A Practical Guide to choosing the Best Engineering Thermoplastics

With a growing demand for plastic materials in different applications, engineering thermoplastics are developed to offer high performance in heat resistance, fire retardancy, mechanical strength or chemical resistance. Generally, engineering thermoplastics are known to exhibit heat resistance at high temperatures beyond 100 degree Celsius and also offers good flame retardant properties.

Different varieties of engineering thermoplastics can be created by blending two or more resins depending on the required properties. Thermoplastics are known to provide a cost effective and corrosion resistant alternative to different types of metals in various applications. A wide range of Engineering Thermoplastics are available in sheets, plates, tubes and rods which offers myriad advantages over metallic materials and also offers excellent mechanical and thermal properties.

As a production material, Engineering thermoplastics show reduction in weight, provide electrical and thermal insulation, offers great mechanical strength, durability, superior corrosion and chemical resistance, and ease of processing. The selection of the right set of engineering thermoplastics is an important decision and definitely a daunting task. It is important to consider the application requirements and choose engineering thermoplastics accordingly.

A few common types of Engineering plastics and their general uses are discussed below. The below information will help in your search for the perfect engineering thermoplastics for your application.

  • ABS Sheets – They are available in a wide range of color and texture finishes and offers a lot of versatility.
  • Polyethylene – Different variations are available in the market which are tailored to suit specific market requirements.
  • Acetal & Delrin sheets are considered as one of the strongest among all engineered thermoplastics.
  • Nylon -With their excellent properties and use in various applications, it is one of the most popular engineering plastics.
  • Polycarbonate – With a high heat resistance, it also offers chemical and water resistance.
  • Polypropylene – For applications exposed to cold temperature, PPC and PPH grades are highly preferred.
  • PTFE – It offers unrivalled chemical, thermal and electrical performance.

Additives can modify the properties of engineering thermoplastics which means that addition of fiber makes the thermoplastic strong and stiff, whereas adding plasticizers makes it more flexible. Use of anti-oxidants would make thermoplastics stable under high temperatures, whereas addition of lubricants makes it easier to mold.

With repeating units of monomers, Engineered thermoplastics are made up of long polymer chains. Various fillers from minerals to fibers can be added for strength, impact, and other performance enhancements like thermal conductivity, electrostatic dissipation etc. With professional cutting services, companies have been able to ensure high quality finishes and a quick turnaround time.

Nylon 66 Polymer – Step Reaction Polymerization

Nylon-66 is a polyamide fibre which is manufactured by a process that involves step growth polymerization and condensation polymerization. The generic term used to define long chain synthetic polyamides is Nylon. One of the key members from the group of poly-condensation products of acids and diamines, Nylon-66 has great abrasion resistance, strength andresistance towards heat, water and chemicals.

When compared with Nylon 6, Nylon-66 is a superior version due to its higher melting point, greater dimensional stability and a more compact molecular structure. With a guarantee of excellent performance in high speed spinning processes, it also has good UV light-fastness and dye wash fastness.

There are different ways of referring to Nylon-66 as Nylon 6-6, Nylon 6,6 etc. The Nylon 66 polymer is made of hexamethylenediamine and adipic acid which provides Nylon 66, a total of 12 carbon atoms in each repeating unit.

Availability of Nylon 66

Easily available in both sheet and rod form, Nylon 66 has a wide range of applications. Generally the rods are available from 4mm-200mm diameter and the sheets are from 5mm thick to 100 mm thick.

Manufacturing Process

The ingredients i.e. Hexamethylenediamine and adipic acid are combined with water in a reactor. The outcome of this process is the nylon salt which is sent for evaporation which removes any excess water. The nylon salt is then passed through a reaction vessel where a continuous polymerization process makes molten Nylon 6,6. The molten nylon is then passed through a spinning process, with Nylon-66 extruded and sent via spinneret. Once the nylon is air cooled to form filaments.

Favourable Temperatures

Nylon-66 can operate at temperatures exceeding 100 °C, where the maximum limit is 160 °C and generally allowed only for short term applications.

