Description

Thermoplastics and thermoplastic resins are raw, unshaped polymers that turn to liquid when heated and turn solid when cooled. They can be repeatedly remelted and remolded, allowing parts and scraps to be reprocessed. In most cases they are also very recyclable.

Types

Thermoplastics are based upon a variety of chemical systems listed in the GlobalSpec SpecSearch Database. The most important ones include polyvinyl chloride, polypropylene, polycarbonate, ethylene copolymer, and ABS.

Polyvinyl chloride is a thermoplastic polymer widely used in construction because it is cheap, durable, and easy to assemble. It can be made softer and more flexible by the addition of plasticizers. It is a controversial material because of the toxins it may liberate during its production and lifetime.

Polypropylene is a thermoplastic polymer that is used in packaging, textiles, stationary, laboratory equipment, and plastic parts. It is rugged and unusually resistant to many chemical solvents, acids, and bases.

Polycarbonate is a thermoplastic polymer used in electronics, construction, data storage, automotive, aircraft, and security applications. It is a very durable transparent material with a high impact resistance but a low scratch resistance.

Ethylene copolymers are polymers that have ethylene as one of its monomer bases. They are used in packaging, sporting goods, shoe-soles, and as superplasticizers in cement production to improve flow characteristics.

ABS or acrylonitrile-butadiene-styrene is a hard, rigid, thermoplastic polymer. It provides good chemical and creep resistance, along with dimensional stability. ABS is used in many industries and in a wide array of applications. It is generally inexpensive but prone to crack under stress.

Choosing a Filler Material

Some thermoplastics 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.

Properties

Choosing a chemical system and filler determines key performance specifications listed in the GlobalSpec SpecSearch Database. Important specifications for thermoplastics include tensile strength, thermal conductivity, and use temperature.

The tensile strength is the maximum stress a material can withstand while being stretched or pulled before necking deformation occurs. The thermal conductivity of the polymer is a measure of how well the material conducts heat or transfers heat, which is important for temperature conscious environments. Use temperature is the allowable temperature range in which the compound can operate effectively which determines what environments the resin can be used in.

Product Features

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.