ABS vs. Polypropylene (PP): What Are the Differences


  1. What Is ABS?
  2. Advantages and Disadvantages of ABS
  3. What Is Polypropylene?
  4. Advantages and Disadvantages of Polypropylene
  5. ABS vs. Polypropylene (PP): Physical Properties
  6. ABS vs. Polypropylene (PP): Thermal Properties
  7. ABS vs. Polypropylene (PP): Chemical Resistance
  8. ABS vs. Polypropylene (PP): Processing and Manufacturability
  9. ABS vs. Polypropylene (PP): Cost
  10. ABS vs. Polypropylene (PP): Environmental Impact and Recycling
  11. ABS vs. Polypropylene (PP): Applications
  12. ABS vs. Polypropylene (PP): Injection Molding, CNC Machining, & 3D Printing
  13. Final Words

Acrylonitrile Butadiene Styrene (ABS) and Polypropylene (PP) are prominent materials in the plastic industry. Each has unique features that suit various applications. Understanding their differences is crucial for selecting the right material for your needs. This article explores their distinct attributes, applications, and impacts and shed light on the application in injection molding, CNC machining, and 3D printing. It’s worth noting that there are other materials used in 3D printing, such as TPU and PU, which have their own unique properties and performance characteristics. For a detailed comparison of these materials, refer to our article on the performance comparison of TPU and PU materials in 3D printing.

What Is ABS?

ABS is a thermoplastic polymer made from the monomers acrylonitrile, butadiene, and styrene. The combination results in a material that is robust, impact-resistant, and relatively easy to manufacture. Its structure allows for a versatile balance between strength, toughness, and rigidity, making it popular in various industries.

Advantages and Disadvantages of ABS

Advantages of ABS

  • High Impact Resistance: ABS stands out for its remarkable ability to withstand physical impacts. This characteristic makes it particularly suitable for products that must endure bumps, drops, or other forms of rough handling, such as toys, luggage, and protective enclosures for electronic devices.
  • Toughness: The material is not only resistant to impact but also maintains its toughness across a variety of temperatures, contributing to its versatility across different climates and environments.
  • Good Electrical Insulation Properties: ABS is an effective insulator against electrical currents, making it an excellent choice for housing electronic components and devices. Its insulation capabilities ensure user safety and device integrity.
  • Ease of Processing: This material can be easily manufactured through various techniques such as injection molding, extrusion, and 3D printing, allowing for a wide range of product designs and applications. Additionally, ABS can be conveniently painted, glued, and finished, which enhances its aesthetic versatility and application in consumer goods.

Disadvantages of ABS

  • Poor UV Resistance: ABS is not inherently resistant to ultraviolet (UV) light, which can lead to weakening or discoloration over time. Products made from ABS may require additional coatings or protective measures if they are intended for prolonged outdoor use.
  • Sensitivity to Solvents: ABS can be negatively affected by certain chemicals and solvents. This sensitivity means that items made from ABS might not be suitable for use with certain substances or in environments where harsh chemicals are present.
  • Degradation Over Time: Environmental factors besides UV light, including heat and certain chemicals, can also degrade ABS. This can limit the lifespan of products made from the material unless they are properly maintained or protected.
  • Thermal Deformation: While ABS can withstand a range of temperatures, it is [prone to warping or deforming at high temperatures](link to the blog post). This characteristic must be considered when using ABS in environments or applications where heat exposure is significant. If heat resistance is a crucial factor for your 3D printing project, you may want to explore other materials that are specifically designed to withstand high temperatures. Our article on the best heat resistant 3D printing materials provides a comprehensive overview of the top choices available in the market.

What Is Polypropylene?

Polypropylene is a thermoplastic “addition polymer” made from the propylene monomer. It is rugged and unusually resistant to many chemical solvents, bases, and acids. PP is used in a wide range of applications due to its versatility, recyclability, and low cost.

