The ABS vs PP debate is of high interest to plastic items manufacturers and designers. Both ABS and PP are two materials with entirely different properties and compositions. However, both are used in making plastic parts. Although the manufacturing of plastic products requires a large number of raw materials, ABS and PP are both considered to be among the best options. They are the foremost choice for leading plastic manufacturers in the market.

This blog explains the properties, differences and applications of both materials. It will help the plastic manufacturer to decide which material to use for which process and when.

What are ABS (Acrylonitrile Butadiene Styrene) Plastic?

ABS i.e. Acrylonitrile Butadiene Styrene in simple words is a thermoplastic. The ABS material is an impact-resistant engineering thermoplastic. It is both opaque and amorphous. Being amorphous means that after a certain temperature it assumes the form of liquid. However, when the temperature reaches back to normal it becomes solid again. ABS plastics are mostly used in the plastic molding process.

A combination of three monomers makes this polymer. Those three monomers are as follows:

1. Acrylonitrile

Made from propylene and ammonia, acrylonitrile is a synthetic monomer. It gives heat resistant properties to ABS plastic. It also adds to their chemical resistance.

2. Butadiene

Butadiene is the monomer that makes ABS stronger. It is actually a by-product of steam crackers and ethylene production.

3. Styrene

The dehydrogenation of ethylbenzene led to the manufacturing of styrene monomers. The rigidity and processability that the ABS material has is the result of styrene.

What is PP(Polypropylene) Plastic?

Polypropylene or PP is a polyolefin. A polyolefin is a polymer which is derived from a small set of olefins. Polypropylene is slightly harder than polyethylene. It has extremely high heat resistance. However, it has low density. PP is a common material because it is a commodity plastic. A lot of plastic [parts of daily use are made of polypropylene.

1. Manufacturing of Polypropylene

The manufacturing process of polypropylene consists of two different methods:

• Ziegler Natta Polymerization

• Metallocene Catalysis Polymerization The various forms and states of polypropylene depend upon the method that was used to manufacture it. It may be:

• soft in texture or hard

• light weight or heavy weight

• act as an insulator or conductor

What is the difference between ABS and PP?

1. ABS Vs. PP: Properties

The ABS plastic parts and PP plastic items both have different properties. The following table shows a clear classification between the differences of the two plastics in terms of their properties. Plastic manufacturers can take help from this chart while using these two materials for manufacturing purposes.

The following table shows different values of elongation at break, tensile strength and heat resistance for both ABS and PP. It is because both materials have different values or properties for the three different processes of:

• Injection molding

• CNC machining and

• 3D printing

Other differences in the properties of both materials such as density, impact resistance etc. are also mentioned in the table.

2. ABS Vs. PP: Pros and Cons

Both ABS and PP have advantages and weaknesses. In this section we analyze the strengths and weaknesses of both materials individually.

2.1 ABS Pros

Good Electrical insulation:

ABS offer good electrical insulation. Insulation comes from the material’s exceptional dialectical properties. Because of this insulation property ABS plastic is used for the provision of protective electrical insulation purposes.

Suitable for Injection Molding:

ABS is the most suitable material for injection molding applications. Being an inexpensive material, a lot of plastic manufacturers prefer ABS for various injection molding processes. It shows high compatibility with various molding processes.

Solubility:

ABS plastic is not resistant to acetones. When it comes in contact with them it dissolves. This solubility is a major advantage for various plastic manufacturers. They use acetone for finishing purposes. Whenever there is a deformity in the design of an object it is corrected using acetone.

Best for Automotive Prototyping:

Automotive prototyping and aerospace industries make a lot of use of ABS plastics. It is because of the good mechanical properties. ABS plastics show high compatibility with moving parts. Their mechanical properties are an added advantage. Another factor that makes them suitable for this purpose are that they are ductile and malleable. Once shaped they can be deformed and changed into any other desirable shape and form.

2.2 ABS Cons

Low Contraction Upon Heating:

A unique property of ABS plastics that is also a major disadvantage is that they do not contract upon heating. The more you heat them the less they expand. In Fact they contract and you get very less of what is left to work upon.

Bad Odor:

Upon heating ABS plastics release extremely bad odor. This foul smell is the reason why it becomes difficult to work with ABS plastics when heated. This is the reason why it is advisable for plastic manufacturers working with ABS plastics to arrange proper ventilation. This is also important because these plastics are flammable.

Hard to Maintain the Heat:

ABS plastics have a relatively low melting point. Once melted you need to maintain the heat to keep them in the molten form. Therefore, to feed them into the injection molding machine you need to maintain high heat. In the ABSence of adequate heat there might be structural issues in the material.

2.3 PP Pros

Flexible:

PP offers a high degree of flexural strength. It means that it is extremely flexible. Because of flexibility it is easy to modify. Increased flexibility reduces the chances of waste production. High flexibility and minimum waste are therefore good advantages of using PP.

Increased Chemical Resistance:

As mentioned before PP is resistant to a wide range of acids, oxidizing agents etc. This makes PP a perfect material for storage containers. These storage containers are used for both domestic and commercial purposes. They are used for food storage and also in hospitals for medicinal usage.

Durability:

PP made products are very strong and durable. This is probably the reason why a number of household items are made using PP. They are also used for electrical insulation and in the automotive industry for manufacturing of parts. They also offer a high degree of water resistance and wear resistance.

Low Density:

As described before, PP has extremely low density. Its low density makes it so light weight that it can even float on water. This makes items made from PP both lightweight and hard. Gone are the days when quality of materials was associated with their weight. Materials like PP have changed the concept. Now lightweight objects can also be durable and of good quality.

2.4 Cons

Low Melting point:

Low melting point is a major disadvantage for PP products. No matter how hard or good quality a product is when it is exposed to heat it deforms or melts. The melting point is so low that you can even melt it in a microwave oven.

Shrinkage:

Just like ABS plastic when exposed to heat PP contracts. A slight reduction in the heat can cause crystallization. This leads to structural and mechanical issues. Maintaining a constant heat flow is important. Therefore, thermal contraction is a major disadvantage when it comes to PP plastic parts.

UV Degradation:

PP plastic is not resistant to UV rays. Therefore, extensive exposure to sunlight can lead to degradation.

Poor Adhesion:

Poor adhesion is another major disadvantage of PP plastic. They show poor bonding with concrete matrices. If you want them to show good adhesive properties you need to use expensive adhesives. This leads to an increase in the cost of production.

3. ABS Vs. PP: Applications

ABS	PP
● Aerospace applications● Consumer electronics● Household goods● Housing● Construction● Toys● Medical and Surgical Instruments	● Automotive batteries● Semiconductor components● Laboratory settings’● Chemical tanks● Automotive parts such as hinges, gears etc.

Conclusion

Now that you know in detail about both ABS and PP you know that both materials have their own strengths and weaknesses. One is flexible and the other is hard. Both have different values in terms of chemical resistance, tensile strength and melting point. The choice among ABS and PP depends upon the aPPlication you want them to use for.

For example, if you are manufacturing food storage containers then PP is a better choice. However, if you are looking for a raw material for toys or protective insulation then ABS is a better choice. It is also a preferred choice by perfume bottle manufacturers as a raw material for perfume bottle caps. The reason is again its non-reactivity with chemicals and oxidizing agents.