The use of thermoplastics in creating tons of everyday utility products is not new. Their large scale usability is mainly because of their ability to turn to liquid (and not burn) after reaching a certain temperature. ABS plastic, for example, can be liquefied at 221 degrees Fahrenheit and then cooled and reheated again.
This single property makes thermoplastics like ABS a great material for modern molding processes like plastic injection molding.
Before the use of thermoplastics, thermosets were used for various manufacturing processes. However, thermosets have a serious limitation. Heating a thermoset once brings about an irreversible chemical change which causes them to set.
A second heating of the thermoset plastic makes them burn. The recyclability is hence zero as compared to thermoplastics like ABS which can be repeatedly heated and remolded into desired shapes.
What is ABS Plastic?
ABS plastic or Acrylonitrile Butadiene Styrene is an amorphous, impact-resistant, opaque thermoplastic that is widely used in the plastic industry. As the name suggests, the thermoplastic is made out of three monomer units:
- Acrylonitrile: A synthetic monomer produced from ammonia and propylene.
- Butadiene: A monomer that results as a bi-product along with ethylene when produced from steam crackers.
- Styrene: A monomer produced by dehydrogenation of ethylbenzene.
Each monomer unit lends separate properties to the thermoplastic. While Acrylonitrile contributes to its high chemical and heat resistance properties, Butadiene adds strength and toughness and Styrene offers properties like rigidity and processability.
ABS plastic is considered very strong structurally. This makes it an ideal choice for various applications that need strong and stiff plastic that is resistant to external strength impacts. It is highly used in applications like protective housings, camera housings, stiff packagings, etc which need to be structurally sturdy.
Physical properties of ABS plastic:
Following are the key physical properties of ABS plastic:
- High impact resistance
- High rigidity
- Heat and chemical resistance
- High electrical insulating properties
- Abrasion and stain resistance
- Structural/Dimensional stability
- Good surface brightness
Chemical properties of ABS plastic:
Following are some important chemical properties of ABS thermoplastic:
- Chemical formula: (C8H8)x· (C4H6)y·(C3H3N)z)
- Excellent resistance to acids and alkalis (in diluted form)
- Reasonable resistance to aliphatic hydrocarbons
- Liquefying temperature (glass transition): 105 °C (221 °F)
- Injection molding temperature: 204 – 238 °C (400 – 460 °F)
- Poor resistance to alcohols, halogenated hydrocarbons, aromatic hydrocarbons.
Mechanical properties of ABS plastic:
- Tensile strength: 46 MPa (6600 PSI)
- Flexural Strength:74 MPa (10800 PSI)
- Specific gravity: 1.06
- Shrink rate: 0.5-0.7%
- Elongation at break- 10-50%
- Elongation at yield- 1.7-6%
- Hardness Shore D: 100
- Toughness (Notched Izod Impact at Room Temperature): 200 – 215 J/m
- Toughness at Low Temperature (Notched Izod Impact at Low Temperature):20 – 160 J/m
- Heat deflection temperature: 98 °C (208 °F) at 0.46 MPa (66 PSI)
Electrical properties of ABS plastic:
- Dielectric Constant: 2.7- 3.2
- Dielectric Strength: 15.7 -34kV/mm
- Arc resistance: 60-120 sec
- Dissipation factor: 50 – 190 x 10-4
- Volume Resistivity: 14 – 16 x 1015 Ohm.cm
For use in various commercial products, ABS plastic, like most other thermoplastics, is modified by the addition of additives and also by sometimes varying the ration of all three monomer units present in it.
The addition of additives (like fibers, fillers, PVC, minerals, heat stabilizers, lubricants, etc) produce varying material properties and hence result in different grades of the thermoplastic like high and medium impact grade, heat resistant grade, fire retardant grade, electroplatable grades, etc.
While ABS plastic has some excellent properties that make it a highly demanded thermoplastic in the manufacturing industries, some limitations need to be carefully noted as well. Poor solvent resistance (particularly alcohol, esters, etc), low dielectric strength, poor weathering resistance, easy to scratch, etc are some limitations of using ABS.
That said, most of these limitations are modified or overcome by plastic manufacturers by blending ABS plastic with other polymers like PVC, PA, PC, etc. Various ABS plastic blends can be prepared by experienced manufacturers.