Advantages and Disadvantages of Polypropylene

Advantages of Polypropylene

  • Excellent Chemical Resistance:Polypropylene is highly resistant to a wide range of chemicals. This makes it an ideal choice for containers and pipelines that are exposed to corrosive substances, extending the lifespan of these products significantly.
  • Fatigue Resistance:One of the standout features of PP is its ability to withstand cyclic loading – the repeated bending and flexing don’t easily break down the material’s structural integrity. This makes it perfect for creating living hinges and other flexible components.
  • Low Density:The lightweight nature of polypropylene is one of its most celebrated properties. This makes PP ideal for creating products that benefit from being light without sacrificing strength, such as automotive parts, which in turn improves fuel efficiency.
  • Insulation Properties:PP is an excellent insulator, which makes it suitable for use in electrical components and insulation materials. Its ability to resist electricity ensures safety and functionality in applications that involve power or heat.

Disadvantages of Polypropylene

  • Lower Melting Point:Compared to some other plastics, PP has a relatively lower melting point. This characteristic limits its use in applications that involve high temperatures, as the material may warp or deform under such conditions.
  • UV Degradation:Like many polymers, polypropylene is vulnerable to UV light, which can cause it to degrade over time. Without proper treatment, such as the addition of stabilizers, products made from PP can become brittle and lose their color when exposed to sunlight.
  • Poor Paint Adhesion:Polypropylene’s non-porous surface makes it challenging for paints and certain types of adhesives to adhere to it. This can make finishing processes more complex and potentially increase production costs.
  • Scratch Sensitivity:While PP is durable in many respects, it is more susceptible to surface scratches and abrasion compared to some other plastics. This can affect the aesthetic appeal and longevity of the finished product.

ABS vs. Polypropylene (PP): Physical Properties

ABS is renowned for its superior strength and rigidity, qualities that contribute to its widespread use in robust, demanding environments. For instance, ABS can typically endure tensile stresses of 39-60 MPa (mega pascals), which makes it a strong, stiff material ideal for high-impact products such as protective gear and automotive parts.

On the flip side, Polypropylene shines in scenarios that demand flexibility and endurance against repetitive motions. Thanks to its exceptional fatigue resistance, PP is the go-to material for items that must withstand continuous bending and flexing. Its fatigue resistance is such that PP can endure thousands, even millions, of deformation cycles without significant degradation. This characteristic is particularly vital in creating living hinges – thin sections in plastic products that fold and unfold repeatedly without breaking.

In terms of aesthetics, ABS often has the upper hand with its smoother surface finish. This aspect is crucial in consumer products that demand a polished appearance, such as gadgets, appliances, and toys. The surface finish not only contributes to the visual appeal but also enhances the product’s tactile quality.

ABS vs. Polypropylene (PP): Thermal Properties

ABS demonstrates commendable heat resistance, Its glass transition temperature is approximately 105°C. This resistance makes it particularly suitable for applications subjected to high temperatures, such as automotive interior components, electronic housings, and kitchen appliances where safety and structural integrity at elevated temperatures are paramount.

Conversely, Polypropylene, with its lower melting point, typically between 160°C to 170°C, is less resistant to heat compared to ABS. However, this property does not detract from its utility; rather, it defines its niche. PP is inherently suited for applications like living hinges and flexible parts, where high flexibility rather than high temperature resistance is required. Despite its lower heat tolerance, PP’s resilience under repetitive stress without heat exposure makes it invaluable for parts that need to retain flexibility over time.

ABS vs. Polypropylene (PP): Chemical Resistance

Polypropylene boasts remarkable chemical resistance, making it virtually impervious to a wide range of chemical solvents, acids, and bases. This resistance makes PP an ideal candidate for applications in chemical processing, laboratory equipment, and any setting where exposure to corrosive substances is common.

ABS, while durable and resistant to physical impacts, does not share PP’s resilience against harsh chemicals. It holds its own against aqueous solutions, mild acids, and alkalis, but it falls short when exposed to organic solvents, which can lead to material degradation. This susceptibility limits its use in environments where chemical exposure is a routine concern.

