Everything You Need To Know About ABS Plastic
ABS plastic is a commonly used thermoplastic that is very versatile, and can be used in many unique applications. You will encounter ABS plastic used in lego blocks and 3D printing filaments. Its popularity in the industry is due to ABS being a tough plastic that is lightweight and economical. Hence, it is very useful in making product prototypes.
What is ABS Plastic?
ABS stands for Acrylonitrile Butadiene Styrene. It is a thermoplastic polymer that is composed of three monomers: acrylonitrile, butadiene and styrene. Styrene Acrylonitrile copolymers were initially introduced in the 1940’s. To improve its properties even further, a rubber monomer (butadiene) was introduced to the polymer. ABS was patented in 1948 and commercialized in 1954.
A thermoplastic is a type of plastic polymer that becomes soft and pliable at high temperatures, and hardens into a tough plastic material when cooled. They differ from thermosets in that they can be re-heated and remolded over many cycles, since the initial heating process does not cause permanent changes to molecular bonds.
Thermoplastics like ABS have low melting points and are not as strong compared to thermosets, but are suitable in applications that require reheating and recycling. Nylon, polypropylene, PVC, acrylic and PLA are also examples of thermoplastics and in some cases, can act as alternatives to ABS.
ABS is classed as a terpolymer, made by the polymerisation of styrene and acrylonitrile, with polybutadiene. Styrene makes up the highest percentage of ABS, between 40%-60%, butadiene can be between 5%-30% and acrylonitrile can make up between 15%-35%. The proportions of these monomers can be changed to give different physical and mechanical properties of ABS.
Properties of ABS Plastic
Here are some average values for different physical, mechanical and chemical properties of ABS:
Physical and mechanical properties:
Density:
1.01-1.2 g/cc
Hardness (Rockwell, R):
68-118
Ultimate Tensile Strength (breaking point):
22.1-74 MPa
Yield Strength:
13-65 MPa
Young’s modulus:
1.79-3.2 GPa
Elongation at yield:
2-30%
Melting Point:
170-320C
Processing Temperature:
76-240C
Chemical Properties:
Here are some average values for different physical, mechanical and chemical properties of ABS:
It is an all-purpose aluminum alloys that can be formed in a variety of ways. Hardness is better than 6063, It is commonly used for machining because it has good weldability and corrosion resistance.
How is ABS plastic made?
Here are some average values for different physical, mechanical and chemical properties of ABS:
- Acrylonitrile: Synthetic monomer that is a product of ammonia and propylene.
- Butadiene: Petroleum hydrocarbon that is a by-product of steam cracking
- Styrene: Monomer obtained through the hydrogenation process of ethylbenzene
The end result of the polymerization reaction is a long chain of polybutadiene that is crisscrossed with shorter chains of poly(styrene-co-acrylonitrile). The toughness of ABS also requires a process known as ‘rubber toughening’. This is where tiny elastomer (rubber) particles are interspersed within the polymer matrix.
The Benefits of ABS Plastic
ABS plastic has some characteristic physical and mechanical properties that have made it one of the most popular plastic polymers in manufacturing. Its notable mechanical properties include:
- Great toughness, meaning it doesn’t break easily
- Good impact resistance, so it does not scratch or fracture easily with sudden impacts.
- Good rigidity, meaning it will not deform easily when a force is applied and has good dimensional stability
- Heat resistant compared to other thermoplastics. It can withstand temperatures up to 100ºC
- Good chemical resistance, so can be used in a variety of environments
- Opaque and easy to color
- Easy to cut, machine and glue
- In addition to good mechanical properties, ABS also has good electrical insulation properties. These properties stay constant over a wide range of frequencies and temperature conditions.
Applications of ABS Plastic
ABS is so incredibly versatile that you can find it in almost everything from electronics, lego blocks, musical instruments to 3D printing filaments. Here are various applications of ABS plastic that you will find in everyday life:
Musical Instruments
ABS plastic is commonly used to manufacture musical instruments such as recorders, flutes, tambourines and percussion instruments. The rigidity and impact resistance of ABS makes it a good choice for use in musical instruments.
Medical Equipment
ABS can be used to manufacture different types of medical equipment such as compressors and nebulizers. Again, its toughness, rigidity and impact resistance are useful properties here. However, ABS is generally not used for delicate applications such as medical implants.
Gardening tools
Gardening tools require materials that have good durability, chemical resistance, rigidity and impact resistance. ABS is often used for gardening tools such as small shovels, rakes, and other hand tools. ABS has a good strength to weight ratio, and is easy to machine and color.
Automotive parts require materials that have superior toughness, impact resistance, chemical resistance, and are lightweight. ABS fits the bill for all these characteristics, and is relatively economical. It can, in some cases, be used as an effective alternative to metal to save weight and cost. Common uses of ABS in the automotive industry include bumper parts, trim components, door handles and seat backs.
Protective equipment
Protective equipment and clothing such as construction hats require high impact resistance and durability. So, it is quite common for protective equipment and headgear to be made from ABS plastic due to its superior mechanical properties.
Electronic parts and equipment
Electrical items such as computer keyboards and printer components use ABS plastic due to its rigidity, toughness, low weight, abrasion resistance and good electrical insulation properties.
Pipes and fittings
Materials used to make pipes and fittings require a number of mechanical and chemical properties:
- Good dimensional stability (does not deflect too much under forces)
- Toughness and rigidity
- Good corrosion and chemical resistance
- Lightweight
- Economical
ABS plastic possesses all these mechanical properties. It is often used in drain and waste piping systems which require good durability and chemical resistance.
Product prototypes
Oftentimes in the manufacturing industry, you want product prototypes made before investing money into producing the actual product. ABS is a good choice because it is lightweight, economical (and hence many prototypes can be made) and easy to mold. It also has good dimensional stability, so can produce prototypes of an accurate size and dimensions.
3D printing
One of the most common uses of ABS plastic is in 3D printing. As it is a thermoplastic, it can be heated and molded into complex shapes quite easily. The economical cost coupled with good dimensional stability after cooling, makes it a popular choice for 3D printing. It is only used in FDM 3D printing.
The other most commonly used thermoplastic for 3D printing is PLA. Compared to PLA, ABS is a bit more difficult to print with as it has a higher melting point. However, ABS has superior mechanical properties to PLA which breaks easily. ABS is tougher, has better chemical and heat resistance, as well as better dimensional stability. Hence, ABS is used for more industrial 3D printing applications whereas PLA is mainly used for smaller, hobbyist applications.
Injection molding
ABS is also the most commonly used thermoplastic for injection molding due to its good dimensional stability and rigidity. Good dimensional stability means that parts can be molded with more accurate dimensions and more complex patterns. Its low shrink rate means that the molded part doesn’t change too much when it is being cooled. It is also quite an economical choice compared to other thermoplastics.
You can achieve different mechanical properties of the injection molded ABS parts by changing the processing temperatures. For example, ABS that is injection molded at high temperature will give a smoother and shinier product with good heat resistance. Injection molding ABS at lower temperatures produces parts with high impact resistance and toughness.
Another reason ABS is commonly used for things like injection molding and 3D printing is its ease of processing. It can be machined and cut relatively easily.
Is ABS Plastic Toxic?
ABS is completely recyclable and is not toxic under regular room temperature and pressure conditions. It also has negligible carcinogens present. It only becomes toxic at very high temperatures (above 400C).
At these temperatures, ABS can break down to its constituent monomers. On their own, butadiene and acrylonitrile are potential carcinogens.
Author
Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.