Various Applications

Probably, one of the most important and popular engineering plastic, it can be utilized for a wide range of applications like bearings, gears, pulleys, screws, bushes etc.

Around 55 years back, Remington Nylon 66 took polymers to a new level with the introduction of world’s first mass produced rifle made from something other than wood.

Properties

The long molecular chains of Nylon 66 results in higher number of hydrogen bonds which also makes it extremely resilient. Being an amorphous solid, it is slightly soluble in boiling water and has large elastic properties. It offers immaculate dimensional stability, high melting point and excellent abrasion resistance. With the use of reinforcements, the physical strength of Nylon-66 can be improved multiple times. Few popular applications of Nylon includes carpet fibres, swimwear, parachutes, tyres, ropes and air bags etc.

Polycarbonate Panels – Various Applications and Benefits

Composed of thermoplastic polymers, Polycarbonate panels are usually found in several industrial applications. Polycarbonate is a polymer which includes numerous identical units of bisphenol A which are interlinked by carbonate. This type of polymer liquefies when heated and converts into a glassy state when cooled. Polycarbonate panels offer high impact resistance and protection from cracking, breaking or chipping. These panels are available in different sizes, shapes and colors.

The polycarbonate panels are reasonably lightweight and usually available in single, double and triple wall panels. To achieve the desired shape and finish, the polymer is melted and forced through a die. Polycarbonate panels are processed using the following main processes like injection molding and extrusion.

  • Injection molding: Initially the polymer is heated, melted and then pressed into a mold, so that it can take the desired shape of the mold. Usually used to manufacture single end products, injection molding is highly effective.
  • Extrusion: The polycarbonate is melted and pressed through an orifice which allows the molten polymer to take the shape of the die. Most manufacturers use this process to produce large sheets, pipes and profiles.

There are several benefits associated with the use of polycarbonate panels which are usually used in glazing applications.

  • High durability and strength: The polycarbonate panels are used in a wide range of industrial applications. The high durability features of the panels allow it to withstand harsh climatic conditions, resistance to chemicals and abrasion.
  • Highly cost-effective: There are several factors which decide cost effectiveness like installation cost, maintenance cost and the aspect of time. Polycarbonate panels are generally expensive, so what makes them cost effective? They offer longevity which means that they maintain their condition and shape for several years, thereby providing complete value for money.
  • Greenhouse construction: Polycarbonate panels are in great demand for greenhouse construction. This is because, the panels fulfill almost all requirements of any greenhouse glazing panel. By enhancing light diffusion and guaranteeing longevity, polycarbonate panels are popular among farmers.
  • Effective design: The polycarbonate panels are available in different designs and finishes. They tend to offer a mixed variety of several properties like energy saving, moderate light transmission, insulation properties, longevity, etc.

In case of residential buildings, these panels are usually used for awnings and overhead shades because they provide protection from harmful UV rays and easily withstands strong forces. In comparison to other type of panels made with glass or plastic, the polycarbonate panels are extremely lightweight which translates to lower transport and labor costs.

Amorphous Thermoplastics – Characteristics of Non-crystalline materials

Plastics are loaded with macromolecules which are made under the action of heat and pressure such that it can be processed into the desired shape. There are two broad classifications of a thermoplastic i.e. amorphous thermoplastics and semi-crystalline thermoplastics. When the thermoplastic is shaped at a temperature over the glass transition temperature Tg, then it is classified as Amorphous Thermoplastics. Whereas, when the temperature is over the melting temperature Tm, it is classified as Semi-crystalline thermoplastics.

Completely amorphous thermoplastics are generally brittle, stiff and quite clear in their unprocessed state. Temperature and pressure can cause the molecular arrangement to change along with the properties of the polymer. Tg or the glass transition temperature is defined as the point when the molecular rotation about single bonds becomes favorable. There are different varieties of Amorphous thermoplastics which includes materials like polystyrene, acrylics, polycarbonate, Acrylonitrile-butadiene styrene and polyvinyl chloride.