ABS vs. Polypropylene (PP): Processing and Manufacturability

In manufacturing and processing, ABS (Acrylonitrile Butadiene Styrene) and Polypropylene (PP) each display distinct advantages that cater to different industrial needs. Both plastics are well-suited for a variety of manufacturing processes, notably injection molding, a method favored for its efficiency in mass production.

ABS is particularly user-friendly when it comes to secondary operations. It bonds well with adhesives, making it straightforward to assemble with other components. Furthermore, ABS’s surface accepts paints and coatings with ease, allowing for a broad spectrum of color options and finishes. This adaptability makes ABS a preferred choice in applications requiring aesthetic versatility and strong, durable bonds, such as in automotive interiors and consumer electronics.

On the other hand, PP is known for its cost-effectiveness in production. Its lower raw material cost combined with faster cycle times during injection molding translate into significant savings, especially in large-scale manufacturing. This economic efficiency, however, comes with trade-offs. PP’s surface does not naturally adhere well to paints and adhesives, which can complicate the finishing process. Despite this, its cost benefits and quick production turnaround make PP a favored option for items such as disposable containers, packaging, and other mass-produced goods.

ABS vs. Polypropylene (PP): Cost

The cost comparison between ABS (Acrylonitrile Butadiene Styrene) and PP (Polypropylene) is intricate and influenced by various factors.

Raw Material Costs

  • Polypropylene (PP): The average cost of PP ranges from $0.50 to $0.80 per pound, depending on market fluctuations and bulk purchasing agreements.
  • Acrylonitrile Butadiene Styrene (ABS): ABS typically costs between $0.70 and $1.50 per pound, reflecting a premium due to its enhanced mechanical properties and finish.

Processing Costs

  • Cooling Time and Energy Consumption: PP’s lower melting point (160°C to 170°C) significantly reduces cooling times in injection molding processes compared to ABS, which has a melting point around 230°C. This results in PP having approximately 15-20% faster cycle times in typical injection molding applications, directly translating into lower energy and labor costs.
  • Post-Processing: ABS’s compatibility with various finishes reduces labor and costs associated with painting and bonding by approximately 10-30%, depending on the complexity and scale of the finishing required.

Production Scale and Final Product Requirements

For large-scale production, PP’s lower raw material and processing costs can result in substantial savings. For example, in a production run of 100,000 units, the cost efficiency of PP could result in savings of up to $10,000 to $30,000 purely on material costs, and additional savings on processing.

Conversely, for products requiring high aesthetic quality or complex assembly, the reduced post-processing needs of ABS can offset its higher initial cost. If post-processing costs for ABS are 20% lower than PP for a specific product, this can equate to significant savings in high-volume production scenarios.

In short, while PP generally presents a more cost-effective option due to lower per-pound pricing and more efficient processing, the total cost evaluation should encompass the full production lifecycle. For items requiring less finishing or lower mechanical performance, PP might offer the best economic value. However, for products that demand superior aesthetic appeal, strength, or are subjected to more intensive post-processing, the higher initial cost of ABS could be justified by lower downstream expenses.

ABS vs. Polypropylene (PP): Environmental Impact and Recycling

Both ABS and PP are recyclable, which aids in reducing their environmental footprint. However, their recyclability and overall environmental impact can vary significantly depending on local recycling capabilities and practices.

PP stands out for its lower density, which translates into lower energy consumption during production and transport. This characteristic, combined with its widespread use in packaging, often makes PP a more environmentally friendly option in contexts where efficient recycling systems exist.

In contrast, ABS’s recycling and environmental metrics can vary more widely. While it is recyclable, the actual rates of ABS recycling and the efficiency of those processes can be influenced by factors such as the presence of additives and the availability of recycling facilities. Nonetheless, innovations in recycling technologies and growing environmental awareness are helping to improve the sustainability profiles of both materials.

