Copolymers vs. Homopolymers: Comparing ABS, POM, PEEK, and PTFE Materials

Plastic materials are widely used in manufacturing plastic parts in engineering. The selection of plastic materials depends on the required material properties , that is, the properties of the plastic itself. So, when you select the plastic materials for your projects , have you ever wondered the causes of the plastic’s properties in chemistry?

 

This article will share you knowledge of copolymers and homopolymers. With examples of four common plastic materials, you will understand what properties plastics have when they are copolymers or homopolymers. 

 

 

Copolymers and Homopolymers：Difference Between

 

 

How Do We Define Copolymers and Homopolymers?

As the diagram shows, copolymers are combinations of different types of bonded monomers. Homopolymers are combinations of one type of monomers.

 

 

Difference Between Copolymers and Homopolymers

 

For the copolymers

More than one type of bonded monomers in copolymers making the copolymers achieve the balance of plastics properties. Different types of bonded monomers alter the properties of the plastic. 

 

 

For the homopolymers

Homopolymers exhibit the properties more leanly influenced by that type of monomers, which means the main chain of the structure.

 

 

Table 1: Comparision of Copolymers and Homopolymers

 

 

 

To further disscuss the specific properties of plastics when they are copolymers or homopolymers, I will illustrate with examples of ABS, POM, PEEK, and PTFE in the following.

 

 

ABS Plastic: A Copolymer

 

 

 

 

ABS stands for Acrylonitrile-Butadiene-Styrene. It is a copolymer of three monomers: Acrylonitrile (A), Butadiene (B), and Styrene (S), polymerized using an emulsifier as a medium. 

 

 

Impact of Polymerization on ABS 

The interactions among acrylonitrile (A), butadiene (B), and styrene (S), as well as their relative ratios, affect the properties of ABS. (Ratios are changable).

 

 

Table 2: Impact of Polymerization on ABS

 

 

Typical Applications of Copolymer ABS

Combinations of three types of monomers in ABS achieves a balance of strength, toughness, and processability, making it suitable for:

• Appliance housings (e.g., refrigerators, washing machines)
• Electronic product housings (e.g., computer monitors, printers)
  
• Automotive parts (e.g., dashboards, trims)
  
• Toys (e.g., LEGO bricks)

 

 

 

POM Plastic: A Copolymer or Homopolymer

 

Polyoxymethylene (POM) exists in both copolymer and homopolymer forms. POM-C is a copolymer, while POM-H is a homopolymer.

 

 

Impact of Polymerization on POM-C and POM-H

 

 

Table 3: Impact of Polymerization on POM-C and POM-H

 

 

The copolymer POM-C has a small amount of ethylene oxide participating in the reaction, which compensates for the poor thermal stability of the homopolymer POM-H, making the copolymer POM-C have better resistance to heat aging and chemical resistance. However, the trade-off is a slight decrease in crystallinity and a slight sacrifice in strength.

 

The homopolymer POM-H has a more regular main chain, resulting in higher crystallinity, higher strength, and better wear resistance.

 

 

Typical Applications of POM-C and POM-H

POM-C

• Valve bodies (e.g., water control valves, pneumatic valves)
• Pipe fittings (e.g., connectors, couplings)
  
• Sliding parts (e.g., guide rails, sliding bearings)
  
• Spray pump components (e.g., nozzles, pump heads)
  
• Moving parts in kitchen appliances (e.g., hinges, dispensers)

 

POM-H

• Precision gears (e.g., timing gears, worm gears)
• Bearing housings (e.g., support bearings, roller housings)
  
• Pump impellers (e.g., centrifugal pump rotors, water pump wheels)
  
• Industrial sprockets (e.g., conveyor sprockets, drive chains) 

 

 

 

PEEK Plastic: A Homopolymer

 

 

PEEK stands for Polyether ether ketone, formed by the polymerization of a specific monomer sequence (p-Hydroxyacetophenone), and is a highly ordered linear homopolymer.

 

 

 

Impact of Polymerization on PEEK

Properties of PEEK lean to it’s linear main chain( –O–Ph–O–Ph–CO–Ph–).