The molecules in case of amorphous thermoplastics are entangled in solid state. Most of them are transparent in their natural form, however ABS is an exception. In general, amorphous thermoplastics are known to have lower chemical resistance and lower stiffness and strength when compared with crystalline materials. However, the amorphous thermoplastics have uniform shrinkage rates which means that their shrinkage can be calculated easily.

There are additives and fillers used with both amorphous and semi-crystalline thermoplastics to alter the physical, electrical, thermal and mechanical properties of the base resin. Amorphous thermoplastics can be used in a wide variety of applications because of its diverse range of properties. With state of the art molding machine controls and latest material formulation methods, Polymer Resources guarantees high quality and consistent molded parts.

There are different varieties of crystalline materials which includes Nylon, polypropylene, polyacetal, and thermoplastic polyesters. In case of semi-crystalline thermoplastics, the size of the crystals is larger than the wavelength of visible length, thereby making the materials translucent. Depending on the branching and cooling rate, there are different degrees of crystallinity. Close to 85% of the resins produced are thermoplastics which are further classified as amorphous thermoplastics and crystalline thermoplastics. The amorphous regions of the thermoplastics contributes to the elasticity of the thermoplastic whereas the crystalline regions contribute to the strength and durability of the thermoplastic.

The cost saving opportunities associated with the use of injection moulding technology of thermoplastics need to be ensure proper material usage and cycle time to achieve optimized results. Amorphous thermoplastics exhibit lower mold shrinkage and lower tendency to buckle under pressure when compared with semi-crystalline materials. They lose their strength and rigidity very quickly once above the glass transition temperature Tg. The randomly ordered molecular structure allows amorphous thermoplastics to soften gradually as the temperature increases.

ABS Resin Plastic – Features, Limitations and Variations

One of the best resins of the styrene family, ABS (Acrylonitrile Butadiene Styrene) is widely used in the automotive industry and in the manufacture of electrical and electronic equipment. The increased utilization of ABS Resin plastic means that there would be substantial volumes of material which would need to be recycled at the end of life of these products. Research studies focused on the impact of reprocessing on the physical and mechanical properties of ABS products have shown minimal impact therefore establishing the benefits of ABS Resin plastic as an easy to recycle material.

ABS is a common thermoplastic resin which guarantees high rigidity, durability, dimensional stability and excellent chemical resistance. The high quality features of ABS resin can be attributed to its composition where it brings in the strength and durability of Acrylonitrile along with the toughness of butadiene rubber. It also allows a wide range of modifications to its composition which allows to improve its impact resistance, heat resistance and toughness.

Some of the most common and well known features of ABS Resin includes:

  • Excellent ductility
  • High Impact strength
  • Extremely tough and rigid
  • Dimensional stability
  • High tensile strength
  • Heat and chemical resistance
  • Electroplatable
  • High and low temperature performance

Although there are several benefits associated with the use of ABS Resin, there are certain limitations as well like its poor solvent resistance, poor weather ability and heavy generation of smoke when burnt.

There are huge variations possible with ABS Resin, however the most common variations of ABS material includes General Purpose ABS, High Impact ABS, Low Viscosity ABS, Plate-able ABS, ABS FR and many more. The modifications of its properties is possible with the use of additives, modifiers and reinforcing agents.

ABS plastics are largely used for mechanical purposes and in the automotive industry, however it also boasts good electrical properties which show minimal impact with temperature and humidity changes.

The two most common reprocessing or recycling process used for ABS products include mechanical recycling and solvent based process. Several research studies and experiments have proved that the microstructure of ABS resin is not affected by the recycling process. For painted parts, it is usually recommended to use the solvent based recycling process to ensure minimal butadiene loss.

Known for its medium strength and performance at affordable pricing, ABS Resin is commonly used for injection molding applications. The mechanical properties of ABS Resin plastic makes it ideal for drilling, turning, die-cutting and shearing. It also possesses excellent creep resistance, abrasion resistance and electrical properties, thereby making it one of the most widely used resins ever. Because of its great versatility, ABS Resin is used in a wide variety of applications. The three components used in the manufacture of ABS resin are combined by different methods which involves polymerization, combinations and physical mixtures.