products are also available. Fabricated or finished shapes or parts are formed through a variety of molding, casting, extrusion, pultrusion, machining, welding, and grinding processes. Resins, liquids, gels, and powders are common raw materials. Electrical, electronic and optical-grade materials are also available.
Thermoplastics and thermoplastic materials are based upon a variety of chemical systems. Examples include acrylics and polyacrylates; butyl, polybutene and polyisobutylene; polymers such as liquid crystal polymer (LCP) and polyolefin; ethylene copolymers such as polyethylene acrylate acid (EAA); fluropolymers such as polytetrafluorethylene (PTFE) and polyvinylidene fluoride (PVDF); and vinyl and polyvinyl chloride (PVC). Common thermoplastic and thermoplastic materials include ionomers, ketones such as polyetheretherketone (PEEK), polyamides and polycarbonates, polyester and polyether block amide (PBA), and polyphenylene oxide (PPO) and polyphenylene sulphide (PPS). Styrene-isoprene-styrene (SIS) and styrene-butadiene-styrene (SBS) copolymers are used in pressure sensitive adhesive (PSA) applications. Styrene butadiene rubber (SBR) has good resistance to petroleum hydrocarbons and fuels. Styrene acrylonitrile copolymers include styrene acrylonitrile (SAN), acrylic styrene acrylonitrile (ASA) and acrylonitrile ethylene styrene (AES).
Selecting thermoplastics and thermoplastic materials requires an analysis of physical, mechanical, thermal, electrical, optical and processing specifications. Physical specifications include overall thickness, overall width or outer diameter (OD), overall length, and inner diameter (ID). Mechanical properties include tensile strength or break, tensile modulus, and elongation. Thermal specifications include use temperature, deflection temperature, thermal conductivity, and coefficient of thermal expansion (CTE). Electrical resistivity, dielectric strength, and dielectric strength (relative permittivity) are important electrical properties. Index of refraction and transmission are optical specifications. Processing properties for thermoplastics and thermoplastic materials include viscosity, melt flow index (MFI) and water absorption.
Thermoplastics and thermoplastic materials provide a variety of features. Products that are designed for electrical and electronics applications often provide protection against electrostatic discharge (ESD), electromagnetic interference (EMI), or radio frequency interference (RFI). Materials that are electrically conductive, resistive, insulating, or suitable for high voltage applications are commonly available. Flame retardant materials reduce the spread of flames or resist ignition when exposed to high temperatures. Thermal compounds form a thermally conductive layer on a substrate, either between components or within a finished electronic product. Some thermoplastic and thermoplastic materials contain water-based or water borne resins. Others contain solvent-based resins that use a volatile organic compound (VOC) to thin or alter viscosity.