ABS vs. Polypropylene (PP): Applications

Applications of ABS

  • Automotive Components: Used in dashboards, wheel covers, and interior panels due to its strength, durability, and high-quality finish.
  • Electronics Housings: Ideal for computer keyboards, TV remotes, and other consumer electronics because of its rigidity and impact resistance.
  • LEGO Bricks: The material’s precise molding capabilities, color consistency, and strength make it perfect for these popular building blocks.
  • Protective Gear: ABS is employed in making hard hats, toolboxes, and protective casings thanks to its toughness and resistance to impacts.
  • Musical Instruments: Certain parts of musical instruments, like clarinet bodies and piano keys, benefit from ABS’s strength and aesthetic qualities.

Applications of Polypropylene (PP)

  • Packaging: Widely used in food containers, medicine bottles, and wrapping materials due to its chemical resistance and food safety compatibility.
  • Automotive Parts: Employed in battery cases, bumpers, and interior trim for its resistance to chemicals, heat, and fatigue.
  • Textiles: PP is utilized in the production of ropes, thermal underwear, and non-woven fabrics because of its moisture resistance and durability.
  • Living Hinges: Common in bottle caps and container lids owing to PP’s exceptional fatigue resistance.
  • Medical Equipment: Used for syringes, vials, and specimen bottles because it is sterilizable and resistant to many chemical solvents.

ABS vs. Polypropylene (PP): Injection Molding, CNC Machining, & 3D Printing

When considering ABS (Acrylonitrile Butadiene Styrene) and PP (Polypropylene) for manufacturing processes such as injection molding, CNC machining, and 3D printing, it’s crucial to compare their physical and thermal properties. Below, we outline these differences, focusing on melting point, flexural modulus, impact strength, heat deflection temperature, and density:

Property ABS PP Impact on Manufacturing Processes
Melting Point 230°C 160°C to 170°C ABS is energy-intensive to mold and slow to cool, but tolerates heat well. PP molds quickly but is less heat-resistant.
Flexural Modulus 2.1 to 7.6 GPa 1.2 to 1.7 GPa ABS is stiffer for strong parts; PP is more flexible, ideal for bendable components.
Impact Strength 10 to 25 kJ/m² 5 to 15 kJ/m² ABS withstands impacts better, great for tough parts and cases. PP is less tough but good for items that bend or flex often.
Heat Deflection Temperature 88°C to 100°C 100°C to 120°C ABS melts at a higher temperature, but PP can handle more heat in use without losing shape, important for hot environments.
Density 1.04 to 1.07 g/cm³ 0.895 to 0.91 g/cm³ ABS’s density means heavier parts, affecting shipping costs. PP is lighter, reducing transport costs and easing handling.

These material characteristics significantly influence the selection process for different manufacturing needs:

  • Injection Molding:ABS’s higher melting point increases energy requirements, but its superior impact strength and stiffness are advantageous for complex, durable parts. PP’s lower melting point and faster cooling make it ideal for high-volume, cost-effective production, particularly for flexible or lower-strength components.
  • CNC Machining:The higher flexural modulus of ABS makes it preferable for machining, as it can withstand the process without deforming, resulting in smoother finishes and more precise parts. PP’s lower stiffness and susceptibility to heat can complicate its machining process, requiring specialized techniques.
  • 3D Printing:ABS’s strength and higher heat deflection temperature suit it for 3D printed parts that require durability and thermal resistance. However, its higher density can lead to heavier parts. PP, while challenging to print due to warping and adhesion issues, offers advantages for lightweight, flexible designs.

When considering the manufacturing process for your project, it’s essential to understand the differences between CNC machining and 3D printing. Each method has its own strengths and limitations, and the choice depends on factors such as material properties, part complexity, and production volume.

Final Words

Choosing between ABS and PP depends on the application’s specific requirements, such as mechanical strength, thermal stability, and cost-effectiveness. While ABS offers higher strength and thermal resistance, PP stands out for its chemical resistance and lower cost. Understanding the distinct properties and applications of each can guide material selection, ensuring optimal performance and efficiency in product design and manufacturing.

If you’re looking for a convenient way to bring your designs to life using ABS, PP, or other materials, our online 3D printing services can help you achieve your goals without the need for investing in your own equipment.