 

 

Table 4: Impact of Polymerization on PEEK

 

 

 

The hydroxyl and carbonyl groups of p-Hydroxyacetophenone are highly reactive, allowing it to participate in polycondensation reactions as a monomer to produce PEEK. Therefore, the PEEK backbone exhibits a highly aromatic structure: –O–Ph–O–Ph–CO–Ph–.

The PEEK structure contains alternating rigid aromatic rings and flexible ether bonds. The rigid aromatic rings contribute to its high rigidity, high initial creep resistance, high thermal oxidation stability, heat resistance, and chemical corrosion resistance.

The rigid backbone of homopolymer PEEK makes it generally brittle, with low impact strength, resulting in poor processability.Although the flexible ether bonds can provide some flexibility and processability to PEEK, this flexibility and processability are actually limited.

 

 

Typical Applications of Homopolymer PEEK

 

• Aerospace and automotive components (e.g., bearing cages, brackets, structural parts)
• Electrical and mechanical seals (e.g., sealing rings, valve seats)
  
• Medical devices (e.g., surgical clips, dental implants)
  
• Electronic components (e.g., chip supports, insulation parts)
  
• Chemical processing equipment (e.g., pump components, valve housings)
  
• High-temperature structural parts (e.g., turbine components, precision fixtures)

 

 

 

PTFE Plastic: A Homopolymer

PTFE (Polytetrafluoroethylene) is formed by the polymerization of one type of monomer (tetrafluoroethylene).

 

Impact of Polymerization on PTFE

The chemical formula for tetrafluoroethylene is CF₂=CF₂, and the main chain of PTFE, which is polymerized from it, is –CF₂–CF₂–.The strong C–F bonds from polymerization, along with the smooth molecular chains and non-polar nature, impact the properties of PTFE.

 

Table 5: Impact of Polymerization on PTFE

 

 

Typical Applications of Homopolymer PTFE

Homopolymer PTFE possesses excellent chemical resistance, high temperature resistance, low coefficient of friction, and outstanding insulation properties, making it ideal for sealing, insulation, and corrosion-resistant applications.

Typical applications include:

 

• Non-stick cookware (e.g., pans, baking trays) 
• Electrical insulation layers (e.g., wires, cables) 
  
• Self-lubricating components (e.g., bearings, seals, bushings) 
  
• Chemical-resistant linings (e.g., pipes, storage tanks, reaction vessels) 
  
• High-temperature parts (e.g., valve seats, gaskets, expansion joints) 

 

 

 

VMT CNC Machining Plastic Parts Services

A deeper understanding of plastics can help you make the choices of plastic materials for your project. If you have questions about certain plastic material, VMT is here to assist.

VMT is a specialized plastic prototyping and CNC machining factory, dedicated to delivering high-precision custom plastic parts services for diverse industries. With advanced CNC equipment, strict quality control systems, and expert surface finishes, VMT ensures every plastic part meets exact dimensional and surface finish specifications. If you need professional advice on selecting materials for customized plastic parts, welcome to contact us. We are available 24/7.   

 

 

 

FAQs

What are other examples of copolymers?

Other common copolymers include styrene-butadiene rubber (SBR), high-impact polystyrene (HIPS), Nylon 6/6.

 

 

What are other examples of homopolymers?

Other common homopolymers include polyethylene (PE), and polyvinyl chloride (PVC).

 

 

Is polypropylene(PP) a copolymer or a homopolymer? 

Polypropylene (PP) can be both a homopolymer and a copolymer. Homopolymer polypropylene (PPH) is polymerized from a single propylene monomer, while copolymer polypropylene (PPC) is copolymerized from propylene monomer with a small amount of ethylene monomer. 

 

 

Which has a higher density, copolymer or homopolymer?

Both copolymers and homopolymers have a generic density of 0.9 g/cm³, so they have the same density.

 

 

Which has higher strength, copolymer or homopolymer?

In terms of general tensile strength, copolymer has 60 MPa, while homopolymer has 69 MPa. Therefore, homopolymer has higher strength and higher crystallinity.