ABS is considered relatively non-toxic and hence harmless thermoplastics. No known adverse health effects as a result of exposure to ABS plastic have yet been reported. It contains no known carcinogens, does not leach and is stable. It is hence a safe plastic for making kids toys and similar products.
However, ABS is not suitable for use as medical implants fie to various other limitations.
As mentioned again, ABS plastic is completely recyclable and largely biocompatible. This is the reason why it can easily be blended with other materials to produce different commercial products that are high in quality and yet, cost-effective.
As mentioned earlier in the article, ABS Plastic is a combination of three separate monomer units, namely: Acrylonitrile, Butadiene, and Styrene. It is polymerized using the process of emulsion.
Other processes like mass polymerization etc are also used to create ABS thermoplastic. However, emulsification remains the most common global process for the creation of ABS plastic.
Additionally, most industries use old pre-created ABS plastic products as a starting material for creating ABS plastic. Due to its 100% recyclability, ABS plastic products can be heated, liquified and remolded into new products multiple times.
ABS finds use in multiple commercial and industrial applications. Its properties like resistance to chemicals, heat and physical impacts make it a great material for various products.
ABS plastic is fairly easy to machine. Its low melting point makes it a great choice for modern molding techniques like the plastic injection molding process or even the 3D printing process. It is hence a good choice for high heat situations.
Further, the low cost of ABS plastic also adds to its popularity.
All of the aforementioned characteristics as well as properties of ABS plastic make it a good base material for various applications in a wide range of industries like automotive, electrical appliances, sports equipment, toys, building, and construction, etc.
Following are some of the popular applications of ABS plastic:
- Various automotive parts that look for weight reduction factors consider ABS thermoplastic as a great substitute for metals. Commonly used parts include dashboard components, seat backs, seat belt parts, door loners, handles, instrument panels, pillar trim, etc.
- Multiple every day use home appliances and consumer goods like control panels, housings for vacuum cleaners, food processors, refrigerator liners, etc make use of ABS.
- Electrical and electronic applications like computer keyboards, electronic enclosures, etc.
- Construction applications like pipes and fittings are made using ABS plastic. This is because of its properties like high impact strength, resistance to rust and corrosion.
- Music instruments, sports equipment, etc.
- Gardening tools.
- Legos and other plastic toys.
- Medical applications like nebulizers, compressors, etc.
Use of ABS for 3D printing and prototype development
3D printing processes carried out by using FDM machines (fused deposition modeling) utilize ABS plastic. ABS is mostly chosen because of the ease of machinability. The material is easy to glue and decorate which makes it a good choice for prototyping. Due to the good surface finish of ABS, it is relatively easier to produce good cosmetic appearances in terms of color and texture.
Benefits of ABS plastic
Coming down to the benefits of ABS plastic in comparison to other available plastic resins.
So why is ABS one of the most commonly used plastics, especially when it comes to products manufactured by injection molding technology?
As mentioned earlier in the article, the chemical, physical, mechanical and electrical properties of ABS plastic give it some unique characteristics. It’s relatively low melting point and low gas transition temperature makes it an easy to use material for plastic injection molding.
ABS can be easily liquefied and molded into complex shapes through injection molding techniques.
Its 100% recyclability makes it possible to be melted again and again and reshaped without any chemical degradation or burning.
ABS is considered a very “safe to handle” plastic since it cools down and hardens quickly. Further, it is relatively easy to manipulate, paint and decorate which makes it a preferred choice for products that depend on a high-quality finish.
Its strong impact resistance, heat resistance, and shock absorbance make it a preferred choice for applications that require structure, form, and sturdiness.
The lightweight and scratch-resistant characters make it a good choice for automotive applications. Since the need here is to substitute metals with an excellent finish lightweight plastic material, ABS works as a wonderful alternative.
Finally, its reasonably low production costs make it a very economical solution and choice amongst various other thermoplastic options available in the market.
Various thermoplastics serve different purposes based on their physical, chemical, mechanical, and electrical properties. Picking the right plastic material for a particular application requires a thorough understanding of the material. ABS plastic sheet is a versatile thermoplastic that offers a low cost, high-quality alternative to various other materials in the market. Its ease of use, cost-efficiency, and various unique properties make it a popular choice across various industry sectors.